AudioCircle
Audio/Video Gear and Systems => Cheap and Cheerful HiFi => Topic started by: steve k on 16 Jan 2010, 06:49 pm
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Being a tube guy, I've been leery over the years of the ability of Class D amps to come close to the best sonic aspects of tube amps. That was until a couple tube-lover friends of mine started using this Class D amp instead. They came from totally different backgrounds--one was using 2A3 monoblocks to drive Klipsch LaScalas. The other was using ASL monoblocks to drive Maggie MG 12's.
At the time I was biamping Maggie IIIA's with VTL monoblocks on the top/mids and a modified Hafler DH-500 on the bass panels. The VTL's were rated at 125 wpc into 4 ohms as is the Class D Audio amp at 120 wpc that my friends recommended. So I sprang for the kit just for kicks. After all, both these guys couldn't be crazy I thought. The kit consists of the amp board, the heavy duty power supply board and the toroid transformer--all for $175. I mounted them on a cutting board and fired it up.
Amazing is all I can say. The noise floor was much lower than the VTL's so I was getting a lot more low level detail. The mids were very warm and tubelike and the highs were much sweeter and less edgy than the VTL's were especially when driven hard. I was shocked! I'm only using this amp above 400Hz but my friends tell me the bass is really good too as they are using theirs full range. All I can say is I'm a believer. Class D amps have come a long way. I've since sold the VTL's and I'm using the Class D Audio amp exclusively on the mids/highs.
Lucky for me, my friends are both good wood workers and they made a case for me. Have fun with this! :thumb:
http://classdaudio.com/index.php/ (http://classdaudio.com/index.php/)
steve
(http://www.audiocircle.com/image.php?id=25503)
(http://www.audiocircle.com/image.php?id=25504)
(http://www.audiocircle.com/image.php?id=25505)
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I think Class D amps do a lot of things right. They are not everyone's cup of tea, though. I think for those who don't like them it is an amalgamations of nitpicks, with prior biases partially to blame.
Class D amps have such a high dampening factor (low Zout) that they are unphased by woofer impedance variation and phase. That is to say that they have great bass, if maybe a bit dry with some speakers not optimized for such.
My understanding of Class D, which wouldn't fill a thimble, is that they essentially don't have crossover distortion, or rather it is so high in frequency and gets filtered out by the inductor that it is moot. I think that might be one key aspect in the tube vs SS debate. So to that point, Class D has characteristics closer to tube amps.
I don't know what the harmonic distortion profile looks like for a typically class d amp but I suspect it is closer to that of a decent tube amp too. Another plus in my book.
The most common complaint of class d is that the highs sound off. I don't know why that would be but I have my suspicions, and it has as much to do with what people are used to hearing.
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The most common complaint of class d is that the highs sound off. I don't know why that would be but I have my suspicions, and it has as much to do with what people are used to hearing.
Yup, definitely my findings, Josh. Also the hiss issue for the ones I have heard are problematic, too. Tripath, JVC's hybrid and one or two others I've had here over the years.
Aside from the hiss, the overall noise floor is so low (much lower than tube amps) that the hiss is most bothersome I think. The low noise floor does make for spooky real image placement I've found...even if the treble sounds weird and the hiss bothersome.
So the higher noise floor of tube amps (only with voltage regulation so the bass is neatly tucked up and not flubby as most tube amps tends to sound to me) end up being preferred in the end, but not without appreciation of what Class D can do.
But, if you use Class D for (primarily) bass frequencies they can sound yummy.
John
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The ps audio c100 modded by cullen circuits, an "icepower" amp, had had no hiss/noise issue. The top end may have been a little softer, but noise was not an issue at all even on the Geddes speakers which are about 95db sensitivity. I liked it very much, very detailed (not everyone's "detailed" is the same so be careful making a judgment on that statement). I went with the redwine 30.2 because I could get even more transparency, and with no hiss/noise either.
Edit: Sorry. Didn't understand that "Class D" in this case was referring to a company's brand... :o
These amps I mentioed don't fit the cheap and cheerful hifi board either.
Sorry
-Tony
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I can't say I've noticed hiss with the Hypex modules. I've heard of the tripath hiss though.
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I've had no hiss problems whatsoever. The highs are extended, smooth and natural sounding. My tube amps by comparison had a bit too much bite in the highs. I've heard several other ICE amps and several Bel Cantos and never warmed up to them. This little amp however is completely different sounding. I think the linear power supply makes a big difference but I'm beginning to see that Class D amps are all brewed a little differently. This amp does not use the ICE chip or the hypex BTW. Tripath is not a Class D amp it is Class T.
steve
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... but I'm beginning to see that Class D amps are all brewed a little differently.
Absolutely. I've only heard a couple class d amps, and they don't sound the same. I have Hypex modules, so that is what I commented on. I've never cared for the ICE based amps I've heard. I think Bel Canto uses ICE. I also have a Sharp mini system with a 15w class D amp, I think it is tripath based, but not sure.
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Well going from this, there isn't much difference
"A Class T amplifier is an audio amplifier product. Rather than being a separate "class" of amplifier, Class T is a registered trademark for Tripath's amplifier technologies. It is an implementation of Class D amplifiers, but improves the control scheme to create more efficient and higher quality audio amplification. "
http://en.wikipedia.org/wiki/Class_T_amplifier
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I stand corrected. :duh:
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Well don't feel bad... its marketing's job to confuse the crap out of everyone and make distinctions that are insignificant -and if they are able to put a meaningless trademark on it, even better
:eyebrows:
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Tony:
Did you buy their kit?
Cheers
Charlie
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did 175 buy all shown in pic?Also does the company sell the transformers as a package?Or does the company just sell the modules? I think ive looked at this site before and cant really make heads nor tails, on just what the heck is needed to make a complete amp.
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I think Steve did. I didn't.
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did 175 buy all shown in pic?Also does the company sell the transformers as a package?Or does the company just sell the modules? I think ive looked at this site before and cant really make heads nor tails, on just what the heck is needed to make a complete amp.
$175 kit buys the amp board, the power supply board and the transformer. All you need to do is wire the 3 together and run a power cord to the transformer. The website shows the amps and the kits. This is the kit I bought:
http://classdaudio.com/index.php/120w-x-2-240w-x-1-amp-power-supply-transformer.html (http://classdaudio.com/index.php/120w-x-2-240w-x-1-amp-power-supply-transformer.html)
Tom threw in the heavy duty power supply board at no additional cost.
steve
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I've had no hiss problems whatsoever. The highs are extended, smooth and natural sounding. My tube amps by comparison had a bit too much bite in the highs. I've heard several other ICE amps and several Bel Cantos and never warmed up to them. This little amp however is completely different sounding. I think the linear power supply makes a big difference but I'm beginning to see that Class D amps are all brewed a little differently. This amp does not use the ICE chip or the hypex BTW. Tripath is not a Class D amp it is Class T.
steve
Steve,
Could you explain the audio/performance difference between the class d amps you built and the Bel Canto for example?
Thanks,
Bill
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This kit looks like something I could do which makes me very suspicious. Could it really be that cheap, that good and that easy?
I'm currently using a Jeff Rowland Design Group 102 amplifier with his PC-1 power factor correction unit. It's hiss free, dead silent, in fact, and rather user friendly and refined. However, if I can achieve similar results for under $200, sign me up.
This prospect is very exciting.
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Macrojack - exactly what I'm thinking.
I hope Steve will share more.
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Yep. This is so crazy I think I need to try it. Anyone have a promo code for ordering????
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Macro, I understand your skepticism. I was skeptical too and just tried this experiment for kicks. Little did I know, I'd be selling my tube monoblocks once I heard it. :o (there was a time when I was biamping with two pairs of tube monoblocks). I should add that I'm still using a tube linestage. I recently heard the Bel Canto 1000 monoblocks and while the bass was fantastic, the mids and highs were a bit dry and unviting IMO. I like a liquid, tubey sound. The Class D Audio delivers just that in my system--a big warm sound with a full midrange and smooth, liquid highs without any stridence or edginess.
The one thing the tube amps did better in my system was creating a 3 dimensional soundstage. I've recently added a Museatex Bitstream DAC to my system which brought back a lot of the 3 dimensional imaging in spades but that's another subject. As always in audio there are tradeoffs and the 3D thing is one of them with this amp. However, it is dead quiet, detailed without being analytical, and very warm and involving.
It may not be everyone's cup of tea but if you like tubelike sound, this is the closest I've heard a Class D amp come to it and at a bargain. I understand Tom is developing a case for his amps so he will soon have a prodect more marketable to a larger audience.
steve
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Steve,
Fantastic post. Can you also mention it at the Lab? A lot of diyers would be interested as well.
Thanks.
Anand.
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This is very interesting.......just might have to try one.
My beef with Class D is that they sound very dry to my tube loving ears. I just don't get the width/depth/air that I get with tubes. I will be very pleased if the current designs have fixed this.
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The nice thing about this, is it's cheap enough to try out for yourself in your own system. It sounds too good to be true for the price and YMMV in different systems but it's already converted three of us from tubes. Never thought I'd say that. :lol:
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My main issue with the low powered tripath amps has been the edginess of the highs which made for fatigue in my instance. I've heard a few folks saying that the newer, higher powered class d amps are different beasts, so to have another credible set of ears testifying to that makes this tempting.
Steve, thanks for the report!!!
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This is fantastic find ( based on your review).
Just finished double mouth, hornloaded enclousures for my newly bought Jordan drivers. It turns out that their power requirements excise what I have on hand.
Seems like this kit might be the answer.
Thanks for interesting post.
Best
Mariusz
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$175?? Not bad but if you want to try out ClassD cheap I think it's hard to beat a 41hz Amp6 basic for something like 36Euros. All you need to do is add a wall wart or battery. I think they sound as good as the trends.
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Can you provide the link for future references ???
Thanks again
Mariusz
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It's in my first post.
http://classdaudio.com/ (http://classdaudio.com/)
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I emailed Tom at class D audio and asked if he would share a Promo code with us at A.C. He instantly said yes. You need to log in here: https://classdaudio.com/index.php/customer/account/login/
In the checkout process use this promo code for a 5% discount: ACircle
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Good thinking. Why didn't I think of that??? :scratch:
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Besides the power output, is one kit better then the other?
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hmm, might those "friends" of yours might make me a cabinet ? :)
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I haven't heard them to compare but I do know all the kits use the same chip except the 600 watt amp and the 160 watt which use a Texas Instrument chip. From what I've read, the TI chip doesn't sound as good but I haven't heard it myself.
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I ordered the 600w kit so we'll find out how that sounds. :D
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hmm, might those "friends" of yours might make me a cabinet ?
I will ask them. :eyebrows: This might be a good question for the DIY'rs on the Lab.
steve
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A couple things you might want to discuss with Tom if you are ordering one of these amps:
He recommends an input impedance up to 600 ohms. So if your preamp output impedance is higher, I'd talk to him about it first.
Second,
His standard amp board is set at 32 dB gain. We had him lower it to 26 dB since that is more standard in the industry.
I don't know enough about the theory here to know how significant these issues are but I thought it was worth mentioning.
steve
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will have to ask him as my preamp impedence is 1 mega-ohm....
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will have to ask him as my preamp impedence is 1 mega-ohm....
are you sure that is the output impedance? sounds like it's the input impedance. i have never heard of a preamp w/output impedance higher than ~2kohms...
doug s.
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I emailed Tom at class D audio and asked if he would share a Promo code with us at A.C. He instantly said yes. You need to log in here: https://classdaudio.com/index.php/customer/account/login/
In the checkout process use this promo code for a 5% discount: ACircle
Dude! You're the man!
Best,
Anand.
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you be right, thats the input impedence...been a dreary day here in seattle...as usual :)
are you sure that is the output impedance? sounds like it's the input impedance. i have never heard of a preamp w/output impedance higher than ~2kohms...
doug s.
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There has been some talk about these at DIYAudio for a while. For those interested:
http://www.diyaudio.com/forums/class-d/152980-class-d-audio-who-these-guys.html
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Can anyone recommend a place to purchase an aluminum amplifier case to put these amp board and transformer into?
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Look here: http://www.radiodaze.com/
Go to their "components" tab.
Can anyone recommend a place to purchase an aluminum amplifier case to put these amp board and transformer into?
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Look here: http://www.radiodaze.com/
Go to their "components" tab.
Blair,
Thanks for that resource.
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See here (http://www.goldpt.com/enclosures.html) as well.
Best,
Anand.
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See here (http://www.goldpt.com/enclosures.html) as well.
Best,
Anand.
Very nice. :thumb: Wonder if the PCB and the Toridal will fit. We'll find out!
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You can get the toroid dimensions here: http://www.antekinc.com/index.php (http://www.antekinc.com/index.php) These are the trannies Tom uses.
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Just checked. The PCB will. But the toroids are a little too tall! I was thinking initially of a 2 chassis case, with one chassis holding the amp pcb + ps pcb while the other would have the toroid.
Oh well.
Anand.
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http://www.hammondmfg.com/scpg.htm
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You can try Lansing enclosures (http://www.lansing-enclosures.com/main/graybox/b-style/index.html). You basically need at least a 3 inch internal height.
Off topic: The dB Audio Labs Tranquility dac uses a D-style enclosure (http://www.lansing-enclosures.com/main/micropak/d-style/index.html) it seems.
Best,
Anand.
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Although the classdaudio.com website works well mechanically, I am confused over much of the information.
It appears that all of the amps title descriptions are power output @ 4 Ohms. But one model "Class D Power Amplifier, 250W X 2 - 8 Ohm" lists the output under Specifications as "Output: 250 X 2 - 8 Ohm, 250 X 2 - 8 Ohm"
What does that mean? Can it not operate at 4 Ohm?
Under Features it says "Stereo or Bridged Configuration", but under Specifications it says "Bridged Output: Not Recommended"
????
Seriously, I am confused over the differences between models, what chips are used in models other than the two using TI5615/5630, etc. If ever a feature/specification matrix table comparison was needed, it would be for these products.
Steve
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Some good enclosure choices here (http://stores.ebay.com/Antek-inc_Enclosures_W0QQ_fsubZ5QQ_sidZ55712608QQ_trksidZp4634Q2ec0Q2em322).
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It appears that all of the amps title descriptions are power output @ 4 Ohms. But one model "Class D Power Amplifier, 250W X 2 - 8 Ohm" lists the output under Specifications as "Output: 250 X 2 - 8 Ohm, 250 X 2 - 8 Ohm"
What does that mean? Can it not operate at 4 Ohm?
Under Features it says "Stereo or Bridged Configuration", but under Specifications it says "Bridged Output: Not Recommended"
I agree about the website--it needs work. I asked Tom about this particular amp recently because I was considering trying it on my bass panels which are a 4 ohm load. He said as it currently stands it needs more heatsink to operate in 4 ohms and he is working on that and that his prototype is working successfully. So hopefully he'll have a design out that will operate in 4 ohms soon.
As for the chips, I believe they all use an International Rectifier IRS 2092 chip but the 600 watt and 160 watt amps which use the TI TAS5630 chip. I'd suggest you email Tom at ClassD Audio. He is quite helpful.
He generally doesn't recommend bridging his amps into a 4 ohm load.
steve
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Dude! You're the man!
Best,
Anand.
Just happy to help. I used it for my 600w kit. Looking forward to it.
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Some good enclosure choices here (http://stores.ebay.com/Antek-inc_Enclosures_W0QQ_fsubZ5QQ_sidZ55712608QQ_trksidZp4634Q2ec0Q2em322).
Excellent slushpuppy - thanks.
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Par-metal (http://www.par-metal.com/) is a very good source for enclosures.
This place (http://www.thlaudio.com/indexE.htm) also lists some nice looking chassis, but I've never dealt with them and they don't list prices on the website.
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WOW! I just went through all 19 pages here: http://www.diyaudio.com/forums/class-d/152980-class-d-audio-who-these-guys.html
I asked Tom if he would join this forum to help answer any questions. He mentioned that he will try but if you have any questions to just email him and he'll answer them via email. He did say that he's busy working 7 days per week (designs and running a small business) so his forum time get limited nowadays.
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Antek has toroid covers, in case you want to mount it above the chassis. I saw them on Ebay. :D
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http://cgi.ebay.com/DIY-Audio-Power-Amp-Toroidal-Transformer-Cover-CA-400_W0QQitemZ250562718618QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item3a56b3ab9a
Do these covers provide any benifit if used inside a case?
I decided to give the 120 watt a try based upon your review Steve, should be here by the end of the week. Thanks again for the heads up!
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http://cgi.ebay.com/DIY-Audio-Power-Amp-Toroidal-Transformer-Cover-CA-400_W0QQitemZ250562718618QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item3a56b3ab9a
Do these covers provide any beniifit if used inside a case?
I decided to give the 120 watt a try based upon your review Steve, should be here by the end of the week. Thanks again for the heads up!
I wouldn't think so. I'm trying one as well (600w)...
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Great service from these guys. E-mail questions were responded to quickly and my order arrived the day after ordering. Now I just need to find an enclosure to fit. So far I'm very pleased with the purchase.
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got my 600w today. Should have it up and running by the end of the weekend.
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Got my 120 watt today also but still waiting for transformer. Hopefully have my up and running sometime this weekend also if trans arrives. :drool:
I made a bamboo case to house my amp till something better materializes.
(http://i59.photobucket.com/albums/g295/mrnick_2006/IMG_3008.jpg)
(http://i59.photobucket.com/albums/g295/mrnick_2006/IMG_3009.jpg)
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Looking forward to it fellas! :thumb:
I've been in discussions with them for an amp that puts out 500 watts/8 ohms and 750 watts into 4 ohms. Talk about dirt cheap power. Looking for subwoofer power! Looks like it can all be done for about $500. $400 for the amp/transformer itself, and $100 for the case/connectors/etc...
Best,
Anand.
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Look here: http://www.radiodaze.com/
Go to their "components" tab.
Thanks for this link, I'm trying one of these for another project and need some radio goodies as well.
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Got my 120 watt today also but still waiting for transformer. Hopefully have my up and running sometime this weekend also if trans arrives.
I made a bamboo case to house my amp till something better materializes.
Looking good Nick. You should put a piece of white plex on top when you're done. The blue LED's on the PS are ultra brites and they'll light up the whole room! :eyebrows: I'm anxious to hear what you guys think of this little puppy.
Regards,
steve
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Here's another case built by my buddy Mark. The face is spalted maple and the feet are cherry turned by Bob, the lathe master.
(http://www.audiocircle.com/image.php?id=25722)
(http://www.audiocircle.com/image.php?id=25723)
(http://www.audiocircle.com/image.php?id=25724)
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steve
(http://www.audiocircle.com/image.php?id=25503)
Can we see the wires (red / black) that you have tucked under the board? Why do you have them going under? Picture?
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Anybody actually listening to these yet? How do they perform? Curious minds want to know.
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jtwrace - I'm guessing here but I believe the red and black wires going under the board emerge on the top side wrapped in grey sheathing. They are probably the AC line running to the wall outlet. No?
The RCAs are the inputs and the red and white wires are the speaker leads.
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jtwrace - I'm guessing here but I believe the red and black wires going under the board emerge on the top side wrapped in grey sheathing. They are probably the AC line running to the wall outlet. No?
The RCAs are the inputs and the red and white wires are the speaker leads.
what he said. :wink:
doug s.
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Yes the red and black wires coming off the transformer go to an IEC that I have the power cord plugged into. They're just tucked under the board to get them out of the way. I didn't want hot leads exposed where inquiring cats might sniff. :o Remember, this was just a temporary setup.
steve
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I am a little confused - I see a thread about an amp that is 120wpc, and then people talking about sub amps. I will be shopping for a sub amp in the not too distance future, thus my desire to clarify.
Does this amp produce 240wpc at 4 ohm when bridged?
I see there are $169 BASH 300w sub amps (and I have been using one since 1999), so I am not sure why this one would be better as a sub amp?
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I think under normal circumstances these wouldnt be used as a sub amps but Anand is a bassaholic. :lol:
I am a little confused - I see a thread about an amp that is 120wpc, and then people talking about sub amps. I will be shopping for a sub amp in the not too distance future, thus my desire to clarify.
Does this amp produce 240wpc at 4 ohm when bridged?
I see there are $169 BASH 300w sub amps (and I have been using one since 1999), so I am not sure why this one would be better as a sub amp?
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Yes the red and black wires coming off the transformer go to an IEC that I have the power cord plugged into. They're just tucked under the board to get them out of the way. I didn't want hot leads exposed where inquiring cats might sniff. :o Remember, this was just a temporary setup.
steve
Thanks!
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I am a little confused - I see a thread about an amp that is 120wpc, and then people talking about sub amps. I will be shopping for a sub amp in the not too distance future, thus my desire to clarify.
Does this amp produce 240wpc at 4 ohm when bridged?
I see there are $169 BASH 300w sub amps (and I have been using one since 1999), so I am not sure why this one would be better as a sub amp?
This amp's output is 60 watts per channel into 8 ohms, 120 wpc into 4 ohms, 240 wpc bridged into 8 ohms. Tom doesn't recommend running his amps bridged into 4 ohm loads.
As for sub amps, he has kits up to 500 wpc bridged for $189 up to a 1000 wpc into 8 ohms stereo amp for $375.
steve
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Nice to see these getting finished; they look great. Based on the comments here, I ordered one (125 watt in 8 ohm version) that should ship next week. Tom has been very helpful.
A few questions about appropriate wire for those with some amp-building experience as I have none.
- Wire to carry power?
- Wire from the pre-amp inputs to the amp module?
- Wire from the amp module to the speaker outputs?
I know this is a can of worms, but since I have to buy it all anyway, I'm hoping for some recommendations.
My guess is that the wire to the torroid and between the power supply and the amp module should beefy (14-16 gauge?), and the wire from the inputs small (20-24 gauge?). No idea as to wire to the outputs.
General tips?
Thanks :)
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Until you get the amp kit in a case with real binding posts, the little blue screw connectors will take up to a 14-16 ga. wire. I used 14 ga. silver plated copper wire for all the PS/amp board connections on the breadboard version. Speaker wires (the red and white ones were 16 ga.). Amp board to preamp--you can use any IC you want. If you have speaker cables with spade connectors, you might be able to slide one tong of the spade into the screw connectors on the amp board. I did this for awhile until I had it in a case.
steve
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Color me confused :duh:
I dont know what i have now, i thought i was getting 120 into 8ohms???
This amp's output is 60 watts per channel into 8 ohms, 120 wpc into 4 ohms, 240 wpc bridged into 8 ohms. Tom doesn't recommend running his amps bridged into 4 ohm loads.
As for sub amps, he has kits up to 500 wpc bridged for $189 up to a 1000 wpc into 8 ohms stereo amp for $375.
steve
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Nope. If you want 125 wpc into 8 ohms you need this amp. http://classdaudio.com/index.php/class-d-audio-amplifiers/home-and-pro-class-d-audio-amplifiers/class-d-power-amplifier-250w-x-2-500w-x-1.html (http://classdaudio.com/index.php/class-d-audio-amplifiers/home-and-pro-class-d-audio-amplifiers/class-d-power-amplifier-250w-x-2-500w-x-1.html)
As I said, Tom's website is a bit of a mess. Some amps he lists the 4 ohm load first, others the 8 ohm load. Some he just lists outputs and no impedance loads. You're best off shooting him an email and telling him what you want and he'll get you set up with the right amp. Sorry for the confusion.
steve
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(http://www.audiocircle.com/image.php?id=25826)
I have had the 125x2 8ohm version of the class d audio amp up and running for a few months now and I am really pleased with it. It sounds great and was very easy to get up and running. As mentioned earlier Tom from class d audio is extremely helpful and will answer all your questions quickly. IMO this is an extremely nice amp for the$$. I have added a few links to the chassis,power inlet and wiring that I used.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250501444095&ssPageName=STRK:MEWAX:IT
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200424519369
http://stores.ebay.com/Johns-Silver-Teflon-Wire-Shop
http://classdaudio.com/index.php/class-d-amplifier-kits/home-kits/250w-x-2-500w-x-1-amp-power-supply-transformer.html
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Steve and Avionic, thanks for the replies. Avionic I'll chase those links as soon as I finish this reply.
Until you get the amp kit in a case with real binding posts, the little blue screw connectors will take up to a 14-16 ga. wire.
I guess I'm wondering what's considered ideal for the final build.
Amp board to preamp--you can use any IC you want.
I asked Tom to leave off the input connectors on the board so I can install them on the chassis. He was happy to oblige.
So as a general rule, does that mean input wires should be narrow gauge (like ICs) and output wires heavier, like speaker wire?
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I have had the 125x2 8ohm version of the class d audio amp up and running for a few months now and I am really pleased with it. It sounds great and was very easy to get up and running. As mentioned earlier Tom from class d audio is extremely helpful and will answer all your questions quickly. IMO this is an extremely nice amp for the$$. I have added a few links to the chassis,power inlet and wiring that I used.
Excellent Avionic,
Can you tell us a little more about your system, what speakers you're driving with the amp etc. And your impressions of the sound quality?
Thanks,
steve
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So as a general rule, does that mean input wires should be narrow gauge (like ICs) and output wires heavier, like speaker wire?
Yes. In my case I used 24 gauge silver wire for the IC's and 16 ga. silver plated copper for the binding posts.
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Steve I powered up my amp and after about 15-20 sec it blows the fuse in the iec.
Tom suggested i use a 6amp slow blow fuse, is that large enough? I have triple checked all wireing.
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(http://www.audiocircle.com/image.php?id=25826)
I have had the 125x2 8ohm version of the class d audio amp up and running for a few months now and I am really pleased with it. It sounds great and was very easy to get up and running. As mentioned earlier Tom from class d audio is extremely helpful and will answer all your questions quickly. IMO this is an extremely nice amp for the$$. I have added a few links to the chassis,power inlet and wiring that I used.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250501444095&ssPageName=STRK:MEWAX:IT
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200424519369
http://stores.ebay.com/Johns-Silver-Teflon-Wire-Shop
http://classdaudio.com/index.php/class-d-amplifier-kits/home-kits/250w-x-2-500w-x-1-amp-power-supply-transformer.html
Is the yellow wire the chassis ground? It's kinda hard to see...
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Has to be ground, yeah?
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Steve I powered up my amp and after about 15-20 sec it blows the fuse in the iec.
Tom suggested i use a 6amp slow blow fuse, is that large enough? I have triple checked all wireing
I didn't fuse mine but I would think the fuse is big enough. Did you check your transformer taps? You have to get the correct blue and green together for the center tap. If you don't you'll cook the tranny. Believe me, I know from experience. Tom should tape the correct two leads together for the center tap but he didn't in my case and I guessed wrong. :duh:
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I didn't fuse mine but I would think the fuse is big enough. Did you check your transformer taps? You have to get the correct blue and green together for the center tap. If you don't you'll cook the tranny. Believe me, I know from experience. Tom should tape the correct two leads together for the center tap but he didn't in my case and I guessed wrong. :duh:
hmm. how do you know which ones go together?
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Well that's the question. I told Tom to tape the correct 2 together before he ships them out. Don't know if he's doing this now or not. If they're not taped together, I would ask Tom.
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Well that's the question. I told Tom to tape the correct 2 together before he ships them out. Don't know if he's doing this now or not. If they're not taped together, I would ask Tom.
Mine aren't taped together.
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Very interesting, i didnt think it mattered which blue vs green. Mine certainly were not marked :(
How the heck are you suppose to know which is which?
I emailed Tom to try and figure out which two go the center tap. Major heads up!
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Well I'm over my head here because I couldn't tell them apart either (help me out DIY'rs). You have a 50/50 chance of getting it right. If you get it wrong, the tranny will heat up pretty quickly and eventually smoke (like mine did). It works fine though and Tom assured me it could take the load that way--it would either work if it was OK or not if it was fried.
Or, if you get it right, it will work fine.
That's why I suggested to Tom that he mark the leads before shipping because this could happen to someone else and it looks like it did. So you can either role the dice or give Tom a call. That's the best I can do guys.
steve
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The wire I used for the rca's is 24 ga solid silver with teflon outer and the speaker wire is 3 twisted strands of 22ga silver plated copper stranded. I removed the rca connectors from the board and soldered directly to the board. As far as power wire goes I had an old 14ga power cord that I cut and used those indivdual wires fo power hook up. That way you can keep the color codes the same. Yes the yellow wire is a ground it is actually green and yellow. The amp is running some tweaked paradigm studio 40's through a modded onix xcd-99 and volume is via passive preamp. Sound quality to my ears is very good. Very smooth and extended with excellent bass response. Vocals sound great as well.
I have replaced the output capacitors on the amp with auricaps since the photos and that seemed to smooth things out even more. Who knows really, but it seemed to make a difference. The fuses that I have in the IEC module (dual fuse) are 6amp slow blow. The nice thing about the IEC module is that the plug,fuse holder and switch are all in 1 unit. Less wiring to do :D
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Well that's the question. I told Tom to tape the correct 2 together before he ships them out. Don't know if he's doing this now or not. If they're not taped together, I would ask Tom.
If you look at the transformer there are 2 sets of green and blue wires the most outward green and the most outward blue are a pair. The green and blue that are right next to eachother coming out of the transformer are the other pair. Clear as mud?
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You can kind of get an idea of what I am talking about by looking at the pic of my amp. Please shoot Tom an email though just to be 100% sure. He will answer right away.
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If you look at the transformer there are 2 sets of green and blue wires the most outward green and the most outward blue are a pair. The green and blue that are right next to eachother coming out of the transformer are the other pair. Clear as mud?
Thanks, I clearly didnt happen to just pick the correct ones randomly then. I am fresh out of fuses but i least my tranny didnt heat up.
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If you look at the transformer there are 2 sets of green and blue wires the most outward green and the most outward blue are a pair. The green and blue that are right next to eachother coming out of the transformer are the other pair. Clear as mud?
BRILLIANT!!! Thanks for clarifying that! :thumb:
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Quote from Tom:
There are 4 wires from the transformer. Two blue and two green, the blue and the green wires in the middle go to the CT. The outer green goes to the AC-L and the outer blue goes to the AC-N.
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Quote from Tom:
There are 4 wires from the transformer. Two blue and two green, the blue and the green wires in the middle go to the CT. The outer green goes to the AC-L and the outer blue goes to the AC-N.
:thumb: I am glad that Tom replied. For the record I smoked my first power supply board because I did not get that right the first time :duh:
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Tom told me that he was taping the leads to identify the center tap but my trans shipped direct from Antec and wasnt marked. Hope to get it rewired and up later.
I did confirm also that it is indeed only 60 wpc, more than a little frustrating since i was looking forward to 120wpc.
Yeah! No more blown fuses after rewire on center taps.
(http://i59.photobucket.com/albums/g295/mrnick_2006/IMG_3018-1.jpg)
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How does it sound without blowing fuses? I got the last of my supplies today. This weekend will be it!
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I had a chance to hear Steve's rig last week with the Class D amp driving the top half of his Maggies and I have to agree there's something special with it in place. We all commented just how quiet (or rather nonexistent) the noise floor was with the big Hafler on bottom, the Class D amp and a VTL tubed pre. I tend to be a tone junky and everything just seemed to meld together so well. Good stuff Steve. :thumb:
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I'm getting my parts together and hope to build soon. Looking forward to it!
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Greetings,
Have a couple of questions.
Has anyone heard both the 120w & 250w kits using the internal rectifier chip?
Any difference sonically? I notice a couple of you have built your amps in wooden cases, any sonic penalty due to lack of shielding? Thanks.
boone
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I have the 120 amp up and running, I got it all hooked up this morning and gave a listen for a few minutes. My first impression was wow this thing is very warm and musical, relaxed and liquid almost syrupy. I was almost unable to tear myself away from the house for work, I was enjoying it so much. I wasnt so sure about the bass yet but certainly was enjoying the much less edgy highs and warm mids.
I let it play the rest of day while i was away to help faciltate breakin if there is any. Upon futher listening the second time i find the bass tight and accurate and i have had no inclination to fire up my sub. I am finding that i now have a much larger soundstage and almost holographic presentation. It is still coming across as warm and musical and nonfatigueing which is just what the doc ordered because my room tends toward bright. I am really enjoying the sound and feel the 60 watts are adequate for my GR Research OB/7's.
I entered this whole thing as a huge skeptic but was certainly intruiged by the low investment since i was in the market for a used audiophile amp but my budget was keeping me from being successful. Even after ordering the amp i continued to shop for another amp thinking i could sell this classD if need be. Well the search is over and i am now a believer. Thanks Steve!
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Glad to hear you have enough power with this amp! I was a skeptic too. It's too hard to believe for the price. Tom's website may be a little rag tag but he knows what he's doing with Class D amps. He told me he's working on a metal case for it. Look out when that hits the market! :eyebrows:
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Do you have the TI or the IR based amp kit?
I have the 120 amp up and running, I got it all hooked up this morning and gave a listen for a few minutes. My first impression was wow this thing is very warm and musical, relaxed and liquid almost syrupy. I was almost unable to tear myself away from the house for work, I was enjoying it so much. I wasnt so sure about the bass yet but certainly was enjoying the much less edgy highs and warm mids.
I let it play the rest of day while i was away to help faciltate breakin if there is any. Upon futher listening the second time i find the bass tight and accurate and i have had no inclination to fire up my sub. I am finding that i now have a much larger soundstage and almost holographic presentation. It is still coming across as warm and musical and nonfatigueing which is just what the doc ordered because my room tends toward bright. I am really enjoying the sound and feel the 60 watts are adequate for my GR Research OB/7's.
I entered this whole thing as a huge skeptic but was certainly intruiged by the low investment since i was in the market for a used audiophile amp but my budget was keeping me from being successful. Even after ordering the amp i continued to shop for another amp thinking i could sell this classD if need be. Well the search is over and i am now a believer. Thanks Steve!
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Do you have the TI or the IR based amp kit?
Beats me! How do i tell? I ordered the same one that Steve has.
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It's the IR chip.
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Okay when your wife comes home and says wow that sounds incredible then you know your not fruity. She seldom takes notice of my hobbie but was very impressed. Described it as sounding big refferring to the new huge soundstage.
I am having fun. :eyebrows:
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I have the 120 amp up and running, I got it all hooked up this morning and gave a listen for a few minutes. My first impression was wow this thing is very warm and musical, relaxed and liquid almost syrupy. I was almost unable to tear myself away from the house for work, I was enjoying it so much. I wasnt so sure about the bass yet but certainly was enjoying the much less edgy highs and warm mids.
I let it play the rest of day while i was away to help faciltate breakin if there is any. Upon futher listening the second time i find the bass tight and accurate and i have had no inclination to fire up my sub. I am finding that i now have a much larger soundstage and almost holographic presentation. It is still coming across as warm and musical and nonfatigueing which is just what the doc ordered because my room tends toward bright. I am really enjoying the sound and feel the 60 watts are adequate for my GR Research OB/7's.
I entered this whole thing as a huge skeptic but was certainly intruiged by the low investment since i was in the market for a used audiophile amp but my budget was keeping me from being successful. Even after ordering the amp i continued to shop for another amp thinking i could sell this classD if need be. Well the search is over and i am now a believer. Thanks Steve!
Okay when your wife comes home and says wow that sounds incredible then you know your not fruity. She seldom takes notice of my hobbie but was very impressed. Described it as sounding big refferring to the new huge soundstage.
I am having fun. :eyebrows:
Told you. :singing:
And you fellas jest thinking that his bigger offerings won't make even greater sub amps! I am looking forward to my 500 watt/8 ohm, 750 watt/4 ohm build! :eyebrows:
Anand.
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I'm looking forward to my 600w build. If all goes well, maybe I'll make 600w monos.
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I have replaced the output capacitors on the amp with auricaps since the photos and that seemed to smooth things out even more.
Avionic, you mentioned you replaced the output caps with Auricaps. How did you determine which ones are the output caps? How difficult was it to connect film caps in place of the small electrolytics on the amp board?
I was thinking of replacing the power supply caps.
steve
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Couple of questions for folks who have the amp already.
How difficult is it put together for person who has never done any DIY stuff?
What are the components that I need to supply or does the kit come with everything other than the case? Do I need to worry about getting RCA jacks etc. If yes, any recommendation on where to get some.
Looking at the web page I cannot figure out which amp is based on TI vs IR and which one runs cooler? Leaning towards the 250w X 2 8ohms (http://classdaudio.com/index.php/class-d-amplifier-kits/home-kits/2-000-watt-rms-class-d-amplifier-kit.html or http://classdaudio.com/index.php/class-d-amplifier-kits/home-kits/250w-x-2-8-amplifier-power-supply-and-transformer.html) to drive the LS6 speakers and x-omni surrounds from AV123.
TIA
-Deepak
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As far as I know, the only two amps Tom sells with the TI chip are the 600 wpc and the 160 wpc. As far as assembly, if you're just mounting the boards on a breadboard, you'll need longer screws to get into the standoffs from underneath depending on how thick your board is.
Other then that, it's pretty easy. All the connections are screw connections requiring small screwdrivers. The tranny bolts down with a through-bolt. The amp board has RCA inputs already. The speaker connections are small screw blocks but will accept a 14 ga. wire or possibly one tong of a spade connector depending on the spade size. It's really meant to be mounted in a box and is easily done using all the same screw connections to new RCA's and binding posts.
If you have other questions, you should email Tom at: sales@classdaudio.com
steve
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Avionic, you mentioned you replaced the output caps with Auricaps. How did you determine which ones are the output caps? How difficult was it to connect film caps in place of the small electrolytics on the amp board?
I was thinking of replacing the power supply caps.
steve
Hey Steve I shot you a P.M.
Some people have said that the TI chip amps sound a little brighter than the IR amps. I couldn't say as I only have the IR based amp.
Shadowlight you can get a pre made case for about $50.00 and the rest of the parts that you need will probably be another $50.00. Of course you could spend a lot more depending on how exotic you want to get with wiring and such. Ebay is a good source. As is parts express or parts conexxion and many others.
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I just used some scrap mdf to mount the boards and some bamboo flooring scraps i had to make the case. I just mounted the board toward the back of the case so i could still ultilize the on board rca's. I picked up an iec/fuse and a pair of binding posts and a power switch and led lights for $26 at partsexpress. A little wire and the longer screws at the depot and then it just a matter of mounting the boards and wireing things up. Of course a nice metal case is ideal then the mounting screws will work. I soldered the led leads and the power switch to the board but you dont have too, one could use the onboard power switch or leave it powered on continually. You can almost make it as basic as you want to by mounting as Steve did in his first photo. The results are amazing, I have also heard most perfer the IR appliciation. I will definatly be keeping an eye out for Tom's case offerings.
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Been following this thread with great interest.
Avionic, could you please post a picture so I can know which caps are the output couplers?
Thanks,
JakeJ
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I'm hoping to case this up this weekend, but have a question. How are you guys connecting the ground on the iec? Especially those that are using all wood cases. Input would be appreciated. Thanks!
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I'm hoping to case this up this weekend, but have a question. How are you guys connecting the ground on the iec? Especially those that are using all wood cases. Input would be appreciated. Thanks!
Good question, mine is currently not connected. I sent Tom an email asking about this and will update.
EDIT: Tom said as long as using a toroid transformer there is no need to ground unless having hiss or noise issues. I am having no such issues.
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Avionic - will you please let us know what Tom says about the TI versus IR amps and if one is brighter sounding than the other (or conversely, one is more softer or rolled off sounding) I want to avoid the softer, rolled off.
Hey Steve I shot you a P.M.
Some people have said that the TI chip amps sound a little brighter than the IR amps. I couldn't say as I only have the IR based amp.
Shadowlight you can get a pre made case for about $50.00 and the rest of the parts that you need will probably be another $50.00. Of course you could spend a lot more depending on how exotic you want to get with wiring and such. Ebay is a good source. As is parts express or parts conexxion and many others.
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Here's a quote I received from Tom:
All of our amps are very clean and detailed, but in my opinion, our IR based amps are the smoothest sounding
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Thanks to everyone who responded to my question. I am going to reach out to Tom and see what he recommends as amp that will drive the AV123 LS6 which are 91db or around there efficient.
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Hi guys.
Just pulled the plug on 250W X 2 500W X 1 Amp + Power Supply + Transformer (kit).
This should be plenty for my new 88db drivers. oh yeah - total paid = just under $200 shipped with promo code ACircle.
Cheers
Mariusz
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sounds great, I will have to look into them myself. :thumb:
Mr C :D
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Enough with the ordering, already! Let's hear about the tweaks and upgrades. :smoke:
I'll pass this along from the diyaudio forum. The author is referring specifically to the 250W ClassD amp w/ IR chip. There seems to be an error in the initial reference to the cap value, but it is clarified later:
One last recommendation for this amp: I highly, highly, highly recommend replacing the 2 .47 uf .1 uf Epcos and output filter caps (the big blue caps). I have replaced mine with the well-regarded Dayton film / foil bypass caps. Cost: $ 5. I no longer need the buffer. All the issues with this amp that I believed needed to be corrected by the buffer or preamp are now gone.
Parts-Express.com:*Dayton DFFC-0.47 0.47uF 400V By-Pass Capacitor | polypropylene capacitor polypropylene PAC PA low pass foil film and foil dayton capacitor caps cap ac 47uf .47uf
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Enough with the ordering, already! Let's hear about the tweaks and upgrades.
:lol:
You are playing with yours but rest of us are just exited. :dance:
And thanks for the tip.
Have you compare it to other amps? If so, what did you find?
And....... does anyone knows if it can run on batteries?
Thanks
Mariusz
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:lol:
And....... does anyone knows if it can run on batteries?
Thanks
Mariusz
That would be awesome!
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That would be awesome!
I think it can be done.
(I will ask around :wink: - just wonder how long will reasonable stock of batteries
make this efficient amp sing? Guessing - 6h - 8h would work for most of us.)
Mariusz
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I think it can be done.
(I will ask around :wink: - just wonder how long will reasonable stock of batteries
make this efficient amp sing? Guessing - 6h - 8h would work for most of us.)
Mariusz
My Dodd Audio Tube Buffer is off the grid. I have a 28ah battery which will last 22 hrs without going below 11VDC.
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My Dodd Audio Tube Buffer is off the grid. I have a 28ah battery which will last 22 hrs without going below 11VDC.
I am thinking about Dodd's mini amp in the future (will wait for integrated version).
Grid in N.Y really sucks and can be annoying .... especially with high efficiency speakers.
Also wonder if getting it off the grid is a worthy idea?? ($ v.s SQ)
best
Mariusz
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I am NOT playing with mine! My hands are not even down my pants. :oops:
I don't have a ClassD amp yet. :?
I don't see why it shouldn't run off a battery. By the way, there is the trick of installing a cap across the power feeds between the SMPS and the amp. I actually preferred this to battery operation on my T amps. Of course, I had already invested in the batteries. :duh:
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I'd be especially interested if anyone can actually compare the sound of these amps to other Class D amps, as they are orders of magnitude cheaper than a "finished" product.
Wyred4Sound and Bel Canto come to mind as direct competitors - based on ICE module. Wyred4Sound positions itself as a "value" alternative, so a comparison to it would be most interesting.
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I'd be especially interested if anyone can actually compare the sound of these amps to other Class D amps, as they are orders of magnitude cheaper than a "finished" product.
I agree. Nuforce??
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I've heard the Class D compared to Bel Canto monoblocks and I much prefered the Class D amp. The midrange and highs were much more emotional and involving (more tubelike and three dimensional) than the Bel Cantos which had great bass slam but were too dry for my tastes on the mids and the highs.
steve
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Enough with the ordering, already! Let's hear about the tweaks and upgrades. :smoke:
I'll pass this along from the diyaudio forum. The author is referring specifically to the 250W ClassD amp w/ IR chip. There seems to be an error in the initial reference to the cap value, but it is clarified later:
One last recommendation for this amp: I highly, highly, highly recommend replacing the 2 .47 uf .1 uf Epcos and output filter caps (the big blue caps). I have replaced mine with the well-regarded Dayton film / foil bypass caps. Cost: $ 5. I no longer need the buffer. All the issues with this amp that I believed needed to be corrected by the buffer or preamp are now gone.
Parts-Express.com:*Dayton DFFC-0.47 0.47uF 400V By-Pass Capacitor | polypropylene capacitor polypropylene PAC PA low pass foil film and foil dayton capacitor caps cap ac 47uf .47uf
I grabed these photos from a guy over at diy and he said it was a real pita swapping the caps as i suspected. My soldering skills were tested by just getting this up and running. Its a small board to work on and the sound i have now is pretty amazing. I might wait for a few more reports till i jump on this.
(http://i59.photobucket.com/albums/g295/mrnick_2006/classd.jpg)
(http://i59.photobucket.com/albums/g295/mrnick_2006/img_1812.jpg)
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Hmmmm... interesting pics.
My notion was to replace the big blue caps, but this wasn't done in these pics.
I'm dizzled about what I am seeing... but, what's new.
Don't those Vitamin Q's resemble Russian mil teflon caps?
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OK, sorry if this has been posted already. . .I've read through most posts, but may have glanced over this.
If I am going to build this, I need:
1. A case
2. Wire (approximately how much?)
3. Binding posts
4. Power cable w/ amp and wall connections
Is construction this simple?
1. Connect / solder the transformer, PS and amp via wires (transformer via its own wires)
2. Connect / solder binding posts and power cable
Anything else? What's a good source for these? Getting everything at one place would be great.
Thanks!
Paul
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Hi Paul,
I haven't built one yet myself but if you look at the pictures Steve posted in the op you'll see all you need is a small screwdriver to connect the wires from tranny to PS module and that to the amp module and then to the speakers. Probably the only soldering you might have to do is the mains inlet (if you decide to go with an IEC connector) which is recommended as you can find them with a built in fuse holder. OK, and the speaker binding posts. I will likely pull off the board mounted RCA connectors and use good quality chassis mount RCAs.
After I get the taxes and a refi of my home out of the way I'm gettin' one of 'em!
Hope this helps,
Jake
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1. A case
You don't need a case, but it's a good idea. Several possibilities were offered earlier in the thread. This seems like a nice option:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250501444095
2. Wire (approximately how much?)
You need only a few feet of 12-14 gauge to wire the power side of the amp, then something to run from the amp module to the binding posts. I plan to use 15 gauge stranded there because I have it lying around.
If you get the input mounted on the board (which is the default), you don't have to wire those. I opted to mount inputs on the chassis. For that, using wire approximating IC wire (18-22 gauge) seems pretty standard.
3. Binding posts
Yep, unless you want to run speaker wires directly from the amp. Lots of options and every place carries some. I bought Vampire.
4. Power cable w/ amp and wall connections
Not necessary, but most buy a female IEC connector and mount that to the chassis, plus a fuse holder.
Is construction this simple?
Looks like!
What's a good source for these?
Lots of options. I ordered from Parts Express and Sonic Craft. PE is a good group, but they always seem to be out of 1/2 the crap I need. It's a good place to start.
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I grabed these photos from a guy over at diy and he said it was a real pita swapping the caps as i suspected. My soldering skills were tested by just getting this up and running. Its a small board to work on and the sound i have now is pretty amazing. I might wait for a few more reports till i jump on this.
(http://i59.photobucket.com/albums/g295/mrnick_2006/classd.jpg)
(http://i59.photobucket.com/albums/g295/mrnick_2006/img_1812.jpg)
This looks real similar to how my board looks after installing the output caps. Only mine are audience auricaps. I also found it easiest to mount 2 on top and 2 on bottom. These amps are really easy to put together. The only thing that seems to give folks some trouble is the wiring of the transfo, which has been discussed in this thread. As mentioned already these amps sound great and probably even better because you put it together :wink:
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Here is the answer from Tom regarding battery power supply:
" This is a very high power amp, so in order to run it from a battery, you
would have to use one of our 12V DC power supplies that we make for car and
marine use. You will still need a powerful batteries as the amps need allot of
current. Also, this power supply is only for the 250W X 2 500W X 1 amp."
I also asked about integrating volume pot and touched on overheating concerns.
Overall good communication and fast response indicated top notch costumer service.
Best
Mariusz
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I haven't posted here for a long time, but I thought I'd jump in since I was made aware of Class D Audio's products at the same time as Steve K, and I too am a proud owner of their amps. I say amps, plural, as I purchased two of the 60w x 2 into 8 ohms with upgraded power supply, and I'm running them bridged, as mono blocs.
I find it interesting that Tom is developing a higher performance heat sink for these amps so they will be better suited for 4 ohm loads, as I'm running mine into Magnepan MG12s, which are rated at 4 ohms, and although I don't usually play at very high spls, my heatsinks barely get warm at all. My amps are stock, but I did have Tom adjust the gain to 26 db when I placed my order. And for the record, I'm using a tubed preamp.
I am making good progress on making enclosures and will share photos soon. The fact that I am spending the time to make enclosures is indicative of how I feel about these amps--not only are the breadboards soon to be history, so are the tube mono blocs I have been running full range and enjoying for eight years. As much as I enjoyed my tube amps (even my moniker reflects that), I just can't say enough good things about Tom's amps. As Steve mentioned, soundstage depth isn't quite as good as with the tubes, but everything else is just excellent. I didn't know my speakers were capable of this kind of bass, and the etch-free detail I now hear consistently evokes the words "oh my", even at very low volumes. This has been an enormous step in the search for "real" sound.
Both Steve and I were initially skeptics, and now, after reassuring each other that we weren't deceiving ourselves, it's great to see others discovering such an inexpensive path to audio enjoyment.
Bob
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I didn't know my speakers were capable of this kind of bass, and the etch-free detail I now hear consistently evokes the words "oh my", even at very low volumes.
I am having the same reaction, i didnt know my speakers were capable of such awesome bass. :green:
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I'm Interested in anyone's experience with adding volume pot to the 250 x 2 amp. What impedance value mates well, and wiring pics or diagram if possible.
I have one ordered and would like to be able to use it as integrated, as well as adjust gain for use with preamp. I had Tom reduce gain to 26db as others have.
My speakers are 2 ways with a 12 sealed with a small widerange on ob.
These sound like nice amps.
Really appreciate this thread.
Don
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why are you guys adjusting the gain?
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why are you guys adjusting the gain?
I'm no expert, but here's what I've gathered....
26 db is pretty standard if you have an active preamp; if you have a passive preamp of some sort, extra gain is helpful. With a high gain amp, lots of active preamps would only be able to use a narrow range of theei volume control.
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why are you guys adjusting the gain?
Because 26 dB gain is more typical for amp gain in the industry. Higher gain might produce more noise in the signal and give you less control over the volume with your preamp.
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What is the gain if you don't ask for a change (which I didn't)?
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32 dB
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I didnt ask about it either but it performs flawlessly with the pre-outs on my HK. :green:
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hmm. Wonder if I'm screwed. I use a tube buffer.
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Jason, your fine with the gain at 32db. I have had one of the 250Wx2 @4ohms for awhile now and I haven't said anything because I am doing something different with mine. I'll be letting everyone know when I am finished with it. Let me say though that even totally stock these things are wonderful!! :drool:
Gary
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Jason, your fine with the gain at 32db. I have had one of the 250Wx2 @4ohms for awhile now and I haven't said anything because I am doing something different with mine. I'll be letting everyone know when I am finished with it. Let me say though that even totally stock these things are wonderful!! :drool:
Gary
WooHoo! Now that's service...from the maker of my tube buffer. Gary Dodd. Can't wait to see what you're doing with yours.
:banana piano:
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That's high praise from you Gary, and nice of you to offer up.
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Interested in any experience with adding volume pot to the 250 x 2 amp. What impedance value mates well, and wiring pics or diagram if possible.
I have one ordered and would like to be able to use it as integrated, as well as adjust gain for use with preamp. I had Tom reduce gain to 26db as others have.
My speakers are 2 ways with a 12 sealed with a small widerange on ob.
These sound like nice amps.
Don
I am running a passive pre with a 10k pot and it works great.
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You don't need a case, but it's a good idea. Several possibilities were offered earlier in the thread. This seems like a nice option:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250501444095
From that Ebay ad I went to their website. Just in case someone needs some extra money as a sideline business, you can go here and buy these cases on a wholesale basis. I just wish I knew what you guys were doing, I would go for it myself. But since I don't, I would buy one already mounted in a case.
You can get big discounts if you buy these cases in bulk.
http://par-metal.com/price.php
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It took me about an hour of time to get it to this point. This is the 600w version. Considering this cost ($240) to my door and my 300w Class A amps cost $14k, this is scary. :duh: I need more time to listen but out of the gate, it sounds really good. :thumb: :drool:
I will post more pictures when I complete my aluminum case for it.
(http://www.audiocircle.com/image.php?id=26062)
(http://www.audiocircle.com/image.php?id=26064)
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Thanks for the pictures jtwrace. If I can see all the details, and yours gave me plenty of clues, I just will probably try it myself. The circuits of these amps looks so simple, that could be the reason for such great sound.
Less parts=better sound. I have believed in that philosophy for over 30 years.
If you look closely to the Channel Island's D100 mono amps for $1600 a pair, these circuits look very similar to those. And those amps never get bad reviews.
http://www.ciaudio.com/D100.html
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It took me about an hour of time to get it to this point. This is the 600w version. Considering this cost ($240) to my door and my 300w Class A amps cost $14k, this is scary. I need more time to listen but out of the gate, it sounds really good.
Enjoy, my friend!!
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Thanks for the pictures jtwrace. If I can see all the details, and yours gave me plenty of clues, I just will probably try it myself. The circuits of these amps looks so simple, that could be the reason for such great sound.
Less parts=better sound. I have believed in that philosophy for over 30 years.
If you look closely to the Channel Island's D100 mono amps for $1600 a pair, these circuits look very similar to those. And those amps never get bad reviews.
http://www.ciaudio.com/D100.html
No problem. I'd more more then happy to take more if you need some. I also agree with your philosophy.
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Enjoy, my friend!!
Steve,
Thanks...I already am. :thumb:
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This is with the volume at 80dB and listening to rock.
This is the Amp draw from the Class D amp.
(http://www.audiocircle.com/image.php?id=26065)
Watts=10w (my 300wpc Class A amps idle at 600w)
(http://www.audiocircle.com/image.php?id=26066)
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Be a DIY'er
Control your destiny! :D
See...you don't have to spend kilodollars to get great sound.
Thanks for the update jtwrace. Heh...aren't you a neighbor in NC? Near Charlotte?
Anand.
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Be a DIY'er
Control your destiny! :D
See...you don't have to spend kilodollars to get great sound.
Thanks for the update jtwrace. Heh...aren't you a neighbor in NC? Near Charlotte?
Anand.
Yes sir. Huntersville to be exact
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Watts=10w (my 300wpc Class A amps idle at 600w)
How warm does your amp get at that load?
steve
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Thanks Avionic. I'm generally following your build from the pic you posted. Bought the switch/fuse holder from ebay. I like the idea of adding vol. pot directly to this amp, will see what develops.
Good thread.
Take care, Don
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Following this thread with interest and have now ordered one of the kits. Quick question, from looking at the pics, where did you builders ground the amplifier? From the IEC inlet ground terminal with a wire to the chasis? Sorry if I missed the ground in the pics, just curious how builders are grounding so I can finish my assembly plans in advance of the kit arriving.
Regards.
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Following this thread with interest and have now ordered one of the kits. Quick question, from looking at the pics, where did you builders ground the amplifier? From the IEC inlet ground terminal with a wire to the chasis? Sorry if I missed the ground in the pics, just curious how builders are grounding so I can finish my assembly plans in advance of the kit arriving.
I asked Tom this and he said it doesn't really need grounding but if you want to he recommended grounding to one of the heatsink screws underneath the amp board.
steve
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What are you guys liking for Chassis RCA's and Speaker Posts?
How about internal wiring cable?
thanks,
Jeff
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How warm does your amp get at that load?
steve
The heat sinks on the Class A get to 130*F
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Sorry I meant the Class D.
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Sorry I meant the Class D.
Not very. I can measure if you would like.
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I was curious how warm your heatsink gets being much higher powered amp than mine. Mine barely gets warm even at high volume.
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I was curious how warm your heatsink gets being much higher powered amp than mine. Mine barely gets warm even at high volume.
Yes, ours are the same.
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Are you driving 4 ohm speakers?
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I wanted to keep my enclosures as small as possible while still being able to have easy access to all the components, so this is what I came up with. The box in front, which is without one side, shows the shelf that both boards are attached to--back to back. A larger top lid will cover the transformer and the output board, and a smaller bottom "lid" will cover the power supply board. A front plate will accommodate two switches, marked "on" and "off" and "mute" and "play". Three colors of LEDs will indicated what's going on.
Bob
(http://www.audiocircle.com/image.php?id=26074)
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Some more pics. Keep in mind that this is for the 600w version using XLR balanced inputs. I don't want anyone to hurt themselves or their equipment by following these pictures. Consult your manual or email Tom.
Power Supply Board from 400VA Antek Transformer:(http://www.audiocircle.com/image.php?id=26075)
Speaker Board-using XLR inputs:
(http://www.audiocircle.com/image.php?id=26078)
XLR Panel Mount Jack / Speaker Jacks. These parts I got at Radio Shack. I wanted to make sure that I liked it before spending more money on "high end" stuff.
(http://www.audiocircle.com/image.php?id=26077)
XLR Balanced Jumper on speaker board:
(http://www.audiocircle.com/image.php?id=26079)
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Are you driving 4 ohm speakers?
They are minimum 4.7 @ 70Hz.
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Looks good Bob!! Can't wait to see the faceplate. The main difference between Bob's case and mine is mine has the tranny mounted vertically like the Channel Islands monoblock layout. It's really amazing how compact these boards are. Since they run at a frequency of 400kHz, the signal paths must be as short as possible.
steve
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The 250x2 watt kit order,which will be 125wx2 for the LS6.
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XLR Panel Mount Jack / Speaker Jacks. These parts I got at Radio Shack. I wanted to make sure that I liked it before spending more money on "high end" stuff
Thats what i did also, i just picked up some dayton audio binding posts and home depot thhn wireing. Now i am wondering how much difference vampire posts and better wireing would make. Now that i know its a keeper i am still decideing if upgrades are a worthy investment.
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Thats what i did also, i just picked up some dayton audio binding posts and home depot thhn wireing. Now i am wondering how much difference vampire posts and better wireing would make. Now that i know its a keeper i am still decideing if upgrades are a worthy investment.
What change? Probably none!
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What change? Probably none!
Precisely what i was thinking. Think i am gonna kick back and enjoy the music. :duh:
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jtwrace,
Are you using the TI based amp?
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jtwrace,
Are you using the TI based amp?
Yes Sir!
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I got three Class D amps: Two tripath and one 500W kit from Class D Audio. :D
I haven't had time to do the most recent one form Class D, but must say it's impressive looking. The last one I set up was 100 watts into 4 ohms and came from Hong Kong. It's using all solid capacitors! It cost a mere $39.00 with FREE SHIPPING! It's Tripath. The first one I tried is that little guy from Parts Express.
Can't wait to set up the big one!
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I wanted to keep my enclosures as small as possible while still being able to have easy access to all the components, so this is what I came up with. The box in front, which is without one side, shows the shelf that both boards are attached to--back to back. A larger top lid will cover the transformer and the output board, and a smaller bottom "lid" will cover the power supply board. A front plate will accommodate two switches, marked "on" and "off" and "mute" and "play". Three colors of LEDs will indicated what's going on.
Bob
(http://www.audiocircle.com/image.php?id=26074)
Very nice. Even though I've not received my kit, I was thinking about making a set of monoblocks and stacking the boards.
Thanks to all of you for offering up your pics!
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I'm drawing a case design up and am looking for feedback. Do you guys think it's necessary to have the status lights on the front panel? Also, what do you think of the power switch on the bottom front (underside) of the front panel? Personally, I like that with an illuminated power switch and that's it! Simple.
Thoughts?
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I like the status lights in front just to know if it's on or in standby and if a channel is off for some reason. The power LED's go out if the amp goes into overcurrent or undercurrent protection although mine has never done that. OTOH, If you mount the tranny behind the faceplate, getting the LED wires past it can become a space issue. I have my power switch on the bottom centered right behind the face plate. I think it's cool to have a hidden power switch. It's totally up to you. Mark (the white case) just put one LED on the front to tell if it's on. A lighted power switch would work just as well.
steve
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And just for the fun of it, I'm going to have the two switches and a total of six LEDs on my face plate (four will be lit up at one time), including two that will come off the power supply board (I'll remove the bright blue LEDs there). There will be a bundle of wires inside, but I don't think that will effect the sound any. Power amps tend to be a bit boring to look at (just a block of metal), so I'm going to dress mine up. To each his own.
Bob
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I like the status lights in front just to know if it's on or in standby and if a channel is off for some reason. The power LED's go out if the amp goes into overcurrent or undercurrent protection although mine has never done that. OTOH, If you mount the tranny behind the faceplate, getting the LED wires past it can become a space issue. I have my power switch on the bottom centered right behind the face plate. I think it's cool to have a hidden power switch. It's totally up to you. Mark (the white case) just put one LED on the front to tell if it's on. A lighted power switch would work just as well.
steve
Steve
Thanks for the input. I think I'll go for the illuminated power switch on the front bottom.
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Is it necessary to shut these amps off?
I don't know if I will be building any of these since I don't really need anything. Too many amps now. Two are for sale. Nonetheless, I can't help thinking about the subject. Would it make sense to build one of these vertically, so that each of the three components was situated on a separate tier with the toroid's weight on the bottom for stability? It seems that would be very compact and would allow for all connections to be near the outside walls of the case, which could actually remain open on two sides for ventilation. Is wood the ideal case material? If not, why not?
Would the whole thing fit in a 6 inch square of about 8 inches height? Wouldn't this config allow for shorter leads internally?
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Is it necessary to shut these amps off? NO. THEY'RE WIRED SO THAT THE AMP BOARD STAYS HOT IN STANDBY MODE AND ONLY THE MOSFETS ARE TURNED ON WHEN THE AMP IS SWITCHED ON. THIS EXTENDS THE LIFE OF THE MOSFETS.
I don't know if I will be building any of these since I don't really need anything. Too many amps now. Two are for sale. Nonetheless, I can't help thinking about the subject. Would it make sense to build one of these vertically, so that each of the three components was situated on a separate tier with the toroid's weight on the bottom for stability? It seems that would be very compact and would allow for all connections to be near the outside walls of the case, which could actually remain open on two sides for ventilation. NO REASON WHY THIS WOULND'T WORK. THE LARGEST TOROID IS ABOUT 5 1/2" IN DIAMETER. THE MAIN THING IS TO ALLOW YOURSELF EASY ACCESS TO THE BOARDS AS THEY ARE SMALL (APPROX. 4 1/2" x 4 1/2"). REMOVABLE SIDES WOULD BE GOOD. Is wood the ideal case material? If not, why not? WOOD IS JUST EASIER TO WORK WITH TO MAKE A CUSTOM SIZE AS YOU PROPOSE. METAL CASES ARE LIMITED TO STANDARD AVAILABILITY. I HAVEN'T NOTICED ANY PROBLEM WITH RF OR EMI IN A WOOD CASE WITHOUT SHIELDING.
Would the whole thing fit in a 6 inch square of about 8 inches height? Wouldn't this config allow for shorter leads internally?POSSIBLY. MY CASE IS PRETTY TIGHT TO WORK IN AND ITS ABOUT 6 1/4"W. x 8" H X 11 1/4" D.
Steve
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Avionic,
The case that you have listed did it come with precut holes for the IEC cable and rca/speaker connectors or did you have to cut them? If you cut them what are the tools needed? Another question is related to the cable link. Any particular type I should get?
Sorry for asking basic questions. It is my first DIY build.
Thanks
(http://www.audiocircle.com/image.php?id=25826)
I have had the 125x2 8ohm version of the class d audio amp up and running for a few months now and I am really pleased with it. It sounds great and was very easy to get up and running. As mentioned earlier Tom from class d audio is extremely helpful and will answer all your questions quickly. IMO this is an extremely nice amp for the$$. I have added a few links to the chassis,power inlet and wiring that I used.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250501444095&ssPageName=STRK:MEWAX:IT
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200424519369
http://stores.ebay.com/Johns-Silver-Teflon-Wire-Shop
http://classdaudio.com/index.php/class-d-amplifier-kits/home-kits/250w-x-2-500w-x-1-amp-power-supply-transformer.html
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I'm drawing a case up now...those of you that can wait, I would as this case will have all the cut outs and be ready to go. I'll get the case design done then quoted and see if it's something that you'll be interested in.
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I'm drawing a case up now...those of you that can wait, I would as this case will have all the cut outs and be ready to go. I'll get the case design done then quoted and see if it's something that you'll be interested in.
I would be interested. Can I make a suggestion, just to make the case future proof can you think about putting in another punchout for second set of speakers connectors in case folks want to use the case for dual mono.
Thanks
EDIT: Ignore that suggesetion. I just looked at the case and it does not have enooght space for secondd set of power supply and amp board.
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I would be interested. Can I make a suggestion, just to make the case future proof can you think about putting in another punchout for second set of speakers connectors in case folks want to use the case for dual mono.
Thanks
The case will have inputs for XLR & RCA. The mono version will be just that. The problem is that I'm trying to have one design otherwise there are unused holes which doesn't look good IMO even with blank plates. This way the stereo version will be just right. The mono will be identical but leaving half of the inputs / speaker output off. It's simple and cost less.
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So now that you've heard the Class D for awhile, how would you compare the sound to your Class A Monoblocks? Inquiring minds want to know. :eyebrows:
steve
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So now that you've heard the Class D for awhile, how would you compare the sound to your Class A Monoblocks? Inquiring minds want to know. :eyebrows:
steve
I still need a little more time to go back to the Class A but considering the cost (less then 20%) :duh: of my Class A amps, it's really good. I'm going through the effort to make a case if that's an indication. :D
I will report more once I get my amp back together. :( I had to take it apart to measure everything for the CAD drawing...
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added this to Sweet Deals as well: http://www.audiocircle.com/index.php?topic=77175.0
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I finally got mine put together on a block of wood. I'm hoping to test it out soon.
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Any thoughts on fitting a DAC in the case?
Jeff
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Any thoughts on fitting a DAC in the case?
Jeff
Personally, I wouldn't.
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If I were building a case for an amp, I would build with wood, if possible.
I don't know if my experience is purely a result of mere psychology, but I tend to prefer the sound of an amp or other components encased in wood or, at least, not metal. The Lessloss site discusses this issue in an interesting manner.
Just my 2 cents worth.
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Received my 120 wpc kit yesterday and got it toghether for some initial testing and listening. The kit arrived promptly and was packed very well. The vendor also was very responsive and quick to answer questions, so a good experience before it even arrived.
This was a very easy build. The instructions were clear and having screw terminals on the boards to minimize soldering made it a breeze.
Fired it up on my Ascend 340s and although I have to listen a while before commenting, initial song I listened to sounded pretty nice.
Overall, I am pretty pleased in that the build was simple and my initial listening session was favorable. Thanks to those who have posted and generated my interest in this amp.
Cheers.
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Great Chadmat! Give us a full report after you've listened to it for awhile.
steve
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Tom tells me all the acitivity aabout his amps here on Audiocircle has gotten him a request from Affordable Audio to review one of his amps. It will probably be coming up in May. More later. :thumb:
steve
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Tom tells me all the acitivity aabout his amps here on Audiocircle has gotten him a request from Affordable Audio to review one of his amps. It will probably be coming up in May. More later. :thumb:
steve
That's great news!
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Tom tells me all the acitivity aabout his amps here on Audiocircle has gotten him a request from Affordable Audio to review one of his amps. It will probably be coming up in May. More later. :thumb:
steve
Awesome news well deserved! Congrats Tom! and Steve! hehe
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So after a bunch of listening, I plugged the amp into the power conditioner. WOW! What a difference that made. Wish I did that from the get-go. :duh:
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So how is your case design coming?
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So how is your case design coming?
Very well! Should have it finalized early next week.
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I did a trick with a SMPS for a t-amp. I had been listening with battery power because it was better that the SMPS. Then I read that installing a cap between the low-voltage leads between the SMPS and the amp would help. It sure did. It sounded better than battery power.
My 2 pfennigs.
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I did a trick with a SMPS for a t-amp. I had been listening with battery power because it was better that the SMPS. Then I read that installing a cap between the low-voltage leads between the SMPS and the amp would help. It sure did. It sounded better than battery power.
My 2 pfennigs.
Give some more details...what value? Picture?
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Very well! Should have it finalized early next week.
Pencil me in for two - I have a pair of 600W burning in now. They are certainly case worthy.
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Pencil me in for two - I have a pair of 600W burning in now. They are certainly case worthy.
will do. I'll post more info when it's done.
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Awesome news well deserved! Congrats Tom! and Steve! hehe
This one's all on Tom. I'm just trying to spread the word a bit. I'm glad you're all seeming to hear what I hear and I'm not hallucinating. :lol: He's da man. :notworthy:
steve :thumb:
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So after a bunch of listening, I plugged the amp into the power conditioner. WOW! What a difference that made. Wish I did that from the get-go. :duh:
Just curious what conditioner, everyday like the Belkin or high dollar?
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That is great news for Tom. Super nice guy! I guess I should buy a couple more before the inevitable price increase.
jtwrace: I am looking forward to seeing your finished enclosure as well.
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I ordered a kit tonight. Despite the fact that I assembled a couple of Hafler DH-200 amps back in the late 70s, I'm feeling very daring and challenged about the prospect of actually making this work. I hope I know what I'm doing.
Oh well, I'm sure I've spent more money in worse ways in my past. Like the time I pissed away more than half a grand on an online real estate course. I couldn't read that crappy legal jibberish for more than twenty minutes without lapsing into a trance. Bad investment and I should have known myself better.
I've been resisting the temptation to purchase one of these amplifier kits as I avidly followed this thread. Tonight I reached a point where I could no longer ignore the impulse.
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I ordered a kit tonight. Despite the fact that I assembled a couple of Hafler DH-200 amps back in the late 70s, I'm feeling very daring and challenged about the prospect of actually making this work. I hope I know what I'm doing.
You won't have any problems. If you have any questions just ask here or email Tom.
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It really is easy. If you've assembled Haflers this will be a piece of cake. No soldering at all in the breadboard model--just screw connections. If you put it in a case, you may have some soldering on the board and with your binding posts and RCA's but again, its relatively minor. Tom makes these really easy to assemble--all the better--you can hear it quicker that way! :lol:
steve
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From looking at the pictures on his site and in this thread I get the impression that crimp on spade lugs might be a good idea for connecting wires under the screws. I figured I'd just cross that bridge when I come to it but since we're talking, I may as well ask you guys.
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jtwrace:
The cap in question was .22 or .47uf. It's not critical, I think. I know nothing about electronics, so I took the advice of someone on AC.
You only need to separate the power lines, strip a bit of insulation off each one and attach a cap lead to the load and neutral sides. The arrangement is as if you were shorting the circuit. It seemed to me that there should have been a pop, a spark, a puff of smoke or ozone and no sound when I powered up, but it worked just like I was told.
The sonic result was that the amp had the punch and liveliness of the SMPS, but the smooth quality of a battery. That after I bought two SLAB's and a charger. For the price of a cap, a little electrician's tape and a lumpy power cord, I got better sound. Of course, YMMV, but if you don't like the result, you can just remove the cap and tape the wires.
Small investment for a really nice improvement.
Hope this helps.
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From looking at the pictures on his site and in this thread I get the impression that crimp on spade lugs might be a good idea for connecting wires under the screws. I figured I'd just cross that bridge when I come to it but since we're talking, I may as well ask you guys. Logged
The photos are deceiving. The screw connections on the boards are really small. They can handle maybe one 14 gauge wire max. for each. It's easier in the breadboard model to just strip the wires and stick them in the screw connectors.
Even when I put mine in a case, I continued to use the screw connectors on the boards.
steve
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Just curious what conditioner, everyday like the Belkin or high dollar?
I use an Audio Magic Nexus which is plugged into an UberBuss.
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jtwrace: I am looking forward to seeing your finished enclosure as well.
Me too! I'll post when it's done....
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I ordered a kit tonight. Despite the fact that I assembled a couple of Hafler DH-200 amps back in the late 70s, I'm feeling very daring and challenged about the prospect of actually making this work. I hope I know what I'm doing.
Oh well, I'm sure I've spent more money in worse ways in my past. Like the time I pissed away more than half a grand on an online real estate course. I couldn't read that crappy legal jibberish for more than twenty minutes without lapsing into a trance. Bad investment and I should have known myself better.
I've been resisting the temptation to purchase one of these amplifier kits as I avidly followed this thread. Tonight I reached a point where I could no longer ignore the impulse.
No need to worry. It's very simple to assemble and you have many peope willing to help.
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jtwrace:
The cap in question was .22 or .47uf. It's not critical, I think. I know nothing about electronics, so I took the advice of someone on AC.
You only need to separate the power lines, strip a bit of insulation off each one and attach a cap lead to the load and neutral sides. The arrangement is as if you were shorting the circuit. It seemed to me that there should have been a pop, a spark, a puff of smoke or ozone and no sound when I powered up, but it worked just like I was told.
The sonic result was that the amp had the punch and liveliness of the SMPS, but the smooth quality of a battery. That after I bought two SLAB's and a charger. For the price of a cap, a little electrician's tape and a lumpy power cord, I got better sound. Of course, YMMV, but if you don't like the result, you can just remove the cap and tape the wires.
Small investment for a really nice improvement.
Hope this helps.
Thanks. I'll have to check into this some more.
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Oh well, I'm sure I've spent more money in worse ways in my past
No worries on this one, it worth many times its price. :eyebrows:
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That's what I'm hoping, Nick. If all goes well, I intend to replace some pricer amps with these little guys. I went for the Sony HD tuner and the OPPO BDP-83 and I'm looking for other ways to take money out of my system without cutting out it's heart and soul. So far, so good.
If my big horns like this amp, I'll be buying at least one more.
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If all goes well, I intend to replace some pricer amps with these little guys. I went for the Sony HD tuner and the OPPO BDP-83 and I'm looking for other ways to take money out of my system without cutting out it's heart and soul.
That's exactly what I was trying to accomplish. After being out of work over a year, I was looking to extract some cash out of my system without giving anything up in sound. To my amazement, my system sounds much better now!
steve
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I don't really have the background or ability to figure things out in an amplifier. Therefore, I require clear instructions in common English. So my big concern lies in whether or not the instructions are as confusing as the web site. I just bought the amp Steve recommended because it was too difficult to compare apples to apples, and because I know where I can find a picture to follow in the opening of this thread.
What is the difference between an amp and a kit?
I have an actively bi-amped system using a Jeff Rowland Capri pre-amp into a dbx Drive Rack PA. The signal is split in there and frequencies above 400 Hz go through my Jeff Rowland 102 amp to the horns. Below 400 Hz is sent through a Perreaux PMF 1850 to 15 inch woofers in vented cabinets. I'm planning to try replacing the Perreaux with the ClassD. After that, who knows? My dbx has XLR connectors so using balanced cables to the amps would be a nice bonus. For that reason, the 600 watt amp looked kind of attractive but I really don't need that kind of power since my speakers are well above 90 db efficient.
Does anyone have suggestions as to a path I might consider? Any body want my tube amps?
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I don't really have the background or ability to figure things out in an amplifier. Therefore, I require clear instructions in common English. So my big concern lies in whether or not the instructions are as confusing as the web site. I just bought the amp Steve recommended because it was too difficult to compare apples to apples, and because I know where I can find a picture to follow in the opening of this thread.
What is the difference between an amp and a kit?
I have an actively bi-amped system using a Jeff Rowland Capri pre-amp into a dbx Drive Rack PA. The signal is split in there and frequencies above 400 Hz go through my Jeff Rowland 102 amp to the horns. Below 400 Hz is sent through a Perreaux PMF 1850 to 15 inch woofers in vented cabinets. I'm planning to try replacing the Perreaux with the ClassD. After that, who knows? My dbx has XLR connectors so using balanced cables to the amps would be a nice bonus. For that reason, the 600 watt amp looked kind of attractive but I really don't need that kind of power since my speakers are well above 90 db efficient.
Does anyone have suggestions as to a path I might consider? Any body want my tube amps?
Calm down.. :) If you can setup the dbx, I promise you'll have no issues. Again, if you do, we're here to help. Relax and smile lots! :D
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Setting up my dbx is like following the footprints on Arthur Murray's dance floor.
Do I sound like that much of a basket case? Will I make it through this ordeal without medication? Tune in next week and find the answers to these and other questions.
But, while we're on the subject, I have a hissing sound. It's quiet but it's impossible to overlook. My horns are rated 108db efficiency but I pad them down in the dbx to the level of my woofs, which I would estimate to be about 95 db. The sound is like what you hear when you put a seashell to your ear. What's the problem? How do I eliminate it? Fixing that would certainly make me smile.
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Do I sound like that much of a basket case?
Umm. :rotflmao:
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How would these do with a passive pre? Would they be driven well with a standard DAC output level?
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How would these do with a passive pre? Would they be driven well with a standard DAC output level?
I'm driving my 600w with a Tube Buffer (Dodd Audio) and it works great!
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Setting up my dbx is like following the footprints on Arthur Murray's dance floor.
Do I sound like that much of a basket case? Will I make it through this ordeal without medication? Tune in next week and find the answers to these and other questions.
But, while we're on the subject, I have a hissing sound. It's quiet but it's impossible to overlook. My horns are rated 108db efficiency but I pad them down in the dbx to the level of my woofs, which I would estimate to be about 95 db. The sound is like what you hear when you put a seashell to your ear. What's the problem? How do I eliminate it? Fixing that would certainly make me smile.
I am in the same boat related to doing the build but the guys in the thread have been real helpful in providing guidance :thumb:. I received the boards yesterday but still waiting for the transformers. I plan to wire up everything and take good close up pictures and post it. Want to make sure that everything is wired up correctly before I hook it up to any kind of power.
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If anyone gets a 600w version I've posted decent pics in this thread. I could certianly take more if needed. I'll will post pics when I have it in my case that will be available to all...
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Is the 600 watt amp the only one that can be run balanced?
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Send Tom an email. He's quite helpful.
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Out of curiosity, is anybody making their own power supplies for their Class D amp modules?
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Out of curiosity, is anybody making their own power supplies for their Class D amp modules? Logged
Not that I know of but I wouldn't think it would be difficult. It's a separate board with bridge rectifier and 6 electrolytic caps. Tom provides two different PS boards and a variety of toroids to meet his requirements.
steve
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I received the 250 W x 2 @ 4 ohm model yesterday and am pretty impressed with it, sonically.
There are a few issues that have been mentioned in the thread I can hopefully address:
How would these do with a passive pre? Would they be driven well with a standard DAC output level?
I run my system with DAC direct to amp, so I have some experience here. This setup works with a few caveats: The amp has a very low input impedance (something I asked Tom to which he never responded). I estimate it at ~ 3 k ohms. This means that your dac needs to have output caps ~ 6 uF or larger (6 uF puts the high pass at ~ 10 Hz and should have minimal effect on most music). Also, the amp's gain is a few dB lower than the spec Tom gave me (he said 34 dB, I measure closer to 31 dB). 31 dB is a little low for my tastes in a passive system. The gain is adjustable by changing resistors in the feedback circuit. Tom speced the 120 x 2 amp at 26 dB of gain in its stock configuration, which is too low for most passive systems. He can adjust the gain for you, but be sure to ask before you order.
I've seen much discussion on swapping the caps on the output filters. A few notes on this: This amp and the 120 x 2 are based on the IRS2092 (http://www.irf.com/technical-info/appnotes/an-1138.pdf) chip and is pretty similar to this amp (http://www.irf.com/technical-info/refdesigns/iraudamp7d.pdf) design. The caps being discussed are in the low pass filter and the zobel network --both caps are parallel to the loudspeaker. Since these are on the output of the amp, some special considerations need to be taken into account because you're dealing with RF rather than normal audio frequencies (see this article (http://www.audioholics.com/education/amplifier-technology/switching-amplifier-class-d-basics) for a nice primer on Class D and its peculiarities). The ideal caps for this position are low inductance (I've never seen an audiophile cap's inductance measured) with leads as short as possible. Low inductance is importance because at RF frequencies, caps act like inductors and inductors act like caps. So, the low pass filter become a high pass filter at RF frequencies if the parts aren't carefully chosen. Long leads hanging off the board are bad because the caps effectively become small FM antennae. Because of these issues, the best caps for these positions are radial polyester film caps.
Another note on the output filter cap: looking at the schematic, the output filter seems to be optimized for 4 ohm loads and is a bit too high Q for 8 ohm loads, leading to a rising response above ~ 5 kHz --verified by my own measurements. So, tweaking the value of the 0.47 uF cap might be in order.
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gitarretyp,
Thanks for the input. That input impedance is about the lowest I have every seen in an amplifier. Indeed, it would be important to make sure the output impedance of your preamp/dac isn't much higher than 300 ohms to work well.
The output filter cap is not something I was planning on fooling around with, as I was going to purchase a pair of the amp boards to build a sub amplifier, i.e. 500 watts/8 ohms and about 750 watts into 4 ohms (when each board is bridged).
Anand.
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Hi,
Knowing that the input impedance is very low on these amps, would a preamp or dac with an output impedance of 100 ohms work and not create a mismatch or loss of frequency extremes?
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Hi,
Knowing that the input impedance is very low on these amps, would a preamp or dac with an output impedance of 100 ohms work and not create a mismatch or loss of frequency extremes?
My tube buffer (Dodd) has an output impedance of 130 Ohms. No problem at all.
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My VTL5.5 has an output impedance of 200 ohms and they're a perfect match.
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Anything with an output impedance less than 300 ohms is certainly fine from an impedance matching standpoint. I would be more concerned with the size of the output coupling caps installed on most dacs/preamps producing a high pass filter in the audio band.
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I would be more concerned with the size of the output coupling caps installed on most dacs/preamps producing a high pass filter in the audio band.
Hmm. I'm not sure what you're getting out there. FWIW, I think I have better overall extension at both ends of the spectrum with the Class D amp than I had with my tube amps. I suppose that's a question for Tom. As far as impedance matching, my friend Mark uses a Conrad Johnson preamp with his Class D. The Connie has an output impedance of 800 ohms (above the 600 ohms recommended by Tom) and has no issues.
steve
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Hmm. I'm not sure what you're getting out there. FWIW, I think I have better overall extension at both ends of the spectrum with the Class D amp than I had with my tube amps. I suppose that's a question for Tom. As far as impedance matching, my friend Mark uses a Conrad Johnson preamp with his Class D. The Connie has an output impedance of 800 ohms (above the 600 ohms recommended by Tom) and has no issues.
steve
Here's a measurement of the amp driving my speakers (measure at the amp's output)
(http://www.audiocircle.com/image.php?id=26446)
(ignore the red and grey lines)
The green line is with ~ 6 uF caps on my DAC's output and the yellow line is ~ 3 uF. You might not notice the difference if your speakers don't have output below 40 Hz.
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Interesting. I'm biamping my speakers with the Class D on top so it could be that I haven't noticed any bass rolloff. I will know soon though as I'm going to try the 250wpc/8 ohms amp on the bass. My speakers go down to 32Hz +/-3dB. Has anyone else running their amps full range noticed a bass rolloff?
steve
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I have Magnepan MG12s and whether I use my sub or not, bass with the class Ds (full range mono blocs) goes deeper and is tighter than with my tube mono blocs.
Bob
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(Edit. . .ooops. . .misread your post regarding the caps and a DAC. . .so, stupid question :duh:)
The roll-off isn't significant--looks to be -3 dB @ 20 Hz worst case and -1 dB @ 20 Hz best case. However, would this concern those who do plan on using these for sub activities? Of course, EQ is a possible solution for those frequencies, after any room gain.
Again, I'm truly asking out of ignorance. Also, the high-end starts jumping up pretty good after 10 KHz. That can also be tamed with EQ (for those that go that route), but wouldn't this concern others? Regardless, it sounds like people love these damn things! :thumb:
Simply based on this thread, these amps have jumped to the top of my list for my future speaker purchase in a few months or so. I plan on going active with them and depending on configuration, will need at least 4, but possibly 6, channels of amplification. . .7, if I decide to replace the amp I currently have for my sub.
Thanks,
Paul
Here's a measurement of the amp driving my speakers (measure at the amp's output)
(http://www.audiocircle.com/image.php?id=26446)
(ignore the red and grey lines)
The green line is with ~ 3 uF caps on my DAC's output and the yellow line is ~ 6 uF. You might not notice the difference if your speakers don't have output below 40 Hz.
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Here's a measurement of the amp driving my speakers (measure at the amp's output)
(http://www.audiocircle.com/image.php?id=26446)
(ignore the red and grey lines)
The green line is with ~ 3 uF caps on my DAC's output and the yellow line is ~ 6 uF. You might not notice the difference if your speakers don't have output below 40 Hz.
Jason,
Did you mean the green line is for 6 uf and the yellow line is for 3 uf? The green line seems to be more extended in the low end to me :scratch: Given the minimal differences at 20Hz Paul, it wouldn't deter me from using this amp for sub bass duties.
And what is the dB level at 20kHz? Is that really +4dB? If so, tweaking that 0.47uf cap may be useful, let us know what you settle on.
Anand.
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Sorry, I switched the 6 and 3 (now corrected). 3 uF results in a first order high pass at ~ 18 Hz, and 6 uF is half that.
Yes, that really is +4 dB at 20 kHz. It's audible but mostly adds "air/spaciousness" and shimmer to cymbals that probably shouldn't be there, i.e., it's noticeable but not in a bad way. If you take a look at page 11 of this data sheet (http://www.irf.com/technical-info/refdesigns/iraudamp7d.pdf), you'll see that into an 8 ohm load the amp is ~ +2 dB at 20 k. I think the Nathan's are probably closer to 16 ohm at 20 k; thus, the more boosted top end.
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Jason,
Do an impedance plot on your Nathan's to be sure. The Abbey's are dead flat from 2Khz up to 20khz at about 10-12 ohms to be honest. Given that they both have the same tweeter and stem from the same philosophy, I wouldn't think the Nathan's should be any different. Still, the top end will be a little boosted.
Anand.
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Can someone take additional pictures and post please. I received the transformer today and started to put it together and ran into a snag right away.
Here is what I have done so far:
1) Took the center blue/green cables and connected it up to CT (on the powersupply board.
2) Connected the outside blue wire to AC-N
3) Connected the outside green wire to AC-L
Now the big question. There are two brown wires coming out of the transformer and I do not see any documentation on where to connect it up. Same question related to the two red and black wires.
Close up pictures of the amp to powersupply connections would be much apprericiated.
TIA,
Deepak
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Email Tom. He's there now, I just heard from him.
steve
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E-mailing Tom is probably your best bet, however, if you can:
Give us the model number of the Antek transformer you are using.
Most likely the brown wires are additional 12V secondaries which may or may not be used (i.e. they can just be tied off if not used).
The red and black wires are primary wires. Tie the reds together and connect it to AC live or HOT (with a fuse and switch in series). Tie the blacks together and that is connected to AC neutral. This is only for a 115V/120V North American connection. If you live overseas, where there is 220VAC then see schematic below.
See schematic for 115V AC here (http://classdaudio.com/documents/transformer_115VAC_instructions.pdf).
See schematic for 220V AC here (http://classdaudio.com/documents/transformer_230VAC_instructions.pdf)
Best,
Anand.
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You kids have captured my interest. As I pursue the right amp to power my passive HT sub, I keep coming back to this thread...
I have emailed Tom some questions, I might find myself building a mono sub amp in the near future, if I can sort out which is the right option for me.
Considering Pro Audio amps too, for my install, so not 100% sure of direction at this point.
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Now the big question. There are two brown wires coming out of the transformer and I do not see any documentation on where to connect it up. Same question related to the two red and black wires.
Close up pictures of the amp to powersupply connections would be much apprericiated.
TIA,
Deepak
I'm guessing you ordered one of the kits with an upgraded transformer? If so, the brown wires are extra 18 V secondaries and should be tied off, as Anand suggested.
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You kids have captured my interest. As I pursue the right amp to power my passive HT sub, I keep coming back to this thread...
I have emailed Tom some questions, I might find myself building a mono sub amp in the near future, if I can sort out which is the right option for me.
Considering Pro Audio amps too, for my install, so not 100% sure of direction at this point.
Honestly, I think it's really tough to beat pro amps for subwoofer applications.
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As I pursue the right amp to power my passive HT sub
Interesting timing. Tom has been tweaking his 250wpc/8 ohm amp for me to run my bass panels which are 4 ohm. He designed a larger heat sink to dissipate the heat without using a cooling fan. To test it, he ran a passive sub on each channel all weekend at loud volumes. He claims it works fine. The mosfets he's using don't double at 4 ohms but this amp might be an option for you.
What's funny is I liked my Hafler DH-500 on the bass panels until I got Tom's 120 wpc amp for my mid panels and ribbons and it's so quiet, I really notice the fan noise on the Hafler now. So this might be the ticket. More later.
steve
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Thanks Guys. Heard back from Tom and here is what he had to say:
"The brown wires are extra 12V wires… not used for this kit, but can come in handy if you ever want to use it for a small preamp power supply or?
Just tape off the brown wires.
The two red get tied together, and the two black wires get tied together… this is for 115VAC here is the USA.
Make sure the two wires that go to CT are the green and blue from the center of the four wires."
I ended up purchasing the following kit which includes a 400VA transformer: http://classdaudio.com/index.php/class-d-amplifier-kits/home-kits/250w-x2-500w-x1-amp-large-power-supply-transformer.html
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That's the same model I decided to go with, and I was considering using the extra secondary taps for something along those lines --building a buffer, such as the Pass B1, into the amp could be a fun project.
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Just ordered another amp... 250 x 2. Curious to hear that one compared to the 300 x 2.
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Just ordered another amp... 250 x 2. Curious to hear that one compared to the 300 x 2.
Cool! It should be interesting to hear first hand a comparison between the TI chip and the IR chip. Mine is on the way too. Should be biamping with 2 Class D's this weekend. Woohoo! :dance:
steve
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Very well! Should have it finalized early next week.
Any updates on this? Although I probably won't get the amps for a couple more months, if there is a group buy on these cases, I would likely be in for 2. :thumb:
Paul
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Any updates on this? Although I probably won't get the amps for a couple more months, if there is a group buy on these cases, I would likely be in for 2. :thumb:
Paul
No updates yet...I'll post pics when they are done. Probably a couple of weeks at least. I'll be sure to keep everyone updated once I have more info.
:thumb:
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Can someone tell me what size fuse to use with the 250 x 2 amp?
Thanks,
Jeff
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Jeff, somewhere I saw that a 6 amp slow blow was recommended.
That's second hand information, though, not direct from Tom.
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Following the thread with interest, never did an amp build, but what the hey.
Does anybody know the dimensions of the amp and supply board, and the diameter and height of the 400va trans, looking to get a head start on the chassis.
Went with the $325 500wx2 kit.
Thanks
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Went with the $325 500wx2 kit.
Thanks
What speakers are you driving that you need that much power?
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I have a large room and a hunger for power. I have tried the PS Audio/ Bel Canto 120w and 500w and prefer the 500w sound, maybe the headroom, I don't know. I roll speakers in and out, so from 87db to 95db efficiency.
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I have a large room and a hunger for power. I have tried the PS Audio/ Bel Canto 120w and 500w and prefer the 500w sound, maybe the headroom, I don't know. I roll speakers in and out, so from 87db to 95db efficiency.
Cool. :green:
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Just a thought...Those of you who've tried Tom's amps now and like them might want to drop a quick review of them on his website.
I'm still waiting for my 250/8 ohm model. Some parts got delayed by the weather if you can imagine that. :lol: Can't wait to get all Class D on my maggies. :dance:
steve
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I received a box from Class D in today's mail. Should I open it?
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I received a box from Class D in today's mail. Should I open it?
no, it might explode - better send it to me, where i can get my buddies at the dept of state to check it out first. :green:
doug s.
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O.K. Doug. Go wait by the mail box until it's delivered. Be patient because the weather has slowed the mail down somewhat. Thanks for being such a buddy.
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I am afraid that "Open Sesame" just won't do it.
(have fun)(http://www.freesmileys.org/smileys/smiley-char078.gif) (http://www.freesmileys.org/smileys.php)
Mariusz :thumb:
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Guys i replaced my Volex power cord on my 120amp with a very good diy cord. It has taken the amp to another level. I now have a level of detail and transparency that is certainly making me think twice about messing with any caps. These things seem to respond favorably to a good power cord. :eyebrows:
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Guys i replaced my Volex power cord on my 120amp with a very good diy cord. It has taken the amp to another level. I now have a level of detail and transparency that is certainly making me think twice about messing with any caps. These things seem to respond favorably to a good power cord. :eyebrows:
I noticed that the amp responded well to my power conditioner. Just think it's wise to make sure the power cord doesn't cost 3x of what the amp does. :green:
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I have the 250WX2 amp with the IR chip, and it is extremely responsive to changes (the pics earlier in the thread w/ the cap mods are from my board). I've changed the power cord, fuse and fuse holder (both can be had good and cheap from Acme) as well and all have clear effects. More so than w/ my previous amps. 8)
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I finally got everything hooked up and when I plug the power in the plastic wrapper around the transformer is starting to melt? Is that suppose to happen or did I just fry something? Currently, the way that I have everything hooked up is with a two prong plug. The left prong where the blade is wider is connected to the red wires on the transformers and the narrower prong is connected to the the black. Do I potentially have the wires flipped and that is the reason for the plastic melting.
I already sent Tom a message but I figure I will try here also.
Thanks
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I finally got everything hooked up and when I plug the power in the plastic wrapper around the transformer is starting to melt? Is that suppose to happen or did I just fry something? Currently, the way that I have everything hooked up is with a two prong plug. The left prong where the blade is wider is connected to the red wires on the transformers and the narrower prong is connected to the the black. Do I potentially have the wires flipped and that is the reason for the plastic melting.
I already sent Tom a message but I figure I will try here also.
Thanks
NOT suppose to work that way. How is the transformer wired to the power board? The blue and green wires? The red and black wires can be used with a two prong plug...the black wire goes to the brass screw.
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I finally got everything hooked up and when I plug the power in the plastic wrapper around the transformer is starting to melt? Is that suppose to happen or did I just fry something? Currently, the way that I have everything hooked up is with a two prong plug. The left prong where the blade is wider is connected to the red wires on the transformers and the narrower prong is connected to the the black. Do I potentially have the wires flipped and that is the reason for the plastic melting.
I already sent Tom a message but I figure I will try here also.
Thanks
you definitely have the transformer mis-wired. it may or may not still be ok, depending on how long it was plugged in. i can't tell you the right way to wire it, but i know what happens when you wire it wrong... :|
doug s.
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The blue and green wire that are CLOSEST to each other coming off the tranny should be wired together to the center terminal. You probably have the other blue and green wired together. I did the same thing.
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you definitely have the transformer mis-wired. it may or may not still be ok, depending on how long it was plugged in. i can't tell you the right way to wire it, but i know what happens when you wire it wrong... :|
doug s.
Less than 20 seconds is how long I had it connected.
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Less than 20 seconds is how long I had it connected.
re-wire it correctly, (per steve k's instructions?), and it will hopefully still be ok...
doug s.
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The blue and green wire that are CLOSEST to each other coming off the tranny should be wired together to the center terminal. You probably have the other blue and green wired together. I did the same thing.
have the two center wires plugged into the ct, the outside wire is plugged into the ac-n and the outside green wire is plugged into to ac-l. tom responded requesting pictures which i forwarded to him.
(http://www.audiocircle.com/image.php?id=26651)
(http://www.audiocircle.com/image.php?id=26652)
Just talked to Tom and he said everything is wired correctly and he thinks that there is a sort in the transformer. He is shipping out a new one on Monday.
EDIT: The amp board (amber/yellow) and the power supply led's (blue) were on when I powered up the amp, which is what led Tom to believe there might be short in the tranny.
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From the pics, it looks correct. It makes sense that if the lights were on, it was correct. Tom will take care of it...
Let us know how you make out when you get the new tranny.
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From the pics, it looks correct. It makes sense that if the lights were on, it was correct. Tom will take care of it...
Let us know how you make out when you get the new tranny.
Yep, he is shipping a new tranny on Monday. I will most likely get it Thursday, since I am in NJ and Antek is in NJ also :thumb:
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Yep, he is shipping a new tranny on Monday. I will most likely get it Thursday, since I am in NJ and Antek is in NJ also :thumb:
If it ships from NJ on Monday you might have it Tuesday...Wednesday at the latest.
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If it ships from NJ on Monday you might have it Tuesday...Wednesday at the latest.
My trans came direct from Antek cause he was out of stock, maybe you should shoot him an email.
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I think Antek ships direct to everyone..
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I think Antek ships direct to everyone..
Lol...... I thought normally the tranny came in the same box with amp kit. :duh:
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If it ships from NJ on Monday you might have it Tuesday...Wednesday at the latest.
If it arrives on Tuesday or Thursday, it really does not matter since I am not going to get a chance to work on it until the weekend :x
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If it arrives on Tuesday or Thursday, it really does not matter since I am not going to get a chance to work on it until the weekend :x
Gotcha! Let us know how it goes
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Just for kicks, I'll be taking my new 250/8 ohm amp over to a friend's house next weekend to compare it with a Wyred4Sound STI-500 Integrated on his Maggie 1.6's. The WFS has pre-outs so we can actually compare amp to amp sound. He has the WFS in for a review for Positive-Feedback. This should be fun. :green:
steve
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Steve!
I look very forward to hearing about that! :thumb: The Wyred unit has received a lot of praise for being inexpensive and great sounding, but honestly, I still think it is expensive. Besides they have to pay a distributor markup!
So the Class D/250 watt versus the Wyred for Sound STI-500 comparison should be real interesting.
Try to match up gains, etc...so you don't get easily biased.
Anand.
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Yes we'll match gains and play the same tracks. I'm interested to see how the little guy stands up to the W4S. The W4S uses a switching power supply too so it'll be interesting if we hear any difference because of that.
steve
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Great Steve - I'll be anxiously waiting to hear your findings as I am going to purchase either a W4S or the 1000 watt class d audio kit.
Yes we'll match gains and play the same tracks. I'm interested to see how the little guy stands up to the W4S. The W4S uses a switching power supply too so it'll be interesting if we hear any difference because of that.
steve
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Just for kicks, I'll be taking my new 250/8 ohm amp over to a friend's house next weekend to compare it with a Wyred4Sound STI-500 Integrated on his Maggie 1.6's. The WFS has pre-outs so we can actually compare amp to amp sound. He has the WFS in for a review for Positive-Feedback. This should be fun. :green:
steve
Steve have you compared the 250 to the 120 yet?
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No I don't have it yet. I should get it this week.
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No updates yet...I'll post pics when they are done. Probably a couple of weeks at least. I'll be sure to keep everyone updated once I have more info.
:thumb:
jwtrace, do you have thoughts on external dimensions as well as which of the kits the enclosure will support?
Thanks,
Jim
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jwtrace, do you have thoughts on external dimensions as well as which kits the enclosure will support?
Thanks,
Jim
External dimensions should be about 12.25" wide x 16.25" deep x 3.75" high. It will fit all the Class D Audio kits. I'll post more info when I have the prototype complete.
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External dimensions should be about 12.25" wide x 16.25" deep x 3.75" high. It will fit all the Class D Audio kits. I'll post more info when I have the prototype complete.
Any idea on the cost?
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Any idea on the cost?
Should be at $175. It will be an aluminum black anodized case. All holes punched. I'll post pics when I have the prototype.
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I ordered a 250x2 kit as well ... found a couple Avel transformers when I moved recently and need to use them for something. I'll compare mine with the ICE 1000ASP based amps that Chris (BPT) modded, and have been my reference for some time. It should be an interesting comparison. I also have some Teflon V-Caps and Mundorf Silver/Oil/Gold caps that would be great to try in the output section. I can say that for sure when we added the V-Caps to the ICE amp it made a significant improvement.
But I'll start with a stock comparison and get used to it that way before doing any mods.
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Should be at $175. It will be an aluminum black anodized case. All holes punched. I'll post pics when I have the prototype.
Including the 4 channel kits, or just 2 channels?
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Including the 4 channel kits, or just 2 channels?
Really the 2ch but you could make it a 4ch if you are creative...The case will fit the tranny, two amp boards and power filter. You'll just have to configure the inputs / outputs to your liking.
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hey,
will the case have holes in it for xlr connectors?
thanks
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hey,
will the case have holes in it for xlr connectors?
thanks
Sure will.
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External dimensions should be about 12.25" wide x 16.25" deep x 3.75" high. It will fit all the Class D Audio kits. I'll post more info when I have the prototype complete.
Very cool. Sounds like it will be a hit!
-Jim
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Has anyone had a chance to compare this amp to one of the Peachtree Audio amps, the Nova or Decco 2? I realize that everyone is comparing these to much more expensive units, but this seems to be to be a rational comparison since the both utilize class D amplification in a similar wattage and price range.
Thanks,
Ed
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Steve!
I look very forward to hearing about that! :thumb: The Wyred unit has received a lot of praise for being inexpensive and great sounding, but honestly, I still think it is expensive. Besides they have to pay a distributor markup!
Anand.
Hi-
I'm also interested in the comparison as I was thinking of buying the WFS 2X500.
BTW, Wyred has one distributor, but you can buy directly from them at their web site. They specifically claim that's one way they keep the price down - not having a distributor/retail chain to support.
Danny
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Thanks for the reply on the xlr holes.
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Thanks for the reply on the xlr holes.
You're welcome.
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Just finished my 250 x 2. Breaking in - amp sounds sweet!
Jeff
(http://www.audiocircle.com/image.php?id=26751)
(http://www.audiocircle.com/image.php?id=26752)
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Nice and clean Jeff. I am itching to finish mine soon.
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Very nice, Jeff. How about a look under the hood?
steve
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Really the 2ch but you could make it a 4ch if you are creative...The case will fit the tranny, two amp boards and power filter. You'll just have to configure the inputs / outputs to your liking.
Any further insight regarding the "if you are creative" part? I would want this amp for my future speakers, which I plan on going active with. If the biggest IR Class D amp is suitable enough to fit the bill with just one PS and tranny, I would just dump it all into one chassis. Would save a nice chunk of change, as I would go without the 2nd case, PS and tranny. . but would therefore like 4 RCA input and 4 binding post punchouts.
Thanks,
Paul
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Any further insight regarding the "if you are creative" part? I would want this amp for my future speakers, which I plan on going active with. If the biggest IR Class D amp is suitable enough to fit the bill with just one PS and tranny, I would just dump it all into one chassis. Would save a nice chunk of change, as I would go without the 2nd case, PS and tranny. . but would therefore like 4 RCA input and 4 binding post punchouts.
see mine here: http://www.diyaudio.com/forums/class-d/87913-class-d-amp-photo-gallery-18.html#post2011069
I just drilled the holes where I wanted them in the chassis and filed the edges to make square ones for the switch and power connector. These amps are great.
- Doug
-
Thanks, Doug. What size drill bit do you need for the RCAs? If different, what do you need for the binding posts?
jtwrace,
Please don't take this the wrong way, but with some of the posts I've seen regarding cases, why is the one you're going to be working on estimated to be $175? How much of the cost is to have those punchouts? I've seen some pretty nice ones for a lot cheaper.
Paul
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Thanks, Doug. What size drill bit do you need for the RCAs? If different, what do you need for the binding posts?
jtwrace,
Please don't take this the wrong way, but with some of the posts I've seen regarding cases, why is the one you're going to be working on estimated to be $175? How much of the cost is to have those punchouts? I've seen some pretty nice ones for a lot cheaper.
Paul
Ughhh...jtwrace I wouldn't even bother answering this. Its a CUSTOM enclosure. The ones on eBay are, of couse, NOT custom. CUSTOM = $$$.
I'm stoked for your enclosure, jtwrace.
-Jim
-
I'm not trying to step on his toes. . . just wanted some clarification / more details. Truly sorry if it came off the wrong way. :oops: Didn't realize they were totally custom. Had thought it was an off-the-shelf enclosure with punchouts made for this amp.
There's a very good chance I'll be getting his enclosure. :thumb:
All apologies.
Paul
-
Ughhh...jtwrace I wouldn't even bother answering this. Its a CUSTOM enclosure. The ones on eBay are, of couse, NOT custom. CUSTOM = $$$.
I'm stoked for your enclosure, jtwrace.
-Jim
Thanks Jim! It sure is totally custom.
-
I'm not trying to step on his toes. . . just wanted some clarification / more details. Truly sorry if it came off the wrong way. :oops: Didn't realize they were totally custom. Had thought it was an off-the-shelf enclosure with punchouts made for this amp.
There's a very good chance I'll be getting his enclosure. :thumb:
All apologies.
Paul
No problem. I understand that some will like and some will not. Yes, I designed these from scratch. I was trying to hold off on the fine details until the prototype was complete and I could post pictures. The holes are all there for ALL the Class D Audio amps. XLR / RCA inputs, IEC, main power switch and speaker binding posts. The top cover will be vented as well. I will post pics when I have the prototype and also have a recommended parts list with part #'s / suppliers for the few items that will be needed (XLR, RCA, IEC, binding posts....).
-
my future speakers, which I plan on going active with.
Thanks,
Paul
Ahh. That's my next plan....maybe.
-
No problem. I understand that some will like and some will not. Yes, I designed these from scratch. I was trying to hold off on the fine details until the prototype was complete and I could post pictures. The holes are all there for ALL the Class D Audio amps. XLR / RCA inputs, IEC, main power switch and speaker binding posts. The top cover will be vented as well. I will post pics when I have the prototype and also have a recommended parts list with part #'s / suppliers for the few items that will be needed (XLR, RCA, IEC, binding posts....).
Thanks! I will hold all further questions and comments until I see the pics. :oops: Looking forward to it. :thumb:
Paul
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Thanks, Doug. What size drill bit do you need for the RCAs? If different, what do you need for the binding posts?
That will depend on your actual connectors I think mine were ~1/4" and 3/8" (I used a drill press + whatever size drill was most appropriate). I used insulated connectors so the signal ground is not connected to the case (but the case is still grounded to the house electrical ground). This way there is no possibility for ground loops (I am using a DCX2496 to drive the amps with XLR-to-RCA connectors).
I was originally going to go for a custom case (Front Panel or Modu) but decided against it once I priced them out. What I ended up with cost around ~$160 for the case + connectors + wire, etc. So at ~$485, total, it was not exactly cheap - but that's still only ~$120 per channel.
-
Ordered the following yesterday, hoping they get here before the weekend:
RCA Connector - http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=350197324175&ssPageName=STRK:MEWNX:IT
IEC Power - http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200435755054&ssPageName=STRK:MEWNX:IT
Case - http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250501444095&ssPageName=STRK:MEWNX:IT
Binding Post: http://cgi.ebay.com/20-Pcs-GOLD-RCA-CONNECTOR-FEMALE-CHASSIS-SOCKET-CRADLE_W0QQitemZ320510873543QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item4a9fefcfc7
Edit: Added updated binding post info
-
Ordered the following yesterday, hoping they get here before the weekend:
RCA Connector - http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=350197324175&ssPageName=STRK:MEWNX:IT
IEC Power - http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200435755054&ssPageName=STRK:MEWNX:IT
Case - http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250501444095&ssPageName=STRK:MEWNX:IT
What are you using for binding posts?
-
What are you using for binding posts?
I picked up http://www.radioshack.com/product/index.jsp?productId=2102838 from Radioshack. I picked up the rca connectors also from Radioshack but they do not have the plastic/rubber (http://www.radioshack.com/product/index.jsp?productId=2103234#) washers and that seems to be a no-no with potential hazard.
Updated the original post with binding post info.
-
Well, you guys talked me into it. I received my 120W@4 ohms amp today. It appears to be very well built. I have it running directly from my Havana DAC which is 800 ohms out, not ideal but seems to work well in spite of that issue. Initially I thought it sounded a little ragged but that has cleared up somewhat in the last 2 hours. I believe I read that Tom recommended about 100 hours on it prior to doing any critical listening, so I will. It is definitely case worthy so I will be building a case similar to what Bob did, sizing it to match the Dodd buffer as closely as I can from a width standpoint. More after it has burned in.
Best,
Ed
-
FWIW, I've been listening to my Classdaudio amp w/ a B1 Buffer for the past few days (I also lowered the buffer impedance output from stock 1k to 330). I did an A/B with and without and no doubt the amp benefits a couple notches from the buffer.
-
Update on my 120W amp. Much better :thumb:. I was hearing a lttle raggedness early on, I have since disconnected the sub amp from the speaker ckts out of the ClassD unit, much better, smoother and clean. Very musical, nice amp!
Best,
Ed
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I have a tiny bit of hum or buzz when I put my ear up to the speakers.
Are there any rules on internal cable lengths or routing I have to be mindful of?
***Edit: re-routing the input lines solved the problem.
Jeff
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I kept all my leads as short as possible mainly cause i was short on wire. hehe
But i have the darkest background i have ever experienced. :green:
-
I thought I would be receiving my new 120 wpc amp kit today, but it looks like Monday will be the day. You guys got me excited. I'm really looking forward to putting it all together and hearing what it might sound like in my system. I've even thought about getting another and taking a crack at building a couple of OB subs. I'll probably need help with that project, though. Anybody willing to give advice on this?
-
Hey congrats on the amp, another Austinite :eyebrows:
Are you still running the RW Audio amp? Look forward to your impressions.
-
This was asked awhile ago and I didn't see an answer: Are there any upgraded PS for this floating around out there? I'm not talking about modded ones. Just curious.
Has anyone talked to Paul Hynes, Wayne, or anyone else about one?
Thanks!
Paul
-
BEHOLD THE 500WX2
(http://www.audiocircle.com/image.php?id=26954)
(http://www.audiocircle.com/image.php?id=26955)
(http://www.audiocircle.com/image.php?id=26956)
(http://www.audiocircle.com/image.php?id=26957)
(http://www.audiocircle.com/image.php?id=26958)
The binding posts, RCA, and XLR adapters from Parts Express, IEC from the ebay ad others are purchasing from, Oak sides and front, 3/8" bottom and back.
$400 total with everything.
Looking to replace my PS Audio 120w ICE amps. So far more powerful, of course, but letting the tones break in before I give an overall opinion. Quite easy to wire up, case is what you make of it. Buying a metal case would have been easier, I'm sure but the oak wood has a beautifuldark character to it that matches my wlanut flooring nicely without being to dark.
Will be getting a second to biamp my speakers, then :drums: :guitar: :rock: :flame: :uzi: :weights: :guns: :guns:
:icon_twisted:
I will post as the week goes on and give my opinions against the PS Audios.
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Nice work! Thats alot a power, what are you driving. :drool:
-
BEHOLD THE 500WX2
Cool. I plan on getting this kit, but going the 4 channel route with it.
Paul
-
Thanks
I am driving Emerald Physics CS2 right now, I love power.
I like the idea of the 4-channel ability as well. More bass than the PSA, of course, and the highs are not out of line and should get better. :green:
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What pre are you using? I looked at your system and you have the Boston Acoustics receiver listed under "Preamp," but used for HT duties.
Paul
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Im sure he's using the Camelot Uther as a pre.
-
Hey congrats on the amp, another Austinite :eyebrows:
Are you still running the RW Audio amp? Look forward to your impressions.
Yep, still with the RWA Sig 30. I've seen no reason to change it out. However, I do wonder what might happen if more power was available. I'll definitely check back in with impressions.
-
The Camelot Uther it is, seems to mate nicely.
-
...seems to mate nicely.
with anything in my experience.
-
That's great to hear. My pre will be a Peachtree Nova. This is from the SignalPath website: 'Outputs: If you want to add a subwoofer or outboard amplifier, the Nova features a “Class A” <30 ohm variable preamp-output that will impedance match to almost any amplifier while pushing up to 100 ft of cable.'
Paul
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The Camelot Uther it is, seems to mate nicely.
Sweet! But i was wondering what speakers needed all that power? :eyebrows:
-
Would there be an easy way to have an option to make the kits with 2 amp modules be able to go from 4 channels to 2 channels bridged? I want to make my amp as flexible as possible.
Paul
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Sure. You'd just need swap a couple of external cables and a DPDT switch in place of the on board jumpers.
-
Here is a view into the inside of my build.
I plan to add another board shortly.
I think I will change the layout and put the amp boards
in the back and the PS in the front. However, at this point the
amp is dead quiet.
Jeff
(http://www.audiocircle.com/image.php?id=26981)
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I think I will change the layout and put the amp boards in the back and the PS in the front.
Funny, I looked at the photo before I read your description and that was my thought... as a means to keep the signal wires as short as possible.
Nice work!
-
JKelly - nice build.
Does anyone have any comparisons ready - Wyred 4 Sound or other?
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The Class D Audio 250 meets the Wyred4Sound STI-500 integrated amp.
Yesterday Kent J. hosted an amp comparison with my new modified Class D Audio 250 amp to compare it to the Wyred4Sound STI-500 integrated amp he has in for review. Both produce 250 wpc into 8 ohms. The W4S produces 500 wpc in 4 ohms while the Class D's Mosfets don't quite double down. We listened to the W4S first on his stock Maggie 1.6's and using his new Sony XA5400ES multiplayer which has a very nice internal DAC btw. We listened mainly to redbook CD's.
As a good comparison, we then listened to the Class D (dBop as I call it) using the W4S's internal preamp. After a couple hours or so of this setup we switched to Kent's Dodd tube pre with the dBop.
There were three of us GASSERS who witnessed: Kent, Mark and myself. The overall consensus was the dBop sounded better. As Mark said, "It (the W4S) had better bass when used as an integrated, but it didn't match your amp's smoothness and musicality." Kent felt like the dBop was simply easier to listen to.
To me the W4S sounded more "electronic". It called more attention to itself and how it was reproducing the music. The highs were grainier, the mids weren't as warm and musical as the dBop's. The bass was about equal to me. The W4S produced fast tight bass with excellent control over the maggie's bass panels as did the dBop. With the W4S, however, I kept noticing things like a tad of sibilance on vocals or a bit of grittiness on cymbals--things that caught my attention that I don't hear in my system.
The dBop OTOH just seemed to get out of the way of the music and disappear. The sound was more natural, liquid and organic to the point that you quickly forgot about focusing on what the amp was doing and just immersed yourself in the music. I also noticed the soundstage to be a bit wider with the dBop to my ears.
As I said earlier, I'm a tube guy and adding some tubes into the mix with the dBop is the best way to go IMO. Running the dBop with the Dodd preamp took the sound up another notch. The sound was a tad fuller and richer with better instrumental timbers (all the things tubes do so well) without being overly euphonic or plump. The soundstage was a bit denser and wider.
Overall it was a fun session for all of us. I will say the W4S is extremely well built. The fit and finish was top knotch and it's built like a tank. I like the no-nonsense contemporary design and the phase flip function on the remote was interesting to play with. Mark was particularly emamored with that button. :lol:
We listened mostly to acoustic music. Some of the tunes that I can remember were:
Tierney Sutton: Something Cool
KD Lang: Hymns of the 49th Parallel
Miles Davis: Someday My Prince Will Come Remastered
Palle Daniellson: Opening
Brian Bromberg: Wood
Jacques Loussier Trio: The Four Seasons
Rob Wasserman: various
Fiona Apple: Extraordinary Machine
The Corrs: Live in Dublin
unfortunately, we neglected to play some Julie London, who watched over the entire session. :eyebrows:
steve :thumb:
(http://www.audiocircle.com/image.php?id=27000)
Kent and Mark
(http://www.audiocircle.com/image.php?id=26997)
Mark channels Tierney Sutton
(http://www.audiocircle.com/image.php?id=27004)
W4S on the medal podium as Julie looks on.
(http://www.audiocircle.com/image.php?id=27001)
Running hte dBop through the W4S's preamp
(http://www.audiocircle.com/image.php?id=27002)
the dBop on the medal stand
(http://www.audiocircle.com/image.php?id=27003)
My amp with the supercharged heatsink. Funky speaker connections huh??? :o
(http://www.audiocircle.com/image.php?id=26998)
Kent's rack
(http://www.audiocircle.com/image.php?id=26999)
The Dodd and Sony
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Thanks for the report Steve. Are you able to comment on how the 120 sounds vs. the 250?
Best,
Ed
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I didn't bring it. Didn't seem fair to compare and amp half the power. Now that I have both in my system though, they definitely have very much the same sonic character.
-
Thanks Steve - the dbops look like a winner, as the W4S amps are highly regarded.
Thanks for sharing!
-
I didn't bring it. Didn't seem fair to compare and amp half the power. Now that I have both in my system though, they definitely have very much the same sonic character.
Thanks Steve. Fair enough, I wouldn't expect the 120 to keep up with the 250, especialy at higher demands. I thought you may have driven your Maggies with both of them and could offer an opinion from that experience.
Thank again,
Ed
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Yes, thanks for taking the time to post, and for the pics. While looking at your amp-on-a-board, it occurs to me that one might place a cage over the top in a nice glossy black and have a nice amp. No need to enclose it in a box. I think I'm getting an idea! :eyebrows:
-
Thanks, Steve! :thumb:
Regarding the heatsinks, do you know if Tom is going to make that a regular option or will it be standard? How much of a price increase?
Thanks,
Paul
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Yes, thanks for taking the time to post, and for the pics. While looking at your amp-on-a-board, it occurs to me that one might place a cage over the top in a nice glossy black and have a nice amp. No need to enclose it in a box. I think I'm getting an idea!
I'll tell you one thing, if you use a cage, the PS blue LEDS will act as a lamp in your room. These things are like zenon headlights. :thumb: If you stare directly down into them for any length of time, you will be permanently blinded! :o
I'd like to see your cage idea
steve
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I thought you may have driven your Maggies with both of them and could offer an opinion from that experience.
I did but the way I have mine wired I can only biamp them. I did switch them around (120 on bass 250 on top) and other than the difference in bottom end impact, the sonic character was identical.
-
Regarding the heatsinks, do you know if Tom is going to make that a regular option or will it be standard?
Paul,
Tom added the additional heat sink material because I wanted to run the 250 watt/8 ohm amp into a 4 ohm load. My maggie bass panels are a tough load. He said the amp could do it, he just needed to dissipate the additional heat. After experimenting with additional heatsink bars, he ran this amp with two passive 4 ohm subs without a problem. The amp actually runs moderately warm under loud conditions. NO additional charge. I don't know if he's going to make this standard or not. Now that he's solved the problem though, it makes sense to make them all this way. You should ask him.
steve
-
Thanks again!
-
I'll tell you one thing, if you use a cage, the PS blue LEDS will act as a lamp in your room. These things are like zenon headlights. If you stare directly down into them for any length of time, you will be permanently blinded!
I have several components with blue LEDs, and anyone of them can perform Lasix eye surgery for free.
The wavelength is wrong for the human eye, they are all too bright, and all manufacturers who continue to use them need to be slapped.
Death to blue LEDs!
Steve
-
Death to blue LEDs!
I agree. I like it dark when I listen and they are so damn bright! I've been known to resort to a small piece of electrical tape as a temporary fix.
-
I did but the way I have mine wired I can only biamp them. I did switch them around (120 on bass 250 on top) and other than the difference in bottom end impact, the sonic character was identical.
Thanks Steve ! :thumb:
I am enjoying my 120 right now. Thanks for bringing this amp to our attention.
Best,
Ed
-
I agree. I like it dark when I listen and they are so damn bright! I've been known to resort to a small piece of electrical tape as a temporary fix.
To cut Class D Audio some slack, his LEDs were never intended to be seen, and only the concept of a cage enclosure (or plexiglass or glass) would expose their evil hearts.
But to the rest of the manufacturers who put them on a front panel - you're officially on notice!
Just take these blue buggers off the market.
Steve
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Steve K - thanks for the report - very informative and helpful.
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I been watching this post for 1 1/2 weeks and have decided
to give one a try. I might be asking some questions from time to time and I have not a clue
at times what you people are talking about but it looks like fun so please be patient. I have
dismantled an old NAD tuner that was dead and will use the carcass for the encloser, cost
was $8.00 at Salvation Army add apiece of oak or maple to front should look OK
(http://www.audiocircle.com/image.php?id=27021)
(http://www.audiocircle.com/image.php?id=27022)
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Welcome all lurkers. Don't worry, we don't know what we're talking about either! :thumb: As many times as I've read how this amp works, I couldn't begin to explain it to someone else. :scratch:
steve
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I've been lurking here since the beginning of this thread. Now, I feel compelled to buy one of these amps. So, I've got to find a suitable pre (tubed?) to drive it. Does anyone have a specific recommendation? I mean, is there some particuar electronic characteristic of the "dBop" that causes it to sound better with some particular kind of pre. :scratch:
I've already been told by a well-informed person that using my passive pre is possible, but it would entail more futzing than I want to do.
-
I just picked a Mod Squad Line Drive passive that I plan to try it with
-
I've been lurking here since the beginning of this thread. Now, I feel compelled to buy one of these amps. So, I've got to find a suitable pre (tubed?) to drive it. Does anyone have a specific recommendation? I mean, is there some particuar electronic characteristic of the "dBop" that causes it to sound better with some particular kind of pre. :scratch:
I've already been told by a well-informed person that using my passive pre is possible, but it would entail more futzing than I want to do.
I'm sure there are a zillion recommendations for preamps but I still recommend the Nelson Pass B1 Buffer. It's extremely easy to build, others report performance easily surpassing their >$1k pre's (Enjoy the Music had it more or less tied w/ an $18k pre. http://www.enjoythemusic.com/Magazine/equipment/0708/first_watt_b1_preamplifier.htm (http://www.enjoythemusic.com/Magazine/equipment/0708/first_watt_b1_preamplifier.htm) Sheesh, not bad for $80 in parts.
http://www.passdiy.com/order.htm
Most importantly you can make the output impedance extremely low to match the Class D Audio amps. After A/Bing with and without the buffer, you'd have to pry the Pass out of my cold dead hands.
:duel:
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I just picked a Mod Squad Line Drive passive that I plan to try it with
Well, you might want to make sure it will work. It's all beyond me, but someone who knows, I think it was gitarretyp, told me there would be some special electronic considerations if one were to use a passive pre.
Maybe it was the low impedance issue he mentioned. Now that I think of it, his reply to me is probably in this thread... I hope everyone is enjoying my stream of consciousness. Forgive me, I'm tired!
Yes, it was gitarretyp. It's on page 13 of this thread.
-
I hope driving one of these kits from the preamp output of a regular AVR (Pioneer VSX-21) is ok without have to mod the kit.
-
I'm sure there are a zillion recommendations for preamps but I still recommend the Nelson Pass B1 Buffer. It's extremely easy to build, others report performance easily surpassing their >$1k pre's (Enjoy the Music had it more or less tied w/ an $18k pre. http://www.enjoythemusic.com/Magazine/equipment/0708/first_watt_b1_preamplifier.htm (http://www.enjoythemusic.com/Magazine/equipment/0708/first_watt_b1_preamplifier.htm) Sheesh, not bad for $80 in parts.
http://www.passdiy.com/order.htm
Most importantly you can make the output impedance extremely low to match the Class D Audio amps. After A/Bing with and without the buffer, you'd have to pry the Pass out of my cold dead hands.
:duel:
Wow, thanks, Wushuliu. I'll look into it.
-
I hope driving one of these kits from the preamp output of a regular AVR (Pioneer VSX-21) is ok without have to mod the kit.
It should work fine. I was using something similar before building the B1 Buffer. The amp sounded great, but the buffer takes it up several notches.
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I hope driving one of these kits from the preamp output of a regular AVR (Pioneer VSX-21) is ok without have to mod the kit.
I could be wrong (Lord knows it happens a lot) :green: but I think the impedance matching with these amps is less and issue than a lot of people think. I've seen these amps fed with a VTL preamp, a Conrad Johnson preamp, an AMC tube pre, a Yamamoto pre, a Musical Design SP1, a Dodd tube pre and the front end of a Wyred4Sound Integrated. I imagine the output impedances of all these preamps are all over the map and haven't made any difference in the quality of the sound.
I could also be lucky to not have run into a problem. :thumb:
steve
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wushuliu - thanks for the quick response. Pardon my ignorance, but I presume that connecting the preamp output from the AVR to the B1 buffer, and then connecting that to the amp is not an option for improving SQ. In other words, using the AVR preamp output precludes the use of the B1 buffer?
-
Well, you might want to make sure it will work. It's all beyond me, but someone who knows, I think it was gitarretyp, told me there would be some special electronic considerations if one were to use a passive pre.
Maybe it was the low impedance issue he mentioned. Now that I think of it, his reply to me is probably in this thread... I hope everyone is enjoying my stream of consciousness. Forgive me, I'm tired!
Yes, it was gitarretyp. It's on page 13 of this thread.
Well I have a Mcintosh C712 Adcom GTP-400 and a Marantz 1060 intergrated that I can remove the jumpers and use that as well so I have a few options but I do appreciate you keeping an eye on me Thanks.....Bill
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wushuliu - thanks for the quick response. Pardon my ignorance, but I presume that connecting the preamp output from the AVR to the B1 buffer, and then connecting that to the amp is not an option for improving SQ. In other words, using the AVR preamp output precludes the use of the B1 buffer?
Right now the AVR output is indeed going through the B1, which is being setup as a pre for the AVR, a gamma1 dac, and a Hagerman bugle Yes the SQ is hugely improved from the AVR output pre of my Marantz SR4002.
-
I hope driving one of these kits from the preamp output of a regular AVR (Pioneer VSX-21) is ok without have to mod the kit.
Im driving my 120 wpc with HK AVR and its actually working really well. I tried direct from my Paradisea with SB3 volume and was maybe a little more refined but lost alot of bass.
-
The low input impedance of these Class D amps is something to keep in mind, but I wouldn't be that concerned with it, overall. I'm using the Class D amp in a passive system myself and am quite happy with it.
There are two issues with the amp having a low input impedance:
1) If your preamp (or other device immediately preceding the amp) has coupling caps at its output and they aren't larger than 6 uF, you will be losing a couple of dB of output below ~40 Hz. Whether this will be noticeable will depend on your system. In my case, I have pretty flat response to below 20 Hz and found the high pass filter created by the interaction of the amp and my DAC very noticeable. This is the problem Keith (Nick77) had using the Paradisea as his source rather than his receiver.
2) If your preamp has a high output impedance (above 400 Ohms), your preamp will be required to supply more current than it would otherwise need to supply into a higher impedance load. This will lead to increased levels of distortion relative to a larger load. I don't think this problem would be noticeable in most cases.
-
Dude,
You're smart! :thumb:
-
Here's a sweet deal for someone who hasn't already purchased one of these.
http://www.head-fi.org/forums/f42/class-d-audio-300-wpc-amplifier-473760/ (http://www.head-fi.org/forums/f42/class-d-audio-300-wpc-amplifier-473760/)
I already have the 120wpc kit, or I'd be all over this.
-
Well I'm all in now I just ordered my kit now to ebay and other sources
http://classdaudio.com/index.php/class-d-amplifier-kits/home-kits/250w-x2-500w-x1-amp-large-power-supply-transformer.html
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=350207584020&ssPageName=STRK:MEWAX:IT
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200435755054&ssPageName=STRK:MEWAX:IT
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110469293757&ssPageName=STRK:MEWAX:IT
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Dude,
You're smart! :thumb:
You said it! Told ya he was well informed.
And, yeah, what he said!
So, what I'm left wondering, among other things, is if I should try to get my hands on a PassDIY buffer.
I see that there are plans posted on the Pass site, but I can't read a schematic. If they had a complete kit and instructions, I'd like to make one to go with the dBop.
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If it's of any help, here's my BOM for the Pass. Everything should be available from Mouser or Digikey. It's fairly straightforward, just solder according to the values on the board. And Alps pot matches directly with the inputs, etc. It's a nice sized board too, so no squinting or tight spaces to sweat about.
BOM
Resistors
(6) 1Mohm
(4) 1k
(2) 221K
(2) 10k
(1) 15k
(1) 1 ohm / 3 watts
Capacitors
(2) 10uF - high quality. Signal caps.
(1) 1uF - polyester or better. PS bypass cap
(2) 15000uf 25v
JFETs.
(4) JFET - 2SK170's, LSK170's or 2SK370
(available from Pass w/ his PCB)
(1) 1N914 type diode
(1) 18v-24v wall transformer power and jack
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=T987-P5P-ND
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CP-037A-ND
(1) 25k Potentiometer
(1) Switch / Selector
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Wushuliu, thanks. Appreciate it. I'll take your word for building it and order the parts. I didn't realize the board contained part values. Now, we'll see if I can read the board. Here goes....
This should make a great partner for the dBop.
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Hey - providing that BOM is really cool. Do you think the B1 buffer board could fit in the same standard sized chassis along with the class D amp boards?
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Hey - providing that BOM is really cool. Do you think the B1 buffer board could fit in the same standard sized chassis along with the class D amp boards?
I use a wood enclosure for the amp, so dunno. but the dimensions for the B1 are here:
http://www.passdiy.com/order.htm (http://www.passdiy.com/order.htm)
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Wushuliu, thanks. Appreciate it. I'll take your word for building it and order the parts. I didn't realize the board contained part values. Now, we'll see if I can read the board. Here goes....
This should make a great partner for the dBop.
Be sure to add a couple extra resistors to each order just in case I missed one! (and it's always good to have spares anyway).
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Ok, I have got the amp wired up. Would like another pair or more eyes to look over the connections to make sure that I have not wired it wrong before I plug it in.
I also screwed up and put the IEC connection on the wrong side, hopefully that does not impact the sound. If it does I will have to get the new back plate.
Sorry for loading so many pictures.
(http://www.audiocircle.com/image.php?id=27054)
(http://www.audiocircle.com/image.php?id=27055)
(http://www.audiocircle.com/image.php?id=27056)
(http://www.audiocircle.com/image.php?id=27058)
(http://www.audiocircle.com/image.php?id=27059)
(http://www.audiocircle.com/image.php?id=27060)
(http://www.audiocircle.com/image.php?id=27061)
(http://www.audiocircle.com/image.php?id=27062)
(http://www.audiocircle.com/image.php?id=27063)
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As far as I can tell from the photos, it looks right to me. The power supply and speaker connections look good. I can't really tell with the RCA conncections. It looks good!!
steve
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As far as I can tell from the photos, it looks right to me. The power supply and speaker connections look good. I can't really tell with the RCA conncections. It looks good!!
steve
Thanks Steve. The rca connections has the positive going to the center post and the negative going to the ring. Hopefully, that is correct.
(http://www.audiocircle.com/image.php?id=27069)
(http://www.audiocircle.com/image.php?id=27070)
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Sounds good! So how does IT sound?
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Sounds good! So how does IT sound?
Sorry, have not plugged it in yet. Will do so tomorrow.
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Your killing me!! :lol:
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Sorry, have not plugged it in yet. Will do so tomorrow.
The young Jedi is having cold feet. Don't worry Steve, he will come around to the DARK SIDE.
MOOOHOOOHAHAHAHAHAHAHAHA!
Anand.
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Well, I took my first steps towards a complete amp. I ordered the wiring! :lol:
Paul
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Man when you do things, you jump in with both feet! :thumb:
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If you guys are considering building the Pass B1, this kit (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&Item=320484651290&Category=3280&_trkparms=algo%3DLVI%26its%3DI%26otn%3D1) is probably the cheapest way to do so. I have no personal experience with the kit, but some people on diyaudio have had success with it.
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Man when you do things, you jump in with both feet! :thumb:
:lol:
Well, I would have also ordered the RCAs, binding posts and IEC, but I'm waiting for jtwrace's prototype for all the specs. As a result, figured it would be no harm to put off buying the amp kit also, as I can buy some more music equipment now, instead. :thumb: I'm guessing it would be at least a month before the case is ready to go, ordered and shipped to me.
Paul
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If you guys are considering building the Pass B1, this kit (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&Item=320484651290&Category=3280&_trkparms=algo%3DLVI%26its%3DI%26otn%3D1) is probably the cheapest way to do so. I have no personal experience with the kit, but some people on diyaudio have had success with it.
Except the seller has a serious typo. The kit only requires 18V @ 20mA not 18V @ 200 mA. And...(I could be wrong and this happens to Nelson routinely), I doubt Nelson is authorizing this sale, so he gets no profit from it, however small it is :nono:. Go here (http://passdiy.com/order.htm), buy the kit and purchase the parts from Digikey, etc... of which there are so few. If sold out, then there are always fellas at diyaudio who fabricate their own boards with permission from Nelson. Get your elbows greased and DIY! It's part of the fun!
Anand.
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I also doubt the kits are authorized, but I did say cheapest, not necessarily the most ethically sound way to build the B1.
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After removing the back panel off the NAD tuner and sanding off all the writing I decided
to go another route, went to my local fabricator. He bent up a new back plate out of aluminum
which will be much easier to work being a softer material and I don't have to paint it. That will
be a time saver. For those interested the cost was $3.00. A can of spray paint
must cost that much.................Bill
(http://www.audiocircle.com/image.php?id=27082)
(http://www.audiocircle.com/image.php?id=27083)
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Very nice!
Paul
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What no pumpkin case? Come on people where's your creativity??? :lol:
steve
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What no pumpkin case? Come on people where's your creativity??? :lol:
steve
Steve Steve Hey Dude orange HiFi gear is so Passe ! (always good to have fun)
Just went to Home Depot bought a piece 1"x6"x18" poplar for the face and stainless rack handles
Not to sure about using rack handles
(http://www.audiocircle.com/image.php?id=27087)
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I think it looks great! You can get some orange varnish stain there too. :wink:
It looks a lot like my Hafler DH-500 but I like the wood better.
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Classic stuff! :thumb:
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So much for turning on the amp today and having a listen. Turn it on, no power :scratch:. Started checking all the connections making sure everything is wired up correctly. Finally decided to check the IEC fuse section, guess what no fuses :duh:. Will make a trip to home depot on my way home from work and pickup couple of 6amp slow blow fuse.
The adventure continues.
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Sorry, I had to laugh. We've all had days like that I'm afraid. It'll be worth it when it's up and running. :thumb:
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Sorry, I had to laugh. We've all had days like that I'm afraid. It'll be worth it when it's up and running. :thumb:
Yeah I did that too, after I smacked myself upside the head for making assumption related to the fuse being included and JKelley asked the question earlier in the thread and he is using the IEC plug :green:
There are couple of folks in NJ/PA/NY area who want to listen to it before that put the order in. Was hoping to get some burn in done before they arrive.
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Steve Steve Hey Dude orange HiFi gear is so Passe ! (always good to have fun)
Just went to Home Depot bought a piece 1"x6"x18" poplar for the face and stainless rack handles
Not to sure about using rack handles
You have a nice build going Bill.
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Is there any way (or adavantage) in building some kind of dual mono configuration? I guess the amp modules have common power supply connections for the channels, so doubling up on the transformers and/or power supply boards wouldn't be a possibility.
I don't see any specific mono amp boards, and since I would be using 4 ohm speakers, I'm assuming I wouldn't want to go with a bridged configuration and have the amp see a 2 ohm load.
Steve
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I don't see any specific mono amp boards, and since I would be using 4 ohm speakers, I'm assuming I wouldn't want to go with a bridged configuration and have the amp see a 2 ohm load.
I think that depends on the load and how loud you like to listen. My buddy Bob is driving his Maggie MG-12's with a pair of 120's in bridged monoblock mode with no problem at all.
I tried doing the same thing with the ribbons/midrange on my MGIIIA's and at moderate to higher volumes, the amps kept shutting down from the protection circuits. They're both 4 ohm speakers. I'm assuming my speakers presented a tougher 2 ohm load to the amps than Bob's. Turns out with only one amp in stereo, I have all the power I need anyway for the mids/highs.
Might be worth discussing with Tom. :thumb:
steve
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Hey Steve. . .I took another GIANT leap today. Ordered the IEC, binding posts and RCAs. . . :rotflmao:
Paul
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Oh the humanity!! :o
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You have a nice build going Bill.
Yes DP this has gotten my juices flowing. I don't want just a plane jane though.
I'll have to do something to smarten it up visually I've been informed all I've ordered is
on it's way except my binding posts
I'm sure this has been discussed some wire comes with the kit what will I need to buy as far as that extra wire
What say you Steve
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I'm not an expert on wire but I used 16 ga. silver coated copper for all my power connections, twisted pairs I yanked out of some Cat 5 wire for the LED's, and I used 26 ga. DIY silver IC's from the amp board RCA's to the case RCA's. There's probably better stuff out there though, right guys?
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Cheap Metal project box.
http://www.surplussales.com/Cab-RacksHardware/encl_2.html
You can see pictures here:
http://www.surplussales.com/Cab-RacksHardware/Close-ups/encl_nabu.html
Hope that help. :eyebrows:
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Two more question:
1) I have put one rubber gasket/pad under the transformer and one on the top. Hopefully that is the right way.
2) For the ground wire can I just take the bare wire and find a secure place to attach directly to the case.
Thanks
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Yes DP this has gotten my juices flowing. I don't want just a plane jane though.
I'll have to do something to smarten it up visually I've been informed all I've ordered is on it's way except my binding posts
I'm sure this has been discussed some wire comes with the kit what will I need to buy as far as that extra wire
What say you Steve [/size]
I went the cheap route with what ever was laying around.
I use 16 ga wire that came out of yard master for the power supply to amp board, rca input connection and speaker connections. Picked up 12ga stranded wire from Home Depot for IEC to tranny connection.
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I went the cheap route with what ever was laying around.
I use 16 ga wire that came out of yard master for the power supply to amp board, rca input connection and speaker connections. Picked up 12ga stranded wire from Home Depot for IEC to tranny connection.
Yard Master ? Is your amp going to be able to cut grass.
Bring it to the next rave
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Yeah I did that too, after I smacked myself upside the head for making assumption related to the fuse being included and JKelley asked the question earlier in the thread and he is using the IEC plug :green:
There are couple of folks in NJ/PA/NY area who want to listen to it before that put the order in. Was hoping to get some burn in done before they arrive.
Surprisingly i didnt experience alot of breakin improvment, it sounded really good right off the bat.
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I used a little Yard Master on mine too. Seems like it works great.
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I'm I building an amp or a kitchen drawer
You be the judge
(http://www.audiocircle.com/image.php?id=27106)
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Very nice case, lots of bang for the buck. :thumb:
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That's exactly what I thought while doing it too. :lol:
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Funny comment - while wondering about possible shortcuts in building a case, I am considering just using a kitchen drawer and putting a piece of perforated metal on top. Why not?
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Works for me! It's the sound that counts. Maybe you could put the LED's in the handle holes?? :green: I'm currently building a box for my new 250 using my friend Mark's as a prototype. I have to say, it's a real challenge matching his accuracy. :duh: No closeup shots of this one. Uh uh.
steve
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This is with the volume at 80dB and listening to rock.
This is the Amp draw from the Class D amp.
(http://www.audiocircle.com/image.php?id=26065)
Watts=10w (my 300wpc Class A amps idle at 600w)
(http://www.audiocircle.com/image.php?id=26066)
Jason, did you happen to check the idle draw of the Class D? The reason I ask is that I have been only turning mine off with the side switch, not killing power. I would check myself but I dont have a way to do it at the moment.
Thanks,
Ed
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I will do it and let you know.
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I will do it and let you know.
Thank you :thumb:.
Best,
Ed
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Before I leap, I'd like to look at a list of what I need to add to the amp kit to make it functional. I've seen mentioned an IEC connector, RCA connectors, connecting wire for ??? Does anyone have a list of what's needed to make this amp functional?
I'm a total amateur, so am likely to get lost without it. I take directions well, generally, but I need to know what I need. :scratch:
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Price check now all I need is the guts
1. Old NAD tuner 8.00
2. New back panel 3.00
3. Poplar and handles 8.50
4. quart Minwax Clear 16.00 to use about 3 taplespoons worth
(http://www.audiocircle.com/image.php?id=27122)
(http://www.audiocircle.com/image.php?id=27124)
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Looks damn good! :thumb:
Paul
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Looks damn good! :thumb:
Paul
Thank you, As I have stated if I can do this anyone can believe me this is nothing special.....Bill
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I'll be doing one soon enough. However, I'm going the moderately expensive route. Unless it turns out to be butt ugly :P , I'm going to get one of jtwrace's custom cases.
Going to do the 1000 watt kit and use it in 4 channel "mode." Have already dropped over $100 on the 4 RCAs, 4 sets of binding posts, Furutech IEC (all previously listed parts I got from Cryoparts) and wiring. :roll: Don't even have the amp kit yet! :lol: Spending a little more on "upgrades" now will prevent me from having the "what if?" upgraditis that I am prone to. Guess you can call me an audiofool.
Paul
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Have already dropped over $100 on the 4 RCAs, 4 sets of binding posts, Furutech IEC (from Cryoparts) and wiring. :roll: Don't even have the amp kit yet! :lol: Spending a little more on "upgrades" now will prevent me from having the "what if?" upgraditis that I am prone to.
Paul, we have the same symptoms of this disease! So, the binding posts, IEC and wiring is all you need to make this guy go?
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Beautiful job!! This has to be the quickest case assembly yet. You win the prize for fastest! :wink:
I've seen mentioned an IEC connector, RCA connectors, connecting wire for ???
As for a parts list, if you're going to put it in a case the minimum you need are:
2 RCA connectors
2 pairs of binding posts
IEC (you can buy one with an integral switch and fuse to eliminate those extra parts.
Connecting wire for your power supply 16 ga.
Wire for connecting the RCA's to the board--could be 22-26 gauge.
steve
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Paul, we have the same symptoms of this disease! So, the binding posts, IEC and wiring is all you need to make this guy go?
No. You need the amp kit itself, too. :lol: (just kidding, of course!)
Yep, as Steve listed, that's all you need. The RCAs are optional, if you don't want to use the ones attached to the amp module. I will be getting my kit w/o the RCAs on the amp modules. You can also directly wire up the tranny instead of going the IEC route.
Paul
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Unless it turns out to be butt ugly :P
Paul
:nono: You definetely don't know me! :)
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:nono: You definetely don't know me! :)
:guns:
Hehe. :rotflmao:
As I said in a PM the other day, after looking at your DIY sub, I know I am going to enjoy the case! :thumb:
Paul
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:thumb:
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Funny comment - while wondering about possible shortcuts in building a case, I am considering just using a kitchen drawer and putting a piece of perforated metal on top. Why not?
You'd probably need a sturdier bottom to hold the weight of the transformer. Also, getting the connectors through a thickness of material might require some work to mill it out on the inside.
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Thank you :thumb:.
Best,
Ed
At idle the amp draws (125VAC):
.9 watts
.11 amps
This is with the amp on just no music playing.
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I did a little progress on my box but still need to drop-in the guts.
Maybe this weekend :scratch:
(http://www.audiocircle.com/image.php?id=27129)
(iPhone camera)
Regards
Mariusz :thumb:
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Lord, I hope so -- that pretty well describes my situation.
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At idle the amp draws (125VAC):
.9 watts
.11 amps
Remarkable... thanks for measuring that.
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At idle the amp draws (125VAC):
.9 watts
.11 amps
This is with the amp on just no music playing.
Thanks Jason, much appreciated!
Best,
Ed
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My first package arrived today from Class D Audio
with the snow coming I will not have much time till the weekend...............Bill
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I have been lurking in the background on this subject for awhile now and would like to jump in on one unit...I would like to build a stereo unit with at least 200 watts per channel into an 8 ohm load...What do you guys recommend? :scratch: I would put unit in metal chassis with switch on front and RCA's and binding posts on rear panel...Any guidance would be appreciated...
TIA :eyebrows:
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I have been lurking in the background on this subject for awhile now and would like to jump in on one unit...I would like to build a stereo unit with at least 200 watts per channel into an 8 ohm load...What do you guys recommend? :scratch: I would put unit in metal chassis with switch on front and RCA's and binding posts on rear panel...Any guidance would be appreciated...
TIA :eyebrows:
Are we talking about bridged mono or straight stereo? If straight stereo you can go with http://classdaudio.com/index.php/class-d-amplifier-kits/home-kits/250w-x-2-8-amplifier-power-supply-and-transformer.html but the kit does not handle 4ohm load. You can go mono with the following kit http://classdaudio.com/index.php/class-d-amplifier-kits/home-kits/1000-watt-class-d-amplifier-kit.html.
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My first package arrived today from Class D Audio
with the snow coming I will not have much time till the weekend...............Bill
Time to take advantage of the bad weather and build the kit out :).
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shadowlight - what do you mean by "the kit does not handle 4ohm load"? The product description itself is a little confusing and perhaps contradictory in this area. It states "With the included components you can build a 1000W 8 Ohm stereo amplifier or 4 channel X 500W 4 Ohm or 4 X 250W 8 Ohm. ". Do you think the kit goes into protection mode at 4 ohms?
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Time to take advantage of the bad weather and build the kit out :).
None of the other parts have arrived yet
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but the kit does not handle 4ohm load.
This is due to excessive heat in 4 ohms, not that the amp won't drive a 4 ohm load. Tom can modify the heat sink to dissipate the additional heat so it will run fine in 4 ohms. I just bought one.
steve
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shadowlight - what do you mean by "the kit does not handle 4ohm load"? The product description itself is a little confusing and perhaps contradictory in this area. It states "With the included components you can build a 1000W 8 Ohm stereo amplifier or 4 channel X 500W 4 Ohm or 4 X 250W 8 Ohm. ". Do you think the kit goes into protection mode at 4 ohms?
When I had put the order in I exchanged email messages with Tom about th 250x2 8ohm kit and here is what he had to say about it:
"The 250W X 2 into 8 ohm is $55.00 more. If you’re using it for anything other than 8 ohm, I really don’t recommend this kit. The one you ordered will run just about anything and is very stable. If you want to upgrade. Let me know and I’ll cancel the order you placed and you can e-place it.
Thanks,
Tom"
Since, than I believe he has designed a larger heatshink to help handle 4ohm loads, which is the one that SteveK mentioned as part of the comparision with Wryed for Sound amp earlier in the thread. My suggestion is to reach out to Tom he has answer all my questions and has great customer service.
If the amp that I ordered works out in my current environment I plan to touch base with Tom to see if I can purchase the 250w x 2 8ohm kit with the upgraded heatsink in case in the future I end up with 4ohm load speakers. My current speakers are 8ohm but would like to future proof my amp as much as possible.
Hope that makes sense.
EDIT: Steve beat me to it and in shorter form to boot :thumb:
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OK - thanks for the info on the 250x2 8ohm kit. I'm thinking seriously about pulling the trigger on this one.
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Inspired by the Pumkin king i hit the depot and picked up a new faceplate. The bamboo i had didnt stain well at all so i swapped it out for poplar. I like it alot better as it matches the bookcase. :eyebrows:
(http://i59.photobucket.com/albums/g295/mrnick_2006/IMG_3061.jpg)
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Nice! :drool:
Paul
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Inspired by the Pumkin king i hit the depot and picked up a new faceplate. The bamboo i had didnt stain well at all so i swapped it out for poplar. I like it alot better as it matches the bookcase. :eyebrows:
(http://i59.photobucket.com/albums/g295/mrnick_2006/IMG_3061.jpg)
Nick that looks GREAT !!!......Bill
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Nice work NIck! I like the LED's :thumb: It's really cool to see some final results from you guys. I'm still butchering wood on my second one but it won't look any different than the first. Thankfully my buddy Mark is doing the cherry faceplate for me so you won's see any closeups of the rest of it. :lol: Tom told me he's working on a new "Super D" class of amps now. :o :eyebrows: Just what we need to hear right? There's always something new and better on the horizon. :drool:
steve
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Tom told me he's working on a new "Super D" class of amps now.
Sounds sexy. :lol:
I am in. :drool:
Cheers
Mariusz
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These are some great looking builds. I wonder how they sound. Maybe some of those who have completed their builds could comment on the sound in their systems. Maybe to compare them to other amps they have. That would be interesting. :banana piano:
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I'm still waiting on IEC,Binding posts and RCA's
This is as far as I could go Listening to Magical Mystery Tour and starting on my amp
(You know I couldn't wait)
(http://www.audiocircle.com/image.php?id=27153)
Maybe next time mount the power supply in a different case something to think about.
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'cause I'm thinking that we are going into this with little experience, or maybe knowledge, of how this thing sounds. I see lots of enthusiasm, myself included, but not lots of experience with the sound.
Maybe it is discussed elsewhere and I don't know it. What is the basis of our enthusiasm? :scratch:
I know why I want one, but I would like to know more before I order the amp.
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I fired up the amp today and it was heating up again. Sent a message to Tom and he asked to try couple of things, while checking those thing noticed something that I over looked. The two brown 18v wires. I had them capped together :nono:.
Once I capped the brown wires under separate caps the tranny stayed cool. Listened to it for 5 minutes with laptop directly hooked up to the amp. Going to fix the wire that goes from iec power to tranny, which is about 2" short and feels stretched. Once that is done will hook it up to the main speakers and have a listen.
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'cause I'm thinking that we are going into this with little experience, or maybe knowledge, of how this thing sounds. I see lots of enthusiasm, myself included, but not lots of experience with the sound.
Maybe it is discussed elsewhere and I don't know it. What is the basis of our enthusiasm? :scratch:
I know why I want one, but I would like to know more before I order the amp.
Take a look at some of the earlier messages posted by Steve (page1, 2, 19 (comp with wyred for sound)Nick (page 6), Jason and avionics (page 4). They have the amps running and posted their feedback. Both Steve and Jason have ordered multiple amp boards. Jason has 600W based on TI chip and 500 watt based on IR chip.
Couple of other things to think about. Gary Dodd (page 8) mentioned earlier that he has been playing with one and plans something special around it and other is Blair (Niteshade) just released a amp based around classd board (http://www.audiocircle.com/index.php?topic=78167.0)
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Take a look at some of the earlier messages posted by Steve (page1, 2, 19 (comp with wyred for sound)Nick (page 6), Jason and avionics (page 4). They have the amps running and posted their feedback. Both Steve and Jason have ordered multiple amp boards. Jason has 600W based on TI chip and 500 watt based on IR chip.
Couple of other things to think about. Gary Dodd (page 8) mentioned earlier that he has been playing with one and plans something special around it and other is Blair (Niteshade) just released a amp based around classd board (http://www.audiocircle.com/index.php?topic=78167.0)
Thanks for the references. I too would like to hear more about the sound of these units.
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Tom told me he's working on a new "Super D" class of amps now. Just what we need to hear right? There's always something new and better on the horizon.
Steve your right about that :duh: I wonder if any of these changes can be implemented on our boards? As Shadow mentioned Gary Dodd said he was playing with one and would have some updates also. Looks like Blair improved upon the PS. Im pretty happy with the results i am getting now but i hope we can upgrade to Super D! :drool:
Edit: Asked Tom about the new prototype, he has had requests for balanced inputs so the new board has balanced inputs and adjustable gain. New features will not be available for exsisting boards.
If you need balanced inputs the new boards should be ready in several weeks.
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Hi, Steve! :wave: Ummmm. . .I just actually ordered the amp kit! The big boy. . .1000 watt IRS kit. Plan on making it into a 4 channel amp. :hyper: :banana piano: :dance: :rock: :beer: :bounce: :thankyou: :singing:
(EDIT:) Ordered my kit without the input jacks, output jacks and (as mentioned in my post below), asked him to adjust the gain as necessary.
Regarding the "Super D" amps, just chatted with Tom. To assuage any fears, he said it's the same amplifier section, but will be a little bigger/more expensive, due to accommodating balanced inputs. I'm assuming this means it will have XLR inputs on the board itself.
Please correct me if I'm wrong, but I believe you can just wire up the amp balanced, using external connections. . .correct?
Now, jtwrace. . .just waiting on you!!!! :P :rotflmao:
(It's a smiley-festival day)
Paul
P.S. Just a friendly reminder. Do not forget to use the "ACircle" code when checking out for a 5% discount.
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I'm assuming this means it will have XLR inputs on the board itself.
That's how the 600w board is that I have...it just has a blue connector on it that clamps down on the wire. See my pics in the beginning of this thread and you'll see. I'm sure he's doing the same thing.
Please correct me if I'm wrong, but I believe you can just wire up the amp balanced, using external connections. . .correct?
Well you can wire using an XLR connector.
Now, jtwrace. . .just waiting on you!!!! :P :rotflmao:
Good things come to those that wait. :) Should have pics in two weeks.
(It's a smiley-festival day)
Paul
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Well, just got the following e-mail from Tom. It is regarding balanced inputs / wiring (referring to the IRS boards) and gain adjustments:
Regarding balanced inputs: "These amps do not have a balanced input, but a standard single ended input. You can always use an unbalanced to balanced converter with these amps to convert them to balanced."
Regarding gain adjustments: "Some customers have preamps with only balanced outputs, and some want to run long cables, so this is the reason for the new amps."
I'm sure many of you knew this, but I'm pretty ignorant on the technical side of things. I ended up just giving him my preamp specs and told him I will leave it up to him to adjust the gain down or not. (Edit: He just responded with the following: "I’ll take a closer look at your preamp specs and make adjustments as necessary. We will ship tomorrow." Great customer service! :thumb:)
Good things come to those that wait. :) Should have pics in two weeks.
Can't wait! Literally. . . :lol:
Paul
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Can't wait! Literally. . . :lol:
Paul
If you start wallking now, I promise they'll be done when you arrive in NC. Deal? :lol:
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I'm sure Tom wouldn't mind me mentioning this. . . He said AC has generated a lot of interest in his products and is very thankful. He's been super busy and will pop in here as soon as things settle down. :thumb:
Paul
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Finally Done (for now)
(http://www.audiocircle.com/image.php?id=27174)
(http://www.audiocircle.com/image.php?id=27175)
:eyebrows:
Sound Awesome with Dodd Buffer.
:thumb:
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@trungt
Can you list where you got the extra hit sink from and it seems that you are using different case for transformer and power supply. Can you post additional pictures for future reference, especially the inside part :thumb:
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Does anyone know the input impedance of the 120 wpc and/or 250 wpc amp?
I'm not exactly a beginner, but I'm no tech either. The manuals are good but not "step-by-step". I could definitely use some help wiring the transformer and power section. I'm not completely confident in my ability. Anyone up to a little "tutoring"? Thanks.
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Does anyone know the input impedance of the 120 wpc and/or 250 wpc amp?
I'm not exactly a beginner, but I'm no tech either. The manuals are good but not "step-by-step". I could definitely use some help wiring the transformer and power section. I'm not completely confident in my ability. Anyone up to a little "tutoring"? Thanks.
Edit: Please take a look at the manuals included and consult with Tom. The info below is how I hooked up mine which is a 250wpc x 2 amp kit but your kit might require different configuration/connection.
From my trial and error which included frying a transformer for the 250wpc x 2 amp kit:
1) Make sure that the two brown wires are separated from each other and capped off. I had initially twisted those two together and capped it which is what fried the tranny.
2) Twist the two red together and two black wire together, which will be connected to the IEC power adapter.
3) Take the middle blue and green wire from transformer and hook it up to the power supply CT
4) Take the outside green wire from the tranny to power supply AC-L
5) The outside blue wire from tranny goes to power supply AC-N connection
6) Take one positive, one negative and one ground from the power supply to amp board.
7) If you are holding the IEC plug in front of you with the power switch facing away from you, the red wires from the transformer goes to the outside left connector on the IEC adapter and the black wires to the right most connector.
I think that covers hooking up the transformer, power supply and amp board.
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The input impedance is ~3k Ohms.
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1) Make sure that the two brown wires are separated from each other and capped off. I had initially twisted those two together and capped it which is what fried the tranny.
7) If you are holding the IEC plug in front of you with the power switch facing away from you, the red wires from the transformer goes to the outside left connector on the IEC adapter and the black wires to the right most connector.
Regarding #1, great to know!
Regarding #7, what goes to the ground lug on the IEC, then? Would that just be to ground the chassis? From some pics, it looks like some aren't doing this. Is this safe, or am I just overlooking something? No part of the tranny is hooked up to the ground of the IEC?
Paul
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Regarding #1, great to know!
Regarding #7, what goes to the ground lug on the IEC, then? Would that just be to ground the chassis? From some pics, it looks like some aren't doing this. Is this safe, or am I just overlooking something? No part of the tranny is hooked up to the ground of the IEC?
Paul
I have it connected to one of the chassis screw as ground for the chassis and it does not connect to transformer in anyway. Pictures that I have seen without any ground wire seem to be in wood case and that might be the reason for you not seeing it. If you have a metal case find a way to plug the ground in to be on the safe side.
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I have it connected to one of the chassis screw as ground for the chassis and it does not connect to transformer in anyway. Pictures that I have seen without any ground wire seem to be in wood case and that might be the reason for you not seeing it. If you have a metal case find a way to plug the ground in to be on the safe side.
I spoke to Tom about the ground in a wood case and he said a ground isnt needed unless your having some hum issues. I dont a ground connected to my iec plug in my wood case.
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Thanks for all the info on connecting. Doesn't the kit come with instructions? There's seems to be a lot of interest in these kits, especially with novice builders like myself. It would be nice to have some kind of "Wiki" with all the learnings on one page so that we don't fry ourselves. :lol:
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The website should have pdfs of amp manuals and toroid/fuse/switch wiring. The wiring is very, very straightforward. The ground/brown wiring is new though. Mine came w/o it.
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For those assembling these units, I would suggest that you ping Tom at ClassDAudio with any questions you may have on grounding (or anything else, for that matter). On his suggestion, I kept the signal ground disconnected from the chassis (and house wiring) ground. This works fine. It's safe because everything in enclosed in a grounded chassis (in my case) and it's quiet because the shielded cables connected to the outer ring of the RCA inputs are grounded though other components in the signal chain, and no ground loops are possible. Speaking of safety, an 8 amp fuse on the transformer input is a good idea as well (this would have saved your first transformer, shadowlight).
- Doug
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The website should have pdfs of amp manuals and toroid/fuse/switch wiring. The wiring is very, very straightforward. The ground/brown wiring is new though. Mine came w/o it.
See here: http://classdaudio.com/index.php/manual/?___store=default
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From my trial and error which included frying a transformer for the 250wpc x 2 amp kit:
1) Make sure that the two brown wires are separated from each other and capped off. I had initially twisted those two together and capped it which is what fried the tranny.
2) Twist the two red together and two black wire together, which will be connected to the IEC power adapter.
3) Take the middle blue and green wire from transformer and hook it up to the power supply CT
4) Take the outside green wire from the tranny to power supply AC-L
5) The outside blue wire from tranny goes to power supply AC-N connection
6) Take one positive, one negative and one ground from the power supply to amp board.
7) If you are holding the IEC plug in front of you with the power switch facing away from you, the red wires from the transformer goes to the outside left connector on the IEC adapter and the black wires to the right most connector.
I think that covers hooking up the transformer, power supply and amp board.
That's very kind of you to post. Keep in mind that some kits are different. My 600w TI chip based amp does NOT hookup like yours...For everyones saftey, always consult the manual for proper hookup. If you are not sure, ask Tom at Class D Audio.
Remember this voltage can cause harm or death!
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Count me in as another one waiting for one of those cases!
For the Noobs out there, if I was able to get it together, anyone can. Just be sure to post questions or ask Tom (who held my hand the whole way on a Sunday). For me, this is the first time I even soldered anything (and I advise reading up on how to solder a good connection and practice - so you don't have to re-solder - or blow a fuse like I did because of a poor connection). Turning it on, seeing the lights come on and hearing the sound was incredibly rewarding - and it sounds fantastic!
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That's very kind of you to post. Keep in mind that some kits are different. My 600w TI chip based amp does NOT hookup like yours...For everyones saftey, always consult the manual for proper hookup. If you are not sure, ask Tom at Class D Audio.
Remember this voltage can cause harm or death!
Thanks for the reminder and I agree. Updated my original post to include the warning.
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Shadowlight
Class D amp 12V battery powered, so it does not have transfromer, since the 12V power supply are small as you see, it's easy to made it fit in the small bamboo box.
The heatshink is just a recycle part I found somewhere. :duh:
I do have 100A AGM battery here to feed all Dodd Battery gears and the class D amp.
Cd player and DAC are only 2 things pluged on the wall (beside the battery charger)
:eyebrows:
(http://www.audiocircle.com/image.php?id=27190)
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Pretty cool Trung! It would be interesting to compare your amp's sound to one with a linear PS (which is already quiet). I bet yours is even quieter. Very nice compact layout. Bravo. :thumb:
I think these amps are going viral here! :green:
steve
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Thanks Steve
I did hook up with the linear PS before, to me the 12V just give little more punch at the bottom end. :thumb: and quiet
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Years ago when I was in college, I assembled a Heath Kit amplifier. I was even more inexperienced than I am now. But the HK came with diagrams and instructions and had many more parts than one of these amps. Even so, I was successful and it worked great.
That's what some of us need... a couple of diagrams and some step-by-step instructions. Thanks to Shadowlight for his help, that's what I'm talking about.
A wiring diagram, NOT SCHEMATIC, would be immensely helpful if not mandatory for people like me. I know that I can put one together, but I just want something I can refer to and be assured it's done right. I don't think I'm alone in this.
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What roymail said :). Also, I think it would be helpful if some final sanity checks could be listed such as "Measure the resistance across A and B. It should be x ohms or "Measure the voltage across points A and B. It should be x volts." If this can be done, I think it could reduce the chance of an expensive accident (but I'm not an electrical engineer or tech). Otherwise, I'm looking for a set of cheap, sacrificial speakers before I throw that switch.
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Another lurker bites the dust! Just ordered the 250W X 2 amp kit and the Pass B1 board to boot... and I really don't need another amp or preamp. Am considering putting everything in one box and calling it an integrated amp.
Would anyone who has built a B1 please confirm what power supply you are using? I will order the 24VDC wall mount as listed on page 20 if anyone can confirm that it is okay. Best I can tell Nelson Pass recommends anything between +18 and +24 Volts, but says the B1 only draws 1/10 what the supply delivers in amperage... and I really don't want to destroy my project with an obvious oops! Also, for anyone using a B1, do you just leave it on all the time, or did you install an on/off switch?
Thanks to everyone for the posts and thread. :thumb: Now I've gotta get some peripherals ordered.
Neil
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Neil, is there a kit available for the B1? Sorry, I may be the only person on here who doesn't know the answer to that question. :?
Thanks,
Roy
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Neil, is there a kit available for the B1? Sorry, I may be the only person on here who doesn't know the answer to that question.
Yes. I've got one on order. It's about $50. The store is on eBay. The address was mentioned in this thread a few pages ago.
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Another lurker bites the dust! Just ordered the 250W X 2 amp kit and the Pass B1 board to boot... and I really don't need another amp or preamp. Am considering putting everything in one box and calling it an integrated amp.
Would anyone who has built a B1 please confirm what power supply you are using? I will order the 24VDC wall mount as listed on page 20 if anyone can confirm that it is okay. Best I can tell Nelson Pass recommends anything between +18 and +24 Volts, but says the B1 only draws 1/10 what they supply delivers in amperage... and I really don't want to destroy my project with an obvious oops! Also, for anyone using a B1, do you just leave it on all the time, or did you install an on/off switch?
Thanks to everyone for the posts and thread. :thumb: Now I've gotta get some peripherals ordered.
Neil
Hi Neil, the wall wart I linked works great. Amperage poses no harm. I don't use a switch. IMO, it draws so little power I don't see the need.
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Thanks wushuliu! I was hoping the amperage was more or less irrelevant. Gotta go order that transformer and connector. Thanks again for posting the whole parts list too... really simplifies the ordering process when I know exactly what I should be getting.
And Roy, you can order the kit available from China (see ebay link by gitarretyp on page 21 of this thread) or order the board and matched transistors from Nelson at http://wwwpassdiy.com/order.htm and then populate the board with the parts listed by wushuliu on page 20 of this thread.
Neil
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Why don't you also start a new thread on this? I'm sure many would like this detailed parts list...they will not find it here though.
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That's a good idea. Mariusz can you split this into a new topic?
steve
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Guys, thanks a bunch for the great info and parts kit stuff.
Wushuliu, thanks for a great resource list. I truly appreciate your efforts. I agree that it should be made available to others perhaps in a separate thread.
Also, I appreciate the heads-up regarding the China parts. I'll definitely go with Nelson Pass on the board and digi-key and mouser as suggested.
All this could be of significant help to others, too. Thanks again! :D
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Mouser Electronics often has better prices on discreet components than most other places. Check them out.
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Does anyone know what size LEDs are used on this amp? I want to put the same size LEDs on the faceplate. Also, if you know of a part number or a place that carries them that would be appreciated. I have an email into Tom but haven't heard back.
Thanks,
Ed
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Ed-
just take a ride down to Radio Shack. They got 'em!
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According to Tom, the blue LED is 3 to 3.4 volt, and yellow is 2 to 2.4 volt. They are extremely bright, by the way (you might want to tone them down with some resistors.
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Ed-
just take a ride down to Radio Shack. They got 'em!
Already looked there, they didnt have them.
According to Tom, the blue LED is 3 to 3.4 volt, and yellow is 2 to 2.4 volt. They are extremely bright, by the way (you might want to tone them down with some resistors.
Thanks, I didn't realize they were different voltages. I am wondering what physical size those are, I would like to use the same size in my faceplate.
Thanks guys,
Ed
edit: nevermind, measuring one it appears to be about 1/8" which converts to about 3mm.
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Use whatever size you like. The onboard ones are ~1/8" in diameter.
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That's a good idea. Mariusz can you split this into a new topic?
steve
You got it.
link to B-1 kit/build new thread HERE (http://www.audiocircle.com/index.php?topic=78312.msg742227;topicseen#new)
Regards
Mariusz :thumb:
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LED's
http://www.mouser.com/Optoelectronics/LED-Indication/LED-Panel-Mount-Indicators/_/N-74ga2?Keyword=led&FS=True
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Do you have to use the same color led? Can I replace blue with green that I picked up from Radioshack? I find the blue to be very bright
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Yes. I replaced the yellow with red and the blue with green.
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Yes. I replaced the yellow with red and the blue with green.
Glad we can do that.
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Yes. I replaced the yellow with red and the blue with green.
Ahh the Christmas amp
Waiting on the RCA's
(http://www.audiocircle.com/image.php?id=27221)
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Ahh the Christmas amp
Waiting on the RCA's
Stuff from Hong Kong showed up before the stuff from down south. I have some spare rca that you can have.
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Stuff from Hong Kong showed up before the stuff from down south. I have some spare rca that you can have.
I didn't do a round over DP after looking at your case online. A round over might interfere with the screw holes...............Bill
(http://www.audiocircle.com/image.php?id=27231)
I ordered all my extras from the lower 48 thinking they would get here faster
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That looks great and will be a great addition :thumb:
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Yes. I replaced the yellow with red and the blue with green.
Ahh the Christmas amp
:dance: :xmas: :xmas: :dance:
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Hey Ed, send me a pm with your address and I will ship you out a couple of LED's already soldered up to some 6 inch leads.
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Yes. I replaced the yellow with red and the blue with green.
I found the blue to be more musical and transparent. hehe
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Power on
(http://www.audiocircle.com/image.php?id=27266)
Sitting on top of the Mcintosh
(http://www.audiocircle.com/image.php?id=27267)
I'll relay my observations at a later date
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Congrats oh King of Pumpkins. We'll be awaiting your review. In mean time, don't put the knives and forks in it by mistake! :lol:
Nice job.
steve
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Nicely done! :thumb:
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Congrats oh King of Pumpkins. We'll be awaiting your review. In mean time, don't put the knives and forks in it by mistake! :lol:
Nice job.
steve
Very GOOD Steve if I put any in they will plastic no shorting out components
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This was a very fun project so what's next, as this amp will be going to my 83 year old father.
Maybe 3 seperate cases,mono amps and power supply What do you guys think ?
Next time the cases will built from the ground up as they say................Bill a.k.a. The Pumpkinking
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This was a very fun project so what's next, as this amp will be going to my 83 year old father.
Maybe 3 seperate cases,mono amps and power supply What do you guys think ?
Next time the cases will built from the ground up as they say................Bill a.k.a. The Pumpkinking
I've been actively lurking, but this is exactly the type of project I was thinking of. If you do, please take pics and post away.
BTW, are there any recommended mods on these boards which can be done by ordinary mortals? Those cap swaps from DIYAudio look interesting, but daunting. . . .
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I've been actively lurking, but this is exactly the type of project I was thinking of. If you do, please take pics and post away.
BTW, are there any recommended mods on these boards which can be done by ordinary mortals? Those cap swaps from DIYAudio look interesting, but daunting. . . .
Gitarretype made a good point earlier that as those caps are not directly in the signal path the gains made may not be worth the risk to the board. The 22uf input coupling caps however... hmmm
All in all though, these are not mod-friendly boards.
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Here's my 250w IR amp. I can't afford pricey enclosures so I got some baltic birch cut at Eagle Rock Lumber and Hardware (thanks Pat!) and did a little Rustoleum spray paint action. Drilled some holes for ventilation and LED glow. 8) Pretty cheap (and cheerful!). :D
(http://www.audiocircle.com/image.php?id=27303)
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Here's my 250w IR amp. I can't afford pricey enclosures so I got some baltic birch cut at Eagle Rock Lumber and Hardware (thanks Pat!) and did a little Rustoleum spray paint action. Drilled some holes for ventilation and LED glow. 8) Pretty cheap (and cheerful!). :D
I think your enclosure is SWEEEEET !!! My bad never could spell worth a damn
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I think your encloser is SWEEEEET !!!
sounds like a CBS drama:
The Encloser
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Do the modules come with detailed instructions or are you supposed to walk in the dark and guess by the wiring schematics? Anyone has detailed instructions or actual photo walk through of the assembly?
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Here you go:
http://classdaudio.com/documents/transformer_115VAC_instructions.pdf (http://classdaudio.com/documents/transformer_115VAC_instructions.pdf)
http://classdaudio.com/documents/70V_Manual.pdf (http://classdaudio.com/documents/70V_Manual.pdf)
http://classdaudio.com/documents/TI_Amp_Connections.pdf (http://classdaudio.com/documents/TI_Amp_Connections.pdf)
All from here: http://classdaudio.com/index.php/manual/?___store=default (http://classdaudio.com/index.php/manual/?___store=default)
Plenty of info and pics in the previous posts, also. I know people here and Tom from ClassDAudio would help you with any questions.
Paul
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I asked the same question on page 26...
That's what some of us need... a couple of diagrams and some step-by-step instructions. Thanks to Shadowlight for his help, that's what I'm talking about.
A wiring diagram, NOT SCHEMATIC, would be immensely helpful if not mandatory for people like me. I know that I can put one together, but I just want something I can refer to and be assured it's done right. I don't think I'm alone in this.
I hope that someone who has successfully built one of these amps will step up and help us "less tech savy guys." That would be great! :thumb:
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I'm no techy. Those manuals seem pretty straight-forward to me. :thumb:
Paul
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Here's my 250w IR amp. I can't afford pricey enclosures so I got some baltic birch cut at Eagle Rock Lumber and Hardware (thanks Pat!) and did a little Rustoleum spray paint action. Drilled some holes for ventilation and LED glow. Pretty cheap (and cheerful!).
Another Christmas amp!! I like it! Very nice, classic and simple Wushu!
steve
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Another completed 250 x 2 amp here. :thumb: Followed avionics layout. From his pic, and a few others in this thread, along with the included instruction manual and sheets was clear how to put it together. But I did hesitate a little worrying about making a mistake. At first no sound, reread the manual and found the tiny on/off switch on side of amp board was off. :lol:
Lost my camera so can't include pics or I would to help out you guys wanting more support. But don't get too worried, everything is straight forward and someone will answer your questions.
Sounds nice and clear, and I like having the power as recently got some nice 12" bass drivers that wanted more. Using widerange (Fostex 108ez) for mids and treble now but may work on a 3 way.
Thanks for the thread Steve.
Don
Oh, one thing. It interferes with my tv antenna reception - because I made a wood case. Might shield it or build metal one.
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Oh, one thing. It interferes with my tv antenna reception - because I made a wood case. Might shield it or build metal one.
Interesting. That's the first I've heard of that. I would pass that on to Tom so he knows. Congrats!! This is getting to be a pretty big circle of amp owners now. So far no complaints. We'll see. :thumb:
I got my box for the 250 assembled today finally. Just a little sanding, priming and painting and I'll be ready for assembly. Woo hoo! :dance:
steve
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Oh, one thing. It interferes with my tv antenna reception - because I made a wood case. Might shield it or build metal one.
That was my first thought when I saw some were building wooden cases. Having a linear power supply might produce less interference than if it had an SMPS, but there is still the possibility of interference generated from the high speed transistor switching of class D.
Steve
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So I drove up to Shadowlight's yesterday to hear his amp, he was driving his LS6s with it, I simply couldn't believe it possible with a diy kit, but there it was.
The Pumpkinking brought his unit as well, it may look like a kitchen drawer, but it should perform like Shadowlight's, which means it should kick butt.
Then he threw out a thought I can't shake, "what about building a pair of 500 watt monoblocks".
Now that's intriguing.
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Then he threw out a thought I can't shake, "what about building a pair of 500 watt monoblocks".
Now that's intriguing.
That's what I'm doing!
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That's what I'm doing!
Will there be a seperate thread to document it?
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Will there be a seperate thread to document it?
Probably not...I was just going to post some pics when I'm done. :green:
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Jtwrace-
What amplifier/power boards are you using?
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Jtwrace-
What amplifier/power boards are you using?
I'm going to use the IR for this one. I've got the TI as well....
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I'd like to pass on two important things I learned from Tom this morning:
1. Since the various LEDs are part of the circuit, NEVER run the amps without appropriate LEDs in place. If you plan on removing the stock LEDs as part of the external LED installation process, such as I'm doing, install the new LEDs before turning the amp on.
2. It's OK to run the amps without a load on the outputs. I want to turn my amps on to check switches and LEDs before screwing down the lids, so this knowledge will allow me to do that.
Bob
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Is it ok/easy to add external LEDs in addition to the stock LEDs - for instance, wiring the external LEDs in parallel with the stock LEDs? I would assume that anyone building an enclosure might consider this, and it would be convenient if connectors or solder posts were available to accommodate.
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Is it ok/easy to add external LEDs in addition to the stock LEDs - for instance, wiring the external LEDs in parallel with the stock LEDs? I would assume that anyone building an enclosure might consider this, and it would be convenient if connectors or solder posts were available to accommodate.
not an issue...there is a spot for them on the PCB.
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You can do that, but what I found when I stuck one of my new LEDs into the L-on and R-on holes while the amp was on was that the new LED barely glowed at all. I'll need to remove the stock LEDs to get enough voltage to fire up the new ones properly. Your mileage may vary.
Bob
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Hmm. I wonder if this is an issue where the stock LED is sucking up too much current and/or the external LED is not getting enough. Perhaps better results could be obtained by selecting a different external LED with the right electrical characteristics to match the stock one?
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I wired mine directly from the board without unhooking the stock ones with no problems, certainly bright enough for my tastes.
(http://i59.photobucket.com/albums/g295/mrnick_2006/IMG_3061.jpg)
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Another Christmas amp!! I like it! Very nice, classic and simple Wushu!
steve
lol. this amp is the gift that keeps on giving... can't wait for the Affordable Audio review.
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Probably not...I was just going to post some pics when I'm done. :green:
If you undertake this, would you take some pictures as you slowly begin to wire things together? And, if you can upload it with some comments, that would make it all the so much easier. Not that it is not as easy as it is. Visual companion would just make things 100% better.
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If you undertake this, would you take some pictures as you slowly begin to wire things together? And, if you can upload it with some comments, that would make it all the so much easier. Not that it is not as easy as it is. Visual companion would just make things 100% better.
I'll try but time is very hard for me...
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Do the modules come with detailed instructions or are you supposed to walk in the dark and guess by the wiring schematics? Anyone has detailed instructions or actual photo walk through of the assembly?
I understand your fears. Have you looked at the beginning of the thread? There's quite a bit of pictures...
If you can read and have basic knowledge of electrical, you can do this. It's REALLY easy.
The other bonus is if you run into trouble, you contact Class D or just post on this thread with some pics. You'll be fine. Take your time and follow the instructions.
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If you undertake this, would you take some pictures as you slowly begin to wire things together? And, if you can upload it with some comments, that would make it all the so much easier. Not that it is not as easy as it is. Visual companion would just make things 100% better.
If you have a camera it may be easier to just buy the amp kit and start putting it together, post pics and we can walk you through it. Once you have it physically in front of you, with the wiring diagram and shadowlight's pics from earlier in the thread - it will all make sense.
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Hmm. I wonder if this is an issue where the stock LED is sucking up too much current and/or the external LED is not getting enough. Perhaps better results could be obtained by selecting a different external LED with the right electrical characteristics to match the stock one?
I gave the specs of my LEDs to Tom and they seem to be just right. Also, Steve informed me that he installed his without disconnecting the stock LEDs and there were no problems, so I don't know. I'll just remove the stock ones and see what happens.
Bob
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If you have a camera it may be easier to just buy the amp kit and start putting it together, post pics and we can walk you through it. Once you have it physically in front of you, with the wiring diagram and shadowlight's pics from earlier in the thread - it will all make sense.
Great idea! :thumb:
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Has anybody compared the 500w & 600w modules?
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My new 250 case--the lady in red. A work in progress. I'm about ready to start installing components. This will have the same cherry faceplate and cherry feet as my first amp. I chose pegboard this time around for better ventilation. The toroid mounts vertically in front behind the face plate. Behind that the power supply board mounts on the bottom and the amp board mounts on a removable ventilated tray above that.
steve
(http://www.audiocircle.com/image.php?id=28801)
(http://www.audiocircle.com/image.php?id=28803)
(http://www.audiocircle.com/image.php?id=28804)
(http://www.audiocircle.com/image.php?id=28805)
(http://www.audiocircle.com/image.php?id=28806)
(http://www.audiocircle.com/image.php?id=28807)
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I got my 250x2 kit together a couple of weeks ago, it sounds great however from what I have heard it should be dead-quiet but I do hear a low hum if I put the ear next to the drivers. I can't hear it from more than about 2 feet away. It is however, noisier than my Denon receiver. I also have the noise if I hook up directly to my Squeezebox or from other inputs (TV/PS3).
It is not dependent on volume so Tom does not think it is an issue with the Amp and has offered to check it out if I send it back. I wanted to see if anybody has any ideas of things to look at before I do that.
I am a complete novice at electronics and essentially did a poor job the first time I soldered. I've got that down now and re-soldered all my connections.
I have it on a board (waiting for that rumored case!) and have a power cord soldered directly to the transformer and fuse holder. There were no RCAs on my board so I soldered some RCAs I got from PartsExpress to the hookup wire to the board.
I am driving Salk SongTowers and I have also tested it out on NHTs classics 3s with the same result.
Anyone have any ideas of things to try? Do you think is impacting the overall sound?
Thanks,
Mark
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Hum sounds like a ground problem. You might check your IC's and make sure they're no picking up extraneous noise from power cords they may be crossing. Are your IC's shielded? You could also try lifting the ground on the Class D amp witha cheater plug to pull it out of any ground loop you might have.
steve
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After seeing all of you people "doing" it, I could not keep out of the fray and got me a set of modules and some parts. After I begin my complete odyssey, I will provide pictures for double checking before I risk it and my other gear from early electrical death due to novice stupidity.
Can someone here who have decided to go with the chassis leds provide me with a LED parts list and counts, as well as good sources for them?
Thanks. :thumb:
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LED source already listed here:
jtwrace
Registered+
Posts: 923
Lets make it!
Gallery
Re: $175 Class D amp--120 wpc
« Reply #522 on: 26 Feb 2010, 08:52 PM »QuoteLED's
http://www.mouser.com/Optoelectronics/LED-Indication/LED-Panel-Mount-Indicators/_/N-74ga2?Keyword=led&FS=True
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I have it on a board (waiting for that rumored case!)
Thanks,
Mark
:nono: No such thing with me...I do what I say. :D
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After seeing all of you people "doing" it, I could not keep out of the fray and got me a set of modules and some parts. After I begin my complete odyssey, I will provide pictures for double checking before I risk it and my other gear from early electrical death due to novice stupidity.
Can someone here who have decided to go with the chassis leds provide me with a LED parts list and counts, as well as good sources for them?
Thanks. :thumb:
Great! You'll enjoy it and we're here to help ya. :)
Edit: You're probably best off assembling the amp first and trying it before doing the LED's. This way you'll not be overwhelmed at first. Get it working and then modify if you wish. Just my .002
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Hum sounds like a ground problem. You might check your IC's and make sure they're no picking up extraneous noise from power cords they may be crossing. Are your IC's shielded? You could also try lifting the ground on the Class D amp witha cheater plug to pull it out of any ground loop you might have.
steve
By shielding the IC - you mean the connection between the RCA Inputs and the hookup wires - no I didn't. What should I use to shield the connections?
Thanks for the help!
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No I mean the interconnects your using between your preamp and the D amp. Are they shielded cables?
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No I mean the interconnects your using between your preamp and the D amp. Are they shielded cables?
I think they are some generic cheap cables I had lying around. So I assume not. Let me try getting some shielded cables.
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www.bluejeancables.com is a good source for low cost good quality cables. This may or may not solve your problem but at least at blue jeans prices, you won't be out a lot of money.
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Well here's my tale. I hooked up the amp to a Mcintosh C712 preamp and Vandersteen 3A speakers. I right off the bat noticed there was a hum coming out of the speakers, the amp didn't stay in the system long. I then moved the amp out
by my computer using a Adcom GTP-400 pre and Missiom bookshelf speakers NO HUM and high end which was not really present before appeared. I've been told input impedance my be a issue as this amp has a low value and maybe the Adcom
was just a better match for this amp. Thoughts on this please ........Pumpkins just don't know
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Hey Mr. Pumpkin,
Any comments to make about our listening session at Shadowlights? Wink2
Pleasure meeting your wife, for sure!
-Mike
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Hey Mr. Pumpkin,
Any comments to make about our listening session at Shadowlights? Wink2
Pleasure meeting your wife, for sure!
-Mike
We were listening to I believe a Cherry Class D amp $2000.00(?) Brought by someone on Sunday.
The big diff. that I noticed was that bass was much tighter in the Cherry. The Cherry was very very nice amp
Shadowlight was using a tubed pre his Class D sounded much better than mine hooked up to the Mcintosh
......................................P umpkins just want to have fun
If anyone is interested I found a link to the Cherry http://www.digitalamp.com/ Of course this is not CHEAP and cheerful
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I've been told input impedance my be a issue as this amp has a low value and maybe the Adcom was just a better match for this amp. Thoughts on this please...
Well, Tom told me that the amp's input impedance is 45K. That doesn't sound low to me. :?
We need to clear up this hum issue so others can avoid it.
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I've been told input impedance my be a issue as this amp has a low value and maybe the Adcom was just a better match for this amp. Thoughts on this please...
Well, Tom told me that the amp's input impedance is 45K. That doesn't sound low to me. :?
We need to clear up this hum issue so others can avoid it.
I was told it's value was 3000 which would be low by someone on line..............Bill
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Here's the email.
Hi Roy,
Yes, the impedance is 45K. Please let me know if I can be more help.
Thanks,
Tom
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Here's the email.
Hi Roy,
Yes, the impedance is 45K. Please let me know if I can be more help.
Thanks,
Tom
Which amps are we talking about, the IR based amps or the TI...
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I asked about this one...
http://classdaudio.com/index.php/class-d-power-amplifier-250w-x-2-500w-x-1.html
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We were listening to I believe a Cherry Class D amp $2000.00(?) Brought by someone on Sunday.
What Class D Audio amp were you comparing to what Cherry amp?
steve
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What Class D Audio amp were you comparing to what Cherry amp?
steve
Shadowlight's which is the same one I did, but to me this is not apples to apples.
Price point says that all buy itself.
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I just looked over the website, and the Cherry Jr. and DAC 4800A appear to be nearly the same and the price, too. Very, very nice... would love to hear one, but I'd love to hear a lot of stuff. :icon_lol:
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Pumpkinman -
Don't forget, Shadowlight showed us that when he toggled a switch in back of the Bella the hum was noticable, then not noticable, and he thought the toggle was matching the impedance, or at least changing the value to something more agreeable to the classD amp, thus diminishing the hum.
Gene
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Pumpkinman -
Don't forget, Shadowlight showed us that when he toggled a switch in back of the Bella the hum was noticable, then not noticable, and he thought the toggle was matching the impedance, or at least changing the value to something more agreeable to the classD amp, thus diminishing the hum.
Gene
The Bella Pre has a -6db switch in the back which made the hum go away on the amp. When I hooked up the amp directly to the squeezebox or to yamaha htr receiver I do not hear any hum. Most likely what we were hearing was tube hum or one of the tube is not functioning correctly because I get that hum with the Butler, Threshold or VAC amp.
I liked the sound of the Cherry also but currently the price is out of my range/budget. If I had the coins would I spring for the Cherry amp and the answer would have to be yes.
What I will most likely end up doing is purchase a second amp board and run the two together in bridge mode to get 250wpc @ 8ohms.
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I think we may have been hearing an impedance mis-match with Shadow's pre and his ClassD kit. The difference between his Bella (900 ohm IIRC) and ClassD kit vs. the the VAC preamp and Cherry Jr was so striking as to make me think something was not matched up right. Perhaps the switch on the Bella was coming into play? If I'm right about the 900 ohm output of the Bella and the 3Kohm input of the kit, that's quite a way from the oft-cited 10:1 ratio.
Sure cheap and cheerful is great, but it's gotta be hi-fi too :thumb:
This has really gotten me thinking about the importance of impedance matching.
Is the Pass B1 kit supposed to be used in between a preamp and the kit? Sound like a lot of doing to be able to drive a 3K input impedance.
Just trying to be honest so people can get the most from their kits.
-Mike
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I don't recall where I heard the 3Kohm input impedance value from - If mistaken I apologize for the misinformation.
-Mike
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I don't recall where I heard the 3Kohm input impedance value from - If mistaken I apologize for the misinformation.
-Mike
One of the earlier post had mentioned 3kohm but post 173 (quoted email from Tom) says 45k ohms.
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One of the earlier post had mentioned 3kohm but post 173 (quoted email from Tom) says 45k ohms.
a 900 ohm output impedance from the Bella should be fine for the IR based Classd amps. I've read 3k input impedance from several places, and the pdf for the IR chip actually states to use a source with no more than 600 ohms. But clearly good performance is being had at higher values. So it's hard to say what works best. If Tom says its 45k, though, I'll defer to him.
I will say that from all the playing around I've done with my amp, I believe it is very, very transparent. Any changes upstream are noticeable straight away. Whether or not a buffer like the B1 is *necessary* to get the most out of the amp is uncertain. People certainly seem to be enjoying them without it!
Maybe once my build is done we can do what Audiokarma (aptly) does for some gear and send it around to different people to try out w/ their own classdaudio amps and pres and report back (it's light and should easily fit in a Priority medium flat rate box).
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I'm the one that originally mentioned the 3k input impedance in this thread. The measurements from which I derived that input impedance are on page 13, and I'm quite certain the input impedance of my amp is ~3k ohm. Also, as wushuliu stated, 3k is the value given in the spec sheet for the amp (also posted by me on page 13), and others on diyaudio have stated the input impedance is 3k. I would be very curious to see Tom's measurements demonstrating an input impedance of 45 k or to know if he's made changes to the amp since I ordered mine.
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That's a great idea. I'm curious to hear what the buffer does myself. I agree about the transparency. In my experience, the Class D amps are very sensitive to changing interconnects, power cords and even types of internal wiring.
steve
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Maybe once my build is done we can do what Audiokarma (aptly) does for some gear and send it around to different people to try out w/ their own classdaudio amps and pres and report back (it's light and should easily fit in a Priority medium flat rate box).
I would be glad for an opportunity to hear the amp on tour. The reason being that, over the past three years, I bought several amps that were highly touted in the audio press and in forums, including tripaths and tubes. I no longer have any of those amps because my 25 year old Cary 807 surpassed them by far. In other words, I've misspent my meager audio budget, several times, and I do not want to repeat that unsound exercise.
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(http://classdaudio.com/media/catalog/product/cache/1/image/5e06319eda06f020e43594a9c230972d/t/i/ti-amp2-1_whitebk_2.jpg)
This thread has me thinking of trying the 600W module, mainly since its touted as stable into 2ohms, and my bass section is just under 4ohms. Plus I have found that there is no substitute for power when it comes to bass. I currently biamp, with a crossover point @ 320Hz.
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I would be glad for an opportunity to hear the amp on tour. The reason being that, over the past three years, I bought several amps that were highly touted in the audio press and in forums, including tripaths and tubes. I no longer have any of those amps because my 25 year old Cary 807 surpassed them by far. In other words, I've misspent my meager audio budget, several times, and I do not want to repeat that unsound exercise.
See Niteshade post of "amplifier tour", they have one based on the ClassDamp design that they are sending out on tour
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When I asked Tom at Class D Audio to compare the TI amp to the IR amp as far as sound quality, the reply was:
"The 600W amp is the TI chip and sonic quality is not as good as our other amps with the IR chip. Our IR based amps are some of the finest sounding audio amplifiers on the market today. The TI rating of 600W is actually at 10% distortion, so our 250W X 2 4 ohm, 500W X 1 8 ohm is actually rated full power at 1% so actually are more powerful. Our IR based amps are more powerful than people think and all are surprised when they listen to them. The actual distortion levels of these amps through almost all of the power range is more like .006%.... very good!"
Steve
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When I asked Tom at Class D Audio to compare the TI amp to the IR amp as far as sound quality, the reply was:
"The 600W amp is the TI chip and sonic quality is not as good as our other amps with the IR chip. Our IR based amps are some of the finest sounding audio amplifiers on the market today. The TI rating of 600W is actually at 10% distortion, so our 250W X 2 4 ohm, 500W X 1 8 ohm is actually rated full power at 1% so actually are more powerful. Our IR based amps are more powerful than people think and all are surprised when they listen to them. The actual distortion levels of these amps through almost all of the power range is more like .006%.... very good!"
Steve
Being an owner of both amps I'd agree with his statement.
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So it would seem the only reason one might choose the TI amp is to either drive a load of 2 ohms to 4 ohms in stereo mode or a 4 ohm load in bridged mode?
The description says "with a power stage designed to drive 2-Ω to 8-Ω speakers at up to 300 W per channel in stereo, or up to 600W bridged".
It doesn't mention the impedance range in bridged mode, but I would assume that it would be limited to 4 ohms in bridged mode, whereas the IR-based amps would be limited to 8 ohms in bridged mode?
Steve
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This thread has me thinking of trying the 600W module, mainly since its touted as stable into 2ohms, and my bass section is just under 4ohms. Plus I have found that there is no substitute for power when it comes to bass. I currently biamp, with a crossover point @ 320Hz.
Martin,
Let me know if you want to borrow the 250x2 amp to try out.
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The Primary Election in Texas is over and my client won. Now I get to move on to the really exciting stuff when my extra parts arrive...probably on Friday.
Anyway, here's what I have so far and I'm looking forward to wiring this puppy up and hearing what it sounds like.
(http://www.audiocircle.com/image.php?id=27375)
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Looks awesome, i think you will be impressed. Are you still running the single driver speaks? :eyebrows:
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The Primary Election in Texas is over and my client won. Now I get to move on to the really exciting stuff when my extra parts arrive...probably on Friday.
Anyway, here's what I have so far and I'm looking forward to wiring this puppy up and hearing what it sounds like.
I don't think you will be dissapointed. I have about 90 hrs on my 120x2 and it is sounding sweet! :thumb:
Best,
Ed
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Looks awesome, i think you will be impressed. Are you still running the single driver speaks? :eyebrows:
Yep, still have the Omega Bipoles and am really looking forward to what a little extra power might do. Running them like I do, in bipole mode, will produce an 8 ohm load, which will double the 30 wpc I now have with the Sig 30.
I don't remember exactly what my system comprised of when last we spoke, but now it's a Bolder modified Squeezebox III into a Burson buffer, to a Mapletree pre, to the RWA Sig 30 and out to the Omegas. I think with the buffer and the pre I'm going to have some latitude in setting this amp up to perform at its best...at least I hope so.
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So it would seem the only reason one might choose the TI amp is to either drive a load of 2 ohms to 4 ohms in stereo mode or a 4 ohm load in bridged mode?
The description says "with a power stage designed to drive 2-Ω to 8-Ω speakers at up to 300 W per channel in stereo, or up to 600W bridged".
It doesn't mention the impedance range in bridged mode, but I would assume that it would be limited to 4 ohms in bridged mode, whereas the IR-based amps would be limited to 8 ohms in bridged mode?
Steve
maybe this will help (from Tom)
The TI amp is a completely different configuration. The chip is actually 4 amps, so in stereo mode it’s actually 2 amps running in bridge mode, which actually quadruples the power rating from one amp, and when you put it into parallel bridged mode, it doubles again. The TI amp can run low loads from 2 ohm and up in stereo or bridged mode. The IR amps… other than our highest power one can also run 4 ohm in bridged mode with no problems. The power won’t double to 1000W at 4 ohm in bridged mode due to current limiting protection circuitry. The parts just aren’t made to run 1000W, but still very powerful.
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I'm the one that originally mentioned the 3k input impedance in this thread. The measurements from which I derived that input impedance are on page 13, and I'm quite certain the input impedance of my amp is ~3k ohm. Also, as wushuliu stated, 3k is the value given in the spec sheet for the amp (also posted by me on page 13), and others on diyaudio have stated the input impedance is 3k. I would be very curious to see Tom's measurements demonstrating an input impedance of 45 k or to know if he's made changes to the amp since I ordered mine.
To clarify this, I asked Tom and he indicated he has modified the input impedance on his amps to be more compatible with more preamps on the market. It is indeed now 45K ohms. Here's a quote from Tom:
"I’ve modified the input impedance to 45K. Also lowered the gain. I’m trying to make them more compatible with all equipment. They’ve always worked with almost all preamps, but a few had had problems, so I make changes when necessary to always try to improve them. The sound quality has not changed, and it’s something most would never notice, unless of course they were one of the few that had a preamp mismatch."
steve
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Thank you for clarifying the impedance issue.
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To clarify this, I asked Tom and he indicated he has modified the input impedance on his amps to be more compatible with more preamps on the market. It is indeed now 45K ohms. Here's a quote from Tom:
"I’ve modified the input impedance to 45K. Also lowered the gain. I’m trying to make them more compatible with all equipment. They’ve always worked with almost all preamps, but a few had had problems, so I make changes when necessary to always try to improve them. The sound quality has not changed, and it’s something most would never notice, unless of course they were one of the few that had a preamp mismatch."
steve
Strong work. 45K will be far more compatible with nearly anything for that matter. Still, it would be nice to see the actual measurement as gitarretyp had noted. I'm glad that Tom is flexible with his amps. Perhaps he'll post this on his website when he has some time.
Anand.
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To clarify this, I asked Tom and he indicated he has modified the input impedance on his amps to be more compatible with more preamps on the market. It is indeed now 45K ohms.
I received my third 120x2 board just a couple days ago . . . its input is configured the same as the previous boards received. Rin is 4k Ohms on all the boards. It is not obvious how that could be significantly changed, since Rf/Rin determines overall gain, and Rf (100k in the 120x2 board) is constrained by the needs of the input integrator. The obvious "solution" is to add a unity gain buffer (like the unity gain inverter used on channel 2 in bridge mode), and perhaps that will appear on a new board revision. As of two or three days ago, however, the input impedance of boards delivered was not 45k Ohms.
Perhaps you can ask Tom exactly what he has changed? The boards I have follow the IR reference amp almost exactly (although layout is different to accomodate the smds, and part numbers are changed, which makes circuit tracing more difficult). If there is going to be new input circuitry it would be nice if it were documented . . .
I should note that the nominal gain of my boards is 24, and the equivalent IR reference amp has a Rin of 3.3k Ohms and a nominal gain of 30.
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Anyone put a volume pot on theirs?
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Perhaps you can ask Tom exactly what he has changed? The boards I have follow the IR reference amp almost exactly (although layout is different to accomodate the smds, and part numbers are changed, which makes circuit tracing more difficult). If there is going to be new input circuitry it would be nice if it were documented . . .
I should note that the nominal gain of my boards is 24, and the equivalent IR reference amp has a Rin of 3.3k Ohms and a nominal gain of 30.
I suggest you ask Tom this directly. He's very responsive to emails.
steve
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I'm very pleased with my amp so I'm going to build a case from scratch I will have help from the sheet metal shop
(http://www.audiocircle.com/image.php?id=27386)
Since Pumpkins rule there will have to be some orange included in this project
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Pumpkin that looks very cool, curious about what your costs will be?
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These amps are easy to drive, so a volume control will work perfectly. There is no need for an active preamp. Actives still work well, but you will find less travel in the volume control.
Anyone put a volume pot on theirs?
That was a good bit of information regarding the sound qualities of the TI based amp, posted earlier on.
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I would be interested in building one of these amps, Not very familiar with any amp/speaker combo. Would anyone here is this thread recommend these for LARGE ADVENTS? Which AMP/Watts would be best?
Any thoughts?
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Pumpkin that looks very cool, curious about what your costs will be?
Total costs at the sheet metal shop will be $15.00 Should I use spikes or just rubber feet ?
Poplar for the sides mdf for the top (paint grade) I was thinking about a Maple front. My primary reason
for doing this is I want the switch in the front this time and because like the mountain it's there.
Total costs should no more than 40.00 I'm guessing.Depending on feet. After reading some of the posts
it seems that an all wood cabinet is not the way to go that's why I went to the sheet metal shop......................Bill
Right after posting I remembered I had three cones I can use as feet
(http://www.audiocircle.com/image.php?id=27387)
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Pumpkinman,
You either have a friend at the metal shop, or got lucky and found one that is uber-reasonable, but I think the majority of us would have trouble finding a shop that would cut and bend an aluminum back panel for $3.00 or a chassis for $15.00!
Steve
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After reading some of the posts
it seems that an all wood cabinet is not the way to go that's why I went to the sheet metal shop.........
While i wouldnt mind a grounded case my all wood cabinet works great and the price was very cheap and cheerful. :eyebrows:
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Pumpkinman,
You either have a friend at the metal shop, or got lucky and found one that is uber-reasonable, but I think the majority of us would have trouble finding a shop that would cut and bend an aluminum back panel for $3.00 or a chassis for $15.00!
Steve
My father was a sheet metal man, making custom duct work for heating and cooling of residential and commercial housing and businesses. A good sheet metal man could knock one of those cabinets out in 15 minutes or less. Look under heating contractors in the phone book.
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You either have a friend at the metal shop, or got lucky and found one that is uber-reasonable, but I think the majority of us would have trouble finding a shop that would cut and bend an aluminum back panel for $3.00 or a chassis for $15.00!
It's the power of the pumpkinking!! :thumb: :lol:
steve
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I suggest you ask Tom this directly. He's very responsive to emails.
I have, and got no response to requests for schematics, information about changes from the IR reference design, or the NiO (apparently) input coupling cap. He did respond about the undocumented change from RCA connectors (still pictured on the web site) to input terminal strips, and gain (but without noting the specific change made to change gain from the 30 of the reference design to the (nominal) 24 as delivered on mine). Fortunately except for part numbering (a pesky inconvenience for circuit tracing) there appear to be no significant deviations (other than parts numbering and use of SMDs) from the circuit of the IRAUDAMP7S as described at:
http://www.irf.com/technical-info/refdesigns/iraudamp7s.pdf
unless you regard the input cap and output filter (particularly the inductor type) as significant, and that makes it (relatively) easy to figure things out.
Having had limited luck getting information about product actually delivered to me I wouldn’t expect to have any luck getting information about product still “on the drawing board”. That’s why I directed that question to you . . . since Tom seems willing to discuss future plans with you. A date for when he plans to start delivering the new 45k Ohm input impedance boards would be nice (for the users to whom it matters), as would schematics (and parts list) of the amps already, and to be, delivered.
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I have no doubt that a competent metal man could make a chassis in 15 minutes. But I still think that the charge would normally be more than $15.00, and to have someone do anything to a piece of metal for $3.00 out the door is incredible!
So, if anyone else has a custom chassis made for them, please report back and let us know what you got and what you paid.
Steve
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I have no doubt that a competent metal man could make a chassis in 15 minutes. But I still think that the charge would normally be more than $15.00, and to have someone do anything to a piece of metal for $3.00 out the door is incredible!
So, if anyone else has a custom chassis made for them, please report back and let us know what you got and what you paid.
Steve
Here's a hint. If you walk in, wearing a suit and tie, with a blue-tooth hanging from your ear, texting from a Blackberry, expect to pay retail+. OTOH, walk in wearing a stained white tee shirt, holey jeans, with a sketch on a dirty napkin FTW.
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Pumpkinman,
You either have a friend at the metal shop, or got lucky and found one that is uber-reasonable, but I think the majority of us would have trouble finding a shop that would cut and bend an aluminum back panel for $3.00 or a chassis for $15.00!
Steve
Actually you are quite correct I've been friends with Scott for about 25 years and he would do it for nothing
if I asked him to. This does include the friendship factor which I never a second thought about.......Bill
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If the amp works laying on a board, why wouldn't it work fine in a wood enclosure?
But, what do I know? :?
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Here is a scrap piece that I tried out which will be the center of the front
Having a friend at the shop I hope won't diminish in any way my cabinet, to my
AudioCircle friends. I thought a circle in the center were the switch will be would
look good the center will orange in honor of all my pumpkin brothers......................Bill
(http://www.audiocircle.com/image.php?id=27389)
To bad I'm home again as there is no work again that's why I can fool around with it today................. :(
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These amps are easy to drive, so a volume control will work perfectly. There is no need for an active preamp. Actives still work well, but you will find less travel in the volume control.
Blair, thanks for that info. What value VC do you recommend? How about 20K ohms? :D
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I thought a circle in the center w[h]ere the switch will be would look good the center will [be] orange in honor of all my pumpkin brothers
Maybe you could find a painter who isn't a friend and does lousy work, so that the end result will have plenty of "orange peel".
Steve
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If the amp works laying on a board, why wouldn't it work fine in a wood enclosure?
But, what do I know? :?
It works fine in a wood enclosure, but the amp design/layout is not the best in terms of minimizing RF generation from the circuit board itself. So, using a non-metal enclosure increases the chances of interference of television and radio reception.
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It works fine in a wood enclosure, but . . . not the best in terms of minimizing RF generation
Exactly so . . . and the cost of EMI compliance/certification is probably part of the reason there is no assembled product or even complete "kit". As it is the responsibility for emission control lies with the individual builders.
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Maybe you could find a painter who isn't a friend and does lousy work, so that the end result will have plenty of "orange peel".
Steve
Orange peel that would give it a hammered steel look, what a great idea !! Thanks Steve
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Exactly so . . . and the cost of EMI compliance/certification is probably part of the reason there is no assembled product or even complete "kit". As it is the responsibility for emission control lies with the individual builders.
Welcome to AudioCircle
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Welcome to AudioCircle
Well thanks . . . I'd visited before, but it was the experience of others with the IRS2092 based amps that got me to register. They seem to be the best thing going at this time for the Class D DIYer, and the 2092 boards from classDaudio are a great deal with only a couple minor, and easily corrected, issues. As you know, they sound great . . .
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only a couple minor, and easily corrected, issues
Care to enlighten us. :drool:
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Care to enlighten us. :drool:
I don't know how "enlightening" it is, as it's all pretty obvious, but a few issues, in no particular order:
- the SMD input coupling cap is less than ideal (the manufacturer boasts that it's "as good as solid tantalum").
- the output filter is optimized for 4 Ohm loads, and high frequency response varies with speaker load impedance (this is documented in the reference design pdf).
- the output inductor is undocumented . . . it may or may not be a problem, but see the distortion graph in the reference docs . . .
- the power supply could use some snubbing/decoupling, especially if two amp boards will be used on the same supply.
- the gain/input impedance issues already discussed.
Nothing really serious . . . all easy to deal with . . .
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I don't know how "enlightening" it is, as it's all pretty obvious, but a few issues, in no particular order:...................Nothing really serious . . . all easy to deal with . . .
I have always wanted a "dual mono" amp, using 1 enclosure and 1 power cord.
I had thought about using 2 of the 250W at 4 ohm boards, bridged, with 2 transformers and 2 HD power supplies.
Both pairs of my current speakers are 4 ohm. Would this configuration accomplish anything meaningful or address any of the power supply or output limitations? Or might a different configuration make more sense?
Steve
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I agree 100% with dewardh. I've optimized the low pass filter on my amp for 8 ohm loads, and it does improve the top end a little. As a caveat, optimizing the filter for 8 ohm loads will lead to a fair bit of roll-off in the top octave for 4 ohm (8 ohm mono) and lower loads.
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Both pairs of my current speakers are 4 ohm.
None of the IR designed boards are speced for use bridged into 4 Ohm loads. Look at the table on page 4 of the Reference Design pdf for suitable configurations.
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Look at the table on page 4 of the Reference Design pdf for suitable configurations.
How about providing links?
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None of the IR designed boards are speced for use bridged into 4 Ohm loads. Look at the table on page 4 of the Reference Design pdf for suitable configurations.
I was going by what Tom had written in an email reply: "The sonic quality is the same in either stereo (half bridge) or full bridge mode. Only the 250W X 2 into 8 ohms is not recommended for 4 ohm in full bridge mode. Our other amps will run 4 ohm with no problem, either stereo or bridge."
Steve
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To use who are currently using these units, how is the bass performance? Tom told me the damping factor was around 120 which seemed surprisingly low....
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How about providing links?
I did, in #628 above. Here it is again:
http://www.irf.com/technical-info/refdesigns/iraudamp7d.pdf
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I was going by what Tom had written in an email reply: "The sonic quality is the same in either stereo (half bridge) or full bridge mode. Only the 250W X 2 into 8 ohms is not recommended for 4 ohm in full bridge mode. Our other amps will run 4 ohm with no problem, either stereo or bridge."
Steve
How old was that e-mail from Tom? In a recent e-mail to me he said all higher powered amps will have a new heatsink, allowing 4 ohm operation.
Paul
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he said all higher powered amps will have a new heatsink, allowing 4 ohm operation.
For bridge mode into 4 Ohms they would probably need changes to the output filter as well, to avoid high frequency rolloff, and possible inductor core saturation. The output filter is load sensitive. The output FETs have some current limits (which also effect turnoff timing). Because of the wide variation in loudspeaker loading there is no single turnkey solution for Class D amplifiers . . . there really is a "DIY" component in getting it right.
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How old was that e-mail from Tom? In a recent e-mail to me he said all higher powered amps will have a new heatsink, allowing 4 ohm operation.
2/26/2010
He prefaced the paragraph I quoted above with "Yes, the heatsink for the 250W X 2 into 8 ohm is standard now"
And then went on to say "Only the 250W X 2 into 8 ohms is not recommended for 4 ohm in full bridge mode. Our other amps will run 4 ohm with no problem, either stereo or bridge"
Steve
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dewardh - At a given price point such as this, one can expect certain design and build compromises. Have you had a chance to compare these modules against other well known class D designs such as the B&O ICE modules? Although I don't fully grasp all of the technical details you present, I certainly appreciate your airing of the information.
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At a given price point such as this, one can expect certain design and build compromises.
Oh, absolutely. What’s astonishing about the classDaudio boards, considering their price, is how few compromises there are overall. There’s nothing particularly obscure about the *reason* for the compromises, either . . . “audiophile grade” input coupling caps would cost $10-20 each, and be the largest parts on the board as well, and folks would (will) argue all day about whether they’re worth it.
Have you had a chance to compare these modules against other well known class D designs such as the B&O ICE modules?
I’ve been watching Class D evolve into a useable technology just like everyone else . . . studying, and listening to when possible, the various offerings as they came to market (and watching the manufacturers struggle with some of the same problems discussed here). I almost bit on the Hypex modules when they became available, but the price was too much, and there were aspects of the design that didn’t satisfy. I haven’t seen any DIY friendly ICE modules, although they are now used in a number of commercial amps, and TriPath has its own problems, and not enough power. The overall *sound* of almost all the Class D devices is good, though. I attribute a lot of that to the absence of crossover distortion . . .
The IRS2092 driver design, and the classDaudio copies of the reference board, were the first that really said to me “right stuff at the right price”. They sound as good as the 3886 chip amps, without the power limitation. They do have issues and limitations of their own . . . but all amplifiers do, and so far I haven’t found any “show stopper”. At the moment I think they (along with the 3886) are the best deal going in DIY audio electronics.
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This has really gotten me thinking about the importance of impedance matching.
Some info on impedance matching:
http://www.audiocircle.com/index.php?topic=78263.msg743813#msg743813
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They sound as good as the 3886 chip amps, without the power limitation. At the moment I think they (along with the 3886) are the best deal going in DIY audio electronics.
I'm glad you brought that up because I was wondering how the two would compare. If the ClassD amps can do what the 3886 amps do with more power and authority, then I finally understand what all the *hoopla* is about.
When I got my 3886 recently, it just "unveiled" the sound so I could hear "through the music." Amazing spacial clarity, resolution, depth... :drool: Of course system matching and efficient speakers help.
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Oh, absolutely. What’s astonishing about the classDaudio boards, considering their price, is how few compromises there are overall. There’s nothing particularly obscure about the *reason* for the compromises, either . . . “audiophile grade” input coupling caps would cost $10-20 each, and be the largest parts on the board as well, and folks would (will) argue all day about whether they’re worth it.
How would one go about this mod, are these the same caps a few others have swapped out? The ones located behind the speaker posts? What caps would be reccomended, Sonicaps for instance? Is this one of the upgrades with the new board revision Tom is working on? What mods have you done to the board and results achieved? Thanks for all the insight! :drool:
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I haven’t seen any DIY friendly ICE modules
Check out Marchand Electronics... they are selling the 1000w ICEPower 1000ASP modules for $490 each (SMPS power supply is integral, but you need two modules for stereo).
http://marchandelec.com/amplifiers.html (http://marchandelec.com/amplifiers.html)
A bit pricey for my tastes (though not compared to finished versions being sold) which is why I've been lurking on this thread contemplating the ClassDAudio kits for some time now. I may have to give them a try, but want to make sure my Reference Line Preeminence Passive Pre will work with them first.
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are these the same caps a few others have swapped out? The ones located behind the speaker posts? What caps would be reccomended . . . What mods have you done
I have only seen comments about changing the output filter caps (the large blue cubes by the output terminals), although others may have changed the inputs. The input coupling caps are the orange surface mount devices (3-4 mm on a side) by the input terminals. They are physically tiny by comparison to the output caps (but have somewhere around 100 times the rated capacitance). Replacing them on the board would be near impossible because of size diferences and lack of holes for physical attachment . . . it would be done between whatever RCA input connector is used and a (modified) input on the amp board. I'm not religious about caps, and would (will) use any good quality metalized film (which may already be present in your crossover (as with mine) or pre-amp output). The easiest or best mod depends on your specific enclosure and signal source . . . in some circumstances (decoupling and proper grounding at your source's output) it may not be needed at all (but there *must* be decoupling *somewhere* between the source and the amp input). I'll give detailed reports on the mods I've done after they've been well tested and demonstrated safe. If you bypass the input coupling cap, for example, you CANNOT just plug in any source and expect it to work . . . you have to know the source's output circuit, and that it is compatable with the (modified) amp input.
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The input coupling caps are the orange surface mount devices (3-4 mm on a side) by the input terminals. They are physically tiny by comparison to the output caps (but have somewhere around 100 times the rated capacitance). Replacing them on the board would be near impossible because of size diferences and lack of holes for physical attachment .
It appears that you could remove the orange SMD caps, solder a jumper across the pads and then series the new cap between the RCA input and the positive through hole connection of the removed terminal block. I haven't tried it but it at least apprears to be doable.
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Check out Marchand Electronics... they are selling the 1000w ICEPower 1000ASP modules for $490 each (SMPS power supply is integral, but you need two modules for stereo) . . . A bit pricey for my tastes
A bit pricey for me, too, although probably very nice. It's also *far* more power than I ever need, since I use active crossovers . . .
I've been lurking on this thread contemplating the ClassDAudio kits for some time now. I may have to give them a try, but want to make sure my Reference Line Preeminence Passive Pre will work with them first.
Might be best to wait for the higher input impedance boards that are rumored to be coming, unless you're absolutely sure how the Passive Pre responds to low impedance loads (and the pass-through effect on your sources).
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It appears that you could remove the orange SMD caps, solder a jumper across the pads and then series the new cap between the RCA input and the positive through hole connection of the removed terminal block. I haven't tried it but it at least apprears to be doable.
Yes, that's probably the easiest option. Might want to remove the 100k input "load" resistor too, and move it (and a RC low-pass) to the RCA connector. Exactly how you'd do it depends on physical layout and shielding . . .
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Yes, that's probably the easiest option. Might want to remove the 100k input "load" resistor too, and move it (and a RC low-pass) to the RCA connector. Exactly how you'd do it depends on physical layout and shielding . . .
Deward, are the input caps for the IR amps 22uf per the pdf?
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Deward, are the input caps for the IR amps 22uf per the pdf?
The IR reference design specs 22uf. I do not have an IR reference board to examine. The caps on the classDaudio boards that I have are marked, and measure, 10uf.
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hello audiocircle forum and everyone! just joined extremely tempted by what i've already [34 pages!!] read here..
so my question is .. which one would you be your pick to drive ATC SCM11 ? 250 watts x2 @8ohm ? other ? has anyone tested one of these with ATC gear?
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Hello indietronic and welcome to AC.
As to your question well, it depends on your application and speakers.
The most universal version is 250 X 2 in 4 Ohms IMO.
Edit: 250 in 8 Ohms might be a better choice tho.
Regards
Mariusz
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The loot is in the mail. Will also get parts from my partners in crime in Canada, PartsConneXion very soon.
I need to arrange some sort of case for all the parts, maybe will carve out chunks of cut low grade ply in the garage, that was thinking about using for some never made speakers cabs.
My loot consists of 2 500 watt boards, the heavier duty PS and the toroid. The hardware will be some Furutech IECs, separate fuse holder, Cardas copper short binders, 14 gauge hookups in different colors, also got some Cardas female RCAs, heavy duty toggle switch.
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hello audiocircle forum and everyone! just joined extremely tempted by what i've already [34 pages!!] read here..
so my question is .. which one would you be your pick to drive ATC SCM11 ? 250 watts x2 @8ohm ? other ? has anyone tested one of these with ATC gear?
Blair, Niteshade Audio, knows his stuff and has high praise for this one: 250 watts/channel into a 4 ohm load, 125 watts/channel into 8 ohms. This is the one I'm most interested in myself.
http://classdaudio.com/index.php/class-d-power-amplifier-250w-x-2-500w-x-1.html
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My 250 x 2 has been shutting down if I play it fairly loud.
Anyone else getting shutdowns?
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My 250 x 2 has been shutting down if I play it fairly loud.
What kind of speakers are you using, what is the speaker impedance?
What is "fairly loud"?
What power supply are you using?
Is the enclosure well ventilated?
Is the heat sink too hot to touch when it shuts down?
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What kind of speakers are you using, what is the speaker impedance?
Not sure DIY.
What is "fairly loud"?
Above normal listening levels.
What power supply are you using?
Large
Is the enclosure well ventilated?
Yes
Is the heat sink too hot to touch when it shuts down?
Not sure.
Just wondering if others have been able to shut it down.
Jeff
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Just wondering if others have been able to shut it down.
Jeff
Can you tell us the speakers you are using with these and what type of music you are partial to?
For all that I know, it seems to me that some of these boards are spec for high watts, but perhaps these chips/designs are not as load invariant as some of the other designs out there.
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They are DIY "Scorpion" designed here on the board.
I'll also test with commercial speakers I have including
tough ones like Maggies.
The amp went into shutdown listening to rock.
(http://mysite.verizon.net/jkelly/ac/sp2.jpg)
I am thinking about adding a bigger heat sink or fan.
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Damn, as I suspect, it might be a issue of expecting high watts, but the board is not tolerant to load variance. Might need a fan to be installed or how you said, better heat sinking. I am thinking about using mine as a bass amp.
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Damn, as I suspect, it might be a issue of expecting high watts, but the board is not tolerant to load variance. Might need a fan to be installed or how you said, better heat sinking. I am thinking about using mine as a bass amp.
This thread is getting too long. If you read my post #361, you'll see a picture of my 250/8 ohm amp which Tom has added additional heat sinks to allow it to run into a 4 ohm load. I'm driving the bass panels of my Maggie IIIA's with it quite successfully. It replaced a Hafler DH-500 heavily modded by John Hillig of Musical Concepts (255 wpc/8 ohms, 400 wpc/4 ohms).
JKelly, I suggest you talk to Tom. It sounds like you're getting either undercurrect or thermal shutdown.
steve
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Hello all,
I am new to this site. I found out about this from a link on the Parts Express site. I ordered a 250 watts/channel into a 4 ohm load, 125 watts/channel into 8 ohms kit yesterday. This will be my first amp project. Speakers I have are DIY Mini Statements found here http://speakerdesignworks.com/MiniStatements.html
They are what could be considered 5 ohm speakers and they are the best I have at the moment. I hope this project pans out. If I get good results I will build a Tubelab Simple SE tube amp just for kicks. I was saving up to purchase two Emotiva UPA-1 mono block amps but I could not pass up this project. Thanks for the information in this thread as it has inspired me to do a DIY amp sooner than I hoped to.
Robert
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Welcome aboard, Robert. It's a fun project and a great buy and I think you'll be surprised at the quality of sound. Good luck!
steve
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Finally have mine in place; it's sounds quite good driving my Dynaudio Contour 3.4s.
First the guts, that I stuffed in an old computer peripheral box that I salvaged and sprayed black.
(http://www.audiocircle.com/image.php?id=27467)
Second, in the rack. Please forgive the lousy photo.
(http://www.audiocircle.com/image.php?id=27468)
I inlaid the small bit of aluminum to give the face a feature, but it's a bit much, so I'll swap it out with a piece anodized black at some point.
The wood is Australian blackwood, a close relative of Hawaiian koa.
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Hello all,
I am new to this site. I found out about this from a link on the Parts Express site. I ordered a 250 watts/channel into a 4 ohm load, 125 watts/channel into 8 ohms kit yesterday. This will be my first amp project. Speakers I have are DIY Mini Statements found here http://speakerdesignworks.com/MiniStatements.html
They are what could be considered 5 ohm speakers and they are the best I have at the moment. I hope this project pans out. If I get good results I will build a Tubelab Simple SE tube amp just for kicks. I was saving up to purchase two Emotiva UPA-1 mono block amps but I could not pass up this project. Thanks for the information in this thread as it has inspired me to do a DIY amp sooner than I hoped to.
Robert
I am fairly new to this site also (been lurking for awhile).
I have the 250x2 500x1 amp driving my Mini Statements, the sound quality IMHO is excellent.
I had an Emotiva LPA-1 before I decided to assemble my own amp, and this classD amp is easily it's equal to my ears. My wife, who has better hearing than I do, says the class d sounds better.
Here is my mix and match amp, it was originally 4 TDA8924 modules 3 bridged 1 stereo for 5 channels, now 1 classd 250x2 4ohns and 2 TDA8924 modules for 5 channel.
(http://www.audiocircle.com/image.php?id=27469)
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I am fairly new to this site also (been lurking for awhile).
I have the 250x2 500x1 amp driving my Mini Statements, the sound quality IMHO is excellent.
I had an Emotiva LPA-1 before I decided to assemble my own amp, and this classD amp is easily it's equal to my ears. My wife, who has better hearing than I do, says the class d sounds better.
Here is my mix and match amp, it was originally 4 TDA8924 modules 3 bridged 1 stereo for 5 channels, now 1 classd 250x2 4ohns and 2 TDA8924 modules for 5 channel.
Sounds as if I made a good choice. I like what you have done. This amp will be for two channel only ,however, if all goes well I may put together a three channel setup to power the front end of my HT setup. My Speakers
(http://www.audiocircle.com/image.php?id=27471)
(http://www.audiocircle.com/image.php?id=27472)
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I'm currently building a pair of GR Research NX2 speakers. They have low sensitivity of 85db if memory serves. I'd like to try one of these amps. I would be pushing it with a NAD pre which has an output impedance of 75. There will also be a Grant Fidelity B283 Tube Processor after the pre. Any obvious pitfalls besides not having a good tube pre?
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Very nice looking speakers. :thumb: Makes mine look like a "fisher price" product. LOL
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Excellent progress, gentleman!! :beer: Beautiful woodwork Streidl! I'm glad you guys are hearing what I'm hearing. I'm not crazy after all although some would argue. :scratch:
steve
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Sounds as if I made a good choice. I like what you have done. This amp will be for two channel only ,however, if all goes well I may put together a three channel setup to power the front end of my HT setup. My Speakers
(http://www.audiocircle.com/image.php?id=27471)
(http://www.audiocircle.com/image.php?id=27472)
Now there's a cabinet maker
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The amp went into shutdown listening to rock.
I am thinking about adding a bigger heat sink or fan.
I have been using the Ebay case and if I take the cover off the amp
doesn't shut down. The heat sink was extremely hot - untouchable.
So I think I will put a quiet Papst fan in their.
Can I pick off 12v for a fan off the board somewhere?
Jeff
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I have been using the Ebay case and if I take the cover off the amp
doesn't shut down. The heat sink was extremely hot - untouchable.
So I think I will put a quiet Papst fan in their.
Can I pick off 12v for a fan off the board somewhere?
Jeff
Hmm. surprised it's that warm... you can take the 12v off the board where it says "12V Fan". Might look into one of these http://www.quietpcusa.com/Rasurbo-Ultra-Quiet-40x40x10mm-Computer-Case-Fan-with-3-Pin-Connector-P81C65.aspx
or
http://www.acousticpc.com/silenx_40_x_10mm_14db_pro_fan.html
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The other thing you could do is run a standoff from the heatsink to the case top thus using the case as a HUGE heat sink.
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It appears that you could remove the orange SMD caps, solder a jumper across the pads and then series the new cap between the RCA input and the positive through hole connection of the removed terminal block. I haven't tried it but it at least apprears to be doable.
Well I jumpered the orange smd's and put 22uf dayton/jantzen caps in series w/ input. I'd say there's some improvement (some harshness but I'm sure that'll go away) but unfortunately I also put in a modded ebay dac and am so wowed by that it's hard for me to say how much a difference these new caps have made.
Upside is it's pretty easy to pop out those smd's and try it out for oneself. Only took a few minutes.
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Well I jumpered the orange smd's and put 22uf dayton/jantzen caps in series w/ input. I'd say there's some improvement (some harshness but I'm sure that'll go away) but unfortunately I also put in a modded ebay dac and am so wowed by that it's hard for me to say how much a difference these new caps have made.
Upside is it's pretty easy to pop out those smd's and try it out for oneself. Only took a few minutes.
Which ebay dac?
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Well I jumpered the orange smd's and put 22uf dayton/jantzen caps in series w/ input. I'd say there's some improvement (some harshness but I'm sure that'll go away) but unfortunately I also put in a modded ebay dac and am so wowed by that it's hard for me to say how much a difference these new caps have made.
Upside is it's pretty easy to pop out those smd's and try it out for oneself. Only took a few minutes.
X2
yeah, any links?
I was looking at few ready boards (upsampling and NOS)
but can not decide which one to try.
THX
Cheers
Mariusz
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X2
yeah, any links?
I was looking at few ready boards (upsampling and NOS)
but can not decide which one to try.
THX
Cheers
Mariusz
The most documented would be the gigawork kit. Upsampling board, usb, etc. Comes with a very high quality transformer as well.
http://cgi.ebay.com/Gigawork-24-192-Up-sampling-DAC-DA-CONVERTER-w-USB-kit_W0QQitemZ120474001273QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item1c0ccf5f79#ht_9175wt_996 (http://cgi.ebay.com/Gigawork-24-192-Up-sampling-DAC-DA-CONVERTER-w-USB-kit_W0QQitemZ120474001273QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item1c0ccf5f79#ht_9175wt_996)
Similar board but cheaper, with no usb or upsampling or transformer.
http://cgi.ebay.com/NEW-BIG-24bit-192Hz-HI-FI-DAC-DIY-KIT-ASSEMBLED-MODULE_W0QQitemZ140389033636QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item20afd6a6a4 (http://cgi.ebay.com/NEW-BIG-24bit-192Hz-HI-FI-DAC-DIY-KIT-ASSEMBLED-MODULE_W0QQitemZ140389033636QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item20afd6a6a4)
There's a 250 page(!) thread on these at diyaudio and many more threads on sifferent forums. But the short of it is:
Stock/opamp upgrade: better than dacmagic and up. Bargain as is.
Transformer outputs: bypass opamps and use transformers for the output = nirvana.
This mod is actually very simple.
(http://image.n0t.de/f-e5a84e20f3fc624e9c8e2aa9a801af6f.jpg)
I opted for a middle ground because the transformers can get a little pricey: I just put in different opamps and either removed electrolytics or replaced them w/ polyprop caps.
I don't have experience w/ high end dac's but I can't imagine that they can bring me much closer to the music than this. Maybe different flavor, soundstage, etc. I can't imagine what level the transformers would take it to. Anyhoos there are many, many threads out there with the same conclusion: phenomenal value.
I can start a short thread with some pics, as I don't want to take this off topic...
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I can start a short thread with some pics, as I don't want to take this off topic...
Go for it!
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Hmm. surprised it's that warm...
Are other boards not running hot? Maybe mine has an issue.
I had good luck with these fans when I was modding the Carver ZR1600:
http://www.endpcnoise.com/cgi-bin/e/std/category=Papst_Fans.html (http://www.endpcnoise.com/cgi-bin/e/std/category=Papst_Fans.html)
BTW these amps sound much better with hours on them!
Jeff
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What does Tom have to say about the heat issue? :|
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my amp is barely warm
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Is it exposed to the air, enclosed in a case or have a fan?
Does yours run only warm under a load?
Thanks!
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Is it exposed to the air, enclosed in a case or have a fan?
Does yours run only warm under a load?
Thanks!
My IR amp gets warm but it's never shut down and I've used it unventilated. The last time I read about an overly hot amp was on diyaudio. The person had the 600w amp and I think it eventually fried. Tom sent him a new board. So get in touch w/ Tom stat.
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Are other boards not running hot? Maybe mine has an issue.
Mine runs quite cool, even with a 35V transformer, but I am running 8 ohm, high efficiency drivers. What is are the impedance and efficiency ratings of your speakers?
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I am in contact with Tom who is very willing to check it out.
Just got to get to Monday!
Thanks for all the help and suggestions.
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This thread is getting too long...steve
This is turning into a monster! It's been a fun read so far. :thumb:
I think it would be a great idea to edit the first page of this thread into a wiki containing links to all of the highlights already posted...kind of a "Cliff Notes" for people discovering it. I've seen it work very well for hot topics before in various audio forums. It (somewhat) reduces the clutter of people coming into the thread and asking the same questions over and over and provides a nice resource in general for people discovering the thread.
I believe you could even edit the original subject title to say "Class D Audio Amps" or something like that.
Of course, since you are the OP, only you can do the editing... :green:
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So far this amp sounds great. I'm thinking of getting one for 250X2 or even 500x2 (8 ohms). However, since I can't audition them (I'm overseas), I'd like to hear some comparisons to existing power amps, especially other Class D.
If anyone can do this, it would be great. I saw one favorable comparison on the thread to The Wyred4Sound and the Bel Canto, and that was very encouraging, as both those items get favorable reviews in magazines.
It's clear the amps have power. Does anyone here have a tube amp (or even a SS) with very good micro dynamics they could compare it to? I'd like to hear how the Class D compares.
Thanks
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firedog, on page 33 dewardh said, "The IRS2092 driver design, and the classDaudio copies of the reference board, were the first that really said to me “right stuff at the right price”. They sound as good as the 3886 chip amps, without the power limitation.
My LM3886 gainclone has micro dynamics, resolution, spacial clarity as good as I've ever heard. I'm not sure how one could squeeze more detail out of the recordings. So if the ClassD Audio amps can do this with more power, then they must sound awesome.
I realize this is not a direct A/B comparison, but perhaps it will help in some way. :)
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Does anyone here have a tube amp (or even a SS) with very good micro dynamics they could compare it to?
If you go back to my initial post I compared my Class D amp to my VTL monoblocks.
steve
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Compared one to Digital Amp Co Cherry JR previously in the thread.
Night and day difference in favor of the Cherry. Not even close.
-Mike
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Compared one to Digital Amp Co Cherry JR previously in the thread.
Night and day difference in favor of the Cherry. Not even close.
-Mike
Ofcause that is your opinion Mike.
And keep in mind the price difference.
.... As well as full time job of spokeperson for Tommy. :lol:
Best
Mariusz
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Someone asked, so I gave honest feedback. Believe me, I'm biting my lip here...
Thanks for understanding. - Just trying to help
-Mike
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Someone asked, so I gave honest feedback. Believe me, I'm biting my lip here...
Thanks for understanding. - Just trying to help
-Mike
I have heard Tommy's amp and it is a fine product (wish I had extra $$$ to blow). The only problem - 20 : 1 price ratio.
If you like to explain the differences between these two in some constructive way, please do. (day & night conclusion is not really helpful)
Regards
Mariusz :thumb:
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I'm respectfull bowing out of this one.
Hope to see you at a Rave soon, Mariusz :thumb:
-Mike
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I'm respectfull bowing out of this one.
Hope to see you at a Rave soon, Mariusz :thumb:
-Mike
:scratch:
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The limited experience I've had w/ Class D (referring to amp type here) amps like the Tripath TK2050 and classdaudioamps and research on others, they are extremely responsive and you get out what you put in. I would assume the Cherry amps have much higher quality components and taking the designers experience at face value, a proprietary design that may get the most out of parts used. As an internet direct product I would imagine the Cherry would retail for much, more with a more established company.
So given all that the Cherry *should* sound better.
But I'm not going to spend another $1750 to find out! :D
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If you go back to my initial post I compared my Class D amp to my VTL monoblocks.
steve
Thanks for that. I didn't remember the original post (this is a long thread now) and to be honest, didn't know enough about the VTLs to totally appreciate your comment.
I went back and found some reviews of the VTLs, where they were praised as being extremely good. So if the Class D is better, it must really be good. And if the Cherry is that much better than the ClassD, then it must be close to state of the art. But then, my interest in this thread is mainly due to a desire to find value in audiophile level components, and avoid spending $2-$5K to get something really good. I don't have to worry about the WAF, and so can avoid spending money on the appearance of an amp.
Anthony Michaelson of Musical Fidelity claims that the inspiration for his "V" series of inexpensive components is the fact (acc'd to him) that up to 70% of the ultimate retail price of hi-end components is due to the cost of the cosmetics, and not the functional guts, of the units. Even if he is exaggerating a bit, that would still put the Class D amps easily at the level of components costing $1-$2K or more, especially when the saving of the labor costs for assembly is added in.
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up to 70% of the retail price of hi-end components is due to the cost of the cosmetics, and not the functional guts, of the units.
That's true!
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That's TRUE- BUT...people do not care.
Eye candy counts as much as or MORE than sonic performance. People just won't admit it. People buy according to appearance first.
That's true!
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Blair-
I don't deny it. On some items it is important to me, too. But not with this one. BTW, if your version of the classD had a fancy brushed aluminum case and fancy knobs/switches, it would probably cost $2K in a high-end store, and not half that online.
The other economic analysis of consumer electronics I've read is that typically there is a 7-8:1 ratio between retail price and manufacturer's cost.
This is due to 100% markups along the distribution/retail chain, and financing costs manufacturers and distributors bear in order to get retailers to hold inventory.
Again, I'm not saying that's illegitimate. It just explains why the classD could sound as good as typical hi-end amps costing 10 times or more than it does.
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The other economic analysis of consumer electronics I've read is that typically there is a 7-8:1 ratio between retail price and manufacturer's cost.
This is due to 100% markups along the distribution/retail chain, and financing costs manufacturers and distributors bear in order to get retailers in order to hold inventory.
That's every product...
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up to 70% of the ultimate retail price of hi-end components is due to the cost of the cosmetics, and not the functional guts,
That's WAY conservative . . . even in DIYland it's way easy to spend as much on the enclosure and and connectors as on the actual electronics . . . people in this thread have reported doing just that. Add in overhead, marketing, dealer markup and the designer feeding his kids amortized over a very limited volume of sales and a 10 to 1 (retail) markup over the cost of the electronics doesn't seem all that unreasonable. Then of course they have to claim that it "sounds better" to justify the price of the product to their customers . . .
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That's WAY conservative . . . even in DIYland it's way easy to spend as much on the enclosure and and connectors than on the actual electronics . . . people in this thread have reported doing just that. Add in overhead, marketing, dealer markup and the designer feeding his kids amortized over a very limited volume of sales and a 10 to 1 (retail) markup over the cost of the electronics doesn't seem all that unreasonable. Then of course they have to claim that it "sounds better" to justify the price of the product to their customers . . .
So, who wants to pony up the money to take a "Cherry" and I'll put it in my soon to be released case and see if it can be picked out?
:rotflmao:
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up to 70% of the ultimate retail price of hi-end components is due to the cost of the cosmetics, and not the functional guts, of the units. Even if he is exaggerating a bit
I would certainly agree that high-end cosmetics inflate the cost of a component, but that is exaggerated. Yes, people in this thread have spent as much on enclosure and connectors as the electronics, but that is because these DIY electronics are inexpensive without much margin.
A few years ago, I had 10 - 1U enclosures built at a local fabricator with heavy-duty powder-coated steel chassis, CNC black aluminum anodized 8mm front panel, holes punched and drilled, PEM threaded inserts and PCB standoffs, countersunk screw holes and silkscreened front and rear.
I paid ~$150 per enclosure, not including a few hundred dollars in setup charges.
So if you look at a boutique high-end amplifier that costs $7500, it could have $1000 of wholesale parts, and even if it had an over-machined enclosure like Pass Labs, that couldn't cost more than $500. The rest is distributor markup, dealer markup and manufacturer profit + "high-end bluesky".
Steve
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and even if it had an over-machined enclosure like Pass Labs, that wouldn't cost more than $500.
Steve
I tend to disagree. Have you looked at my gallery? If not, take a look at my sub that I made. There is A LOT more then that in material (6061) cost. If you were to then add my design, machine and assembly time, that's how you get REALLY expensive gear. Of course, that's without the $50k per month TAS ads.
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I tend to disagree. Have you looked at my gallery? If not, take a look at my sub that I made. There is A LOT more then that in material (6061) cost. If you were to then add my design, machine and assembly time, that's how you get REALLY expensive gear. Of course, that's without the $50k per month TAS ads.
The Pass enclosure does not have a comparable materials and machining scope to your subwoofer. It's a steel chassis with some overly hefty CNC machined front panel pieces, and an over-the-top example at that, which I probably shouldn't have picked.
In the context of average "high-end" components, I was merely refuting the comment that "up to 70% of the ultimate retail price of hi-end components is due to the cost of the cosmetics", although it certainly adds to the cost.
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Hope this is legal: http://www.audioholics.com/education/amplifier-technology/clone-amplifiers
The class D amps sound great,especially for a couple hundred bucks. You also get the knowledge and pride of building something on your own. As far as parts for assembly you can go as cheap and cheerful or as exotic as you want making your amp the way you want it.
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The audioholics article links to this: http://www.hificritic.com/downloads/Class-D.pdf
which basically claims that ClassD amps, by definition, aren't even real hi-fi and can't sound good.
Interesting b/c lots of critics and experienced audiophiles have reacted to many of the recent examples saying how "surprised" they are and how "good" they sound. Shouldn't the "ear" test be more important than the "theory" test?
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Shouldn't the "ear" test be more important than the "theory" test?
YES, but data is fun to look at. :)
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Guys
lets keep it on topic.
I certainly won't tolatate bashing other brands on this circle ( not that it happened but it might turn into a pig fight. We do not want to do that. Unless you want this thread locked. :scratch:)
Thank you
Regards
Mariusz :thumb:
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Unless you want this thread locked. :scratch:)
Thank you
Regards
Mariusz :thumb:
No sir!
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I would love to see data on the on-topic Class-D modules. . .even though I would probably have no clue what most of it means. . . :lol:
Paul
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Ummm...hope I am not seeing a sorta theme evolving here, where any dissenting views on the sonic quality of these modules are subject to ridicule and overbearing arm wrangling. That will be a shame since this thread is now over 35pages, however when something has come such a long way there may be the tendency to be over protective.
I have been offered one of these amp module for a home demo, and hope I can post whatever impressions I have compared to what I am currently using which is nothing fancy, a modified Adcom 555II.
The proof is always in the pudding, or tasting thereof.
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Ummm...hope I am not seeing a sorta theme evolving here, where any dissenting views on the sonic quality of these modules are subject to ridicule and overbearing arm wrangling. That will be a shame since this thread is now over 35pages, however when something has come such a long way there may be the tendency to be over protective.
I have been offered one of these amp module for a home demo, and hope I can post whatever impressions I have compared to what I am currently using which is nothing fancy, a modified Adcom 555II.
The proof is always in the pudding, or tasting thereof.
Actually I think we just spent more time on retail manufacturing/cost ratios than on any dissent. There's a lull right now so before the mob gets angry you'd better get on that demo right quick! And it better say what I want it to say or :uzi:!
I suggest 80 proof in that pudding.
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I gotta say that I use 300 wpc Class A mono blocks as my reference amp. These Class D amps are really good.
Like anything in this hobby, it comes down to YOUR preference. In my opinion, you can't go wrong with these amps.
Yes, they're that good! Again, starting at $175. :duh:
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Are there any published specs on these modules that I may have overlooked, other than the brief power ratings, etc. on the site? I've got a kit ready to go. . .again, I'm just curious.
Paul
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The audioholics article links to this: http://www.hificritic.com/downloads/Class-D.pdf
which basically claims that ClassD amps, by definition, aren't even real hi-fi and can't sound good.
Interesting b/c lots of critics and experienced audiophiles have reacted to many of the recent examples saying how "surprised" they are and how "good" they sound. Shouldn't the "ear" test be more important than the "theory" test?
This article was dated 2008. Most, if not all, of the objections raised have been overcome. I cannot speak directly to the amp boards that are the subject of this thread, suffice to say that the Hifi Critic article paints with so broad a brush as to be almost totally useless when discussing specific designs subsequent to its publication.
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Are there any published specs on these modules that I may have overlooked, other than the brief power ratings, etc. on the site? I've got a kit ready to go. . .again, I'm just curious.
Paul
I believe links have already been provided for the IR-based amps. Since these amps are basically equivalent to the evaluation boards, that should be a source for measurement data.
I imagine it's the same for the TA5630 boards (correct me if I am wrong):
http://www.irf.com/technical-info/refdesigns/iraudamp7d.pdf (http://www.irf.com/technical-info/refdesigns/iraudamp7d.pdf)
http://focus.ti.com/lit/ds/symlink/tas5630.pdf (http://focus.ti.com/lit/ds/symlink/tas5630.pdf)
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which basically claims that ClassD amps, by definition, aren't even real hi-fi and can't sound good.
Aren't these the same critics who said the 3886 wasn't "real hi-fi" (until someone put one in a $2000 box and it became "the best of the best" ? ? ?)
nothing fancy, a modified Adcom 555II.
Possibly amusing aside . . . I'm using gutted Adcom 535 II boxes (bought cheap with blown outputs or transformer fuses or whatever) to house my classD amps . . . and gutted 535 boxs (with 4 channels of output connectors already installed) for my 4 channel 3886 amps . . . and note that a 2535 box would work great for two of the 250x2 boards using the existing transformers and ps (with some added filter caps).
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I hope some more folks try replacing the input caps as it's pretty easy. Should have taken pics but I forgot. Got too excited...
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I hope some more folks try replacing the input caps as it's pretty easy. Should have taken pics but I forgot. Got too excited...
What kind of results are you getting? Was that just some basic .22 film caps?
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I hope some more folks try replacing the input caps as it's pretty easy. Should have taken pics but I forgot. Got too excited...
Maybe someone else did or is wiling to do that??? :wink:
Thanks guys
Mariusz :D
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I hope some more folks try replacing the input caps as it's pretty easy. Should have taken pics but I forgot. Got too excited...
Those things are tiny. Did you remove the old ones and if so how hard was it to get them off the board.
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I believe links have already been provided for the IR-based amps. Since these amps are basically equivalent to the evaluation boards, that should be a source for measurement data.
I imagine it's the same for the TA5630 boards (correct me if I am wrong):
http://www.irf.com/technical-info/refdesigns/iraudamp7d.pdf (http://www.irf.com/technical-info/refdesigns/iraudamp7d.pdf)
http://focus.ti.com/lit/ds/symlink/tas5630.pdf (http://focus.ti.com/lit/ds/symlink/tas5630.pdf)
Thanks!
From a technical standpoint, anyone have any concerns based on these specs? I am just totally curious.
Paul
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Has anyone had a chance to compare this amp to one of the Peachtree Audio amps, the Nova or Decco 2? I realize that everyone is comparing these to much more expensive units, but this seems to be to be a rational comparison since the both utilize class D amplification in a similar wattage and price range.
Thanks,
Ed
The Peachtree amps are A/B, not D.
Paul
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I have heard Tommy's amp and it is a fine product (wish I had extra $$$ to blow). The only problem - 20 : 1 price ratio.
If you like to explain the differences between these two in some constructive way, please do. (day & night conclusion is not really helpful)
Regards
Mariusz :thumb:
Hope I'm not crossing some rule by entering the conversation here... Feel free to move this post if so.
OK, add up the cost. Two modules, power supply, chassis, several hours putting it together, the possibility of a "ka-bang" type mistake, etc.
I've sold a few DAC4800A demos for <$1K (not in mint condition, of course). The difference is in the modulation, component selection/design, output filter, power supply topology, and other things. I'm not giving away our secret sauce to prove a point on this board, mind you. I've heard plenty of amps that sound fine until you compare it to something else. More head-to-head comparisons are welcomed.
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What kind of results are you getting? Was that just some basic .22 film caps?
22uf caps. It's hard for me to properly gauge the results because only the night before I finished my dac kit and changed volume pots and was so wowed by that, when I swapped caps it was hard for me to gauge the difference. Darn it. I always do that. Anyhoos, my impression is that it takes clarity up a couple notches but I could be wrong.
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I've heard plenty of amps that sound fine until you compare it to something else. More head-to-head comparisons are welcomed.
In my local comparisons, I've compared the Class D Audio 60/120 watt amp to: My VTL monoblocks with SED EL 34 tubes on the top end of my biamp setup of heavily modified maggie IIIA's; I've compared it to a pair of Aronov Monoblocks running Merlins with a Musical Design SP-1 preamp (both heavily modified by John Hillig; a Yamamoto 2A3 amp with matching Yamamoto preamp running Lowthers. I've also compared the Class D Audio 250/400 amp on my maggie bass panels versus a Hafler DH-500 heavily modded by John Hillig (96,000 uf capaciticance) and I've heard the same Class D amp compared to the Wyred4Sound 500 integrated run through a pair of stock maggie 1.6's. In all cases, the listeners (not just myself) agreed the Class D matched or bettered these amps in these setups.
You can read my report of the W4S comparison in post #361.
steve
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22uf caps. It's hard for me to properly gauge the results because only the night before I finished my dac kit and changed volume pots and was so wowed by that, when I swapped caps it was hard for me to gauge the difference. Darn it. I always do that. Anyhoos, my impression is that it takes clarity up a couple notches but I could be wrong.
Rotflol.............. Love it! Been there, thanks!
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Those things are tiny. Did you remove the old ones and if so how hard was it to get them off the board.
They're pretty easy to get off the board since they're surface mount. Just dab some flux on either side, grasp with tweezer and gently pull off one side at a time with the soldering iron. Then jumper them with solder or a thin piece of metal (I just clip off the end of a spare resistor or led lead).
Of course I would recommend this only for those with a steady hand, and disclaimer I'm not responsible for whatever happens should you listen to me i'm crazy it was your own fault you listened ha ha, etc.
I'm curious tho because w/ tripath class d amps for instance the quality of input caps are a priority.
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X2
yeah, any links?
I was looking at few ready boards (upsampling and NOS)
but can not decide which one to try.
THX
Cheers
Mariusz
FYI to all, I've started a thread on the DAC in the Lab...
http://www.audiocircle.com/index.php?topic=78737.0 (http://www.audiocircle.com/index.php?topic=78737.0)
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@wushuliu
Can you post pictures of your amp with the dac board. Thinking about using the Pass B1 in similar fashion.
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Got the boards, the PS and the transformer today. I need to find a suitable case for the amp project. Perhaps I will cannibalize an old Panasonic VCR case, but it seems that the transformer is quite tall. Yup, that transformer is chunky. Need a tall case. Damn it.
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Hope I'm not crossing some rule by entering the conversation here... Feel free to move this post if so.
OK, add up the cost. Two modules, power supply, chassis, several hours putting it together, the possibility of a "ka-bang" type mistake, etc.
I've sold a few DAC4800A demos for <$1K (not in mint condition, of course). The difference is in the modulation, component selection/design, output filter, power supply topology, and other things. I'm not giving away our secret sauce to prove a point on this board, mind you. I've heard plenty of amps that sound fine until you compare it to something else. More head-to-head comparisons are welcomed.
Tommy (and all AC members)
I just wish to remind everyone the purpose of this Circle.
It is about things that make us happy and cost little.
The last thing we want is to turn it into pissing contest.
Those usually end up in one place we try to avoid.
Doubtfully anyone is questioning your integrity or work you put into your designs but no one can deny the value of a kit that can be had for under $200 and take about an hour to assemble.
Any comparison of this kit to top brand competition should be taken with grain of salt. As we all know, we can be very bias when it comes to audio gear and preferences. But for the most part, everyone is cheerful about this amp.......even Mr. Blair who is known for his long time tube affairs. :wink:
Have fun everyone. :P
Mariusz :thumb:
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@wushuliu
Can you post pictures of your amp with the dac board. Thinking about using the Pass B1 in similar fashion.
I'll get some up in the next couple of days after the B1. The GF wants that project off the dining room table stat! :whip:
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In my local comparisons, I've compared the Class D Audio 60/120 watt amp to: My VTL monoblocks with SED EL 34 tubes on the top end of my biamp setup of heavily modified maggie IIIA's; I've compared it to a pair of Aronov Monoblocks running Merlins with a Musical Design SP-1 preamp (both heavily modified by John Hillig; a Yamamoto 2A3 amp with matching Yamamoto preamp running Lowthers. I've also compared the Class D Audio 250/400 amp on my maggie bass panels versus a Hafler DH-500 heavily modded by John Hillig (96,000 uf capaciticance) and I've heard the same Class D amp compared to the Wyred4Sound 500 integrated run through a pair of stock maggie 1.6's. In all cases, the listeners (not just myself) agreed the Class D matched or bettered these amps in these setups.
You can read my report of the W4S comparison in post #361.
steve
Who else has compared this amp to others? Any Audio Circle "old timers" out there? In any case, I should back out of this thread, being an amp manufacturer and all. :oops:
Do you know anybody with a DAC4800A or Cherry amp that you can compare against?
Thanks.
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Tommy (and all AC members)
I just wish to remind everyone the purpose of this Circle.
It is about things that make us happy and cost little.
The last thing we want is to turn it into pissing contest.
Those usually end up in one place we try to avoid.
Doubtfully anyone is questioning your integrity or work you put into your designs but no one can deny the value of a kit that can be had for under $200 and take about an hour to assemble.
Any comparison of this kit to top brand competition should be taken with grain of salt. As we all know, we can be very bias when it comes to audio gear and preferences. But for the most part, everyone is cheerful about this amp.......even Mr. Blair who is known for his long time tube affairs. :wink:
Have fun everyone. :P
Mariusz :thumb:
OK, this will be my last post on this thread. Have fun, guys...
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Who else has compared this amp to others? Any Audio Circle "old timers" out there? In any case, I should back out of this thread, being an amp manufacturer and all. :oops:
Do you know anybody with a DAC4800A or Cherry amp that you can compare against?
Thanks.
You're more then welcome to post in this thread! :thumb: Just have to make sure you don't turn your posts into ads for your products.
Paul
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Who else has compared this amp to others? Any Audio Circle "old timers" out there? In any case, I should back out of this thread, being an amp manufacturer and all. :oops:
Do you know anybody with a DAC4800A or Cherry amp that you can compare against?
Thanks.
I did a cursory comparison with the amps in my Yamaha RX-Z7 receiver... sounded good to me. It was just a quick check because it was the first time I powered up the amps and my subwoofers (for which I built them) were not done yet. It's on my to-do list to do a more careful comparison - with in-room measurements, but I haven't gotten around to that yet.
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OK, this will be my last post on this thread. Have fun, guys...
Tommy no need to take this personally.
You are more then welcome to post/share/ debate.
Regards
Mariusz
:thumb:
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Jkelly,
My amps have done the heat-up and shut down, but with more ventilation all is good. We have have large rooms with loud listening levels :drums: :guitar: :guitar: :drums:, I do anyway.
I am getting a wicked hiss out of both amps I built, after re-locations, power conditions and the like, not sure where to go from here, any suggestions?
I have emailed Tom but not much there..
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I completely agree and the hours break-in thing.
I had put 1 together 2 weeks ago and now started running a second amp. The second definitely sounded off compared to the first. So now I am just running the second to catch up and verify I did nothing wrong or received different parts.
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Jkelly,
My amps have done the heat-up and shut down, but with more ventilation all is good. We have have large rooms with loud listening levels :drums: :guitar: :guitar: :drums:, I do anyway.
I am getting a wicked hiss out of both amps I built, after re-locations, power conditions and the like, not sure where to go from here, any suggestions?
I have emailed Tom but not much there..
Disconnect signal and house ground (assuming they are connected).
Edit: Ok, forget that - looks like nothing is grounded based on your build pics. Maybe shield the input connectors since they are fairly close to the AC in?
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Face plate
(http://www.audiocircle.com/image.php?id=27592)
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That looks great Bill. Is the power switch in the center of the face plate?
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That looks great Bill. Is the power switch in the center of the face plate?
Yes that's the power switch
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Very nice work! Very pumpkinny! :eyebrows:
steve
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Very nice work! Very pumpkinny! :eyebrows:
steve
Thank you Obi Wan may the force be with you
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Doug
They both hiss with no input as well, and I did add a ground when I had and hiss and a hum, but the hum was fixed by the ground, the hiss remained the same.
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Doug
They both hiss with no input as well, and I did add a ground when I had and hiss and a hum, but the hum was fixed by the ground, the hiss remained the same.
Ok, you got me... Mine are very quiet, but I'm not running them in bridged mode. How are the XLR's connected?
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Without the inputs connected I have hiss, when I plug in either XLR or RCA, the hiss remains exactly the same.
Nobody seems to have an answer...
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If the hiss is just in the tweeter (like mine is) it's probably a gain hiss. Which means you are probably running a high-sensitivity tweeter and it will be fixed by lowering the gain on the amps. I have an email into Tom and will post back when I learn something.
On a side note... this is a great little kit! I have mine running with two TXs and two power supplies. I am next working on building a larger power supply with better parts and doing some mods to the amp boards as well. Fun project!
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On a side note... this is a great little kit! I have mine running with two TXs and two power supplies.
If you are not using two separate amp boards (bridged), how do you connect the two power supplies to the single amp board?
If you are using one power supply for the positive rail and one for the negative rail, is the entire capacitance on each power supply board utilized, or just half?
Steve
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I have two amp boards and am using 4-channels since I am actively bi-amping my speakers.
Right now I have both TXs hooked up to a single IEC (the same way a dual mono setup works). Once my chassis gets here I'll be hardwiring the TXs directly to my power cable and bypassing the IEC.
Each TX goes to its own power supply. Right now I'm only using one rail of each PSU. I hadn't even thought about using both rails per amp board -- though not sure what the implications of that are. The step after that will be to put the PSU in a different chassis from the amp boards.
Everything will be hardwired, no use of binding posts or RCA jacks. One of the largest sources of distortion in a system are the connectors used. My speakers are hardwired as well.
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I too have a hiss. It is mainly from the tweeters - I can hear it up to about 2 feet away . With the the woofers. I need to have my ear much closer to hear it.
I have the 2x250 running it into Salk Songtowers (88db). I tried them with slightly less efficient speakers (NHT Classic 3 - 86db) and the hiss is there but not as loud. The hiss is there if I go directly from my Squeezebox or using the pre-outs of my Denon AVR. I don't have RCA jacks on the board - they are wired to the board and I kind of suspect them as part of the issue.
I do have a hiss if I use the Denon to drive my speakers - but much less. (85Watts).
I have tried something called a HumX from EBTech which is successful with Ground Loop problems to no avail.
I have some shielded cables from BlueJean cables on order so I will see if that helps. I should have those today or tomorrow.
I certainly can't hear the hiss from my seated position. Would the hiss degrade the sound if I can't hear it from more than a couple of feet away?
I'll report back if I have any success.
Mark
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I tried one more thing. Without the input cables connected, the hiss is much less. (Probably I need to have my ears less than a foot to hear the hiss). If disconnect the RCA terminals from the board - I still have that same, lower level hiss. So the input cables are definitely adding in noise.
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I tried one more thing. Without the input cables connected, the hiss is much less. (Probably I need to have my ears less than a foot to hear the hiss). If disconnect the RCA terminals from the board - I still have that same, lower level hiss.
In that case you have two hiss sources . . . one is your source equipment, the other the amplifier itself. Regarding reducing hiss from the amplifier:
Switching (Class D) amps have an inherent noise floor. In the IR reference design for the IRS2092 driver that noise is speced variously as “200 uV” and in the “101dB “dynamic range” figure. The latter is perhaps more useful in understanding what is going on, since what it is really saying is that hiss will be present at 101dB below rated amplifier output in reference design amps. With the same speaker the more powerful amplifier variants will appear to have more hiss. The tradeoff is direct . . . higher (potential) output brings higher (actual) hiss. Using a 500 Watt amp where a 60 will do brings with it a 9dB increase in noise.
But perceived hiss must be considered relative to signal and circumstance. Hiss that you can hear with no input and your ear against the speaker may be of no significance at the listening position, or when playing a CD with a 90dB noise floor (dither), or if there is any masking noise in the listening environment (projector fan, vent noise from the heating system, audience breathing etc.). That said:
Sensitive speakers (especially over 90dB) will often bring amplifier hiss up to audible levels close to the speaker.
Speakers that are “hot” on the high end will make hiss more noticeable.
Speakers with 8 Ohm or higher input impedance (particularly in the tweeter range) interact with the switching amplifier output filter to produce a high frequency response rise, and will make hiss more noticeable.
Where hiss is a problem potential corrective actions include “right sizing” the amplifier, flattening high frequency response (in most circumstances a slight rolloff sounds most natural), and a zobel to lower speaker impedance at high frequency. There are a few other more esoteric possibilities, like noise pickup from external sources on unshielded inputs or with unshielded enclosures, or noise coupling between two amplifier boards on the same power supply, or noise from the power supply itself, but there’s not much point looking there if the more obvious issues have not been addressed first.
Ps. the thermal limits of the reference design amps are almost entirely determined by the on-board heat sink, not the amplifier power rating. The solution to thermal shutdown is better cooling, not a nominally more powerful amp with the same heat sink. That means good ventilation, and perhaps a small fan or a larger (finned) heat sink with good air flow well coupled (thermally) to the existing heat sink block.
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Makes sense as my 120 watt board has a dead quiet noise floor.
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My 2x250s had only barely detectable noise with my ear at the tweeter and the noise was essentially inaudible a few feet away (by I forget how loud they were turned up). I remember thinking that they were close to, but not quite as good as, the amps in my receiver (which are dead silent). The speakers I used for that have a compression driver and waveguide with 95 db sensitivity and 8 ohm impedance (they tail off significantly at the high end, above 10kHz, though). The amps are connected to subs now and are (not surprisingly, given the above) dead quiet.
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Tom said the hiss comes from the gain being too high. He recommended that I replace the R9 and R11 resistors with 10k-ohm resistors to lower the gain. He was also happy to do that for me. I had this same problem with one of my older, high gain amplifiers.
I'll replace the resistors in a few days once the 10k SMDs arrive. I've never heard of higher power equating to more noise.
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O-Noooo........... I just had a buddy over and he brought his Mapletree tube pre over and now its gone :(
I think need to try that Pass Buffer out. :duh:
Thanks again Brett!
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O-Noooo........... I just had a buddy over and he brought his Mapletree tube pre over and now its gone :(
I think need to try that Pass Buffer out. :duh:
Nick,
Can you tell us what you thought about the sound of the Mapletree/classD combo?
Thanks,
Ed
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I am still using my HK avr pre outs to the ClassD. I have a SB3 hooked up to a Paradisea then the HK. When i hook up the dac straight to the ClassD i lose quite a bit of bass and volume but sonics are more refined. The Mapletree corrected that and gave me a nice smooth top end and more defined bass. It seems to be a very good match, wish i could snag the one thats for sale. :duh:
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I am still using my HK avr pre outs to the ClassD. I have a SB3 hooked up to a Paradisea then the HK. When i hook up the dac straight to the ClassD i lose quite a bit of bass and volume but sonics are more refined. The Mapletree corrected that and gave me a nice smooth top end and more defined bass. It seems to be a very good match, wish i could snag the one thats for sale. :duh:
Thanks Nick. Very interesting, I too am using a MHDT DAC (Havana) and am running directly into the classD. I don't have a preamp to connect to yet. I have plans to pick up a Dodd Buffer but I still have to save my pennies for my audio bank.
Thanks,
Ed
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Tom said the hiss comes from the gain being too high. He recommended that I replace the R9 and R11 resistors with 10k-ohm resistors to lower the gain. He was also happy to do that for me. I had this same problem with one of my older, high gain amplifiers.
I'll replace the resistors in a few days once the 10k SMDs arrive. I've never heard of higher power equating to more noise.
I believe the gain on the amp is set to 32db or so unless you asked for it to be lower. I asked for it to be lowered to 26db and I really have to have my head against the tweeter for me to hear very low hiss. Speakers in question are 91db or 92db.
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Tom said the hiss comes from the gain being too high. He recommended that I replace the R9 and R11 resistors with 10k-ohm resistors to lower the gain.
That will reduce the gain (of a 250x2) to between 9 and 10, and may reduce noise coming from a noisy source (if that was your problem). It will not reduce noise generated in the amplifier itself (no input connected, or input grounded). It is important to distinguish noise source when attempting noise reduction. It also helps clarify issues if the amp model and configuration (bridged? gain? etc.) and speaker sensitivity and impedance (especially above 5-10kHz) are mentioned.
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For what it's worth, I'm using two 120x2s in bridged mode as mono blocs fed by an AMC tube preamp into my Maggie MG12s (84db, 4ohm), and if I select CD on my pre without actually playing a disc, I can turn the volume control fully clockwise (very scary) and I don't hear anything even if I put my ear right up to the speaker. I should add that I had Tom reduce the gain on my amps to 26 from the stock 32.
Enclosures are nearing completion--takes longer when you have to build two of them!
Bob
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My speakers are 97dB sensitivity. The hum is only in the highs and it is the same hum I had with an older amplifier I had. The older amplifier actually had a gain knob on the back, as the gain was turned down the hum went away.
The amplifier I'm using is the 1000w kit -- way overkill but the 15" woofers like power. I just added a second power supply and second transformer. The amp is unbridged. One amp board is running the highs and one amp board is running the lows in my setup.
The noise floor of the amp itself is quite low. I have it plugged into an isolation transformer and a high-end power cord. The gain on my amp currently is 32dB. Tom was the person who recommended getting the 10k resistor. I imagine he recommended that resistor because it will bring the gain down to 26dB. 9-10 sounds extremely low.
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My speakers are 97dB sensitivity. The hum is only in the highs and it is the same hum I had with an older amplifier I had. The older amplifier actually had a gain knob on the back, as the gain was turned down the hum went away.
That suggests noise that is coming from your source, in which case reducing amp gain may help. That is different from the case of others who report noise with no input connected.
The amplifier I'm using is the 1000w kit -- way overkill but the 15" woofers like power. I just added a second power supply and second transformer. The amp is unbridged. One amp board is running the highs and one amp board is running the lows in my setup.
I do not see the benefit of using only one amp on each board, but with 97 dB sensitivity speakers you have far more power than you need anyway . . . so 250 Watts (into 4 Ohm) should be plenty.
The noise floor of the amp itself is quite low. I have it plugged into an isolation transformer and a high-end power cord. The gain on my amp currently is 32dB. Tom was the person who recommended getting the 10k resistor. I imagine he recommended that resistor because it will bring the gain down to 26dB. 9-10 sounds extremely low.
The gaine of the 250x2 modules is set by Rf/Rin. Rf is 120k (in the reference design), and Rin is R11 (10k after the change) plus R12 (which is 3k on the boards I have and on the reference design boards. These part numbers are for the classDaudio board non-inverted channel . . . the part numbers in the IR reference design are different.
Good luck with your project . . .
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dewardh,
Thanks for the explanation. It does make sense.
I am the one who has no input while still getting hiss. I just hooked a pair of Silverlines that are 92 db, and the hiss is almost gone. So my current 99db speakers are allowing the hiss through.
What can I do? I have the boards bridged to get the 500w, should I run the highs with an un-bridged board running one channel at 125w (I have an active xover with gains) to lower the hiss, or would it? I may try anyway. I may get other speaker too.
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Dewardh,
Let me correct something, I am running one amp board for the highs (running both channels on that board) and one amp board for the lows (running both channels). LR high and LR Low. I have an active XO and so I am biamping.
There is no noise coming from my source. It's just the interface between a high sensitivity speaker and a high gain amplifier. It's a hiss and not a hum and happens even when the source is unplugged, just like with the old amps. There is no hiss in my woofers, just the tweeter. From my experience, the hiss will be fixed with a lower gain amp.
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500W with 99db speakers (are these horns)? Unless I'm missing something you will have permanent ear damage in less than a minute! Try them unbridged.
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They ARE unbridged, gents. My DAC is low gain as well so they aren't blaringly loud, nor do I play music loudly.
I'm running Emerald Physics, which use pro drivers. The tweeters are high-sensitivity compression drivers.
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I took the tweeter off the bridged mode and into 1 side of the stereo mode, the hiss remains the same.
I guess the speakers are too efficient for this type of amp to expect there to be no hiss. Like I said above, the 89-93 db speakers had hiss to maybe 2' from the speaker, which is better.
Tom mentioned something about adjusting the amp for high efficiency speakers, but never got back to me as to what that is or if I/ he needs to do it.
:cry: :cry:
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I'm thinking that gain reduction down to 26db may be your best bet. From what I've read, Tom does that frequently for those using higher efficiency speakers. :)
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I'm thinking that gain reduction down to 26db may be your best bet.
That would be a fairly "normal" gain for consumer amps, so it's a reasonably safe starting point. IR seems to have chosen gain in the reference amps so that the same input will produce rated output in all the variants, on the assumption that amplifier power would be chosen appropriate to need. ClassDaudio seems to have copied that in their initial designs. The result, though, is unnecessarily high amp gain (on the higher power amps especially) when used in “consumer” applications, leading in many cases to excessive amplification of source noise. Changing to a uniform gain across the line more nearly matches normal “consumer industry” practices.
But ultimately best results will be had when the amplifier is matched, both in power and gain, to the source, the loudspeakers, and the desired acoustic output. As DIYers building our own dedicated systems we know the peak output level of our source, the sensitivity of our speakers, and our target peak acoustic levels. From that it is easy to compute amplifier power needed, and the amplifier gain needed to reach that power (this kind of signal management is called “gain staging” in the pro-audio world). Too much power, or too much gain, usually introduces noise problems, and sometimes an increase in small-signal distortion.
As an example: a Seas W22EX driver has a sensitivity of about 88 dB. 60 Watts will produce an acoustic output of about 105 dB (a common design target) from it, and an amplifier gain of around 24 will reach that level with full output from common consumer sources. The amp runs out of power, the speaker runs out of excursion (at low frequency, depending on the box), and the source runs out of output all at the same time . . . maximizing performance of all.
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Could this gain issue be addressed by adding a rotary gain dial to the amp? This would preclude having to swap resistors to dial in the correct gain. Wish I knew what I was talking about :D
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Tom has included adjustable gain on the new prototype boards soon to be released for newcomers.
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Tom has included adjustable gain on the new prototype boards soon to be released for newcomers.
now that's cool.
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Tom has included adjustable gain on the new prototype boards soon to be released for newcomers.
That would be very nice . . . and all it would take even on the existing boards would be 10k trimpots in place of the two input resistors.
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dewardh,
Can you elaborate on the pots and let me know which resistors would be replaced and where to get the pots, I like the idea of being able to dial the amp in, like the pro amps I have running the subs in my room.
Thanks
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If you change out the resistors and use pots won't yo need to know where and what to measure to insure you have them set correctly or would you adjust them before placing them in the ckt and hope you don't bump them?
Thanks,
Ed
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Mintzar,
I do not see a R9 or 10, On my boards it seems to be 60-61
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Just a few simple hints...
1. Make the power supply as large as possible (big electrolytic caps especially) and as high voltage as specs allow
2. Keep signal path connections as short as possible and use shielded wires, ground the shields
3. Practice good grounding techniques --- beginners should search the net for "star ground"
Regarding #1 above, be sure to account for varying mains voltages when using linear supplies. Use FAT wire. Good luck once again.
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:beer: :thumb:
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Picked up a loaner from fellow ACer Shadowlight.
I am running it full range with my back up speakers, VMPS626R. Main speakers are active-biamped, and takes more effort to integrate a new component, so that will come later, over the weekend.
Right off it sound very clean, but on the lean side. I started off with it plugged right into the wall. I was impressed with the details and slam. However, I think I am hearing a kind of 'ringing' on the edges of some notes, and after a while(about 30minutes) the sound bordered on the irritating...I think I am "hearing" ultrasonic ringing, the only way I can describe it is visually, like seeing a 'flare' after the flame has passed.
I think I ended up a 'headache'(?) which I almost never get. So I thought, maybe I should plug it into my conditioner. And that seem to tame it some, there was less 'flaring' (though not completely gone, but reduced)and the notes had a fuller body, overall it was an improvement, smoother and more warm. But it does have a nice dynamic kick to mid bass notes, and good drive with the lower bass notes, which was my intent for this amp.
After an hour and half I switched over the a Jolida102b for comparison, and yes, I didn't get that impression of mid/upper notes 'ringing/flaring'. So I do wonder if Digital amps tend to have some kind of ultrasonic ringing, which can cause piano notes or percussive instruments to sound "blaring"?
I do have some suggestions for Shadowlight which I think would improve his build, some of which I see AmpDesigner333 has already noted. The power leads are too long and are routed past the RCA inputs, and same with the speaker leads and RCA input leads. With a different layout these connection can be 70% shorter. And of course a better grounding scheme.
Besides the phenomena I mentioned, this amp shows good promise, at least for my bass duties.
I also noted that it took about 40 minutes before it hit its stride, the bottom sounded fuller after that time period.
But I prefer the sound of music via the Jolida, which is slightly modified with paper in oil coupling caps.
Are there coupling caps, or any caps in the signal path of these amps?
I have an Exposure 2010 I hope to compare it to also, more later.
Thanks Shadowlight for the opportunity. :thumb:
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Mintzar,
I do not see a R9 or 10, On my boards it seems to be 60-61
On the boards I have the input resistors one would change are R9 and R11 as on Mintzar's, they're SMDs on the "bottom" of the board, quite close to the input connectors (and that orange input cap). R60 and R61 are axiel lead resistors (220 Ohm) on the "top" of the board, and seem to be part of the power supply circuitry. They are right next to the regulators, by the heat sink. Don't mess with them unless specifically instructed by Tom ! ! !
The input resistors we're talking about are the ones labeled "R2" on the reference design schematic. If you cannot circuit trace the board to positively identify those components (they will have different values depending on board model and gain) you should return your boards to Tom for any changes.
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Just a few simple hints...
1. Make the power supply as large as possible (big electrolytic caps especially) and as high voltage as specs allow
What are the benefits to increasing the power supply that much?
*sigh*
Just when I thought I was out of Digi-key, they pull me back in
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Picked up a loaner from fellow ACer Shadowlight.
However, I think I am hearing a kind of 'ringing' on the edges of some notes, and after a while(about 30minutes) the sound bordered on the irritating...I think I am "hearing" ultrasonic ringing, the only way I can describe it is visually, like seeing a 'flare' after the flame has passed.
I think I ended up a 'headache'(?) which I almost never get. So I thought, maybe I should plug it into my conditioner. And that seem to tame it some, there was less 'flaring' (though not completely gone, but reduced)and the notes had a fuller body, overall it was an improvement, smoother and more warm. But it does have a nice dynamic kick to mid bass notes, and good drive with the lower bass notes, which was my intent for this amp.
After an hour and half I switched over the a Jolida102b for comparison, and yes, I didn't get that impression of mid/upper notes 'ringing/flaring'. So I do wonder if Digital amps tend to have some kind of ultrasonic ringing, which can cause piano notes or percussive instruments to sound "blaring"
Very possible the ringing and blare could be coming from elsewhere. Or just needs more time to settle. Part of the appeal of the classdaudio amps (at the least the IR versions I have) is the smoother top end. With a 4 ohm speaker in particular as the frequency response has a slight roll-off...
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So I do wonder if Digital amps tend to have some kind of ultrasonic ringing, which can cause piano notes or percussive instruments to sound "blaring"?
If we're talking about the IRS2092 family of amps it is unlikely. The switching frequency of 400kHz is beyond the hearing of any of us, and is filtered at the output anyway. Apart from that I don't see any ringing on in-band square waves. If the speaker you were listening with has a rising impedance at high frequencies (8 Ohm or above) there will be a slight rise in high frequency response, however, and that might contribute to fatigue with an already bright speaker or source. That can be dealt with by adding a zobel to control speaker impedance.
Are there coupling caps, or any caps in the signal path of these amps?
There is a single input coupling cap of "questionable" character, and the output filter has shunt caps that might not appeal to the highest audiophile standards (though I personally doubt that the output caps are an issue . . .). There are, of course, lots of caps in the comparator and timing circuits, and in the snubbers on the FET switches, but because of the way the signal is deconstructed for switching it is not clear whether those would be considered "in the signal path".
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I am running it full range with my back up speakers, VMPS626R.
Not questioning what you heard. However, did you make any adjustments to the 626? Midrange and/or tweeter controls?
Paul
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A bigger power supply is ALWAYS a good thing. It will allow for more reserve power, which means larger dynamic peaks. That also means that the amplifiers themselves will be more stable, thus lower the noise. A well designed power supply will make a larger difference in a component than any other mod you will do. The power is what is used to CREATE the audio signal... better power = better audio signal.
The voltage at 100v is just fine for the voltage needed by the amp boards, but the capacitance could be higher. In a perfect world you would use small capacitors, but hundreds of them to get very high level of storage capacitance. By using multiple resistors you are lowering the series resistance. That means less noise and more extension, basically. You can also replace the caps on the power supply with Nichicon Muse (anywhere from $40-$80 per 100v capacitor)... compared to the cheap caps currently on the board you'll find a very nice upgrade.
The R9 and R11 resistors are SMDs on the bottom of the board near the inputs. VERY small. If you're not confident with your soldering abilities I would send it back to Tom to have him replace them.
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Not questioning what you heard. However, did you make any adjustments to the 626? Midrange and/or tweeter controls?
Paul
I had that dialed in previously using RS SPL meter and pink noise. I even backed off some more on the mid panel and tweeter, didn't help...what I was hearing came from the amp...confirmed when I switched amps. (long time VMPSer here, so really familiar with all the 'knobs' :lol: )
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A bigger power supply is ALWAYS a good thing. It will allow for more reserve power, which means larger dynamic peaks. That also means that the amplifiers themselves will be more stable, thus lower the noise. A well designed power supply will make a larger difference in a component than any other mod you will do. The power is what is used to CREATE the audio signal... better power = better audio signal.
The voltage at 100v is just fine for the voltage needed by the amp boards, but the capacitance could be higher. In a perfect world you would use small capacitors, but hundreds of them to get very high level of storage capacitance. By using multiple resistors you are lowering the series resistance. That means less noise and more extension, basically. You can also replace the caps on the power supply with Nichicon Muse (anywhere from $40-$80 per 100v capacitor)... compared to the cheap caps currently on the board you'll find a very nice upgrade.
The R9 and R11 resistors are SMDs on the bottom of the board near the inputs. VERY small. If you're not confident with your soldering abilities I would send it back to Tom to have him replace them.
excellent. thanks.
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I had that dialed in previously using RS SPL meter and pink noise. I even backed off some more on the mid panel and tweeter, didn't help...what I was hearing came from the amp...confirmed when I switched amps. (long time VMPSer here, so really familiar with all the 'knobs' :lol: )
Thanks for the clarification. :thumb:
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I do have some suggestions for Shadowlight which I think would improve his build, some of which I see AmpDesigner333 has already noted. The power leads are too long and are routed past the RCA inputs, and same with the speaker leads and RCA input leads. With a different layout these connection can be 70% shorter. And of course a better grounding scheme.
I agree. When I started to cut the hole for the IEC plug I was not paying attention to it and it ended up being on the wrong side, hence the wires going across the rca. I plan to flip the back plate around and drill new holes. As for grounding I am open to suggestion on how best to do that.
Thanks Shadowlight for the opportunity. :thumb:
You are welcome.
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Oops I need to clarify something in my post...
I said "by using multiple 'resistors' you are lowering the series resistance." I meant to use 'capacitors' not resistors...
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AmpDesigner and mintzar are correct about power supplies . . . it is hard to imagine a serious argument (other than cost) against larger caps in an amplifier power supply, especially for half-bridge Class D amps. You may have to use a higher current bridge rectifier (or a slow start circuit) to keep from blowing diodes on startup, but that’s minor. Good design practice would also include bypass caps and snubbers at least on the supply output, but snubbers especially must be “tuned” to the transformer/capacitors used, and the load, which combined with cost is probably why they are not present on the “general purpose” classDaudio supply boards. It’s another opportunity for DIYers to improve an already good amp with relatively simple mods.
Industry practice is to use caps with a voltage rating about 30% over supply . . . so the 35 V supplies can use 50 V rating parts, the 50 V supplies can use 63 V parts, and 100 V parts are only needed for the 70 V supplies. You can get higher capacitance in smaller cans for less money with the entirely satisfactory lower voltage rating parts . . . there’s no need for 100 V caps on a 35 V supply. Do get the 3000 hour @ 105 degree parts, though . . . they last longer. Low esr is also a plus . . .
There’s an interesting (three part, follow the links at the end of each page) article on power supply design at:
http://www.tnt-audio.com/clinica/ssps1_e.html
and on snubbers (although I think snubbing the supply output is even more important than snubbing the diodes) at:
http://www.hagtech.com/pdf/snubber.pdf
An example of a power supply with a snubbered output is at:
http://myweb.tiscali.co.uk/nuukspot/decdun//gainclonesnub.html
Note the use of 24,700 mfd (and paralleled caps) on each rail of this gainclone power supply. Some might call it overkill, but I don’t.
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AmpDesigner and mintzar are correct about power supplies . . . it is hard to imagine a serious argument (other than cost) against larger caps in an amplifier power supply, especially for half-bridge Class D amps. You may have to use a higher current bridge rectifier (or a slow start circuit) to keep from blowing diodes on startup, but that’s minor. Good design practice would also include bypass caps and snubbers at least on the supply output, but snubbers especially must be “tuned” to the transformer/capacitors used, and the load, which combined with cost is probably why they are not present on the “general purpose” classDaudio supply boards. It’s another opportunity for DIYers to improve an already good amp with relatively simple mods.
You think swapping out the 3300ufs w/ the 250w IR w/ 6800uf would be too much for the diodes?
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You think swapping out the 3300ufs w/ the 250w IR w/ 6800uf would be too much for the diodes?
Don't know. The web site says that the diodes in the "heavy duty" supply have a higher rating, but not by a lot. I'm putting 30,000 mfd on a couple of my boards, so I'll probably change the bridge "just in case". The inrush current can be quite high . . . the caps start out as a dead short, and almost the only thing limiting current is the (quite low) impedance of the transformer secondaries. The bigger the caps the longer the inrush lasts, so the question really is "how many cycles can those diodes handle 10 times (or more) their continuous rating?". 25-35 Amp bridges are cheap . . . and cheap insurance.
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Don't know. The web site says that the diodes in the "heavy duty" supply have a higher rating, but not by a lot. I'm putting 30,000 mfd on a couple of my boards, so I'll probably change the bridge "just in case". The inrush current can be quite high . . . the caps start out as a dead short, and almost the only thing limiting current is the (quite low) impedance of the transformer secondaries. The bigger the caps the longer the inrush lasts, so the question really is "how many cycles can those diodes handle 10 times (or more) their continuous rating?". 25-35 Amp bridges are cheap . . . and cheap insurance.
Is there a particular bridge rectifier you recommend, since digikey and I are so tight...
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Michael Percy Audio sells the Vishay diodes and IXYs diodes, which are the ones I recommend. They are the fastest diodes on the market by far. The diodes need to be at least 2x the voltage of the TX. If you are using larger caps you should make it 4x to be safe. The problem is, that as the voltage gets higher the diode isn't as fast. So it's important to get a voltage rating that is just high enough, but not too high. The big thing with the diodes... and the caps for that matter... is what will fit on the board. You can always build a new PSU board, but it will be substantially easier to just replace the caps and bridge that are already there.
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Hello,
Any new info on the custom case that was being built for these amps?
Thanks
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jtwrace is working on some custom enclousures which are going to be available at reasonable price to anyone interested in dressing up there class D-amp.
Those interested can contact Jason ( jtwrace) for more info.
P.S
Looking forward to some pictures Jason ...... ones they are finished.
Cheers
Mariusz
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Hello,
Any new info on the custom case that was being built for these amps?
Thanks
Not really. I'm just tweaking one thing that I learned from my first prototype.
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jtwrace is working on some custom enclousures which are going to be available at reasonable price to anyone interested in dressing up there class D-amp.
Those interested can contact Jason ( jtwrace) for more info.
P.S
Looking forward to some pictures Jason ...... ones they are finished.
Cheers
Mariusz
I will be sure to post some pics when they're done. I'd say about a couple of weeks if all goes as planned.
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To use who are currently using these units, how is the bass performance? Tom told me the damping factor was around 120 which seemed surprisingly low....
yes it is 120 but I read the info from IR and the damping is 2000 before demodulator and at the class d output it is 120. I see other companies put there damping factor at 1000 and 2000. so it makes me wonder if they are using the factor before the demodulator too have the DF look better. I wonder.. :scratch:
Michael
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Didn't see it on the website or in the manual...anyone know the current draw of the 250x2 amp?
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Michael Percy Audio sells the Vishay diodes and IXYs diodes, which are the ones I recommend. They are the fastest diodes on the market by far. The diodes need to be at least 2x the voltage of the TX. If you are using larger caps you should make it 4x to be safe. The problem is, that as the voltage gets higher the diode isn't as fast. So it's important to get a voltage rating that is just high enough, but not too high. The big thing with the diodes... and the caps for that matter... is what will fit on the board. You can always build a new PSU board, but it will be substantially easier to just replace the caps and bridge that are already there.
Hm, what about one of the supplies listed on this page:
http://connexelectronic.com/index.php/cPath/25_45?osCsid=fplttf8h1r9ap43padpmdodht1 (http://connexelectronic.com/index.php/cPath/25_45?osCsid=fplttf8h1r9ap43padpmdodht1)
(http://www.audiocircle.com/image.php?id=27684)
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Is there a particular bridge rectifier you recommend, since digikey and I are so tight...
My power supply boards as received use:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=641-1358-ND,
which is not what is described on the classDaudio web site (which says “6 Amp 600V rectifier” for the standard ps board). It should be sufficient in most cases. The same manufacturer offers 25A and 35A versions in the same package, which would be drop-in replacements with increased current safety margin.
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=641-1361-ND
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=641-1364-ND
Whether the higher surge rating (400A vs. 250A) is worth a couple bucks is your call . . . it depends on how much capacity you add, and your own comfort margin about such things. I would have replaced what is spec’ed (by classDaudio), I may not replace what was delivered (unless something fails).
Since mine are 35V supplies I’m upgrading with 50V caps . . . the largest (tallest) that would fit my case are:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=P6693-ND
If you’re using a higher voltage supply use higher voltage rated caps to maintain the voltage safety margin.
Hm, what about one of the supplies listed on this page:
They look nice, and the pricing is good. I wonder about the separate fusing (on some models) . . . that invites a single-rail failure which might not be good for the amp boards.
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yes it is 120
Once you add in the resistance of connectors, speaker cables, and most particularly the series resistance of the crossover (unless you're using active crossover) the amplifier is not the limiting factor, and 120 is more than enough.
but I read the info from IR and the damping is 2000 before demodulator and at the class d output it is 120. I see other companies put there damping factor at 1000 and 2000. so it makes me wonder if they are using the factor before the demodulator too have the DF look better. I wonder.. :scratch:
A good catch, that . . . and the lesson is *never believe anything from marketing*. Engineering will usually tell you the truth (although even they may make you dig for it).
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They look nice, and the pricing is good. I wonder about the separate fusing (on some models) . . . that invites a single-rail failure which might not be good for the amp boards.
Thanks for all the PS info deward. So are you going w/ 15k each, for a total of 90k? or just 2 ( you mentioned 30k).
I ordered some ts-ha as well (6800), they seem to get high marks.
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are you going w/ 15k each, for a total of 90k? or just 2 ( you mentioned 30k).
The first experiment will be with 30k per rail (two pair of 15k, 60k total on board) and to use the third position for bypass and snubber parts. If that works well enough I'll clone it for the other amps, box 'em up and move on to serious listening. Apart from input coupling and power supply I haven't identified anything else that I want to change . . . yet . . . :icon_twisted: . . .
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I have a bit of a Class D dilemma.
I currently have this kit (unbuilt): http://classdaudio.com/index.php/class-d-amplifier-kits/home-kits/1000-watt-class-d-amplifier-kit.html (http://classdaudio.com/index.php/class-d-amplifier-kits/home-kits/1000-watt-class-d-amplifier-kit.html)
When I ordered it, I thought this kit contained two of the most powerful IR amp boards. Turns out, it doesn't. :duh: It contains two of these: http://classdaudio.com/index.php/class-d-audio-amplifiers/home-and-pro-class-d-audio-amplifiers/class-d-power-amplifier-250w-x-2-500w-x-1.html (http://classdaudio.com/index.php/class-d-audio-amplifiers/home-and-pro-class-d-audio-amplifiers/class-d-power-amplifier-250w-x-2-500w-x-1.html) (The site still isn't very clear enough for me. . .but, I have it all figure out now)
For my future speakers, I plan on going active and will need 4 channels of amplification. . .and I decided the kit I have, which can be used in a 4 channel "mode," just won't cut it. I don't feel like writing out all the different options I thought of regarding configurations of the Class D amps, so I will just post my current dilemma/options:
1. Keep the kit I have. Use it in bridged mode, giving me 250 Watts x 2 @ 8 Ohms. I would use this to horizontally biamp the speakers and drive the woofer sections. Keep in mind, this kit has 2 amp modules driven off of one PS.
- With #1, I would then get this kit (http://classdaudio.com/index.php/class-d-amplifier-kits/home-kits/250w-x2-500w-x1-amp-large-power-supply-transformer.html). This kit uses the same module in #1. However, it just has a single module and I would use it in stereo mode, giving me 125 Watts x 2 @ 8 Ohms. I would use this to horizontally biamp the mids and tweeters of each speaker.
2. Get the kit that has one of these modules (http://classdaudio.com/index.php/class-d-audio-amplifiers/home-and-pro-class-d-audio-amplifiers/class-d-power-amplifier-1000w-x-1-250w-x-2-8-ohm.html) (the highest powered IR module): This would also give me 250 Watts x 2 @ 8 Ohms. I would also use this to horizontally biamp and drive the woofer sections of each speaker. This module now has the "upgraded" heatsink and is safe into 4 Ohms.
- I would then break apart the kit I have and return or sell one of its amplifier modules. I would use it the same way as described under #1 above.
I guess what it boils down to is this: Is it better to get 250 Watts per channel into 8 ohms with 2 bridged amp modules and 1 PS or just one stereo module and 1 PS?
Hope that's clear! :lol:
Thanks!
Paul
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@Paul (pjchappy),
The first 3 links that you posted all are the same classd boards which are 250 x 2 @ 4ohms. The first link has two boards and that is the reason you are getting the 1000W (250wpc with 4 channels). The 4th link is the 250wpc x 8ohm board. If you plan to go that route please make sure that you get the extra heat sink (the ones that Steve got for his 4ohm speakers and ones that were compared to wyred for sound), in case your plan to run 4ohm speakers with those boards. I would also check with Tom to be sure about the 4th link and your speaker requirement 4 v/s 8 ohms.
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@Paul (pjchappy),
The first 3 links that you posted all are the same classd boards which are 250 x 2 @ 4ohms. The first link has two boards and that is the reason you are getting the 1000W (250wpc with 4 channels). The 4th link is the 250wpc x 8ohm board. If you plan to go that route please make sure that you get the extra heat sink (the ones that Steve got for his 4ohm speakers and ones that were compared to wyred for sound), in case your plan to run 4ohm speakers with those boards. I would also check with Tom to be sure about the 4th link and your speaker requirement 4 v/s 8 ohms.
I totally understand that.
As I mentioned in the paragraph discussing the 4th link, the upgraded heatsink is now standard, and therefore safe into 4 Ohms. (That info is straight from Tom)
Anwyays, I decided not to use the kit I have in 4 channel mode and that is why I now have this "dilemma." (Which I added to the previous post for clarity)
Paul
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I totally understand that.
As I mentioned in the paragraph discussing the 4th link, the upgraded heatsink is now standard, and therefore safe into 4 Ohms. (That info is straight from Tom)
Anwyays, I decided not to use the kit I have in 4 channel mode and that is why I now have this "dilemma." (Which I added to the previous post for clarity)
Paul
:duh: should have read your original post more carefully. I should know better to post when I am half sleeping.
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For my future speakers, I plan on going active and will need 4 channels of amplification. . .and I decided the kit I have, which can be used in a 4 channel "mode," just won't cut it. I don't feel like writing out all the different options I thought of regarding configurations of the Class D amps, so I will just post my current dilemma/options:
What are the future speakers going to be? Why are the 4 channels you have not enough?
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I have it narrowed down to a couple different speakers. The bass sections are known to be power hungry / like a lot of power. With that and with reading people talking about upgrading the PS, I just think 4 x 125 @ at Ohm off of 1 PS may run out of steam.
Another option I have is to just get another PS and transformer and make 2 identical stereo amps, still giving me 4 x 125 Watts @ 8 Ohms, but off of 2 PS. However, for basically $100 more, I could double the power (with option #1 in my previous post). This would have the benefit of making this amp a little more versatile for any future use, too.
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I have it narrowed down to a couple different speakers. The bass sections are known to be power hungry / like a lot of power.
You may be spinning your wheels a bit worrying about power that you really don’t need. While the “1000 Watt” kit may be a little overhyped, especially considering the power supply, 4 channels at 125 Watts each into 8 Ohms is still a lot of power, and if you end up getting/building speakers with 4 Ohm drivers there is even more power available (though you’ll probably need to do some power supply improvement). Are the woofers in the speakers you are considering 8 Ohm or 4 Ohm? What’s their rated SPL at 1 Watt?
Start by evaluating the actual power requirement of the speakers, and since you’re going to bi-amp consider the individual drivers in them. The IR amps *actually deliver* the rated power . . . there is no need to overbuy to get “headroom” (which is the word used to justify money spent for power never used). Look upthread for my post about the power actually needed for a Seas W22EX. My tri-amped speakers are spec’ed 120 Watts/side for the woofers, 60/side for the mids, and 60/side for the tweeters. It is specifically advised *not* to use amps larger than that, as they might damage the drivers. If things work out I’ll be powering the woofers and mids with two 120x2 boards (and two power supply boards, on one transformer). I didn’t buy the 250x2 boards because that’s *more* power than I need . . . .
As for heat sinks . . . it’s better move a little air across a small heat sink than to put a big heat sink in a closed box. These things are in fact quite efficient . . . they don’t generate anywhere near as much heat as a Class AB amp delivering the same power. Even at painful listening levels they generate less heat than the typical laptop computer. They don’t need 20 lbs of Aluminum in a wind tunnel heat sink. That’s for the Class A guys . . . or pro sound at the coliseum.
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The first experiment will be with 30k per rail (two pair of 15k, 60k total on board) and to use the third position for bypass and snubber parts. If that works well enough I'll clone it for the other amps, box 'em up and move on to serious listening. Apart from input coupling and power supply I haven't identified anything else that I want to change . . . yet . . . :icon_twisted: . . .
keep us posted...
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I received my amp kit (250w x , 500w x 1, large power supply, transformer) on March 10.
This is my first ever DIY amp. I hooked up everything on a board to see how it works and will build a proper enclosure soon. No problems hooking everything up. Transformer came with orange and brown leads taped off and also CT leads were taped together so Tom is taking steps to keep people from burning up the transformer. I am using an old Yamaha RX-V850 receiver as a preamp, Harman Kardon FL-8400 CD player, and DIY Mini-Statements speakers. First played some Floyd Dark Side of the Moon and it was an “OMG this is fantastic” moment. All was well then I started to have some problems. The volume of the music, especially lyrics started to fade in and out. Mind you this started about 45 minutes into play time. I don’t think the problem is the amp. I believe it is with the Yamaha because it has a LED in the volume knob and I saw it dim and flicker a few times. This receiver is about 17 years old and has been sitting around in my basement for years. I checked over the amp and all looks okay. Temp of heat sink was 86 degrees and chips attached to heat sink were 107 degrees so amp is not getting too hot. I did not have time to investigate last night and I wanted to not get frustrated so I will check it out more this evening. I will double check all connections and make sure all interconnect cables are tight. If still have the problem I will hook up amp to my HT receiver pre outs and see if old Yamaha is the problem. I may do this anyway to compare sound, however, getting to the back of HT setup is a pain in the rear. Anyone have any ideas as to what may be happing?
Robert
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You may be spinning your wheels a bit worrying about power that you really don’t need. While the “1000 Watt” kit may be a little overhyped, especially considering the power supply, 4 channels at 125 Watts each into 8 Ohms is still a lot of power, and if you end up getting/building speakers with 4 Ohm drivers there is even more power available (though you’ll probably need to do some power supply improvement). Are the woofers in the speakers you are considering 8 Ohm or 4 Ohm? What’s their rated SPL at 1 Watt?
Start by evaluating the actual power requirement of the speakers, and since you’re going to bi-amp consider the individual drivers in them. The IR amps *actually deliver* the rated power . . . there is no need to overbuy to get “headroom” (which is the word used to justify money spent for power never used). Look upthread for my post about the power actually needed for a Seas W22EX. My tri-amped speakers are spec’ed 120 Watts/side for the woofers, 60/side for the mids, and 60/side for the tweeters. It is specifically advised *not* to use amps larger than that, as they might damage the drivers. If things work out I’ll be powering the woofers and mids with two 120x2 boards (and two power supply boards, on one transformer). I didn’t buy the 250x2 boards because that’s *more* power than I need . . . .
As for heat sinks . . . it’s better move a little air across a small heat sink than to put a big heat sink in a closed box. These things are in fact quite efficient . . . they don’t generate anywhere near as much heat as a Class AB amp delivering the same power. Even at painful listening levels they generate less heat than the typical laptop computer. They don’t need 20 lbs of Aluminum in a wind tunnel heat sink. That’s for the Class A guys . . . or pro sound at the coliseum.
Second that....
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So, I've been lurking on this thread for about a week, read the entire thing with great interest.
I'm somewhat close to pulling the trigger on 2, 120w x 2, 240w x 1 to run as mono blocks (with upgraded power supplies).
There's a point that several people have touched on, that I want to explore a little further. Several people have mentioned to keep signal leads as short as possible in order to reject as much RFI as possible, correct?
My question is, does anyone think there would be any advantage in shielding the case with copper (or some other material) to reject RFI? They touch on it here - audioheritage.org/vbulletin/archive/index.php/t-14551.html.
I've read that NUFORCE is 'notorious' for RFI issues. So, it would seem to me, that even if the RFI isn't audible as such, it would still have a harmful affect on the quality of the sound. It may even account for the 'wrongness' some people hear in the upper frequencies.
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So, I've been lurking on this thread for about a week, read the entire thing with great interest.
I'm somewhat close to pulling the trigger on 2, 120w x 2, 240w x 1 to run as mono blocks (with upgraded power supplies).
There's a point that several people have touched on, that I want to explore a little further. Several people have mentioned to keep signal leads as short as possible in order to reject as much RFI as possible, correct?
My question is, does anyone think there would be any advantage in shielding the case with copper (or some other material) to reject RFI? They touch on it here - audioheritage.org/vbulletin/archive/index.php/t-14551.html.
I've read that NUFORCE is 'notorious' for RFI issues. So, it would seem to me, that even if the RFI isn't audible as such, it would still have a harmful affect on the quality of the sound. It may even account for the 'wrongness' some people hear in the upper frequencies.
I was thinking the same thing about shielding yesterday while at Lowe's picking up some wood for the case. The signal leads in my test platform are only about 3 inches long. I have some Kimber kable braided speaker wire and am thinking about cutting some off the end and using it for the signal leads.
Robert
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+2
Since my box is all wood. I was thinking of using copper or aluminum for interior walls. Solving shielding and grounding issues.
Lowe's got thin sheets in rolls (roofing supplies) but it is like $40 per roll and lots of it.
Anybody got different source ???
Mariusz
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Use an aluminum case. :rotflmao:
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Use an aluminum case. :rotflmao:
Ya think maybe? Or stamped steel with lots of vent area for better cooling? :scratch:
Easy enough to mount a wood "dress panel" to hide the sordid reality. I suppose copper screen or a "bird cage" of 1/4 inch hardware cloth (with mounting plates for input and output connectors) would also work . . .
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Ya think maybe? Or stamped steel with lots of vent area for better cooling? :scratch:
Easy enough to mount a wood "dress panel" to hide the sordid reality. I suppose copper screen or a "bird cage" of 1/4 inch hardware cloth (with mounting plates for input and output connectors) would also work . . .
Well, being that I'm making aluminum cases for these, yes, I'd say aluminum. Mine will have vents in the top rear for cooling. :D
There are many ways to "skin the cat" though.
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Well, being that I'm making aluminum cases for these, yes, I'd say aluminum. Mine will have vents in the top rear for cooling.
Could the top rear vents be accompanied by bottom or side intake vents so that there is some kind of convection "air flow"?
Steve
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Could the top rear vents be accompanied by bottom or side intake vents so that there is some kind of convection "air flow"?
Steve
It will not have side vents...Tom said the way I have it, is perfect for venting. Also, there are holes on the bottom so you will get airflow.
:thumb:
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It will not have side vents...Tom said the way I have it, is perfect for venting. Also, there are holes on the bottom so you will get airflow.
Do you have any preliminary information on dimensions (to determine what size (and height) of power supply caps might fit) or ballpark pricing?
Steve
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+2
Since my box is all wood. I was thinking of using copper or aluminum for interior walls. Solving shielding and grounding issues.
Lowe's got thin sheets in rolls (roofing supplies) but it is like $40 per roll and lots of it.
Anybody got different source ???
Mariusz
Check the heating duct isle at Lowe's. I bought some duct steel a few years back and it did not cost much. You just have to pound and bend it flat as it came rolled up. I am glad you brought this up because I need to go to Lowe's and check this out for myself.
Robert
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Do you have any preliminary information on dimensions (to determine what size (and height) of power supply caps might fit) or ballpark pricing?
Steve
External dimensions will be ~13.25" wide x ~16.25" deep. Internal height will be ~3.4"
I don't want to discuss pricing out of respect to AC. You're more then welcome to contact me via PM or email.
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Just wanted to update and let you guys know that replacing the R9 and R11 SMD resistors and lowering the gain DID remove the hiss I was getting in my tweeter as expected.
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Well I couldn't help myself; after all that power supply talk I went and ordered some 6800uf Panasonic TS-HA caps to replace the 3300's that came w/ my 250w amp. Replacing was easier than I expected, as the holes are bigger and I'm getting a handle on working with the solder Tom uses ( needs a good hot iron).
What am I hearing? what I'm hearing is some bass slam. Music's got some kick to it. Low end is a thumbs up. Didn't know my Modula MTMs could go so low with a punch despite the relatively small enclosure (see my gallery pic). I think the midrange is also more forward, or more present. It's a much livelier amp. Maybe that's dynamics, I dunno, I get tired of trying to find the right lingo. It sounds a damn lot better that's for sure.
I've only been listening for a few hours but I am way impressed.
8) :eyebrows:
(http://www.audiocircle.com/image.php?id=27728)
(http://www.audiocircle.com/image.php?id=27729)
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Wushuliu is the mod as simple as just replacing the caps, no other changes to the board ie rectifier or such ??
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You can order a kit which contains larger capacitors: http://classdaudio.com/index.php/class-d-amplifier-kits/home-kits/250w-x2-500w-x1-amp-large-power-supply-transformer.html
Note:
To save some $$$$: Old stereo receiver transformers can be used if they produce anything between 80 to 60 volts with a center tap. The capacitors and rectifiers can be salvaged as well as long as they're good. (I wouldn't bother with the rectifier unless it was a bridge module.)
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I still have to make a top for it :eyebrows:
(http://www.audiocircle.com/image.php?id=27748)
(http://www.audiocircle.com/image.php?id=27749)
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Wow Bill, that case is going to look great. Did you make the rest of the case out of metal?
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(http://www.slashfilm.com/wp/wp-content/images/hal9000wallpaper.jpg)
"What would you like to hear, Dave?"
Building one of these amps inside a computer would be a fascinating project! Not only that- but the ventilation would be perfect. You would have to use a full tower case. Ahh...one with a clear side! :drool:
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Wow Bill, that case is going to look great. Did you make the rest of the case out of metal?
I started out with the metal box made locally and applied poplar panels
all straight cuts then used brackets to secure them to the box. This way
there are no glue joints, this could be with made a 3/8'' plywood box
then cover it in the same way making it simple and resonable. The top
will have a 4" hole with screening installed for heat and I will use small
magnets for the top to make it easier to access the inside.................Bill
(http://www.audiocircle.com/image.php?id=27750)
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mintzar, good to know. What resistors did you use?
Don
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I used 10k 1/4w 1206 Vishay/Dale resistors.
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I've had a great time putting this all together from the NAD case to the one I'm presently working on. So now I would personally like to Thank Steve K for starting this post !! :thumb: :thumb:
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Wushuliu is the mod as simple as just replacing the caps, no other changes to the board ie rectifier or such ??
Yes that's all I did, but check the bridge rectifier to make sure it's a 10 amp per deward's post above. The link by niteshade is to the 4700uf 'Heavy Duty' Supply for those who would rather not diy, but for that same money of course you could triple that or more with a good iron...
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Since I may pick up one of these class d amps I have a really stupid question, how did you guys attach the board to the metal cases. Did you just screw up through the bottom right into the risers? What about the toroidal transformer?
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I've had a great time putting this all together from the NAD case to the one I'm presently working on. So now I would personally like to Thank Steve K for starting this post !!
You're quite welcome! It's been a wild ride. I'm still assembling my second amp and the modders are already modding the power supplies and the amp boards. Amazing. It will be interesting to hear the results of these upgrades and how they improve the sound. I'm still amazed at how well the stock ones sound in my system. I never would have believed they'd be replacing my beloved tube amps. :roll: Time marches on. :thumb:
steve
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Building one of these amps inside a computer would be a fascinating project! Not only that- but the ventilation would be perfect. You would have to use a full tower case. Ahh...one with a clear side! :drool:
Funny you say that, I just grabbed an old IBM Aptiva case out of the neighbor's trash for just this reason.
Now to decide on just what to build.
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how did you guys attach the board to the metal cases. Did you just screw up through the bottom right into the risers?
Correct.
What about the toroidal transformer?
Same, but no riser. All the hardware is provided with the kit.
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Correct.
Same, but no riser. All the hardware is provided with the kit.
Just so you know, the "riser" is actually called a standoff. Just so you know the proper term if you ever have to source them.
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Has anyone attached a 12 volt trigger yet. If so I am curious how this is done.
I have (2 of the 600 watt TI amps) in an enclosure for surround duties and this would be a nice addon for that amp.
I have also put the 250 x 2 (8 Ohm) into a Hammond enclosure with a Hypex SMPS built for the UCD400. This makes for an excellent amp in a pretty small footprint (6 1/2 x 9 x 2 inches). I believe this amp sounds much better the the TI 600 watt amp.
I also built a Lighter Note LDR Preamp (Buildanamp.com) in a similar Hammond enclosure. This combination of the IR amp and the LDR volume control is truly unbelievable for the money.
I think it sounds as good if not better than the 2 UCD amps I have made. A UCD180 & UCD400 amp that both contained the H x R regulators in them.
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I added a relay. Seems to work OK. I still want to get a power conditioner / sequencer, though because I use mine together with a DCX2496, which I cannot control automatically.
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Class D Audio said they were currently working on an audio signal trigger module, and when I inquired about a 12V trigger module, agreed that it would be a good idea and would try to have one of those in the near future as well.
Steve
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You may be spinning your wheels a bit worrying about power that you really don’t need. While the “1000 Watt” kit may be a little overhyped, especially considering the power supply, 4 channels at 125 Watts each into 8 Ohms is still a lot of power, and if you end up getting/building speakers with 4 Ohm drivers there is even more power available (though you’ll probably need to do some power supply improvement).
Regardless, I'm just curious about my previous question: Is it better / different to get 250 Watts per channel into 8 ohms with 2 bridged amp modules and 1 PS or just one stereo module and 1 PS?
Thanks!
Paul
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Regardless, I'm just curious about my previous question: Is it better / different to get 250 Watts per channel into 8 ohms with 2 bridged amp modules and 1 PS or just one stereo module and 1 PS?
Thanks!
Paul
It's fine to use two bridged amps per PS and tranny as far as I know. I've asked Tom about it and that's why the case will be made so you can do just that. Does it sound better seperate? Only you can answer that...
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I know it can be done. I'm just curious if there are any inherent advantages or disadvantages of such a set up? 2 medium powered modules bridged @ 250 Watt / channel @ 8 Ohms vs. 1 high powered module in stereo mode @ 250 Watt / channel @ 8 Ohm.
Again. . .just curious.
Paul
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I know it can be done. I'm just curious if there are any inherent advantages or disadvantages of such a set up? 2 medium powered modules bridged @ 250 Watt / channel @ 8 Ohms vs. 1 high powered module in stereo mode @ 250 Watt / channel @ 8 Ohm.
Since you are using them at 8 ohms, the fact that a bridged amp sees half the impedance probably doesn't make any difference in your application.
But who knows if one might change speakers in the future and end up with a 4 ohm pair. And although Tom @ Class D says all his IR amps, except the 250W @ 8 ohm, can run bridged for a 4 ohm load, International Rectifier's technical manual and other users say otherwise, so I think that configuration may be borderline acceptable.
I don't know how these particular Class D amps' characteristics vary from stereo to bridged mono, but many Class A/B amps I have come across in the past specify higher levels of distortion when bridged.
Steve
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I know it can be done. I'm just curious if there are any inherent advantages or disadvantages of such a set up? 2 medium powered modules bridged @ 250 Watt / channel @ 8 Ohms vs. 1 high powered module in stereo mode @ 250 Watt / channel @ 8 Ohm.
Again. . .just curious.
Paul
I ran mine in bridged mode just to check out extra power and i wasnt that impressed with the results, not scientific or anything just didnt blow me away compared to stereo.
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From my very minuscule know-how/what, bridged amps usually suffer a little quality penalty vs unbridged (based on my use of Adcom/Hafler gear), I have zero experience with Digital Amps.
Over the past few days I have tried Shadowlight's amp in a few different positions, and I like what I hear, its different to what I am used to but it has responded well to better wiring/cables/conditioning. I am 92.5% sold. :lol:
I also noticed that it sounds more relaxed and effortless, after being on for 4-5hours.
I can see this replacing at least one amp in my HT setup.
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My 250 x 2 has been shutting down if I play it fairly loud.
Anyone else getting shutdowns?
Tom's reply to my over heating issue:
"The problem was one of the adjustment pots must have knocked against
something and was not working properly. The amp was running at about twice
the speed it should."
Jeff
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I don't know how these particular Class D amps' characteristics vary from stereo to bridged mono, but many Class A/B amps I have come across in the past specify higher levels of distortion when bridged.
Steve
I asked Tom at Class D this same question, even bringing up my previous unsatisfactory results bridging class A/B amps. and he told me that class D amps do not have that issue.
He said the sound is no different when bridged.
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Birch plywood top :eyebrows:
(http://www.audiocircle.com/image.php?id=27888)
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Looks good! How is it fastened--from the sides? I hope to have mine in the box this weekend for a final pic of the twins. Tom is talking about a new Super D class of amps he's working on. He's sending me a demo. :drool: He claims it has the same performance of his other IR amps except it projects a larger soundstage. I sure hope it all fits in my brand new boxes!! Film at 11.
steve
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Looks good! How is it fastened--from the sides? I hope to have mine in the box this weekend for a final pic of the twins. Tom is talking about a new Super D class of amps he's working on. He's sending me a demo. :drool: He claims it has the same performance of his other IR amps except it projects a larger soundstage. I sure hope it all fits in my brand new boxes!! Film at 11.
steve
It will be held down with 1/2 dia. magnets set into the top and sides
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What about venting? Is it not necessary? Thanks!
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What about venting? Is it not necessary? Thanks!
There will a 3/4 gap in the across back (which isn't done yet) and 2-2" holes in the bottom to allow air
to circulate from the bottom out the back. More pics as I proceed................Bill
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That's looking really sharp! :thumb:
There will a 3/4 gap in the across back (which isn't done yet) and 2-2" holes in the bottom to allow air
to circulate from the bottom out the back. More pics as I proceed................Bill
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Tom is talking about a new Super D class of amps he's working on. He's sending me a demo. :drool: He claims it has the same performance of his other IR amps except it projects a larger soundstage.
steve
That's a bit disappointing, because before I ordered my kit, the only differences he had told me were that the Super D amps were going to have balanced inputs and adjustable gain.
My kit is still not assembled, however. :eyebrows:
Paul
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Yes those are the build differences but Tom was describing the difference in sound. He said the soundstage and imaging were much better than his current line
steve
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With just those changes, what could make the sound difference?
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I think he's done something else that he's not telling. :eyebrows:
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I take it, that we are looking at a small price premium for the 'improved' version?
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I have no idea but he's practically giving these things away as it is. I keep telling him to put it in a nice case. That's where the money's at.
-
Hey, maybe we are the guinea pigs in this, and a full blown product may be his eventual goal. :thumb:
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Damn, and I got the 1000 watt Kit that I am planning to build already here. Hell, there is no way of knowing what is the difference unless you run the older and newer modules side to side and for what I am thinking about using these for, fullrange woofer duties, it matters not a bit. :thumb:
-
Any news on the enclosure front?
-
Hey, maybe we are the guinea pigs in this, and a full blown product may be his eventual goal. :thumb:
I hope you're wrong. As is, this is great for diy, and I hope it continues. :wink:
-
Steve,
Does he have any news on the multi-channel project he was said to be working on?
Thanks,
Robert
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I haven't heard anything about that. He's really busy so if I get an email or two a week from him, I'm lucky. You might ask him.
steve
-
Any news on the enclosure front?
I have the second prototype complete. It's really nice. Next, are the finished anodized units.
-
This is a recent steel box prototype. People have been interested in my power supply, so here it is:
(http://www.audiocircle.com/image.php?id=27936)
1. Dual 25 amp 200v bridge rectifiers in parallel
2. Two 10,000uf 63V capacitors
3. Very short wire runs, for power supply and I/O's
4. Open bottom: I like it! Plenty of ventilation. (Something to think about.)
-
4. Open bottom: I like it! Plenty of ventilation. (Something to think about.)
Open bottom - but doesn't heat rise ? :scratch:
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Yes, heat rises. There are convection cells which can cool adequately with a raised open bottom. A metal enclosure draws heat away too. Note that these modules do not produce much heat. The heat sink can be modified to provide more aggressive heat transfer if it's necessary. Side or back forced air cooling can be used as well. If done properly, it will not be noisy at all.
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Nicely done, thanks Blair. Appreciate the pic and information. :thumb:
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You can 86 the magnets unless there larger they don't hold well at all. I'll simply screw the top down so much for that..............Bill
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Maybe you can use electromagnets that don't allow you to open the amp while it has juice and don't hold the lid in place when current is removed. Or maybe just "screw it" and listen.
-
Rare Earth Neodymium magnets would work. If you get ones that are magnetic from right to left rather than Axially you can attach them that way very easily. Neodymium magnets have a pull strength anywhere from 3lbs-100lbs each and are relatively small and inexpensive (though not as cheap as screws).
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Hey Guys! I finally finished my enlosure. I had a few finishing problems which I figured out were due to my garage being too cold. Because of this I had to redo the finishes a couple of times which always ends up looking worse than if it had taken the first time. At some point down the road I intend to pair this amp with a Dodd Buffer. Anyway, here are the pics.
(http://www.audiocircle.com/image.php?id=27992)
(http://www.audiocircle.com/image.php?id=27990)
(http://www.audiocircle.com/image.php?id=27989)
(http://www.audiocircle.com/image.php?id=27987)
(http://www.audiocircle.com/image.php?id=27988)
As you can see it is pretty tight in there. If I weren't trying to match this so that it can stack with the Dodd Buffer I would have built it larger.
Best,
Ed
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Very nice. Great job! :thumb:
Paul
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Maybe you can use electromagnets that don't allow you to open the amp while it has juice and don't hold the lid in place when current is removed. Or maybe just "screw it" and listen.
Building it is more than half of the fun and I am listening to it in another case so, what up dude :wink:
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ebag4, how did you do the lettering on the front panel?
A little tight, but still a very nice job!
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Rare Earth Neodymium magnets would work. If you get ones that are magnetic from right to left rather than Axially you can attach them that way very easily. Neodymium magnets have a pull strength anywhere from 3lbs-100lbs each and are relatively small and inexpensive (though not as cheap as screws).
Thank You for the info much appreciated........Bill
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Building it is more than half of the fun and I am listening to it in another case so, what up dude :wink:
Bill,
I was kidding.
-
Bill,
I was kidding.
I know I loved the screw it line my wife and I had a good laugh, I was just playing. Honest I take none of this personal this whole time has been great and I've had a lot of fun have a great weekend.....Bill
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Beautiful job Ed! Very professional looking. and I though my case was tight!! How did you get the lettering on the faceplate. Make sure and send a pic to Tom. :thumb:
steve
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Hi Ed
great job
The board arrangement is similar to what I have in my "jewelry box".
-
Hey Guys! I finally finished my enlosure. I had a few finishing problems which I figured out were due to my garage being too cold. Because of this I had to redo the finishes a couple of times which always ends up looking worse than if it had taken the first time. At some point down the road I intend to pair this amp with a Dodd Buffer. Anyway, here are the pics.
As you can see it is pretty tight in there. If I weren't trying to match this so that it can stack with the Dodd Buffer I would have built it larger.
Best,
Ed
I envy some of you guys. I have no problem messing around w/ the insides, but I have no idea how to build anything as remotely as cool for an enclosure...
-
Thanks guys. Yes, it is tight in there. To get the boards out I will have to remove the transformer first.
Regarding the lettering, that was a first time try at engraving. I first printed out a full size label and stuck it to the Maple. Then I tried using a Dremel tool but was having trouble controlling it so I ended up using my trusty multitool (utility knfe) to finish it up. It turned out OK but I think I could do a better job if I started with the knife first.
Best,
Ed
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Ed
I like the look of the amp, you did a great job.
You can go back the logo with a solder iron.
:thumb:
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Ed
I like the look of the amp, you did a great job.
You can go back the logo with a solder iron.
:thumb:
Thanks Trung. I wish I had thought of/heard of the soldering iron trick before I put 4 coats of poly on the maple.
Best,
Ed
-
Ed
We live and we learn.
May be next build turned out even better.
:wink:
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(http://)
Just packed up Shadowlight's ClassD amp. In the week plus it has been here, it was fun trying different tweaks to tailor the sound to my liking. And given the limitation of it not being my amp, I think I came close. Briefly it requires careful selection of wire to compliment (offset its sound-nature) its sound signature, power cables/IC on the warm side of neutral suits my taste best, it sounds better with power conditioning (see the Felix threads in the Lab circle).
When I unplugged it a few hours ago, I swapped in an Exposure 2010 amp to see how it compares, it came close but the Exposure had better (my preference) bass, better soundstage (more 3D), and an overall liquidity to musical presentation. The ClassD amp has a starkness to it, highlighting percussive notes and female voice, the bass was pretty tight but was a tad too dry IMO.
I think its a very good bargain for the sounds quality it presents.
I will be curious to hear impressions of the next version, with promised improved soundstaging.
Thank again to Shadowlight for the audition.
-
(http://)
Just packed up Shadowlight's ClassD amp. In the week plus it has been here, it was fun trying different tweaks to tailor the sound to my liking. And given the limitation of it not being my amp, I think I came close. Briefly it requires careful selection of wire to compliment (offset its sound-nature) its sound signature, power cables/IC on the warm side of neutral suits my taste best, it sounds better with power conditioning (see the Felix threads in the Lab circle).
When I unplugged it a few hours ago, I swapped in an Exposure 2010 amp to see how it compares, it came close but the Exposure had better (my preference) bass, better soundstage (more 3D), and an overall liquidity to musical presentation. The ClassD amp has a starkness to it, highlighting percussive notes and female voice, the bass was pretty tight but was a tad too dry IMO.
I think its a very good bargain for the sounds quality it presents.
I will be curious to hear impressions of the next version, with promised improved soundstaging.
Thank again to Shadowlight for the audition.
Is the nut driver under the Powercord your best tweak ?
-
Ed between your new amp and your Neo project you sir are a craftsman. Your replica's are outstanding! :thumb:
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I read this thread with interest - not the kind of interest that makes me think I will buy one, but the kind of interest in digital amps period - I went through a phase a couple of years ago, trying JVC and Panny receivers, Teac Tripaths in various states of mod, the Sharp digital, a Trends, but eventually found my way back to Class A, this time in el84 tubes. I still own a JVC EX-A1 that I use in the living room, but need to build some fun speakers for it. For the main system, I am loving my old Maggie console pull.
Looks like a great way to get lots of affordable power, and cool to see the efforts and various builds around here!
-
Is the nut driver under the Powercord your best tweak ?
Nah...least favorable tweak...didn't do squat for the sound. :eyebrows:
-
folks,
after reading this thread via link provided by jtwrace, I contacted Tom at ClassDaudio with some questions and with his response, he ask me to pass on the following information:
Hi Mike,
To try to make this a more easy answer... today or tomorrow we are introducing our new "Super D Series" amps with balanced input and adjustable gain. In about a week, we have a version of this amp coming out with balanced input, adjustable gain, but... also can drive loads below 1.5 ohm. This amp is rated at 500 W RMS per channel at 2 ohm! Of course, this new series of amps is more expensive than our other series and on average about $100.00 per amp more. The 500W into 2 ohm is even a little more expensive.
These new amps from us have the finest balanced inputs available anywhere on the planet, and can also take input voltages up to 20 volts. Input impedance on the Super D's is 47k. They also have external adjustable gain controls (work like volume controls). Also, no more soldering for external LED's, switch, or gain controls, as I have incorporated Molex type connectors for all of these, and also include the connectors with wires attached to make things even easier. Larger and better cooling heatsink too. These amps are the same width, but 1" longer than our other IR based amps.
I believe we have answered all requests and comments from our customers with this new amp. I also believe it will possibly prove to be one of the finest audio amplifiers available today and at any price.
I will try to get a news letter out with the new amps in the next few days. Things have been very busy for me here with work from early morning to about 1:00 in the morning 7 days a week, so I might be a little late getting it out. If you're in the Audiocircle.com forum, maybe you can pass on this information for me?
Please let me know if I can be more help.
Thanks,
Tom
so I'm waiting on Tom's latest & greatest and then I've simply got to jump on this bandwagon and give these a try.
-
It will certainly be interesting to hear comparisions of the new amps. Didnt expect a price increase of that much though. :duh:
Steve any update on the demo?
-
Maybe by the end of the week. You'll know when I know.
steve
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Are the Super Ds going to use the same PS?
I'm likely going to sell my two 250 Watt x 2 into 8 Ohm amps (http://classdaudio.com/index.php/class-d-power-amplifier-250w-x-2-500w-x-1.html). They are brand new/unused, but taken out of the package to take a gander at them. PM me if interested. May just sell one. Would use the funds for the Super Ds.
Paul
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Yes as long as they're the same output as the originals. Hopefully we'll know more in a few days. Just hope the new boards fit in my case. :o
steve
-
Gain control will be welcome by many as well as other improvements.
Is it worth the premium? I guess that depends.
But comparison of these amps would be interesting.
P.S
does anyone knows dimentions of the new amp kit ........ just in case. :lol:
Cheers
Mariusz :thumb:
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These amps are the same width, but 1" longer than our other IR based amps
-
Thanks
that clears it up.
:thumb:
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Here's some pics of the new Super D amp. You can see the gain attenuators and the LED extensions for remote LED's. Pretty slick!!
(http://www.audiocircle.com/image.php?id=28114)
(http://www.audiocircle.com/image.php?id=28113)
steve
It seemed more appropriate to move this post to the Sweet Deals thread since that's discussing the new Super D amp.
-
These new amps from us have the finest balanced inputs available anywhere on the planet . . .
\
That would have to be the Burr-Brown INA137/INA2137 audio differential line receiver . . . easy to implement and excellent performance.
It will be interesting to see what changes (other than the heat sink) are made to deal with loads below 4 Ohm . . . the existing output filter won't do, and maybe more robust output FETs to take the current necessary. That's probably where most of the additional money goes. I'm a bit surprised at the new heat sink . . . I would have just added a "crown" on the standard bar . . . (which anyone can do on the amps that they have . . . mask off the board, drill and tap, screw on the radiator). Keeps the trace lengths shorter . . .
-
A little advice:
Before dumping your existing Class D modules, get some feedback on how the new ones sound first. They may not sound better, just different. I think the existing modules are great! Let's see how people like the new ones, what they have to offer.
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looking at the heat sink, i cannot help but wonder - would it not be much more efficient to have the fins perpendicular to the the first thick mounting fin, instead of parallel? much better heat transfer, in the same space... are heat sinks of this shape rare or more expensive, or?
thanks,
doug s.
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are heat sinks of this shape rare or more expensive, or?
thanks,
doug s.
Nope. Not rare at all.
http://www.heatsinkusa.com/
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...are heat sinks of this shape rare or more expensive, or?
thanks,
doug s.
But... mounting the heatsink to the board would be a little more challenging (you can't screw into the now vertical fins, you'd have to screw from the bottom into the thicker plate where the transistors reside).
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Nope. Not rare at all.
http://www.heatsinkusa.com/
nope - must be rare - not one heat sink on that site has first blade running one direction, then all the other blades running perpendicular to it. all the heat sinks on that site are exactly like what's shown in the amp pic, except in the amp pic, the first blade is thicker...
yes, you could re-orient the heat sink per what ohenry talks about, but then you would have a set-up that is difficult to secure to the board.
doug s.
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nope - must be rare - not one heat sink on that site has first blade running one direction, then all the other blades running perpendicular to it. all the heat sinks on that site are exactly like what's shown in the amp pic, except in the amp pic, the first blade is thicker...
yes, you could re-orient the heat sink per what ohenry talks about, but then you would have a set-up that is difficult to secure to the board.
doug s.
Ok. I misunderstood. Yes, these are extruded so you will not have two fins going in different directions unless one is machined for you. Which is possible...not hard at all.
anything is possible...
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Ok. I misunderstood. Yes, these are extruded so you will not have two fins going in different directions unless one is machined for you. Which is possible...not hard at all.
anything is possible...
yes, likely quite a bit more expensive. but, if heat is a problem here, which some users have indicated is the case, it may not be so expensive for a run of this part, which isn't too large, in this case. or, it may be simpler to yust butt one of these extrusions up against a flat bar stock, attached w/suitable screws and heat transfer paste...
doug s.
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yes, likely quite a bit more expensive. but, if heat is a problem here, which some users have indicated is the case, it may not be so expensive for a run of this part, which isn't too large, in this case. or, it may be simpler to yust butt one of these extrusions up against a flat bar stock, attached w/suitable screws and heat transfer paste...
doug s.
Yes, or use some standoffs that would attach to the case (metal of course). Then you'll use the case as a heat sink...we'll see!
-
Has anyone considered going off the grid with the Class D Battery power supply?
-
http://www.audiocircle.com/index.php?topic=76400.480
And awesome with Dodd battery buffer
:thumb:
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Looking at the new heatsink, seems like a poor use of the sink, should have the transistors located on the bottom with the thick fin (where the transistors are mounted) as the anchor to the board, still not the best but would have more efficient heat transfer to the sink. :dunno:
I think it would be better to have all the info in one thread rather than spread out over different circles. Yeah its a big thread, but its all in one place.
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Looking at the new heatsink, seems like a poor use of the sink, should have the transistors located on the bottom with the thick fin (where the transistors are mounted) as the anchor to the board, still not the best but would have more efficient heat transfer to the sink. :dunno:
ya, i was thinking the same thing. certainly, w/o much effort, a much more efficient heat sink could be utilized.
doug s.
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I think it would be better to have all the info in one thread rather than spread out over different circles. Yeah its a big thread, but its all in one place.
Yupp.
At least it is in one place.
And still relative and informative.
Cheers
Mariusz
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"Has anyone considered going off the grid with the Class D Battery power supply?"
Yes, it's something I will do over time and why I've gotten into class D. Have wind, solar, and pedal power projects starting this summer. All small, a few hundred watts.
I'm interested in what others already doing it have accomplished so also hope they'll respond.
As to heat issues. Mine ran hot to the touch before I finished venting the case. Put air slots on bottom below PS and amp boards, and slots above them. Not hot at all now.
I do need shielding or a metal case as with this wood one the tv's antennae doesn't function.
Don
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mjosef,
I'm curious to know the value of the cmc used in your felix? I have a felix made up with a 4mh - 5.2amp cmc, do you think that is enough?
Thanks
boone
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I have a felix made up with a 4mh - 5.2amp cmc, do you think that is enough?
That looks like the ticket. Should be perfect. I tried the amp on a 39mH Felix, and thought it was too much, however on a 2mH Felix it sounded very good. Don't have a 4.5mH built, but it may just be where the sweet spot lives. Try it and let us know your results.
-
Too many batteries. Very,very good linear power supplies can be made for these that are dead quiet. These amps are not that prone to noise problems IF they're wired-in properly.
Has anyone considered going off the grid with the Class D Battery power supply?
-
Hello all,
New to class D. Anything obviously wrong here?
How should it sound at 50+ hours? Those are the IR2092 based boards. Thanks...
Dave
(http://www.audiocircle.com/image.php?id=28158)
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Well boys and girls I finished round 2. With the larger insides and a better understanding
of the proper layout we are done and this time there is no hum in my amp. Many Thanks to all who
helped me along the way................Bill (El Martino)
(http://www.audiocircle.com/image.php?id=28184)
(http://www.audiocircle.com/image.php?id=28185)
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Looking good guys! I don't know about the rest of you but I didn't notice that much of a burn in time with mine. 1/2 hour to an hour or so? Anyone else? :thumb:
steve
-
Is there any RF interference from the boards? I have been thinking about lining the interior of a salvaged wood drawer box from the 1960s with thin copper as I have seen done in other wood/electronic projects. Now the question is, how many millimeters of copper sheeting I need to get and how to attach these sheets effectively to wood.... but going back to the question, whether there is any RF interference from these boards.
-
Pumpkinman, how about a review comparing the sonics of the ClassD amp with your McIntosh amp?
Nice job on the case and build.
-
Looking good guys! I don't know about the rest of you but I didn't notice that much of a burn in time with mine. 1/2 hour to an hour or so? Anyone else? :thumb:
steve
Steve i really didnt notice much break-in either, quite different from any other new audio piece's i have owned. :green:
-
Mine took over 100 hours to stop changing. Interesting about the differences in breakin from amp to amp.
-
Is there any RF interference from the boards? I have been thinking about lining the interior of a salvaged wood drawer box from the 1960s with thin copper as I have seen done in other wood/electronic projects. Now the question is, how many millimeters of copper sheeting I need to get and how to attach these sheets effectively to wood.... but going back to the question, whether there is any RF interference from these boards.
This seems like a good idea. Has anyone tried it before?
-
Pumpkinman, how about a review comparing the sonics of the ClassD amp with your McIntosh amp?
My thoughts exactly.
I want to read a few reviews compared to known class A/B amps.
-
Pumpkinman, how about a review comparing the sonics of the ClassD amp with your McIntosh amp?
It was recommended to me that I turn on my amp and not turn it off for a week which I just turned it on(burn in time) I just recently added copper ICs I'll remove them and put back the MAC Ultra Silvers I was using before as I'm more familiar with the sound, before I give you guys a head to head comparison. First play the thing that stood out was that imaging was far wider than with the Mcintosh.......................Bill
I wanted to add that I would hardly call myself an audiophile. Being involved with the higher end of this hobby for about 1 1/2 years. Thanks to the NY Rave and it's members(all great guys)I've learned alot, but most of all we all interpet things differently. Some like detail others prefer warmth or all of the above and at the end of the day what we really want is to sit back and enjoy
-
"Some like detail others prefer warmth or all of the above and at the end of the day what we really want is to sit back and enjoy"
Absolutely right and well put! :wink:
-
Oh God Bill!!!!!! :o
Don't start talking sense, I'm not prepared for it.
It was recommended to me that I turn on my amp and not turn it off for a week which I just turned it on(burn in time) I just recently added copper ICs I'll remove them and put back the MAC Ultra Silvers I was using before as I'm more familiar with the sound, before I give you guys a head to head comparison. First play the thing that stood out was that imaging was far wider than with the Mcintosh.......................Bill
I wanted to add that I would hardly call myself an audiophile. Being involved with the higher end of this hobby for about 1 1/2 years. Thanks to the NY Rave and it's members(all great guys)I've learned alot, but most of all we all interpet things differently. Some like detail others prefer warmth or all of the above and at the end of the day what we really want is to sit back and enjoy
-
Oh God Bill!!!!!! :o
Don't start talking sense, I'm not prepared for it.
Yaaa give us the Pumpkin version! :green:
-
Hello all,
New to class D. Anything obviously wrong here?
How should it sound at 50+ hours? Those are the IR2092 based boards. Thanks...
Dave
(http://www.audiocircle.com/image.php?id=28158)
Hey!
Neat! Very nice layout in there. :D
That is very interesting and nice chassis you've got there. Any picture with full view of the chassis both open and closed? And info on the chassis? Thanks. :D
Take care,
Buddy :thumb:
-
Hey!
Neat! Very nice layout in there. :D
That is very interesting and nice chassis you've got there. Any picture with full view of the chassis both open and closed? And info on the chassis? Thanks. :D
Take care,
Buddy :thumb:
Yeah your amp looks Kick Butt!!! :thumb:
-
I have no internal pic of the case without the electronics. The case is mostly 1/16" Al, fetched on Ebay and made by Par-Metal.com. 12"x12"4", 50 bucks.
The case needed some attention by file and scotch-brite pad, but otherwise is of acceptable quality. The metal work was done with a Sheet-metal bit and nibbler tool.
I chose this layout to minimize input lead length (~1") and to maximize the critical circuit to XFMR distance. The setup here is temp just to get it up for ventilation.
The cone is cast from hot glue and will serve as feet. I just threw in the damped tubes pic because I think it's kind of neat and it works like crazy.
Finally, my amp's still breaking in after 100+ hrs. A fine product -- potentially on par with my Hillig based monoblocks and my Clayton S100.
(http://www.audiocircle.com/image.php?id=28250)
(http://www.audiocircle.com/image.php?id=28252)
(http://www.audiocircle.com/image.php?id=28253)
(http://www.audiocircle.com/image.php?id=28257)
Thanks for the kind words,
Dave
Chambersburg, PA
-
Finally, my amp's still breaking in after 100+ hrs. A fine product -- potentially on par with my Hillig based monoblocks and my Clayton S100.
S100 - $7000
Class D audio - mmmm, NOT $7000
dang. :o 8) :thumb: :drums: :wine: :xmas: :weights: :dance:
-
The cone is cast from hot glue and will serve as feet.
(http://www.audiocircle.com/image.php?id=28253)
Thanks for the kind words,
Dave
Chambersburg, PA
What did you use as a mold for your feet Great Idea!!....................Bill
-
Just make sure it don't get too warm where that hot-glue feet resides... :eyebrows:
-
Just make sure it don't get too warm where that hot-glue feet resides... :eyebrows:
I had the same thought; I think when you live in Tucson, like me, heat often comes to mind!
-
The cone is cast from hot glue and will serve as feet. I just threw in the damped tubes pic because I think it's kind of neat and it works like crazy.
Wouldn't casting them from silicone have been a better idea?
Seems they'd hold up better, at least.
-
My soldering iron is really to much how many watts is recommended for this type of work
Thanks .................Bill
-
You mean to solder the connections? A 40W. iron should be enough for most soldering.
-
My soldering iron is really to much . . .
I use an inexpensive solder station
http://www.circuitspecialists.com/prod.itml/icOid/7307
for almost everything, with the hot tweezer attachment for smd. It seems adequate. It's been a long time since I last fired up the old Weller "soldering gun". I also have a 30+ year old pencil station (and some 60/40) for repairing older stuff where non-eutectic solder was used . . .
-
Just make sure it don't get too warm where that hot-glue feet resides... :eyebrows:
LOL...Yes, I had the same thoughts, but it turns out the case bottom is basically stone cold.
That Par-Metal case is bottom, side and top slotted. It seems to do a job of encouraging plenty of convection.
Thanks for your concerns guys!
Dave
-
Wouldn't casting them from silicone have been a better idea?
Seems they'd hold up better, at least.
Simoon,
The castings are quite tough. Have you ever handled a hot glue stick?
I chose a certain type (forget) of hot glue stick because of its apparent lossiness. But who knows, Silicone may be better in terms of isolation. Interesting idea.
Dave
-
What did you use as a mold for your feet Great Idea!!....................Bill
Bill,
I used heavy duty Al foil formed into shape by hand. You can see the wrinkles in the casting. I made multiple sizes and they work very well. Got lucky.
A set of 3 easily supports 200 lbs (me).
Dave
-
S100 - $7000
Class D audio - mmmm, NOT $7000
dang. :o 8) :thumb: :drums: :wine: :xmas: :weights: :dance:
Indeed!! I was skeptical. I actually built this for a non-tech 'phile friend and expectations were low.
BUT! -- Gotta have one now. I'll do monoblocks, I guess with these modules; though I hear the 120w units are a little smoother. Hard to imagine.
This morning I was listening to bagpipes. I've never heard them so finely rendered.
I should note that Clayton S100 is a superb amp. The best SS I've heard, til now. But the $$ diff, Egad!
Dave
-
I should note that Clayton S100 is a superb amp. The best SS I've heard, til now. But the $$ diff, Egad!
Dave
Yes, I use the M-300's.
-
Yes, I use the M-300's.
I've added to my gallery, such as it is.
Previous system with Clayton M200s, Intuitive design Pingoras, John Hillig's wonderful Chameleon pre-amp and DAC, and Music Server comp. (I almost went with the M300 JTW. The M200s were magic, and that's with the Isomax transformer.)
I'm still using everything but the M200s. Current nightmarish system pic forthcoming.
Dave
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The case is mostly 1/16" Al, fetched on Ebay and made by Par-Metal.com. 12"x12"4", 50 bucks.
I am considering getting this same case. Now that you've received your case, are you glad you bought it? I ask because they have some more expensive, black anodized cases which look like they might be a little nicer cosmetically.
BTW, thanks to everyone for this thread. I've been looking for an amp for a while and, after reading this thread, ordered the 120 wpc CDA on Friday. :thumb:
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I am considering getting this same case. Now that you've received your case, are you glad you bought it? I ask because they have some more expensive, black anodized cases which look like they might be a little nicer cosmetically.
BTW, thanks to everyone for this thread. I've been looking for an amp for a while and, after reading this thread, ordered the 120 wpc CDA on Friday. :thumb:
Toob,
I used a file to remove the front panel punch-out markings, then proceeded with a scotch brite pad to improve the brushed finish. I think It looks pretty good. An LED would have enhanced the front appearance. I like it, but am not hyper- picky about gear aesthetics.
If you have doubts, perhaps your question is already answered and you should go with the more expensive case. Highly subjective.
Oh yes, I'm glad I bought it and would buy another. You may hate it....Such is the way of things.
Dave
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I have the second prototype complete. It's really nice. Next, are the finished anodized units.
jtwrace, any news (pics?) on the enclosures?
-Jim
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Bill,
I used heavy duty Al foil formed into shape by hand. You can see the wrinkles in the casting. I made multiple sizes and they work very well. Got lucky.
A set of 3 easily supports 200 lbs (me).
Dave
Thanks I may just might try some myself. Chambersburg well you just might find me at your door one day :eyebrows:
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Thanks I may just might try some myself. Chambersburg well you just might find me at your door one day :eyebrows:
Ah...Poconos. We're in south-central PA, kissing the border, 80 mi WNW of DC. 20 mi West of Gettysburg.
If you try the Dave tiptoes, let me me know.
Suggestions!
Dave
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jtwrace, any news (pics?) on the enclosures?
-Jim
They're at the anodizer now. Very soon!!!
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Ah...Poconos. We're in south-central PA, kissing the border, 80 mi WNW of DC. 20 mi West of Gettysburg.
If you try the Dave tiptoes, let me me know.
Suggestions!
Dave
I'm going to try for sure when the glue sticks are hard there tuff takes alot of heat to soften them
I am the Pumpkinking..................Bill
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Herbie's stuff is really nice for footers. Though not as cheap as hot glue, they're very cheap and the best footers I have used. I'm using them under my amp.
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Herbie's stuff is really nice for footers. Though not as cheap as hot glue, they're very cheap and the best footers I have used. I'm using them under my amp.
I believe this is what Mintzar is refering to http://herbiesaudiolab.net/
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You are correct. Thanks for posting the link!
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The Super D's are up in the ClassDaudio page.
My one minor quibble w/ Tom are the typos that pop up on the site. I've shot emails as a heads up,
but some still pop up, and right now the main page has the word 'Ballanced' in giant red font...
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The Super D's are up in the ClassDaudio page.
My one minor quibble w/ Tom are the typos that pop up on the site. I've shot emails as a heads up,
but some still pop up, and right now the main page has the word 'Ballanced' in giant red font...
I see the "Introducing our Super D series..." and photo, but I can't link to a product page, nor is it listed under Amps or Kits.
Steve
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I'm going to try for sure when the glue sticks are hard there tuff takes alot of heat to soften them
I am the Pumpkinking..................Bill
The stuff I used is Arrow Super Power hot melt glue. I selected my sticks by manipulating them, sooth-saying, and a little prayer. I basically looked for the slowest restoration rate.
I made the forms, cut the sticks up into ~3/8" pieces, filled the forms up, onto a cookie sheet and stuck 'em in the oven at about 250 - 275 deg F. Been a while but I think they melted rather quickly. CAREFULLY Pull them out like cupcakes and let them cool. The foil separates easily.
The "tip" or bottom of the form must be flat to sit properly upright.
There -- that's the basic primer!
Dave
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I see the "Introducing our Super D series..." and photo, but I can't link to a product page, nor is it listed under Amps or Kits.
Steve
Yeah, I spoke too soon...
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The stuff I used is Arrow Super Power hot melt glue. I selected my sticks by manipulating them, sooth-saying, and a little prayer. I basically looked for the slowest restoration rate.
I made the forms, cut the sticks up into ~3/8" pieces, filled the forms up, onto a cookie sheet and stuck 'em in the oven at about 250 - 275 deg F. Been a while but I think they melted rather quickly. CAREFULLY Pull them out like cupcakes and let them cool. The foil separates easily.
The "tip" or bottom of the form must be flat to sit properly upright.
There -- that's the basic primer!
Dave
Thanks I wondered how you used a glue gun on this :eyebrows: makes more sense now.............Bill :D
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Does anybody know if there is a difference visually between the 250 wpc amp and the 120 wpc amp? I ask because I just noticed that the additional amp board I ordered came with directions for the 250 wpc amp. It was supposed to be the 120. The only difference I can see between the two boards is that there is one cap that is larger on one board than on the other.
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I really wish I had this product for sale, as I am 99% confident I could double whatever the current sales are and have even happier and more excited customers.
Some of the things I would do are:
1. Have a simple model number for each amp. Referring to the 2 X 250 at 8 ohm , no 4 ohm, no 2 X 125 @, no, wait.......... Gets confusing, and trust me, there is a lot of confusion.
2. If a change is made, for example the 250W X2 @ 8 ohm (I think) is now useable at 4 ohm with an extended heat sink which is now supposed to be standard - the website information would be updated, along with an updated photo.
3. Create a matrix feature and specifications chart. I was looking at the Synology NAS devices for my computer, and wondered about the differences between some of them. Check this out! Sweet! http://www.synology.com/us/products/compare_spec.php (http://www.synology.com/us/products/compare_spec.php)
4. Post to the forum once a day to clear up questions. I know this takes up some designer/engineer/business owner's time, but a lot less time than answering the same question 10 times in 10 separate private emails.
5. Offer some "SE" upgraded boards, both amps and power supplies. You're dealing with 'audiophiles', why make those interested in better, bigger capacitors, etc. unsolder, toss away, source and buy new parts, then resolder? This would create some additional and larger sales and some happy campers.
Just a few thoughts.
Steve
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I agree. But it's clearly a one-man operation for the most part, and there's only so much time in the day.
Howerver, simple model numbers is a GREAT suggestion. That's easy enough to do. There really is way too much unnecessary confusion over what's available.
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I really wish I had this product for sale, as I am 99% confident I could amass double whatever the current sales are and have even happier and more excited customers.
Some of the things I would do are:
1. Have a simple model number for each amp. Referring to the 2 X 250 at 8 ohm , no 4 ohm, no 2 X 125 @, no, wait.......... Gets confusing, and trust me, there is a lot of confusion.
2. If a change is made, for example the 250W X2 @ 8 ohm (I think) is now useable at 4 ohm with an extended heat sink which is now supposed to be standard - the website information would be updated, along with an updated photo.
3. Create a matrix feature and specifications chart. I was looking at the Synology NAS devices for my computer, and wondered about the differences between some of them. Check this out! Sweet! http://www.synology.com/us/products/compare_spec.php (http://www.synology.com/us/products/compare_spec.php)
4. Post to the forum once a day to clear up questions. I know this takes up some designer/engineer/business owner's time, but a lot less time than answering the same question 10 times in 10 separate private emails.
5. Offer some "SE" upgraded boards, both amps and power supplies. You're dealing with 'audiophiles', why make those interested in better, bigger capacitors, etc. unsolder, toss away, source and buy new parts, then resolder? This would create some additional and larger sales and some happy campers.
Just a few thoughts.
Steve
Here Here Thank You for saying what was thinking and beyond what I was thinking...Bill
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I know there is only so much time in a day. But the number of additional man hours required to put my suggestions in play are minimal. I can't tell you the number of qualified electrical engineering and computer students that would be chomping at the bit for some $12 - $15/hr. work to write documentation, matrix charts, update webpages, etc.
It takes some money to maintain and grow a business, and for what I am proposing, not a whole lot.
Steve
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I really wish I had this product for sale, as I am 99% confident I could amass double whatever the current sales are and have even happier and more excited customers.
Some of the things I would do are:
1. Have a simple model number for each amp. Referring to the 2 X 250 at 8 ohm , no 4 ohm, no 2 X 125 @, no, wait.......... Gets confusing, and trust me, there is a lot of confusion.
2. If a change is made, for example the 250W X2 @ 8 ohm (I think) is now useable at 4 ohm with an extended heat sink which is now supposed to be standard - the website information would be updated, along with an updated photo.
3. Create a matrix feature and specifications chart. I was looking at the Synology NAS devices for my computer, and wondered about the differences between some of them. Check this out! Sweet! http://www.synology.com/us/products/compare_spec.php
4. Post to the forum once a day to clear up questions. I know this takes up some designer/engineer/business owner's time, but a lot less time than answering the same question 10 times in 10 separate private emails.
5. Offer some "SE" upgraded boards, both amps and power supplies. You're dealing with 'audiophiles', why make those interested in better, bigger capacitors, etc. unsolder, toss away, source and buy new parts, then resolder? This would create some additional and larger sales and some happy campers.
Just a few thoughts.
Steve
I agree with all these comments. From what I've gathered from Tom lately, he's developed the Super D series to address many of the issues many of us have had regarding gain matching with adjustable gain pots, impedance matching, better heat dissipation to drive lower impedance loads, balanced inputs and board plug-ins for remote power switches and LED's to eliminate soldering on such a small board.
He's told me he is working on getting the website up to date and provding a newletter to describe all the changes he has made in his line. Again from what he's told me, Wushuliu's comments hold true. He's been overloaded with business since this amp news has hit Audiorcicle and part of that was my fault. I didn't realize this thing would skyrocket like it has.
I've suggest to TOm that he make an announcement of his new product line in Industry News where he can hopefully answer questions as well.
I think he just has too much on his plate right now.
But onto the main reason why I'm posting. I've had the opportunity to hear a demo Super D amp board (120/60) on the mids/highs in my system yesterday and all I can say is it's better than the previous versions. It has all the tonal characteristics of the Class D board but with more bloom and a deeper soundstage. I'm hearing more venue "spatial cues" now and the presentation is indeed more three dimensional (and more tube-like in that respect). I got about 5 hours listening in late last night of classical, jazz, female vocals, chamber and symphonic and alt rock music and these characteristics kept coming forward.
So in summation, I think in Tom's defense, he is working toward a really high quality product at a ridiculuously low price so I think we have to cut him some slack here. He's obviously suffering from the growing pains that are the result of his fine work.
More later, :thumb:
steve k
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I've had the opportunity to hear a demo Super D amp board (120/60) on the mids/highs in my system yesterday and all I can say is it's better than the previous versions. It has all the tonal characteristics of the Class D board but with more bloom and a deeper soundstage. I'm hearing more venue "spatial cues" now and the presentation is indeed more three dimensional (and more tube-like in that respect). I got about 5 hours listening in late last night of classical, jazz, female vocals, chamber and symphonic and alt rock music and these characteristics kept coming forward.
Aw, man. Now I gotta shell out more for the Supers! :bawl:
At least I don't have to worry about the PS and toroid, and can just get the amp itself.
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Tom has already done the hard part. He sucessfully reproduced a version of the IRC eval board, sourced the production of the PCB, parts and assembly, and was able to package and sell kits at a reasonable price. And now he's redesigned for a new series, partially fueled by customer feedback.
So, my admiration for a job well done. My hope is that a few of my suggestions will be entertained, so that his hard work can be presented to, and clearly and completely understood by, eager excited hobbyists.
I expressed interest not too long after this thread started, but I am not in a great hurry. I have exchanged a few emails with Tom and a few with AC members, and my confusion has been lessened, but not totally eliminated.
I am still working on the chassis end of it, so I look forward to finding out additional details, pricing and comments on the new Super D from the first customers.
Steve
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I am still working on the chassis end of it,
Steve
Steve
If the chassis is an issue, I'll be able to help with my chassis...
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jtwrace, any news (pics?) on the enclosures?
-Jim
Awesome. Thank you, sir! :thumb:
-Jim
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the typos that pop up on the site. I've shot emails as a heads up
Me too, back in mid-February . . . like the power supply voltage requirement for the 120x2 being incorrect, and the pictures no longer matching what's delivered.
The web site, and documentation in general, does not seem to be a priority. Or even a serious consideration. Written questions often go unanswered, and sometimes the information given out verbally (at least as it's been reported here) is clearly incorrect (or misreported), without any correction from classDaudio. It's unfortunate, because it's a good product that suffers substantially from poor presentation and support.
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Aw, man. Now I gotta shell out more for the Supers! :bawl:
Why? Apart from a balanced input buffer what's changed? Perhaps if your amps are not properly matched to your source then changing the input (particularly the input impedance) might help . . . but if it's already properly matched then adding a balanced-to-unbalanced converter (the input to the IRS2092 is unbalanced by design) offers no improvement. And if your source does not have balanced outputs then the amp input is not balanced either (even if it is capable of taking a balanced signal) . . . you tie one signal lead to ground.
One other thing that might change (although it's not been mentioned so far) is that the original boards are inverting amps . . . so it is important to watch polarity when mixing with the more common non-inverting amps behind an active crossover. You have to wire the speakers "backward" with a classDaudio board to get forward cone motion with a positive going signal. That may be corrected with the new input buffer . . .
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One other thing that might change (although it's not been mentioned so far) is that the original boards are inverting amps . . . so it is important to watch polarity when mixing with the more common non-inverting amps behind an active crossover. You have to wire the speakers "backward" with a classDaudio board to get forward cone motion with a positive going signal.
What the hell...so you mean I had two opposing phase in my biamp set up while auditioning recently? Mhnnn...And why is this information not revealed on the spec sheet on the website?
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I agree with all these comments. From what I've gathered from Tom lately, he's developed the Super D series to address many of the issues many of us have had regarding gain matching with adjustable gain pots, impedance matching, better heat dissipation to drive lower impedance loads, balanced inputs and board plug-ins for remote power switches and LED's to eliminate soldering on such a small board.
He's told me he is working on getting the website up to date and provding a newletter to describe all the changes he has made in his line. Again from what he's told me, Wushuliu's comments hold true. He's been overloaded with business since this amp news has hit Audiorcicle and part of that was my fault. I didn't realize this thing would skyrocket like it has.
I've suggest to TOm that he make an announcement of his new product line in Industry News where he can hopefully answer questions as well.
I think he just has too much on his plate right now.
But onto the main reason why I'm posting. I've had the opportunity to hear a demo Super D amp board (120/60) on the mids/highs in my system yesterday and all I can say is it's better than the previous versions. It has all the tonal characteristics of the Class D board but with more bloom and a deeper soundstage. I'm hearing more venue "spatial cues" now and the presentation is indeed more three dimensional (and more tube-like in that respect). I got about 5 hours listening in late last night of classical, jazz, female vocals, chamber and symphonic and alt rock music and these characteristics kept coming forward.
So in summation, I think in Tom's defense, he is working toward a really high quality product at a ridiculuously low price so I think we have to cut him some slack here. He's obviously suffering from the growing pains that are the result of his fine work.
More later, :thumb:
steve k
What tom told me was they sounded the same but have more features. The output stage is the same. And with the mods people are doing, doesnt have an affect on the sound if it did he would of did it in the first place. He is getting alot of boards that are in need for repair that people tired to mod them and messed them up. It set him back because of it. I feel if you mod it he should not be repairing it for free. :nono:
From Tom,
Yes, I see lots of people are trying to mod these amps… first, if the mods would help, I would build them that way in the beginning. The reason I am so backed up with my work now is several people have tried to modify the amp and ruined them. These are very hard to work on and change parts without damaging them. I have several here that need to be repaired. These are some of the finest sounding amps available, so really no need to try to change them. I understand people are trying to improve them, but allot of the things they are trying to do have no effect on sound quality at all.
Tom
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Dave,
I really like your chassis! I went to the Par-metal.com site and found that the same chassis can be ordered with a conductive coating (Alodine). I am thinking it may be the one that I want. By the way, how did you make all the holes at the rear panel to accomodate the RCA plugs and the speakers terminals? Did you use a hoel saw, a drill press or???
Thanks!
Allan
Toob,
I used a file to remove the front panel punch-out markings, then proceeded with a scotch brite pad to improve the brushed finish. I think It looks pretty good. An LED would have enhanced the front appearance. I like it, but am not hyper- picky about gear aesthetics.
If you have doubts, perhaps your question is already answered and you should go with the more expensive case. Highly subjective.
Oh yes, I'm glad I bought it and would buy another. You may hate it....Such is the way of things.
Dave
[/quote]
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What tom told me was they sounded the same but have more features. The output stage is the same. And with the mods people are doing, doesnt have an affect on the sound if it did he would of did it in the first place. He is getting alot of boards that are in need for repair that people tired to mod them and messed them up. It set him back because of it. I feel if you mod it he should not be repairing it for free.
Tom told me the sound was the same but the soundstage and imaging was different in his system. He asked me my opinion and I agree. I liken the imaging much more to the 3D presentation of a tube amp vs. the flatter, wider soundstaging of his previous amps. Niteshade made reference to these differences in this post: http://www.audiocircle.com/index.php?topic=79188.0 (http://www.audiocircle.com/index.php?topic=79188.0). I prefer the new board better in my system. YMMV.
I agree with you about Tom repairing people's screwups. I'm sure he's trying to keep everybody happy but that can be difficult at times particularly with us crazy audiophiles. :lol:
steve
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The lack of clarity about offerings is an issue that seems easily fixed.
No matter, Tom is a terrific guy. He was remarkably helpful, friendly, and courteous to me when I needed his help to assemble the amp. A real stand-up human.
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Dave,
I really like your chassis! I went to the Par-metal.com site and found that the same chassis can be ordered with a conductive coating (Alodine). I am thinking it may be the one that I want. By the way, how did you make all the holes at the rear panel to accomodate the RCA plugs and the speakers terminals? Did you use a hoel saw, a drill press or???
Thanks!
Allan
FWIW, I'm planning on using 1/4 phone jacks for the line ins and speakers outs and just a 2 wire power line with a strain relief. I've chosen these because they can all be easily and neatly drilled with no other metal working tools required.
Easy peasy. :D
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"Step" drill bits make very nice holes in sheet metal, particularly soft aluminum. You just have to be careful not to inadvertantly keep going to the next step size. I usually use a piece of electrical tape on the next step of the bit to mark the size limit.
Obviously if your panels are thicker than 3/16" (or whatever the depth of each step on your bit) these won't work for that application.
Steve
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Tom told me the sound was the same but the soundstage and imaging was different in his system. He asked me my opinion and I agree. I liken the imaging much more to the 3D presentation of a tube amp vs. the flatter, wider soundstaging of his previous amps. Niteshade made reference to these differences in this post: http://www.audiocircle.com/index.php?topic=79188.0 (http://www.audiocircle.com/index.php?topic=79188.0). I prefer the new board better in my system. YMMV.
I agree with you about Tom repairing people's screwups. I'm sure he's trying to keep everybody happy but that can be difficult at times particularly with us crazy audiophiles. :lol:
steve
steve what power did you get on the super? i have 3 sets of the 250 watts ch @ 8 ohms. there is no doubt i will be gettin a few of the supers. i can use the ones i have now on the bass and subs.
update: oh i think you said 120/60 in power right?
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FWIW, I'm planning on using 1/4 phone jacks for the line ins and speakers outs and just a 2 wire power line with a strain relief. I've chosen these because they can all be easily and neatly drilled with no other metal working tools required.
Easy peasy. :D
The desire to avoid non circular hole drilling shouldn't compromise safety. As SRB points out, a step drill makes the effort easy -
(http://www.audiocircle.com/image.php?id=28358)
The above is a standard electricians step drill for making holes to accommodate either a 1/2 or 3/4" NPT doodad (7/8 & 1 1/8" actual holes).
A wonderful doodad is a cable gland -
(http://www.audiocircle.com/image.php?id=28357)
The above is a 3/4" npt cable gland that will secure a cable up to .72 inches in diameter. Plenty enough room for a 3 wire grounded powercord. Unless you're building to Class II appliance insulation standards (you can't), you really should use a safety grounded power cord so you can safety ground the metallic chassis.
FWIW,
Paul
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steve what power did you get on the super?
The 60w 8 ohm / 120 w 4 ohm.
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I went to the Par-metal.com site and found that the same chassis can be ordered with a conductive coating (Alodine).
I'm wondering if the Par-Metal cases with the Alodine coating will oxidize... Does anyone know?
Maybe I should clear coat it with some sort of clear spray. Any suggestions?
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A wonderful doodad is a cable gland -
(http://www.audiocircle.com/image.php?id=28357)
The above is a 3/4" npt cable gland that will secure a cable up to .72 inches in diameter. Plenty enough room for a 3 wire grounded powercord. Unless you're building to Class II appliance insulation standards (you can't), you really should use a safety grounded power cord so you can safety ground the metallic chassis.
FWIW,
Paul
Good tip, thanks!
Now if I can only find one in the little cow-town I live in. :green:
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Good tip, thanks!
Now if I can only find one in the little cow-town I live in. :green:
Or for another round hole installation, this one allowing for removable power cords, the Neutrik Powercon:
http://www.neutrik.com/fl/en/audio/210_t2_1141147856/NAC3MPA-1_detail.aspx
Only pain would be having to had a Powercon connector to your power cord.
-Jim
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srb, you should contact Tom to see if he's interested in trading an amp for help with his web page. I've made deals like this with small/new companies from both sides of the issue. It's usually easy to come to an agreement that satisfies both people. "Just a thought".
Don
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So on target SRB. Dave
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Tom is participating in DIYaudio.com. A lot of the guys really know their stuff over there.
Dave
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What the hell...so you mean I had two opposing phase in my biamp set up while auditioning recently?
It's possible . . . in fact Mr. Murphy says it's probable. In mixed amp situations one must *always* test for proper polarity (and I've seen a "house system" that had the polarity switch set wrong on a commercial active crossover, too). Polarity is just another of those things one must always check for when comparing amps (along with input impedance, gain, load effects etc.). It's easy enough to see if you do a sweep or look at a noise spectrum . . .
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why is this information not revealed on the spec sheet on the website?
I’m not sure if it’s stated explicitly even in the IR Reference Design documentation . . . if it is I missed it. It is shown in a block diagram (Fig 24, page 20) . . . look at the input and output “signal graphic”:
http://www.irf.com/technical-info/refdesigns/iraudamp7d.pdf
It’s one of those “too obvious to even mention” sorts of things (which are not necessarily obvious to everyone . . .).
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I’m not sure if it’s stated explicitly even in the IR Reference Design documentation . . . if it is I missed it. It is shown in a block diagram (Fig 24, page 20) . . . look at the input and output “signal graphic”:
http://www.irf.com/technical-info/refdesigns/iraudamp7d.pdf
It’s one of those “too obvious to even mention” sorts of things (which are not necessarily obvious to everyone . . .).
Ok, anyone want to dumb down the information, so I can understand what you guys are talking about.
Also, it seems that the SuperD link is onlin: http://classdaudio.com/index.php/sds-254.html?SID=3ba9c442a8c39d65ddfdb888b5f73d1b
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Also, it seems that the SuperD link is online
And amplifier model numbers for all! Woot!
Steve
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Ok, anyone want to dumb down the information
With a non-inverting amplifier (most common) a positive-going signal at the input produces a positive-going signal at the output. With an inverting amplifier a positive-going signal at the input produces a negative-going signal at the output. Although people do argue about it nevertheless it is generally agreed that overall this "polarity" difference doesn't matter, since in general we cannot hear absolute polarity.
However . . . and it's a *big* "however" . . .
if polarity is switched on only one channel of a bi-amped system it typically produces a null at the crossover frequency rather than the woofer and tweeter (or woofer and sub-woofer) summing properly, and that null *will* have audible effect. Since the classDaudio amps are inverting, and most commercial amps are non-inverting, you cannot just "swap amps" when making comparisons . . . it may be also necessary to switch the leads from the driver to maintain correct overall polarity. If that is not done you will not be hearing (just) differences between the amplifiers, but also the difference (in frequency response) between a correctly and incorrectly wired crossover.
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And amplifier model numbers for all! Woot!
Still hasn't corrected the power supply requirement for the . . . "CDA-224" . . .
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@dewardh,
Thanks for the explanation. If you are not bi-amping you do not have to worry about it correct?
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Still hasn't corrected the power supply requirement for the . . . "CDA-224" . . .
Well, the inclusion of model numbers indicate he was at least monitoring this thread, so hopefully the corrections will follow too.
And I still hope to see the Product Comparison matrix, so we can all quickly compare specifications and features between all of the modules at a glance.
Steve
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That new board design and turn around time was impressive but am I the only one getting the feeling that in terms of value, that board might be straying away from the notion of SOTA and Affordable? Perhaps more than just terms of power, it will bring finesse and audiophile characteristics to something as under appreciated and under priced at the $175 board?
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If you are not bi-amping you do not have to worry about it correct?
Correct . . . though remember that if you have a subwoofer you *are* bi-amping, and switching polarity of the L&R channel amps will change subwoofer integration. It's something to watch for when swapping amps for comparison testing. "Convention" is to set up systems so a positive-going signal moves the mid-woofer cone forward . . . once that's done it's only an "issue" if equipment is added (or changed) that inverts polarity.
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I wonder what changes were made to make the soundstage, etc. bigger?
Paul
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I wonder what changes were made to make the soundstage, etc. bigger?
The changes should correct problems some people were having with impedance and gain matching to their source (which can effect overall sound). The "sound" of the amplifier itself is not changed (so far there have been no reported changes inside the amplifier's feedback loop, or in the output filter). It's all about the benefits, where needed, of an input buffer . . .
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The changes should correct problems some people were having with impedance and gain matching to their source (which can effect overall sound). The "sound" of the amplifier itself is not changed (so far there have been no reported changes inside the amplifier's feedback loop, or in the output filter). It's all about the benefits, where needed, of an input buffer . . .
Excuse me? Have you heard it? The "sound" may not be different but the imaging sure is and much to the better.
steve
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Excuse me? Have you heard it? The "sound" may not be different but the imaging sure is and much to the better.
Changing amplifier input impedance (or changing polarity) may well have changed "imaging" in your system. It's hard to tell without knowing the details of your system, the comparison, and how you switched back and forth between the amps to do it.
All that seems to have changed *in the amplifier* is the addition of an input buffer . . . different systems will have different need for and different response to that, and different people will draw different conclusions as to what that means. My system doesn't need an additional buffer, since my crossover's output buffers can drive the "original" board just fine, and I correct for polarity at the drivers. Adding a buffer stage would accomplish nothing for me. I'm glad it helped with your system . . . (did you set the "new" version for normal or inverted polarity?).
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There has been considerable discussion on the mating of the Pass B1 board to the input of the original class D amps as a (variable gain?) buffer to better impedance match input to it. Several have commented on the benefits of doing this. So given that the new amps have an input buffer built in, would it be superfluous to front end the input of the new class Ds with the Pass B1?
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I just bought one of these kits (60 wpc / 8 ohms) and it's not wired up yet, but all this talk regarding an impedance mis-match is a real buzz killer. :green:
I'm going to be using the pre-outs of my Denon AVR and, unfortunately, Denon doesn't specify the pre-amp's output impedance. If there is an impedance mis-match how will I know? Will the pre distort trying to drive the low load? Will the frequency extremes be rolled off? Could this damage my pre?
Give me the straight dope on this. I suppose, if I have to, I could buy the new board or a tube buffer, but I'd rather avoid spending the extra dough.
Thanks.
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I just bought one of these kits (60 wpc / 8 ohms) and it's not wired up yet, but all this talk regarding an impedance mis-match is a real buzz killer. :green:
I'm going to be using the pre-outs of my Denon AVR and, unfortunately, Denon doesn't specify the pre-amp's output impedance. If there is an impedance mis-match how will I know? Will the pre distort trying to drive the low load? Will the frequency extremes be rolled off? Could this damage my pre?
Give me the straight dope on this. I suppose, if I have to, I could buy the new board or a tube buffer, but I'd rather avoid spending the extra dough.
Thanks.
I use my Harmon Kardon AVR with no problems. I suspect the Denon will be just fine. :eyebrows:
And just for the record the HK amp section wasnt even in the same leauge as the ClassD.
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I use my Harmon Kardon AVR with no problems. I suspect the Denon will be just fine. :eyebrows:
And just for the record the HK amp section wasnt even in the same leauge as the ClassD.
Good to know. Thanks. :thumb:
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So given that the new amps have an input buffer built in, would it be superfluous to front end the input of the new class Ds with the Pass B1?
Yes.
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Changing amplifier input impedance (or changing polarity) may well have changed "imaging" in your system. It's hard to tell without knowing the details of your system, the comparison, and how you switched back and forth between the amps to do it.
All that seems to have changed *in the amplifier* is the addition of an input buffer . . . different systems will have different need for and different response to that, and different people will draw different conclusions as to what that means. My system doesn't need an additional buffer, since my crossover's output buffers can drive the "original" board just fine, and I correct for polarity at the drivers. Adding a buffer stage would accomplish nothing for me. I'm glad it helped with your system . . . (did you set the "new" version for normal or inverted polarity?).
The only thing I changed due to the change in input impedance are the two caps in my DAhlquist crossover that set the high frequency cutoff. The cap value is based on the cutoff frequency, and the high/midrange amplifier's input impedance since it is passive. The bass cutoff is active.
You may want to hear something first before determining "the sound of the amplifier itself has not changed". That's a bit presumptious.
steve
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I’m not sure if it’s stated explicitly even in the IR Reference Design documentation . . . if it is I missed it. It is shown in a block diagram (Fig 24, page 20) . . . look at the input and output “signal graphic”:
http://www.irf.com/technical-info/refdesigns/iraudamp7d.pdf
Thanks for posting the pdf link, hadn't seen that before.
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The only thing I changed due to the change in input impedance are the two caps in my DAhlquist crossover that set the high frequency cutoff. The cap value is based on the cutoff frequency, and the high/midrange amplifier's input impedance since it is passive. The bass cutoff is active.
So you potentially changed the frequency response and crossover point if the substitute caps didn't *precisely* match the changed input impedance (and had any effect elsewhere in the circuit). Did you set the "new" amp to invert polarity like the "old" one does, or was that different as well? How many times did you switch between amps while making this comparison? Given all the other changes it's "a bit presumptious" to assume that any change you heard was do to functionally identical amplifiers sounding different.
You may want to hear something first before determining "the sound of the amplifier itself has not changed". That's a bit presumptious.
Are you suggesting that something in the amplifier has been changed in addition to adding an input buffer/phase inverter? Do you have any documentation of that? I'm sure many in addition to me would like to see a schematic of the new input stage, and especially any changes made in the amplifier itself . . .
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Look, its a cheap amp that sounds good. I'm not going to debate the physics. I can't believe how critical some of you people are over a $175 amp! This guy is fixing boards screwed up by "modders" when they're clearly out of warranty and people are bitching about his webstie typos. Hey this isn't Wilson Audio, this is Cheap and Cheerful remember???
This was fun for awhile till all the experts came along and picked it to pieces. Tom told me tonight this is precisely why he doesn't get involved in forums.
I and my friends clearly hear a difference in the imaging of the Super D amp. Tom sent me one to verify this because he heard the difference and wanted some outside verifcation.
That's all. I don't think I need to justify what Tom, myself and my friends heard to you. Be your own judge, but at least listen to it first.
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Are you suggesting that something in the amplifier has been changed in addition to adding an input buffer/phase inverter? Do you have any documentation of that? I'm sure many in addition to me would like to see a schematic of the new input stage, and especially any changes made in the amplifier itself . . .
I am sure these questions can be directeded to designer/manufacturer himself avoiding plain speculations.
And, ........ we all appreciate new offerings from the company but can we please stay on the topic that originated this thread!?
As far as the new product goes, Tom is more then welcome to introduce his new amp in "General Audio Industry News" (http://www.audiocircle.com/index.php?board=122.0) or "Product Support Threads" (http://www.audiocircle.com/index.php?board=155.0) and answer questions as needed. I am aware of the thread that has been already started in regards to new amp design, so this debate can be finished there or in less desirable place.
Cheers
Mariusz :wink:
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This guy is fixing boards screwed up by "modders" when they're clearly out of warranty
That's a bummer. That's pretty lame for someone to send back a board after tinkering w/ it. That's definitely taking advantage.
I think it's time for a little humor break:
(http://icanhascheezburger.files.wordpress.com/2010/03/funny-pictures-cat-is-no-ninja.jpg)
(http://icanhascheezburger.files.wordpress.com/2010/03/funny-pictures-cat-plots-against-dog.jpg)
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That's a bummer. That's pretty lame for someone to send back a board after tinkering w/ it. That's definitely taking advantage.
Agree completely. Once you put the soldering iron to it, it's yours.
As for the classDaudio amps . . . they are great . . . cheap and excellent. If your source can handle the low input impedance get the "original" . . . it's "Cheap and Cheerful". If you need a higher input impedance and volume control on the amp get the "new" version with an input buffer . . . it's not quite so "Cheap", but it's still "Cheerful". It's the same amp (IRS2092), but the input buffer might make it sound better *with your system*.
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Look, its a cheap amp that sounds good. I'm not going to debate the physics. I can't believe how critical some of you people are over a $175 amp! This guy is fixing boards screwed up by "modders" when they're clearly out of warranty and people are bitching about his webstie typos. Hey this isn't Wilson Audio, this is Cheap and Cheerful remember???
This was fun for awhile till all the experts came along and picked it to pieces. Tom told me tonight this is precisely why he doesn't get involved in forums.
I and my friends clearly hear a difference in the imaging of the Super D amp. Tom sent me one to verify this because he heard the difference and wanted some outside verifcation.
That's all. I don't think I need to justify what Tom, myself and my friends heard to you. Be your own judge, but at least listen to it first.
I dont think no one is picking it to pieces. He was just explaining the differences between them which I feel he is right. All the amps Tom makes are great, but with the new super people might be better with the buffer/gain adj. for there needs. The output can only putout what you feed it. In your system steve it must be working at its prime now with the added features where before with your other amp it wasnt because you said the soundstage is better now. So something must of been lacking on your system somewhere with matching with your other amp and pre. Matching is so important as you steve can see now with how your system sounds from now and before.
hope that makes sense im Czech so english is so so ha :)
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Blair Lamphear noted in an earlier post that the original amp (250/4, 125/8) worked quite well with a passive attenuator due to having high gain.
That being the case, why would someone need a buffer? I'm just asking, not stirring the pot. I'm still learning. :wink:
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That being the case, why would someone need a buffer?
I'm not sure under which circumstances one might need the better impedance matching of the input buffer, but because these amps seem to have higher gain (32) compared to most of the amps I've owned (26 - 29), the adjustable gain might be helpful because
1. Your preamp has too much gain, so that the volume control has to be used within a very narrow range ?
2. You have very high efficiency speakers, and reducing the gain reduces the background noise ?
Steve
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Greetings,
I finished (I thought) my amp last week and hooked it up in my system. I have a one system does all set up. I listen to music with computer and combo player as sources, watch DVD's, and watch TV using the same amps (active xo tri amp set up). When I fired up the Class D amp which I have hooked up to drive my mid range drivers sound was great but... it really degrades the picture quality on my TV! Today I'm going to pull it out, pop it open, and install a Felix power conditioner in the case. Hope that will help. Any other suggestions would be appreciated.
Almost forgot.. the amp is the 250x2-500x1 kit which I see is now called CDA-254S.
Sincerely
boone
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I'm not sure under which circumstances one might need the better impedance matching of the input buffer, but because these amps seem to have higher gain (32) compared to most of the amps I've owned (26 - 29), adjustable gain might be helpful because
1. Your preamp has too much gain, so that the volume control has to be used within a very narrow range?
2. You have very high efficiency speakers, and reducing the gain reduces the background noise?
Steve
That is exactly my situation.
High efficient speakers etc.
One of the reasons I am STILL hoping to put my hands on one of those Nelson Pass buffers. :drool:
P.S (to all)
we all enjoy constructive conversation/discussion but keep in mind that this is NOT "The Lab Circle" and most who found this kit interesting, love it because it's easy and cheap.
Over-building/over-complicating this project might take some fun away from this thread. It can also discourage some folks from trying out this very simple kit that isn't only simple but cheap and fun.
Thanks
Mariusz :thumb:
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Am I correct that the amp comes with the 32db gain setting as default but Tom will change it to 26db upon request? I think I read that somewhere on this thread.
If that's the case, it will work well for me since I use a Goldpoint/Elna stepped attenuator with no gain, of course.
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Am I correct that the amp comes with the 32db gain setting as default but Tom will change it to 26db upon request? I think I read that somewhere on this thread.
If that's the case, it will work well for me since I use a Goldpoint/Elna stepped attenuator with no gain, of course.
That is correct. I had asked Tom to set my gain to 26db. I believe on the superd you now have a switch to change the gain.
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I believe on the superd you now have a switch to change the gain.
That is correct.
It's very important to not forget if you email Tom with a specific gain that you request, he's more then happy to build the other amps with that spec'd gain.
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One of the reasons I am STILL hoping to put my hands on one of those Nelson Pass buffers. :drool:
It's comin'! Had to twist some arms to get the seller to send the missing panels...
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I believe on the superd you now have a switch to change the gain.
The gain adjustment control on the Super D series are variable potentiometers with "conductive plastic element for ultra low noise". However, the gain range is not mentioned, but "more specs coming soon" is.
I did notice on the Super D Series that the Product Description mentioned "Our Super D Series amps provide more life-like imaging and sound stage", for whatever technical reason.
Steve
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It's comin'! Had to twist some arms to get the seller to send the missing panels...
Just say when Wush. :drool:
I have changed the idea about the encousure for my D-amp.
Do you or anyone else know a good source (link) for umbilical cord/plugs?
Cheers
Mariusz
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That is exactly my situation.
High efficient speakers etc.
One of the reasons I am STILL hoping to put my hands on one of those Nelson Pass buffers. :drool:
P.S (to all)
we all enjoy constructive conversation/discussion but keep in mind that this is NOT "The Lab Circle" and most who found this kit interesting, love it because it's easy and cheap.
Over-building/over-complicating this project might take some fun away from this thread. It can also discourage some folks from trying out this very simple kit that isn't only simple but cheap and fun.
Thanks
Mariusz :thumb:
It is all people have to do when they order is first ask tom. If the person dont know what one to get ask him to call you and you can tell him what you have for a system and I bet he will be glade to set you up right. He did that for me and Im very happy. So it gets complicated with others are listening to what someone else has for a system and there are like five different ways to go. The good thing now he has a module for everyone's needs now. :)
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Greetings,
I finished (I thought) my amp last week and hooked it up in my system. I have a one system does all set up. I listen to music with computer and combo player as sources, watch DVD's, and watch TV using the same amps (active xo tri amp set up). When I fired up the Class D amp which I have hooked up to drive my mid range drivers sound was great but... it really degrades the picture quality on my TV! Today I'm going to pull it out, pop it open, and install a Felix power conditioner in the case. Hope that will help. Any other suggestions would be appreciated.
Almost forgot.. the amp is the 250x2-500x1 kit which I see is now called CDA-254S.
Sincerely
boone
Do you have it in a wooden cabinet? Dont you have to use some type of metal to shield it? I would email tom and ask what is best. Do you have it next to your PC? if so thats why.
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hasekisgod,
Thanks for responding. Wooden case but clad in copper sheet. Not near my computer, so that's not it. ????
boone
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hasekisgod,
Thanks for responding. Wooden case but clad in copper sheet. Not near my computer, so that's not it. ????
boone
Did you email Tom on classdaudio site and ask him? He is very fast at reply.
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Wooden case but clad in copper sheet.
Does the shield fully surround the amp, and is it bonded to the power cord ground? If it is, then there are really only three routes for switching noise to get out into the “real world": the power cord, the input leads, and the speaker leads. The power cord is least likely, but it is directly connected to your other equipment (and sometimes noise can radiate from the grounded wire too). Input leads are next least likely, but they too may be directly connected to other equipment. Speaker leads are the most likely to carry noise (there is always some switching residual), but they generally don’t connect to anything (except speakers) so any noise from them has to be radiated . . . sometimes just re-routing them away from other equipment and cables can solve the problem. The first test is simply to disconnect the speaker leads and see if the interference goes away. If not, then try the input leads. Once the “leak” is located there are different solutions, from bypassing to ferrite discs to shielded cable to try . . .
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Does anyone know if there will be a 250 watt 8 Ohm Super D (SDS-258)?
I have the CDA-258 and would want another amp similar to it.
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hasekisgod,
No, haven't talked to Tom yet. Will intrude on his busy day when I have checked on a few more things.
dewardh,
We are thinking along the same lines. My first thought was that the amp was somehow polluting my power so my response was to finally install a Felix in the box ( had skipped this initially because I was so anxious to get the amp up and running) but..... found that when I disconected the speaker wires, the noise was significantly reduced. But ( another one)... also noticed that plugging my cable box into a power strip that has some filtering/isolation capability improved the picture somewhat. Then I found that if I routed the cable signal thru my DVR the problem disappeared completely?????? So now I'm completely confused! My problem with picture quality can easily be solved by routing the signal from the cable box to the TV using composite instead of coax ( seems like everyone knows this is a superior way to do it, but I didn't ), but.... I'm left with this nagging feeling that this noise from the ClassD Audio amp is having a subtle negative impact on my audio. Guess I go ahead with the Felix in the amp case and will build a few more to isolate other components as I noticed a small amount of noise when switching other equipment on/off as well. Have to think about how to accomplish shielding the speaker wires, that won't be so easy. Any additional information or suggestions will be appreciated.
Thanks again
boone
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Boone, I was afraid of something like this when people were talking about this ClassD board. Once again, I read that your case is made of wood lined with copper? Can you give details about it? How did you attach the copper to the wood? How thick were the copper sheets and where did you get them? I would also be nice if you can shoot a pic of the interior lay out for us people to see.
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(http://www.audiocircle.com/image.php?id=28438)
(http://www.audiocircle.com/image.php?id=28439)
(http://www.audiocircle.com/image.php?id=28440)
Will take shots of exterior of case later today.
Thanks
boone
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Why use copper to line wood cases? Aluminum would work just as well, is readily available at your local hardware store or home center and is much cheaper.
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Why use copper to line wood cases? Aluminum would work just as well, is readily available at your local hardware store or home center and is much cheaper.
A Faraday cage is built out of a conductive material, and the two best conductors are Silver and Copper. Using Copper as a baseline (100%), silver only has 5% better conductance, so due to it's high cost, is out of the running.
Aluminum only has 60% the conductance of Copper, so at first glance, Copper might make a better cage.
But thickness also has an effect, so the first question would be:
1. If the Aluminum thickness was increased to the point where it was the same cost as Copper, would it make a better cage?
The second question would be:
2. Does the non-ferrous, non-magnetic properties of Aluminum provide a shielding advantage (or disadvantage) for some types of radiation?
My Audio Refinement amplifier touts it's all-Aluminum enclosure as a feature, but doesn't offer techincal explanations.
Marantz Reference series amplifiers tout an Aluminum top cover, a non-magnetic Aluminum case around the torroid transformer, and a double layer bottom plate with one of the layers Copper plated.
A lot of variables in materials, thickness and types of radiation, EMI, RFI, etc.
Steve
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Boone, that box is fascinating as I thought that main physical box would be wood and the inner lining would be copper but in your case, it is reverse. That is something. Would love to see that front face, and would still like details on copper sheeting thickness, where you got the sheet and how you decide to attach it. For me, it seems as if you attached it physically and not by means of glue or anything.
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A Faraday cage is built out of a conductive material, and the two best conductors are Silver and Copper. Using Copper as a baseline (100%), silver only has 5% better conductance, so due to it's high cost, is out of the running.
Aluminum only has 60% the conductance of Copper, so at first glance, Copper might make a better cage.
But thickness also has an effect, so the first question would be:
1. If the Aluminum thickness was increased to the point where it was the same cost as Copper, would it make a better cage?
The second question would be:
2. Does the non-ferrous, non-magnetic properties of Aluminum provide a shielding advantage (or disadvantage) for some types of radiation?
My Audio Refinement amplifier touts it's all-Aluminum enclosure as a feature, but doesn't offer techincal explanations.
Marantz Reference series amplifiers tout an Aluminum top cover, a non-magnetic Aluminum case around the torroid transformer, and a double layer bottom plate with one of the layers Copper plated.
A lot of variables in materials, thickness and types of radiation, EMI, RFI, etc.
Steve
For general shielding purposes, I just don't think the differences will be all that significant. Most of the equipment available on the market today uses aluminum. Copper flashing is readily available, though, and would probably work OK. I guess ferrous materials are used sometimes for transformer shielding, but I'm no expert.
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found that when I disconected the speaker wires, the noise was significantly reduced. But ( another one)... also noticed that plugging my cable box into a power strip that has some filtering/isolation capability improved the picture somewhat. Then I found that if I routed the cable signal thru my DVR the problem disappeared completely??????
Cable drops are notorious for coupling noise/hum/whatever into audio systems . . . it would appear that you've found that your DVR has an isolation transformer in it :D. Running the speaker leads in the vicinity of the cable lead (especially if "bundled" for neatness) increases coupling between them. It would be a good idea to add an isolation transformer at the wall plate (they're cheap, and may be free from your cable provider) to make sure you're not putting interference on the feed and disrupting your neighbor's service.
It sounds like you've got a handle on the problem and will get it resolved . . .
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Perfect timeing for my question, i am looking to mount my amp and power supply in a wood case and i picked up a 6x12 piece of 16 ga steel cause they didnt have any thick aluminum at lowes or HD. I thought i would mount it to the steel and then to the mdf. Did i just buy the wrong product?
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I thought i would mount it to the steel and then to the mdf.
It should work fine as a mounting plate. The shield should surround the amp completely (bottom, top, sides) and be bonded to the power ground (not the neutral). The shield doesn't have to be heavy gauge, or even solid . . . metal window screen, 1/4 inch hardware cloth or perforated sheet works fine, and allows for ventilation. Leads passing in and out of the cage can be bypassed to it at the connectors. Look at how it's done in commercial products.
In most cases none of this is necessary . . . just keep leads (especially speaker leads) short and away from other interconnects, and despite the modest noise emissions you won't have any problem. Where there is interference, as in boone's case, just a little attention to shielding and grounding will almost always solve it. Using a metal enclosure (and proper grounding) will avoid it altogether.
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Question, my 2 channel system is no where near my TV/HT setup. It's in another room down the hall.
Any chance I'll have this interference problem? :scratch:
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Question, my 2 channel system is no where near my TV/HT setup. It's in another room down the hall.
Any chance I'll have this interference problem? :scratch:
There's always a slim chance of some bizare combination of circumstances . . . that's why Federal emissions standards are strict. But the smart money will bet against it . . .
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Does anyone know if there will be a 250 watt 8 Ohm Super D (SDS-258)?
I have the CDA-258 and would want another amp similar to it.
I have had this exact discussion with Tom, and there will be a 250 watts into 8 Super D series module... he's waiting on some parts to build the modules and to finish up testing. He said he should have them in a couple of weeks.
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A couple of photos of the exterior. Copper was salvaged from a kitchen remodel, don't know the guage, it was a 3"x8" duct that ran up through the roof. Attached with brass screws, looking forward to the screws darkening up a little. Thanks for all the help. I really like this amp!
(http://www.audiocircle.com/image.php?id=28460)
(http://www.audiocircle.com/image.php?id=28461)
boone
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A couple of photos of the exterior. Copper was salvaged from a kitchen remodel, don't know the guage, it was a 3"x8" duct that ran up through the roof. Attached with brass screws, looking forward to the screws darkening up a little. Thanks for all the help. I really like this amp!
boone
Far out. Looks like something from Doctor Who... maybe a Senso-Plasmatic Amplificator...
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(http://www.audiocircle.com/image.php?id=28461)
Lookout Starbuck and Apollo it' s a Cylon
That's one far out front very cool !
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It looks like the back end of an old Electrolux vacuum. :?
I would have never thought of that one... :wink:
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Is "Iron Man II" out?????
COOOOL???????
and definitely NOT ordinary.
Love it!!!!!
Mariusz :thumb:
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I have had this exact discussion with Tom, and there will be a 250 watts into 8 Super D series module... he's waiting on some parts to build the modules and to finish up testing. He said he should have them in a couple of weeks.
Website show SDS-258 250 x 2 into 8 as in stock.
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Hmmmm what have we here? :eyebrows:
(http://i59.photobucket.com/albums/g295/mrnick_2006/Picture782.jpg)
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End cap from 1940's Electrolux vacuum, small brass doorknob mounted in a donut of lexan which was then mounted in the hole where the hose once attached. When I ordered the kit, I asked Tom to please mount the LEDs on the bottom of the power supply board so they would shine out the front. Makes me smile every time I look at it. Was actually using Tik-Tok as a model. While scouring the internet for pictures of robots I found a reference to 'Moloch' from the movie Metropolis. One modern translation of the word is "Person or thing which demands or requires costly sacrifices" Pretty accurate description of this audio hobby isn't it?
Thanks for all the kind words.
boone
(http://www.audiocircle.com/image.php?id=28479)
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End cap from 1940's Electrolux vacuum
So how did I know that, born in the 1940's and my mom had one. :o
Like I said before, I would have never thought of that one!
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Take me to you leader. I love it!
steve
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If I had to vote here and now on the coolest case for D-amp kit, this would be IT! :thumb:
P.S
looking strictly from creative point of view. :eyebrows:
Mariusz :wink:
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Well I trepidatiously sold my 60 watt amp cause always in the back of my mind i was fustrated since i fell prey to the 4ohm vs 8ohm confusion. I had always wanted 120 wpc @8ohm from the start.
I had heard more than once that most perferred the sound of the 60 watt amp and i also loved everything about it. I very much think that the 60 watt board with larger power supply is a very special combo and boldly reccomend it. I was very aprehensive switching to the 250 board not knowing if it would measue up.
I decided to try the 250 wpc SuperD amp and i am pleased with the results. I confer with Steve about the increased imaging and slightly overall better sound. But i do have two things working against me, i switched to increased power and i am going off memory. I feel like i have better and tighter bass response and the new board seems to have a better control of the music. This is my first impession and i only have an hr or two on the amp. Once again i highly reccomend the ClassD amps and the new series is also a winner. :thumb:
(http://i59.photobucket.com/albums/g295/mrnick_2006/Picture782.jpg)
A work in progress, my Parts express order was rescheduled :duh:
(http://i59.photobucket.com/albums/g295/mrnick_2006/Picture787.jpg)
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Hope you will post other perceptions and comparisons of the two amps as you can. Thanks!
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This is some info Tom sent me on the new inputs. It mentions single ended inputs also take advantage of the technology, which is what Steve and I both were testing with. I cant help but wonder if balanced improves even more.
“The patented InGenius balanced line receivers overcome a serious limitation of conventional balanced input stages: poor common mode rejection in real-world applications. While conventional input stages measure well in the lab and perform well on paper, they fail to live up to their CMRR specs when fed from even slightly unbalanced source impedances — a common situation in almost any pro sound environment. This is because conventional stages have low common-mode input impedance, which interacts with imbalances in source impedance to unbalance common-mode signals, making them indistinguishable from desired, balanced signals. Developed by Bill Whitlock of Jensen Transformers, the patented InGenius input stage uses clever bootstrapping to raise its common-mode input impedance into the megohm range without the noise penalty from the obvious solution of using high-valued resistors. Like transformers, InGenius line receivers maintain their high CMRR over a wide range of source impedance imbalances — even when fed from single-ended sources. But unlike transformers, these wide bandwidth solid state devices offer dc-coupling, low distortion and transparent sound”
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Okay, here is mine. A good audio friend built it for me. He builds his own tube equipment. He put a volume pot on for me as well. He still has it and is running it in a bit. I'll get it in my system in another week or so and let yall know what I think. Isn't that a sweet wood front panel!
(http://)
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Wow! He does very meticulous work. Awesome! :thumb: :thumb:
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Is that the 120/4, 60/8 ohm amp?
Let us know how it sounds with the VC.
Beautiful job of wiring, and love the front panel.
Thanks! :D
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My SuperD has shipped...Geez, now I have one of each. :D
My aluminum case and some amp boards will be very happy together.
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Is that the 120/4, 60/8 ohm amp?
Let us know how it sounds with the VC.
Beautiful job of wiring, and love the front panel.
Thanks! :D
I'll make sure I pass along the compliments. He does build some beautiful looking AND sounding gear and even does the woodwork. It is the 120 wpc model that started this thread but is the latest version (according to Tom).
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Okay, here is mine. A good audio friend built it for me. He builds his own tube equipment. He put a volume pot on for me as well. He still has it and is running it in a bit. I'll get it in my system in another week or so and let yall know what I think. Isn't that a sweet wood front panel!
(http://)
That is a thing of beauty. It would be really cool if you could provide more details on the build such as specifics on the case, external parts usage, etc. At any rate - compliments!
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Hey!
pardales, that looks nice. The wood front panel looks great!
Take care,
Buddy :thumb:
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I am interested in buying a 250 x 2 amp board if someone is upgrading.
Send me a pm with info.
Jeff
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On March 26 I wrote:
...Finally, my amp's still breaking in after 100+ hrs. A fine product -- potentially on par with my Hillig based Monoblocks and my Clayton S100.
------------------------------------------------------
I am amending this partial conclusion.
Of all gear, I find amplifier assessment to be the most difficult, so this is hard to explain and more elaboration may be desired.
Simply put: Listenability and fatigue. With my current system and 51 year old ears, it took about 10 days to realize that the ClassD amp generated fatigue.
I think most of the break-in curve had flattened out by this time, but in terms of sheer listenability and lack of fatigue, my 2000$ Musical Concept Monoblocks and 7000$ Clayton S100 (ouch!) cream the IR2092 based 250 W modules. In ways....there is more which I will expand upon if desired.
I know the word "Cream" is strong.
Still, perhaps contradictorily, I maintain that the ClassD product provides amazing quality/dollar.
I must, however, temper my quoted previous assessment.
Dave
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On March 26 I wrote:
------------------------------------------------------
I am amending this partial conclusion.
Of all gear, I find amplifier assessment to be the most difficult, so this is hard to explain and more elaboration may be desired.
Simply put: Listenability and fatigue. With my current system and 51 year old ears, it took about 10 days to realize that the ClassD amp generated fatigue.
I think most of the break-in curve had flattened out by this time, but in terms of sheer listenability and lack of fatigue, my 2000$ Musical Concept Monoblocks and 7000$ Clayton S100 (ouch!) cream the IR2092 based 250 W modules. In ways....there is more which I will expand upon if desired.
I know the word "Cream" is strong.
Still, perhaps contradictorily, I maintain that the ClassD product provides amazing quality/dollar.
I must, however, temper my quoted previous assessment.
Dave
At the cost difference you state I don't find this contradictory at all.
Also, I agree completely with your time needed to determine the listener fatigue factor. When ever I put a new piece in my system, with the possible exception of speakers, it usually takes a few weeks to assess its sound. It amazes me when someone listens to an amp for one or two listening sessions and can pass judgment.
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Timind,
What I'm dealing with is a very complex set of sensory and intellectual variables. I don't mean "intellectual" as in high IQ massively educated.
It's just that the trio are so close, yet there is an outlier that destroys the similarities.
Man...so hard to explain. I've got the perfect analysis on the tip of my brain but can't get it out tonight.
I must hear the SuperD. I confess to not following the thread and Tom's site for a few days.
Anyway, I'm glad you understand and didn't put a slug through my ears!
Dave
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If anything, I think it is a good sign just to be able to hang for weeks. It very well may be that the right tube preamp might soothe of that fatigue.
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These are my final versions of the Super D SDS 224 and the SDS 258--the brother and sister. I'm using the adjustable gain pots on the 224 but I had Tom fix the gain on the 258 (bass) amp since I can control its volume at the active crossover. Not to gush but the sound is way beyond what I expected it to be shen I started this thread regardless of the little monetary investment. We've seen some really creative packaging along the way from kitchen drawers to alien vacuum cleaners. :green: I suggest to Tom that he start a gallery on his site.
A friend brought a newly modded Museatex Bitstream DAC over last night (I have a stock version) and the soundstage was literally huge--going well beyond the outside of my speakers on either side. Sound was clean, soundstage deep and imaging was pinpoint-you could easily pick out where each player was playing on stage yet with a smooth, laid back analog sound. The synergy of everthing in my system was the best I've ever heard. So I'm on the journey of getting my Bitstream modded.
This has has really been a gas. Hope it continues to be fun to the newcomers too. Here's a few pics of the kids:
(http://www.audiocircle.com/image.php?id=28533)
(http://www.audiocircle.com/image.php?id=28534)
(http://www.audiocircle.com/image.php?id=28535)
(http://www.audiocircle.com/image.php?id=28536)
(http://www.audiocircle.com/image.php?id=28537)
(http://www.audiocircle.com/image.php?id=28538)
steve k :thumb:
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That is a thing of beauty. It would be really cool if you could provide more details on the build such as specifics on the case, external parts usage, etc. At any rate - compliments!
Here is some additional info on this build:
The wood front panel is Leopardwood bought from this seller on ebay, http://myworld.ebay.com/sago901/
The chassis is from www.partsconnexion.com <http://www.partsconnexion.com/> and it's a Hammond black powder coated steel 16 x 8 x 3 box and cover. The black coating looks very durable.
The volume control is 25k stereo pot from Precision Electronics Components (PEC) bought from www.digi-key.com <http://www.digi-key.com/> .
It's just basic hook up inside. I used shielded two wire cable for the input jacks to the volume control and to the amp board. The shielded cable helps lesson the risk of any noise pickup. The input jacks are isolated from the chassis and they are DH Labs brand (also from www.partsconnexion.com <http://www.partsconnexion.com/> ) , and used a grounded power cord with the ground tied to the chassis. The on/off switch has a green neon indicator built in. I think it's from www.mouser.com <http://www.mouser.com/>.
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Steve those look totally awesome! :eyebrows:
SuperD's all around? Sweet! :thumb: :thumb:
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Just wanted to post that I ordered a CDA-2000 kit yesterday and had Tom set the gain to 26db. Well I got an email back from him at 9 last night saying that the gain change will make the order take an extra day.....so he's upgrading the shipping!!! Talk about costumer service. :thumb:
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I suggested to Tom that he start a gallery on his site.
steve k :thumb:
That's a great idea... I hope he does!
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Made this topic a sticky.
It will be easier to find and fallow.
Cheers
Mariusz :thumb:
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Hi all,
Was looking at getting the S254 kit with the heavier power supply. Now my question, was thinking about increasing the cap values in there. Would have Tom do that for me. Any idea of value size, or would my doing so not really make a difference?
Ray Bronk
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My cases are complete and ready for shipping.
Please check out my gallery for pics and more info.
Thanks for the patience!
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My cases are complete and ready for shipping.
Please check out my gallery for pics and more info.
Thanks for the patience!
Looks great. Nice and clean. You have my money! Looking forward to getting this thing together. Very cool it can fit all the combinations of amps.
Paul
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Jason those cases look awesome :drool:
What are your thoughts on the SuperD?
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Jason those cases look awesome :drool:
What are your thoughts on the SuperD?
Between my full time job and all the other projects I've got going, I haven't assembled it yet. I was waiting for a case! :D Maybe this weekend I'll get it together. I'm very much looking forward to it.
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jtwrace,
Re: Your new cases.
I owe you a ton of Carolina Blondes. A job well done my friend :D. Did you use FPE for the engravings on the rear?
Anand.
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jtwrace,
Re: Your new cases.
I owe you a ton of Carolina Blondes. A job well done my friend :D. Did you use FPE for the engravings on the rear?
Anand.
Thank you! Water with lemon is fine. :) I've never had a sip...No FPE.
:thumb:
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Very nice work! That's just what these amps need is a professional case to house them.
Cheers,
steve
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Very nice job on the case!
Do all of them have holes for the balanced inputs, or did you have some made for us single minded ended guys? If not, then maybe on the next run. :wink:
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Very nice job on the case!
Do all of them have holes for the balanced inputs, or did you have some made for us single minded ended guys? If not, then maybe on the next run. :wink:
The cases have both (RCA & XLR). Then I show the option to have 4 RCA's. All the pics are in my gallery.
:thumb:
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Very nice work! That's just what these amps need is a professional case to house them.
Cheers,
steve
:thumb:
Thank you Steve. You're the one that got me into this. :green:
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The cases have both (RCA & XLR). Then I show the option to have 4 RCA's. All the pics are in my gallery.
:thumb:
Got it... thanks!
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Got it... thanks!
You're welcome.
:thumb:
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Great case. That looks like the "real deal"!!!
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I'm pretty interested in one of these amps. However, I'm too lazy too read through the whole 57 pages of this thread. Is there a summary conclusion somewhere with links to the stuff needed? Pretty please. :roll:
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I'm pretty interested in one of these amps. However, I'm too lazy too read through the whole 57 pages of this thread. Is there a summary conclusion somewhere with links to the stuff needed? Pretty please. :roll:
Page 20 - Pumpkinman listed parts that he picked up (Bill made his own case)
Page 17 - list of parts that I used (I picked up case from ebay that couple of other folks had used before)
EDIT: Make sure that you pick up a fuse for the power switch which is not listed in my BOM list
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or buy my case and I'll provide you with a list and part #'s. See my gallery for case pics. :thumb:
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or buy my case and I'll provide you with a list and part #'s. See my gallery for case pics. :thumb:
How much is your case?
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How much is your case?
due to A.C. rules, I"m not allowed to discuss that...you can check my gallery though. It says it there.
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I'm pretty interested in one of these amps. However, I'm too lazy too read through the whole 57 pages of this thread. Is there a summary conclusion somewhere with links to the stuff needed? Pretty please. :roll:
I'll try to put all useful info in one place (probably 1st page).
Check it out over the weekend or early next week.
jtwrace
Nice case
might help some folks interested in the kit.
I do not thing it would upset anyone if you post a picture or two in this thread.
You can also post it in classifieds. When the summary of this thread is finished, I will inclued the link to either your gallery or classified ad.
Cheers
Mariusz
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jtwrace
Nice case
might help some folks interested in the kit.
I do not thing it would upset anyone if you post a picture or two in this thread.
You can also post it in classifieds. When the summary of this thread is finished, I will inclued the link to either your gallery or classified ad.
Cheers
Mariusz
Thank you! :thumb:
(http://www.audiocircle.com/image.php?id=28755)
(http://www.audiocircle.com/image.php?id=28756)
Please see my gallery for more info and pics.
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No problem. :thumb:
Nice option for those locking skills or tools to build their own enclosures or those looking for more profecional appearance.
Mariusz :P
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Ok this classD stuff has got me!
Just oredered the jtwrace case and the SDS-254 Kit
interested in comparing it to my Virtue one.2 Tamp
first time building an amp, Wish Me Luck, looks simple
enough.
Dave H I am going to send you a pm, I think I saw you are
20 miles west of Gettysburg, PA, I am about 30 miles south
in MD, maybe we can get together if I need help.
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I just finished building the SDS254, its pretty easy now that he has switched to all molexs. Be happy to help with any questions. Looking forward to the comparison, your in for a real treat with that SuperD. :eyebrows:
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Great thanks Nick77
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Great thanks Nick77
You should have Tom set it up for either single ended or balanced inputs. Its only moving some jumpers but having it pre-set is real nice. :green:
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Thanks for the tip. I just read my email and Tom sent a note
saying he set it up for single ended with some tips on wiring
Also upgraded my shipping so I would get it early next week
AWESOME Customer Service for a Cheap and Cheerful Product
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Thanks for the tip. I just read my email and Tom sent a note
saying he set it up for single ended with some tips on wiring
Also upgraded my shipping so I would get it early next week
AWESOME Customer Service for a Cheap and Cheerful Product
Great! and you'll have your case then too.
:thumb:
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Does this IEC Power come with fuse or something? I bought a simple IEC power jack and a switch. I wasn't sure if it's important to buy one with fuse. Would the Class D amp cause fire?
Ordered the following yesterday, hoping they get here before the weekend:
RCA Connector - http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=350197324175&ssPageName=STRK:MEWNX:IT
IEC Power - http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200435755054&ssPageName=STRK:MEWNX:IT
Case - http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=250501444095&ssPageName=STRK:MEWNX:IT
Binding Post - http://www.radioshack.com/product/index.jsp?productId=2102838
Edit: Added binding post info.
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Does this IEC Power come with fuse or something? I bought a simple IEC power jack and a switch. I wasn't sure if it's important to buy one with fuse. Would the Class D amp cause fire?
The one listed has pre-built fuse holder but you have to purchase 6A fuse for it.
EDIT: Please do not buy the binding post that I listed they donot have the washers to prevent contact with the case. I will update that post with the ones that I purchase shortly.
http://cgi.ebay.com/20-Pcs-GOLD-RCA-CONNECTOR-FEMALE-CHASSIS-SOCKET-CRADLE_W0QQitemZ320510873543QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item4a9fefcfc7
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The power module seems to have four connectors from the eBay picture. Does it come with instructions on what connect to what? Thanks!
The one listed has pre-built fuse holder but you have to purchase 6A fuse for it.
EDIT: Please do not buy the binding post that I listed they donot have the washers to prevent contact with the case. I will update that post with the ones that I purchase shortly.
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The one listed has pre-built fuse holder but you have to purchase 6A fuse for it.
EDIT: Please do not buy the binding post that I listed they donot have the washers to prevent contact with the case. I will update that post with the ones that I purchase shortly.
http://cgi.ebay.com/20-Pcs-GOLD-RCA-CONNECTOR-FEMALE-CHASSIS-SOCKET-CRADLE_W0QQitemZ320510873543QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item4a9fefcfc7
Just an FYI, I've bought cheap RCAs like those recently and some of the holes were so tight I broke off the center pin to one of my (expensive) interconnect trying to pull them out, so you may want to test them with some cheap stuff first (for the tight ones I just pushed in and out repeatedly until the hole loosened).
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The power module seems to have four connectors from the eBay picture. Does it come with instructions on what connect to what? Thanks!
The manuals are on the classdaudio website.
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Does anyone know if the Super D amps have soft-start circuitry built in? When the amp is powered on, this helps prevent the speakers from popping. Or do you just leave your amp powered on all the time?
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From the manual, all amps have :
"Click and pop Noise Reduction
Over Temperature Protection
Over/Under Voltage Protectioin
Over/Under Current Proection
MOSFET DC Protection"
So the answer is yes, no clicks or pops in your speakers at turn on.
steve k
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Sorry, I meant the power switch module bought from the eBay. There are four connects from the picture and I was wondering what goes where...
The manuals are on the classdaudio website.
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Soft-start has nothing to do with pops or ticks. It has to do with limiting the current that spikes when the amplifier is turned on before the filter caps have had a chance to charge. This feature would not be part of the amplifier module; rather, it would be a circuit that is part of the power supply. This is a non-issue unless you're running several channels of amplification off the same power supply/switch.
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Sorry, I meant the power switch module bought from the eBay. There are four connects from the picture and I was wondering what goes where...
Use the two outside tabs. I have the red cable going from the transformer to the outside most left one and the black to the outside most right one. Take a look at the picture on page 21 (http://www.audiocircle.com/index.php?topic=76400.400)
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I've been kind of busy and just checked back in here. Thanks for the replies guys!
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Here are some pics of my XLR configured Super D amp. I've got some real work to do so I need to stop for the day. I'll get back to it middle of this week.
(http://www.audiocircle.com/image.php?id=28845)
(http://www.audiocircle.com/image.php?id=28846)
(http://www.audiocircle.com/image.php?id=28847)
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nice work jtwrace, looking forward to doing mine
Couple of questions:
Do you think I could use Paul Speltz speaker wire to do the
leads to the binding posts?
Did you use solid core wire for the inputs?
Do I need to pick up stand offs?
I think the link you gave for the power switch was the round one
from Rat Shack correct, also it mounts on the bottom of the cabinet?
Do you think it would be better to use balanced inputs with single
ended to balance adaptors on my single ended cable?
What size AC fuse do I need?
Sorry for all the questions, when I get my amp the instructions probally
will answer all these questions!
Close up pic of the vents shows that the finish on the case looks real nice!
Cheers,
JT Snead
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nice work jtwrace, looking forward to doing mine
Couple of questions:
Do you think I could use Paul Speltz speaker wire to do the
leads to the binding posts?
as long as the wire gauge will fit into the amp board connector.
Did you use solid core wire for the inputs?
no
Do I need to pick up stand offs?
they come with the package from Class D
I think the link you gave for the power switch was the round one
from Rat Shack correct, also it mounts on the bottom of the cabinet?
Yes, it goes right in (20 mm hole) and you can pick it up locally usually. If not, purchase in the store and they will ship it to you for free.
Do you think it would be better to use balanced inputs with single
ended to balance adaptors on my single ended cable?
no. If your system is single ended, wire it up as such.
What size AC fuse do I need?
That's a question for Tom.
Sorry for all the questions, when I get my amp the instructions probally
will answer all these questions!
Close up pic of the vents shows that the finish on the case looks real nice!
Cheers,
JT Snead
:thumb: I think you're going to be very pleased. I know I am. Be sure to post pics when you get it done. The great thing is once you have everything this kit can be built in this case in a couple of hours if you have a basic idea. No drilling, filing, sanding....... :D
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Yes it does look simple enough
Thanks
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The new input reciever that Tom is using on the SuperD benifits the single ended users also.
Tom told me that a 6amp slow blow is ample.
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I got the CDA254 today. I ordered last Friday and Tom shipped Saturday - very happy with the customer service!
My first impression is that the Transformer is HEAVY. It weights 7 lbs and is heavier than my laptop. Geez, you can never tell the whole story from pictures.
I've read most wiring instruction and just when I feel I know how to wire. The sheet included in the package suprised me a little bit. It said "Do NOT Use CT on Power Supply". I thought the tappered blue and green wire go to the CT on the power supply but the picture asks me to wire it somewhere (AC-N and AC-L). The printed paper is different from the one on Tom's website. My transformer is AN-3332.
Also it says - "Do NOT use GND on Power Supply!". It only asks me to connect V+ to Amp + and V- to Amp -. I saw most pictures connect GND to Amp GND as well. My Amp module is CDA2092X2TB.
Don't want to hook power on before these resolved. Which version is correct?
[EDIT] Tom said it's possible that I received the wrong wiring diagram. The online version is correct - much relieved.. ;)
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follow the sheet that Tom sent with your amp.
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follow the sheet that Tom sent with your amp.
FYI, Tom said to follow the one over the website. I also double-checked with him. Certainly don't want to burn anything. ;)
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:scratch:
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FYI, Tom said to follow the one over the website. I also double-checked with him. Certainly don't want to burn anything. ;)
If you have a fuse installed it will prevent any damage in the event of a miswire.
-
So I wired and fired it up (The printed diagram isn't correct and the online one is correct). It is indeed a higher end amplifier than my HK 635. I need more time to give a better impression. I picked up a few things that I did not have before. The sound stage is better and there is something magical in the mid section that transform the listening experience. I cannot find a word for it, "liquid" perhaps? For $198, wow...
I used both HK 635 and Y1 DAC as preamps to listen to CDs and MP3s. Before I was very happy with HK635, I wouldn't say the improvement is night and day. HK is still a great product and this amp is better. Throw in the price, IMO, it's a keeper and no brainer if I have to recommend someone an amp.
Now, off to build a case for it! Very happy! Thanks Tom for great service and product! Thanks people here discussing this product!
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Here are the latest pics of my Super D amp with my case. It's up and running and sounding really good. I'm still playing around with the gain. I can't believe how quiet it is. :drool: If anyone cares I'll post some pics of the top on and it together.
(http://www.audiocircle.com/image.php?id=28920)
(http://www.audiocircle.com/image.php?id=28921)
(http://www.audiocircle.com/image.php?id=28922)
(http://www.audiocircle.com/image.php?id=28923)
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Beautiful job on the case and the build Jason, very professional!
Best,
Ed
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Here are the latest pics of my Super D amp with my case.
(http://www.audiocircle.com/image.php?id=28923)
Jason, your last photo is blurry and unrecognizeable, and if I didn't know from previous descriptions that it is probably a photo of the power light reflecting off of the shelf....well, I wouldn't know what it was!
However, if that photo were rotated 90 degrees and used as a photo overlay on 2' X 4' acoustic panels behind each speaker (mirror imaged, of course), I think they would be absolutely gorgeous!
Steve
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Jason, your last photo is blurry and unrecognizeable, and if I didn't know from previous descriptions that it is probably a photo of the power light reflecting off of the shelf....well, I wouldn't know what it was!
However, if that photo were rotated 90 degrees and used as a photo overlay on 2' X 4' acoustic panels behind each speaker (mirror imaged, of course), I think they would be absolutely gorgeous!
Steve
Sorry. :duh: I had to take it w/o the flash and didn't use a tripod.
You're more then welcome to the file if you want it. :D
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Beautiful job on the case and the build Jason, very professional!
Best,
Ed
Ed,
Thank you very much. I put quite a bit into this and it's nice to hear that. The best part, it's available to everyone. :thumb:
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Sorry. :duh: I had to take it w/o the flash and didn't use a tripod.
Yes, but in the process you have created striking "art"!
Steve
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Yes, but in the process you have created striking "art"!
Steve
A squirrel finds a nut every once in awhile. :lol:
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Here are the latest pics of my Super D amp with my case. It's up and running and sounding really good. I'm still playing around with the gain. I can't believe how quiet it is. :drool: If anyone cares I'll post some pics of the top on and it together.
(http://www.audiocircle.com/image.php?id=28920)
(http://www.audiocircle.com/image.php?id=28921)
(http://www.audiocircle.com/image.php?id=28922)
(http://www.audiocircle.com/image.php?id=28923)
Jason, very, very nice work. You certainly know your way around a good build. The casework is awesome! I'll be interested in giving them a listen someday. I like the comment about the photoart that you have created, too. You are an artist in many ways, my friend.
Dave
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Looks good Jason,
the transformer that came with my kit has two brown and two orange wires in addition to the red, black, blue and green ones?
The kit did not come with any instructions besides the transformer drawing.
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Looks good Jason,
the transformer that came with my kit has two brown and two orange wires in addition to the red, black, blue and green ones?
The kit did not come with any instructions besides the transformer drawing.
Can't help you on the tranny...I"m sure there are two extra just for other DC items.
No instructions. That's the fun part! Just kidding.
copied from my email from Tom:
I set your amp up for single ended input. The important thing to remember is… do not use the – on the input for single ended. Connect the + to + and the negative to G (ground). If you connect to -, it will damage the amp. For balanced input, just remove J1 and J2 jumpers completely. J1 and J2 have jumpers on pins 2 and 3… this is for single ended input. If you change the jumpers to pins 1 and 2, it will reverse the polarity… most situations this will probably not sound as good, so no need to mess with that.
For the potentiometers included, the black wire goes to the center pin on the pot, and if holding the pot with pins facing up, the yellow wire goes on the left, and the red wire on the right.
That’s really all you have to know. As with our other amps, just be extra careful connecting up the transformer and amp, and everything will be fine. I taped the wires on the transformer to make it easier… but always double check to be sure I didn’t make a mistake.
I’m still trying to get the time to finish a user’s manual. Hope to have it finished soon. Here’s a little more info on the input stage I used in these amps…
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Ok how did you guys attach the transformer to your cases? It seems that bolts that came with my kit are too short to really be attached, or is there a way to do it with the two together and i'm just missing something?
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Ok how did you guys attach the transformer to your cases? It seems that bolts that came with my kit are too short to really be attached, or is there a way to do it with the two together and i'm just missing something?
Did you see my post above?
Bolt goes from underside of panel then place one rubber sheet on the bottom then place tranny then place rubber then metal spacer then lock washer and nut. **tighten** Enjoy!
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Did you see my post above?
Bolt goes from underside of panel then place one rubber sheet on the bottom then place tranny then place rubber then metal spacer then lock washer and nut. **tighten** Enjoy!
I shouldn't post so late at night, I didn't get my question across :duh: It doesn't seem like the bolts that came with the kit are long enough for this, and I was wondering if there was something to using both of them that came with the kit. From the sounds of it, it seem they should fit and if not just buy a longer one.
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I shouldn't post so late at night, I didn't get my question across :duh: It doesn't seem like the bolts that came with the kit are long enough for this, and I was wondering if there was something to using both of them that came with the kit. From the sounds of it, it seem they should fit and if not just buy a longer one.
If your case or whatever you're attaching the tranny to is less then 3/8" the bolt is long enough. Is that what you're concerned about? Or are you speaking about the standoffs used for the board mounting?
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Ok how did you guys attach the transformer to your cases? It seems that bolts that came with my kit are too short to really be attached, or is there a way to do it with the two together and i'm just missing something?
I had to go buy a longer bolt since i attached to mdf. The bolt and stand offs that are supplied are clearly meant for attaching to a metal case.
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Nick,
Could you eleborate on this a little bit? I plan to use 1/2" MDF as the bottom and need to mount the Transformer onto it. The bolt seems quite long to me.
My question is that is it possible to make a "smooth" bottom? The bolt end is quite thick and will stick out if I don't flush mount it into MDF. If I flush mount, I don't know if 1/2 MDF will be "thick" enough to hold the bolt. Perhpas I should use 3/4" for the bottom and flush mount the bolt? Or I have to use "feet" (I was try to avoid that to make a simpler case)
Advises are appreciated!
I had to go buy a longer bolt since i attached to mdf. The bolt and stand offs that are supplied are clearly meant for attaching to a metal case.
-
Advises are appreciated!
You know what I'd recommend... :thumb: :D
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Nick,
Could you eleborate on this a little bit? I plan to use 1/2" MDF as the bottom and need to mount the Transformer onto it. The bolt seems quite long to me.
My question is that is it possible to make a "smooth" bottom? The bolt end is quite thick and will stick out if I don't flush mount it into MDF. If I flush mount, I don't know if 1/2 MDF will be "thick" enough to hold the bolt. Perhpas I should use 3/4" for the bottom and flush mount the bolt? Or I have to use "feet" (I was try to avoid that to make a simpler case)
Advises are appreciated!
I think your concerns are valid, i used 3/4 mdf and flush mounted. I also bought little 1" bolts for the stand offs to work with 3/4". (i forgot the size but HD and Lowes has them)
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You could also add another piece of 1/2" MDO at the tranny (inside) and countersink the bolt so the bottom is flush. You may need a longer bolt. I countersunk the bottom board so I could use the stock screws for the standoffs. You can use a 3/8" bit so you have enough room to get the screws in.
steve
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Well it is after 2:00AM and I got as far as I could on the Super D Amp
Thanks to Jason for a fine looking case. I drilled some holes and added
some threaded cones I had laying around, need to get the IEC inlet, used
all parts and wiring I had in the house, note the Speltz Anti Cable for speaker
outputs. Fun Stuff
(http://www.audiocircle.com/image.php?id=28996)
(http://www.audiocircle.com/image.php?id=28997)
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JT
Looking great, the feets are nice touch.
:thumb:
Dodd DIY Buffer go good with it. :wink:
-
Also wanted to say that Jason's case is very well made and finished. The top cover and sides are one piece bent to slide in between the front and rear of the case. You have to remove the feet to take of the top. I added some sorbethane to the top since I had it off for construction of the amp. The front steel panel is removable also so you could add a custom wood panel front or whatever you would like to look at.
Since is my first amp kit having a case that was ready to go sold me on the whole kit thing. The total project was quite easy, Jason's photos helped with
the layout and connections.
So hopefully I will be powering it sometime today.
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Dodd Buffer? I have been looking at some posts, it does sound interesting.
I do have a tune preamp, but more tubes couldnt hurt!!
Might be fun to do another kit also.
I think Seth at Virtue uses one in his ICE amps.
Maybe, Maybe you got me thinking :duh:
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JT
Check out http://doddaudio.com/DIYINSTRUCTION.aspx
Look easy enough. :wink:
I'm not much on words, but the pictures should help me a lot. :duh:
"JUST DO IT"
:eyebrows:
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Well it is after 2:00AM and I got as far as I could on the Super D Amp
Thanks to Jason for a fine looking case. I drilled some holes and added
some threaded cones I had laying around, need to get the IEC inlet, used
all parts and wiring I had in the house, note the Speltz Anti Cable for speaker
outputs. Fun Stuff
Glad you like the case. :thumb:
Let us know what you think when it's done.
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Glad you like the case. :thumb:
Let us know what you think when it's done.
Nice work, indeed.
Picutres of my amp are back on page 55. I've only had mine up and running a few days since I got it last week. My initial impression is that this amp has great fundamentals. It will take me a more time to discern qualitative differences between it and my Miniwatt.
-
Well it is after 2:00AM and I got as far as I could on the Super D Amp
Thanks to Jason for a fine looking case. I drilled some holes and added
some threaded cones I had laying around, need to get the IEC inlet, used
all parts and wiring I had in the house, note the Speltz Anti Cable for speaker
outputs. Fun Stuff
(http://www.audiocircle.com/image.php?id=28996)
(http://www.audiocircle.com/image.php?id=28997)
Jason's case is a beauty, for sure. He does nice work!
Dave
-
Dave, very nice build. When you get it going, please describe the how it sounds. Thanks! :thumb:
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Dave, very nice build. When you get it going, please describe the how it sounds. Thanks! :thumb:
I wish it was mine! I just commented on Mr. Snead's build on the last page. He got one of Jason's enclosures and is doing a stellar job on his build. I have too many projects going right now, but will be listening to Jason's in about 10 days or so. I'll report back on the sound when I do.
Maybe someday I'll build one for my office... maybe.......someday.................... :wink:
Dave
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Dave, thanks and sorry I didn't notice that. :duh:
But regardless, please do post your impressions after listening to Jason's amp. Thanks!
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Dave, thanks and sorry I didn't notice that. :duh:
But regardless, please do post your impressions after listening to Jason's amp. Thanks!
Hey, no problemo. Believe me, I'm the first guy to offer an opinion. :D
Dave
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Help with Power Switch Module
So I followed the step and bought this power switch module from eBay - Good quality stuff
IEC Power - http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200435755054&ssPageName=STRK:MEWNX:IT
Now I need help as the documentation is vague on how to wire them. It has four connects (A,B,C,D) plus one GND on the back. Which two of (A, B, C, D) I should connect? Which one is AC-L and which one is AC-N?
The fuse holder can hold two fuses - one on each side. Should I put two fuses in or just one? If one, which side should I put in or it doesn't matter?
Thanks!
[Edit] Fuse question answered - This model needs two fuses. For wiring I'd guess it's A and D - A: AC-L, D: AC-N. Need to confirm...
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Help with Power Switch Module
So I followed the step and bought this power switch module from eBay - Good quality stuff
IEC Power - http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200435755054&ssPageName=STRK:MEWNX:IT
Now I need help as the documentation is vague on how to wire them. It has four connects (A,B,C,D) plus one GND on the back. Which two of (A, B, C, D) I should connect? Which one is AC-L and which one is AC-N?
The fuse holder can hold two fuses - one on each side. Should I put two fuses in or just one? If one, which side should I put in or it doesn't matter?
Thanks!
[Edit] Fuse question answered - This model needs two fuses. For wiring I'd guess it's A and D - A: AC-L, D: AC-N. Need to confirm...
Here is how I wired mine. A - connected to the red cable from transformer and D - connected to the black cable from transformer
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Here is how I wired mine. A - connected to the red cable from transformer and D - connected to the black cable from transformer
That's what I "guessed" so I assume it worked in your system and no smoke came out. ;)
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That's what I "guessed" so I assume it worked in your system and no smoke came out. ;)
No smoke when I plugged it in and other folks who have borrowed it have not reported any smoke either :)
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Ok I want to make sure my on/off switch is wired correctly, I have the same one Jason used, has three pins marked 1 2 3, 3 is brass,
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No smoke when I plugged it in and other folks who have borrowed it have not reported any smoke either :)
Corcom customer service answered my call and yes A, D, A for hot and D for neutral. This model needs two fuses. ;)
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nevermind I got, it is laying right now
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I mean playing HAHA
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I mean playing HAHA
great! Be sure to post some finished pics. :thumb:
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Here are a few more...I have one more to take but I need to finish the part. :D :hyper:
(http://www.audiocircle.com/image.php?id=29015)
(http://www.audiocircle.com/image.php?id=29016)
(http://www.audiocircle.com/image.php?id=29017)
Normally I would solder every terminal. I wanted to show that this DIY kit could be done with basic tools.
-
But, you did put solder to the RCAs, right?
-
But, you did put solder to the RCAs, right?
:duh: Yes, RCA and XLR. :oops:
Yes, 10 is still way less time consuming then every one. My kit was done it less then 2 hrs.
-
:duh: Yes, RCA and XLR.
Thanks...couldn't be certain from the pics.
-
Jason
I realize it might take you some time to adjust to the Super, but when your able I am curious if you can detect any differences between xlr and rca. :green:
Steve did you ever try balanced?
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Jason
I realize it might take you some time to adjust to the Super, but when your able I am curious if you can detect any differences between xlr and rca. :green:
Perfect timing! I was just messing around with that. In my system, I don't think there was a difference.
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Ahh so it would appear that the new input reciever Tom is using gives the single ended user all the benifit of balanced. :scratch:
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Ahh so it would appear that the new input reciever Tom is using gives the single ended user all the benifit of balanced. :scratch:
Why the :scratch:?
-
I guess i dont understand it but i sure am enjoying being able to benifit from the Super while only running rca's.
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I guess i dont understand it but i sure am enjoying being able to benifit from the Super while only running rca's.
I'm confused now. sorry.
-
Steve did you ever try balanced?
I really don't have that opportunity with my setup. Since I'm biamping, everthing from the preamp runs though my active crossover which is single ended. I'd have to use a crossover with balanced inputs and outputs to take advantage of the balanced input of the Super D.
I think what Keith is referring to is Tom told me originally when I demoed the Supers that he thought they sounded a little better using the balanced inputs. It sounds as if the differences are miniscule in your system, JT, which is good news to Keith and I.
steve
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Hi,
I am interested in building one of these(ie 120W/C version) Class D to drive my woofer section. Has anyone here measure the actual output power of this amp driving 8 or 4 ohms? I have read at least half of the postings here haven't found any report.
Thanks.
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My journey (finally) is about to really begin. I won't be able to whip out the soldering iron until this weekend.
It is the CDA-254 amp with the heavy-duty power supply. Tom adjusted the gain to 24 dB based on the specs of my preamp. I will be making two of these.
Case -- From jtwrace (http://www.audiocircle.com/index.php?action=profile;u=41254) (a big thanks to him for a great job done!)
IEC -- Furutech FI-10 Gold -- from CryoParts
Binding Posts -- from CryoParts
RCAs -- from CryoParts
XLRs (not shown) -- Neutrik (used, for now, just to fill the holes)
Fuse; Fuse Holder; Power Switch -- RadioShack
Wire:
Hookup -- Silver plated copper wire (may use some shielded Canare cable I have. . .not sure yet. . .suggestions???)
Power -- stranded Belden or misc solid core copper
Power Cable -- Volex 17604
(http://www.audiocircle.com/image.php?id=29025)
(http://www.audiocircle.com/image.php?id=29026)
(http://www.audiocircle.com/image.php?id=29027)
(http://www.audiocircle.com/image.php?id=29028)
Paul
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Jason, your last photo is blurry and unrecognizeable, and if I didn't know from previous descriptions that it is probably a photo of the power light reflecting off of the shelf....well, I wouldn't know what it was!
However, if that photo were rotated 90 degrees and used as a photo overlay on 2' X 4' acoustic panels behind each speaker (mirror imaged, of course), I think they would be absolutely gorgeous!
Steve
Just for you:
(http://www.audiocircle.com/image.php?id=29031)
I aim to please. :)
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Case -- From jtwrace (a big thanks to him!)
Paul
You're very welcome. I'm glad that you like it! :thumb:
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'Tis a cool case! :D
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'Tis a cool case! :D
Thanks Blair! :thumb:
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I would have put this together a couple months ago, but I was waiting for jtwrace's (http://www.audiocircle.com/index.php?action=profile;u=41254) custom case. For those of you that don't know, the case comes with all the cut-outs, etc. for the binding posts, RCAs, IEC, fuse holder, power switch and transformer. It also has the ability to take ANY configuration of amp(s) combination(s) you can think of, including using 2 modules. VERY well thought out and HIGHLY recommended. Will not only save you labor, but is also a very clean, simple set-up. Those of you that are wanting a case for your Class Ds, I would jump on this one ASAP. :thumb: Even fits the new Super Ds. I'm not a big DIYer, so this case is a big plus for that reason, too.
Thanks again, Jason. :notworthy: Can't wait to get this thing up and running this weekend. :dance:
Now, I just have to really start saving up for the reason I got these amps in the first place. . .a BIG speaker upgrade, in which I am going to actively biamp (maybe even triamp). A couple small toys, bachelor part, wedding, and medical bills have definitely taken their toll. . . :banghead: Hoping to swing the speakers in 2 months. . .
Paul
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I would have put this together a couple months ago, but I was waiting for jtwrace's (http://www.audiocircle.com/index.php?action=profile;u=41254) custom case. For those of you that don't know, the case comes with all the cut-outs, etc. for the binding posts, RCAs, IEC, fuse holder, power switch and transformer. It also has the ability to take ANY configuration of amp(s) combination(s) you can think of, including using 2 modules. VERY well thought out and HIGHLY recommended. Will not only save you labor, but is also a very clean, simple set-up. Those of you that are wanting a case for your Class Ds, I would jump on this one ASAP. :thumb: Even fits the new Super Ds. I'm not a big DIYer, so this case is a big plus for that reason, too.
Thanks again, Jason. :notworthy: Can't wait to get this thing up and running this weekend. :dance:
Now, I just have to really start saving up for the reason I got these amps in the first place. . .a BIG speaker upgrade, in which I am going to actively biamp (maybe even triamp). A couple small toys, bachelor part, wedding, and medical bills have definitely taken their toll. . . :banghead: Hoping to swing the speakers in 2 months. . .
Paul
pjchappy
Thank you very much for the kind comments. It means more then you can imagine. :thumb:
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JTwrace, pardon my ignorance, but isn't there any provisions for either a on/off switch in your case or is your amp design always on? I purchased a on/off toggle switch for the amp and I wonder how it would fit in your case. BTW, I am in a quandary about making my ClassD amp with 2 modules, PS module and the transformer.
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JTwrace, pardon my ignorance, but isn't there any provisions for either a on/off switch in your case or is your amp design always on? I purchased a on/off toggle switch for the amp and I wonder how it would fit in your case. BTW, I am in a quandary about making my ClassD amp with 2 modules, PS module and the transformer.
http://www.audiocircle.com/index.php?topic=76400.1160
see post 1160
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http://www.audiocircle.com/index.php?topic=76400.1160
see post 1160
I had trouble seeing where it was also. :oops:
It's a little easier to see in these pics....
http://www.audiocircle.com/index.php?topic=76400.msg765112#msg765112
There is a cutout on the bottom near the front.
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I had trouble seeing where it was also. :oops:
It's a little easier to see in these pics....
http://www.audiocircle.com/index.php?topic=76400.msg765112#msg765112
There is a cutout on the bottom near the front.
There is a cutout. Of course!!! It's 20 mm circle. With purchase I supply a list of parts that will work. Nice and easy.
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I see it. So, instead of the plastic switch in the bottom, I guess I can do the toggle there....just need some large footers in order to get clearance. I am tempted at ordering your case...will have to study the situation this weekend. :thumb:
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I see it. So, instead of the plastic switch in the bottom, I guess I can do the toggle there....just need some large footers in order to get clearance. I am tempted at ordering your case...will have to study the situation this weekend. :thumb:
The switch that I spec'd cost $2.99 from Radio Shack. It will save you a lot of work and headache just to get that one.
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Hi All,
Well, was just thinking about buyng the Super amp kit. Was also considering asking Tom to beef up the supplied power supply. So any recommendations for the higher value caps?
Also thinking about getting the Parmetal case. I had bought one from him when I built my SKA amp. So if you had ordered one, can you give me the order number? I am mainly concerned about the layout of the back panel. Would a 12X12X3 work ok? Different dimensions are ok too. Don't know the height of the transformer and stuff like that there. Would also like some suggestions as to where to place what in the case.
Nope, can't see the Pics. just a blind guy who likes to do some DIY every now and then.
Ray
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Ray most of have found as long as you order the larger power supply you will get great results. Dont know if Tom would be open to upgrade or not, let us know.
12x12x3 will work just fine, i just measured my 400v transformer and it will clear. Not sure about even bigger transformers though.
You might seriously consider JT's predrilled case as the rear panel is already setup and drilled to perfection. Good luck!
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Ray most of have found as long as you order the larger power supply you will get great results. Dont know if Tom would be open to upgrade or not, let us know.
12x12x3 will work just fine, i just measured my 400v transformer and it will clear. Not sure about even bigger transformers though.
You might seriously consider JT's predrilled case as the rear panel is already setup and drilled to perfection. Good luck!
Hi, When it comes time to order, I'll see if I hcan swing the extra bucks for his case. As far as the supply goes, don't know the current values of the caps in the supply. Just thought I'd ask. With reference to the Parmetal case, the one I have is anodized. I want to see if I can get it lightly powder coated, with the screw holes countersunk.
I presume you put the audio board towards the back of the case and the transformer and supply towards the front of the case? Just guessing. .Don't know the diameter of the Transformer, both width and height. Also don't know the dimentions of the two boards, power and audio. That might help a bit to figure out placement.
Ray
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All right guys, I have read this whole thread and I think I am going to put one of these together to go with the DIY Dodd Buffer and GR-Research N2X speakers for a cool 2-channel set-up. Which kit do you recommend for SQ, but the power I will need?
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All right guys, I have read this whole thread and I think I am going to put one of these together to go with the DIY Dodd Buffer and GR-Research N2X speakers for a cool 2-channel set-up. Which kit do you recommend for SQ, but the power I will need?
The N2X are pretty revealing speakers, i would reccomend the SDS224 which is 60 wpc but for just a few bucks more the SDS254 would give you plenty of power for when you upgrade. :eyebrows:
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All right guys, I have read this whole thread and I think I am going to put one of these together to go with the DIY Dodd Buffer and GR-Research N2X speakers for a cool 2-channel set-up. Which kit do you recommend for SQ, but the power I will need?
I agree with Nick77, either one he mentioned or the CDA254 would be very good with plenty of output. Consider these observations from Blair Lamphear, Niteshade Audio.
These amplifiers are tube-like when it comes to representing microdynamics. There is plenty of air around musical instruments and vocals stand out well. Sound staging is different than with tube amps. For example, the power available at any given time is so immense that loud passages will literally jump out at you. With a tube amp, I feel the ambiance is different: Not as forceful, but more enveloping. The bottom end of a Class D amplifier is second to none. Woofer control and bass output are exceptionally good. They love high current, low resistance power supplies for this reason. High frequencies are clean and many will believe they are extended. There is no hint of 'roll off'. I've been spending a considerable amount of listening time with our new Class D. Presently it's connected to a pair of Von Schweikert VR-2's. These speakers are fairly difficult to drive and they're not bi-amped. The Class D was a perfect match! These speakers opened right up and I have to say the sound is flawless. I never heard these speakers sound so good! There is no better definition of 'system synergy' than the sound of these two paired. Amazing! I have driven speakers from 100db down to 85db with great success.
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All right guys, I have read this whole thread
:notworthy: You should get an award (amp) for that. :lol:
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:lol: :lol: :lol: :rotflmao: :rotflmao: :rotflmao:
For sure!! :thumb:
steve
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:notworthy: You should get an award (amp) for that. :lol:
I agree! :lol:
So, should I ask to upgrade from the 400VA to the 600VA ANTek transformer? With the Tube buffer, will I need the variable gain?
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I agree! :lol:
So, should I ask to upgrade from the 400VA to the 600VA ANTek transformer? With the Tube buffer, will I need the variable gain?
I don't think the upgrade in tranny will do much. Stock buffer is fine IMO.
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I agree! :lol:
So, should I ask to upgrade from the 400VA to the 600VA ANTek transformer? With the Tube buffer, will I need the variable gain?
You asked about SQ, its the upgraded input reciever that the SuperD has that you will want. Adjustable gain is just a plus.
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I have a question about the adjustable gain pot's
If I wanted a greater control range on my preamp
I could adjust the gain lower but how do you know
if you have the channels balanced?
I was thinking I could use a test tone but was wondering
if there was a place I could put my AC or DC meter to tell
if the both channels are balanced.
-
I have a question about the adjustable gain pot's
If I wanted a greater control range on my preamp
I could adjust the gain lower but how do you know
if you have the channels balanced?
I was thinking I could use a test tone but was wondering
if there was a place I could put my AC or DC meter to tell
if the both channels are balanced.
**This is Super D onlly**
From my previous email to Tom:
You can measure the pots (yellow and black wire) and make sure they are the same. Some preamps sound better when the volume knob is in the lower half of its range, and some up past half way. You can adjust the gain to where your normal listening level is where your preamp volume control sounds the best. Each channel doesn’t have to be the same… you can adjust them to get the best speaker balance in your room.
He also mentioned that with the pot at half way it's roughly 26dB.
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Each channel doesn’t have to be the same… you can adjust them to get the best speaker balance in your room.
Hmmm... and if you are biamping with a pair, one on each speaker, you could use the gain controls as rudimentary tone controls to change the balance between the high and low frequencies of your speakers.
It's also good for getting the gain right when using these to power subwoofers... I've run into problems where I can't get enough gain out of a particular amp and active crossover combination.
Anyone know what the max/min gain range is of the new Super D amps?
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Anyone know what the max/min gain range is of the new Super D amps?
I will find out and report back...other then low / high. :)
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Thanks Jason,
I will try that when I open up the case again.
With my preamp 9:00 to 11:00 is the most I can adjust
the volume. The dynamics of the amp and other class D
amps really reveals the difference in the original recordings
level.
The sound of the amp is really suprising, very good detail
a little grainy at first but it is getting better. Anybody else
have any listening impressions of the Super D Amp
Krikor, are you using each am to power the low's and high's
of you speakers, or are you using them bridged to drive each channel
full range? Could you post some pictures of your amp interior.
I have always wondered about running two amps one side to power
the lows and highs independently. With these amps and the gain pots
could you do this w/o an outboard crossover?
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Thanks Jason,
I will try that when I open up the case again.
With my preamp 9:00 to 11:00 is the most I can adjust
the volume. The dynamics of the amp and other class D
amps really reveals the difference in the original recordings
level.
The sound of the amp is really suprising, very good detail
a little grainy at first but it is getting better. Anybody else
have any listening impressions of the Super D Amp
Krikor, are you using each am to power the low's and high's
of you speakers, or are you using them bridged to drive each channel
full range? Could you post some pictures of your amp interior.
I have always wondered about running two amps one side to power
the lows and highs independently. With these amps and the gain pots
could you do this w/o an outboard crossover?
You're welcome!
You can biamp your speakers with these. The fact that you have my case, it makes it really simple. Move the tranny to the right, move the power board back add amp board. Drill a pair of binding post holes 1/2" hole on 3/4" centers. Add my recommended RCA that fits into the XLR hole. Now you have a 4 ch amp!
No active crossover needed as long as the passive / wiring in your speakers is setup properly (bi-wiring with two or three passive xovers). Is that what you're asking?
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Yes, since I can get another amp board fairly reasonable.
The single transformer supplys power to the power supply
board and I guess that is why there are two sets of DC
voltage outputs, right?
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Yes, since I can get another amp board fairly reasonable.
The single transformer supplys power to the power supply
board and I guess that is why there are two sets of DC
voltage outputs, right?
No. I think the other DC outputs are lower voltage. You can power both amps from one power board.
-
Krikor, are you using each am to power the low's and high's
of you speakers, or are you using them bridged to drive each channel
full range? Could you post some pictures of your amp interior.
I have always wondered about running two amps one side to power
the lows and highs independently. With these amps and the gain pots
could you do this w/o an outboard crossover?
Nope... not an owner. I'm just a lurker sitting on the fence and contemplating how I might use these amps. I'm currently selling off some older equipment to raise some funds before I jump. I'm really curious to hear how these compare to my modded PS Audio GCC-100.
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Nope... not an owner. I'm just a lurker sitting on the fence and contemplating how I might use these amps. I'm currently selling off some older equipment to raise some funds before I jump. I'm really curious to hear how these compare to my modded PS Audio GCC-100.
:whip:
:lol:
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No. I think the other DC outputs are lower voltage. You can power both amps from one power board.
I'm pretty sure this is the transformer. http://www.antekinc.com/details.php?p=86
I'm not at home so I can't look but almost certain. If you look at the side of the tranny you'll see a part #. Just make sure it matches this one. If so, they are differenet voltages.
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I finally completed the assembly of my first mono bloc--the box for the second one is ready to be filled. I'm using these to power my 4 ohm Magnepan MG12s, and although this amp is running a bit warmer than it did when it was sitting out in the open, I think it will do fine with the current array of vent holes (the floor separating the two boards is vented as well as the top and bottom lids). If I ever upgrade to a Super D, I'll use these same boxes but put the output boards in side-ways.
Bob
(http://www.audiocircle.com/image.php?id=29065)
(http://www.audiocircle.com/image.php?id=29066)
(http://www.audiocircle.com/image.php?id=29067)
(http://www.audiocircle.com/image.php?id=29068)
(http://www.audiocircle.com/image.php?id=29069)
(http://www.audiocircle.com/image.php?id=29070)
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Very nice!
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Yes, since I can get another amp board fairly reasonable. The single transformer supplys power to the power supply board and I guess that is why there are two sets of DC voltage outputs, right?
No. I think the other DC outputs are lower voltage. You can power both amps from one power board.
I thought jtsnead was referring to the two sets of DC output connections on the power supply board. (Obviously the other set of wires on the transformer are AC connections). I thought the terminal strip had two pairs of common screw connections provided for the convenience of connecting two amplifier boards?
Steve
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I thought jtsnead was referring to the two sets of DC output connections on the power supply board. (Obviously the other set of wires on the transformer are AC connections). I thought the terminal strip had two pairs of common screw connections provided for the convenience of connecting two amp boards?
Steve
I think you're right on the power board.
The other wires from the tranny are not AC though. They're DC output. See the above spec sheet that I linked to.
BTW-did you see the picture that you liked? I rotated it 90* just for you.
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The other wires from the tranny are not AC though. They're DC output. See the above spec sheet that I linked to.
With a simple transformer with an AC input to the primary windings, how do you get a DC output from a secondary winding without a rectifier circuit? ;) I think you mean they're just lower voltage AC.
BTW-did you see the picture that you liked? I rotated it 90* just for you.
Yes! That would be the one on the right side, and rotated 90 degrees the other way for the left side. Now I have to find some sources for one-off (actually two-off) 2' X 4' color printing on cloth/canvas.
Steve
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With a simple transformer with an AC input to the primary windings, how how do you get a DC output from the secondary windings without a rectifier circuit?
Yes! That would be the one on the right side, and rotated 90 degrees the other way for the left side. Now I have to find some sources for one-off (actually two-off) 2' X 4' color printing on cloth/canvas.
Steve
You don't! :oops:
I thought maybe a GIK acoustic panel is what you were thinking. They now do custom printing on the panels. http://www.gikacoustics.com/gik_artpanel.html
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I finally completed the assembly of my first mono bloc--the box for the second one is ready to be filled. I'm using these to power my 4 ohm Magnepan MG12s, and although this amp is running a bit warmer than it did when it was sitting out in the open, I think it will do fine with the current array of vent holes (the floor separating the two boards is vented as well as the top and bottom lids). If I ever upgrade to a Super D, I'll use these same boxes but put the output boards in side-ways.
Bob
Beautiful craftsmanship, Bob. So the boards mount back to back? The faceplate is clean yet interesting in the two tone metal. Switching very straight forward like ARC. The interiors are so pretty with the copper paint, they remind me of chinese lacquer work. I'd be tempted to put clear plex tops on them. :eyebrows:
steve
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Very nice!
+1 :thumb:
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+1 :thumb:
+2 :D. Nice design and execution, love the faceplate.
Best,
Ed
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Bob (6NS7),
Nice work on the enclosure. This is, of course, your artistic vision, but I wanted to throw in a comment from a second pair of eyes on one detail.
When I look at the copper subpanel with cool toggle switches, LEDs and engraved legends, i am thinking electronics. When I look at the aluminum main panel with machined details, I am thinking electronics.
But (and I can't help myself) when I look at the chrome acorn nuts with the copper washers that mount the panel, I am thinking plumbing fixture!
Again, nice unique work!
Steve
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But (and I can't help myself) when I look at the chrome acorn nuts with the copper washers that mount the panel, I am thinking plumbing fixture!
Steve
I think the way he mounted the faceplate gives it a cool utilitarian look, I like it!
Best,
Ed
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Thanks for the good comments, guys. As far as evoking thoughts of plumbing fixtures or things "electronic", I guess I can see that. Originally I thought I would take a retro/industrial approach, with something that looked like it came out of a Matrix movie, but eventually the design evolved to this. I might also call it the Ace Hardware/Lowe's look. Whatever the case (so to speak), I wanted goobers on the front instead of a plain vanilla look.
Bob
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Bob,
How did you do the engraved legends on the subpanel?
Steve
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Bob, very nice job and thanks for posting pics! :wink:
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Bob,
How did you do the engraved legends on the subpanel?
Steve
Steve,
The lettering was done with some metal stamps (punches?) I bought at Harbor Freight. I had to make a jig such that each letter lined up with the others, and some of the stamps had to be shimmed with masking tape for better alignment (what do you expect for $4.99?). The letters were done one at a time. I spent more time building the jig and making samples than I did actually doing the final stamping. I considered filling the letters with paint but gave that idea up in the interest of finishing the project.
Bob
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Steve,
The lettering was done with some metal stamps (punches?) I bought at Harbor Freight. I had to make a jig such that each letter lined up with the others, and some of the stamps had to be shimmed with masking tape for better alignment (what do you expect for $4.99?). The letters were done one at a time. I spent more time building the jig and making samples than I did actually doing the final stamping. I considered filling the letters with paint but gave that idea up in the interest of finishing the project.
Bob
At first I thought they might be individual punches, but the impressions were cleaner and more even than I expected, and they lined up too well. Now I understand how, with your construction of a jig (and use of shims!).
Some years ago, I used some number punches and didn't get quite as even results as you did. I was stamping into tough steel, and if that subpanel is indeed softer copper, that could explain how you were able to get superior results.
Nice job!
Steve
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My amp is done now. First amp I have built. Sounds great,however, you folks that have one already know that. :eyebrows:
(http://www.audiocircle.com/image.php?id=29101)
(http://www.audiocircle.com/image.php?id=29102)
(http://www.audiocircle.com/image.php?id=29103)
(http://www.audiocircle.com/image.php?id=29104)
(http://www.audiocircle.com/image.php?id=29105)
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Robert, yours turned out very nice, too I really like it.
The sheet metal lining looks good. Thanks for posting the pics for us to see. Glad to hear it's sounding good, too.
Please come back with some additional impressions about how well it performs after you've had a chance to do some more critical listening. What speaker are you using with it?
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Very nice Robert! I really like your repurposed vents :thumb:. Very clever.
Best,
Ed
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My amp is done now. First amp I have built. Sounds great,however, you folks that have one already know that. :eyebrows:
Nice work, Robert. I really like the engine turned metal--a nice surprise for those looking inside.
Bob
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I finally completed the assembly of my first mono bloc--the box for the second one is ready to be filled. I'm using these to power my 4 ohm Magnepan MG12s, and although this amp is running a bit warmer than it did when it was sitting out in the open, I think it will do fine with the current array of vent holes (the floor separating the two boards is vented as well as the top and bottom lids). If I ever upgrade to a Super D, I'll use these same boxes but put the output boards in side-ways.
Bob
Absolutely stellar Bob. If you have a warm fuzzy feeling inside there's a good reason
after seeing your pics......................Bill
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Pumpkinman -
I just fired up your amp with the Maverick 1 DAC, see that thread for my future observations.
I must say, it all sounds very nice.
Gene
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I am interested in how the Mav D1 and the ClassD amps sound together.
Scott
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Beautiful work all around and thanks to everyone involved in the project. I am also interested in how the Mav D1 and Class D amps sound together.
I am a little confused as to how the output impedance of the Class D works with the Maverick and why.
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Keep on eye for this and other threads on Cheap and Cheerful.
Lots of good people with one goal in mind: great fidelity on the budget.
In the future I (we) will compare Class D amp(original) with Maverick DAC/pre, Nelson Pass B1 buffer (finished) and Dodd Audio battery powered tube buffer kit (in the works).
Mariusz :thumb:
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Thanks Mariusz. I look forward to it.
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For those using a separate switch and fuse, how exactly do you wire it together? I have jtwrace's case and I cannot tell how to connect this via the pics. Not sure how to do it via the Class D diagram, either. :oops:
Thanks!
Paul
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Switch first in line then followed by fuse..
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For those using a separate switch and fuse, how exactly do you wire it together? I have jtwrace's case and I cannot tell how to connect this via the pics. Not sure how to do it via the Class D diagram, either. :oops:
Thanks!
Paul
This diagram should help.
http://classdaudio.com/documents/transformer_115VAC_instructions.pdf
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Switch first in line then followed by fuse..
IEC > fuse > switch
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Should have been clearer in my question. I understand the order, I can't tell for sure how to hook up the power switch, as it has 3 terminals. Again, I'm referring to the set-up using jtwrace's case.
From what I'm seeing, it looks like the transformer's positive leads are going to the center terminal on the switch and then the positive terminal on the switch is connected to the fuse holder. Then, the IEC negative and the transformer's negative leads are all hooked up to the 3rd terminal on the switch. Is this correct?
Thanks again!
Paul
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Yes, the two red leads from the tranny go to the center of the switch.
see here http://www.audiocircle.com/index.php?action=gallery;area=browse;album=2778 take note of the white writing of on the switch as well.
No the IEC ground can go to the case. See the above gallery with the picture marked "tranny". The two black transformer wires go to the switch. There is no ground on the transformer.
Is this clear enough?
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Got it.
Meant to say IEC negative in my post above. :oops: (edited that one. . .)
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Got it.
Meant to say IEC negative in my post above. :oops: (edited that one. . .)
Black to the "N" on the IEC
Red to the "L"
Chassis ground is the middle which is ground.
:dance:
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Hi..
i'm in Italy..and i'm waiting for my enclosure from HiFi2000 here in Italy
(http://www.modu.it/frontale_nero.jpg)
But..in the meanwhile.. :thumb: :thumb: :thumb:
(http://i41.tinypic.com/2d0nuza.jpg)
Cheers
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I hope it doea not sound BOXY :lol:
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UPS version.... aaahhhaaa!!!
PS
it must be the worst day for Italy's industrial design inner circles. :lol:
Mariusz :thumb:
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"Think inside the BOX"
:thumb:
"sound BOXY" "UPS version"
:rotflmao: :rotflmao: :rotflmao:
Ok I hope I can go back to sleep.
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This is one for "the gallery".
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Ehy..is my "MusicalBox".. :P :oops:
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What is the size of the hole for mouting the 300VA transformer?
Thanks!
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What is the size of the hole for mouting the 300VA transformer?
Thanks!
The 400VA transformer requires a .313" hole.
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Well, there is no doubt that the Class D amp is a quality piece of gear. The amp is very dynamic, revealing of inner detail, and reasonably well balanced from top to bottom. There was a lot to recommend it and, of course, it has power to spare. It could easily rock my Horn Shoppe Model 1's without breaking a sweat; the Horns do reward lots of clean power when played at loudish volumes.
Interestingly enough there were a lot of similarities in the sound between the Miniwatt amp and the Class D and the differences were not of kind. The differences were subtle. I thought the Miniwatt was more nuanced, with more layers to the sound stage as well as a deeper soundstage, and it might have grabbed the bottom end a bit better than the Class D. The Class D may have been slightly more transparent and dynamic. The Miniwatt had better presence. All this said, I prefer the Miniwatt.
The Class D probably had about 100 hours on it and might have needed some more hours, whether for break-in or for me to get used to it. It is a really impressive performer and it would not surprise me if other people would prefer the Class D over the Miniwatt -- depending on personal preference and system synergy.
A fun experience. If anyone is interested in taking this Class D amp off my hands send me a PM. There are pictures of it on page 55 of this thread, and some build details on page 56.
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Well, there is no doubt that the Class D amp is a quality piece of gear. The amp is very dynamic, revealing of inner detail, and reasonably well balanced from top to bottom. There was a lot to recommend it and, of course, it has power to spare. It could easily rock my Horn Shoppe Model 1's without breaking a sweat; the Horns do reward lots of clean power when played at loudish volumes.
Interestingly enough there were a lot of similarities in the sound between the Miniwatt amp and the Class D and the differences were not of kind. The differences were subtle. I thought the Miniwatt was more nuanced, with more layers to the sound stage as well as a deeper soundstage, and it might have grabbed the bottom end a bit better than the Class D. The Class D may have been slightly more transparent and dynamic. The Miniwatt had better presence. All this said, I prefer the Miniwatt.
The Class D probably had about 100 hours on it and might have needed some more hours, whether for break-in or for me to get used to it. It is a really impressive performer and it would not surprise me if other people would prefer the Class D over the Miniwatt -- depending on personal preference and system synergy.
A fun experience. If anyone is interested in taking this Class D amp off my hands send me a PM. There are pictures of it on page 55 of this thread, and some build details on page 56.
Now you should try the Super D amp...
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Well, there is no doubt that the Class D amp is a quality piece of gear. The amp is very dynamic, revealing of inner detail, and reasonably well balanced from top to bottom. There was a lot to recommend it and, of course, it has power to spare. It could easily rock my Horn Shoppe Model 1's without breaking a sweat; the Horns do reward lots of clean power when played at loudish volumes.
Interestingly enough there were a lot of similarities in the sound between the Miniwatt amp and the Class D and the differences were not of kind. The differences were subtle. I thought the Miniwatt was more nuanced, with more layers to the sound stage as well as a deeper soundstage, and it might have grabbed the bottom end a bit better than the Class D. The Class D may have been slightly more transparent and dynamic. The Miniwatt had better presence. All this said, I prefer the Miniwatt.
The Class D probably had about 100 hours on it and might have needed some more hours, whether for break-in or for me to get used to it. It is a really impressive performer and it would not surprise me if other people would prefer the Class D over the Miniwatt -- depending on personal preference and system synergy.
A fun experience. If anyone is interested in taking this Class D amp off my hands send me a PM. There are pictures of it on page 55 of this thread, and some build details on page 56.
If you had the larger power supply I think your preference might be different. And then the Super does take it up another level.
Again your amp is gorgeous! :thumb:
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If you had the larger power supply I think your preference might be different. And then the Super does take it up another level.
Again your amp is gorgeous! :thumb:
Thanks...it is a nice build. Maybe i'll get to hear the newer, more powerful, version some day soon. I'd like to hear how the amp sounds with a tube pre in front of it as well.
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Thanks...it is a nice build. Maybe i'll get to hear the newer, more powerful, version some day soon. I'd like to hear how the amp sounds with a tube pre in front of it as well.
Get Dodd Audio buffer kit. :wink:
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Pardales,
I have never heard either amp but I wonder if you had a pre-amp rather than the added volume pot your results may have been different. And I think a tube pre-amp would have made even more of a difference.
Just a thought that came to mind.
Scott
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Pardales,
I have never heard either amp but I wonder if you had a pre-amp rather than the added volume pot your results may have been different. And I think a tube pre-amp would have made even more of a difference.
Just a thought that came to mind.
Scott
I wondered the same things, Scott. It is not hard for me to understand people liking this amp. It really sounded good. Either of the things you mentioned could have made a difference. I have tried various non-tube designs over the years and always seem to come back to tubes though. This amp sounded more like tubes than many other designs I've heard. Mine is for sale by the way, if anyone is interested (PM me).
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OK, here is 1 of 2 of my amps near completion, using jtwrace's cases. I only say near because I plan on replacing some of the wire. I am going to be replacing this wire because I will have 2 of these amps and I want to use the identical wire for both. I discovered I wouldn't have enough, so I have some more of the solid core copper wire on order. I am also a little concerned the output wire may be a bit too small of a gauge (18) to handle the power??? :dunno:
(http://www.audiocircle.com/image.php?id=29214)
(http://www.audiocircle.com/image.php?id=29215)
(http://www.audiocircle.com/image.php?id=29216)
(http://www.audiocircle.com/image.php?id=29217)
I have no clue on any real world difference it would make, but I kept the input and output wires the same length on both channels. If it doesn't make a difference, it'll end up being a cleaner layout. I know it would be a small difference in capacitance and resistance. Would different lengths on both the inputs and outputs be of concern at all?
I plan on replacing the blue output wire (silver plated copper) with the same solid core copper wire used for the power. That wire just fits into the outputs on the board. I had Tom send the amp to me without the input and output jacks.
Will also use the same wire to replace the gray covered 2 conductor cord going from the fuse to the IEC.
Let me know what you think. Should have this amp up and running in a couple days. It basically is good to go now, but I don't want to move everything to hook it up twice.
Will take pics of the final version later this week.
Paul
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Good job, Paul... looks nice. Thanks for posting the pics.
What's the orange wire for on top of the tranny?
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Thanks. I'll clean up the wiring a bit more, too.
Low voltage output(s). At least one is. Not sure if they both are. Just have to separately heatshrink all 4 wires, to prevent a short.
Paul
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Looking good Paul! I thought this day would never come. :wink:
steve
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So, would different lengths of wire for each channel be of any concern?
Ummm. . .thanks, Steve! :lol:
Paul
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I wouldn't sweat it.
steve
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Guys,
Do you guys have a link to the manual for the Super D amplifiers? I am sure they are very similar to the regular class D audio models. The wiring looks super easy since all the work on the boards is done for you.
Thanks,
Anand.
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Tom says they'll be out by the weekend.
steve
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Interesting thread :)
Anybody who has built one of these care to comment on any interference with their AM/FM tuner? I'm considering building one of these but I'm concerned about RFI.
Thanks!
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Interesting thread :)
Anybody who has built one of these care to comment on any interference with their AM/FM tuner? I'm considering building one of these but I'm concerned about RFI.
Thanks!
The amps operate at very high frequency (~400 MHz I think) so this is not likely to be a problem. Mine are in an aluminum case and do not interfere with FM radio at all. I don't listen to AM so I can't comment about that.
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Interesting thread :)
Anybody who has built one of these care to comment on any interference with their AM/FM tuner? I'm considering building one of these but I'm concerned about RFI.
Thanks!
None for me.
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Regarding using the amps in bridged mode, the instructions say to "connect the speaker to the right and left channel + and + speaker outputs only." With that, will it not matter which way I hook up the speaker, regarding phase issues (meaning, is there no longer a positive and negative side? If there still is, which is which?) I'm a bit confused with this one. :scratch:
Thanks.
Paul
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How would you go about installing a headphone jack? I guess I would need to add a switch to change from speaker output to headphone output so speakes are not active when using headphones. Been thinking about getting a good set of "cans" to play with and thought why not use my awesome DIY amp to power them.
Robert
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How would you go about installing a headphone jack? I guess I would need to add a switch to change from speaker output to headphone output so speakes are not active when using headphones. Been thinking about getting a good set of "cans" to play with and thought why not use my awesome DIY amp to power them.
I think you would need to switch between the amplifier output and a completely separate low-power amplifier circuit for the headphones.
The average headphone will require power in milliwats, not watts, and there would be no way to easily, effectively or efficiently attenuate the large power ouput, provide impedance matching, and provide a usable volume control range.
Steve
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Regarding using the amps in bridged mode, the instructions say to "connect the speaker to the right and left channel + and + speaker outputs only." With that, will it not matter which way I hook up the speaker, regarding phase issues (meaning, is there no longer a positive and negative side? If there still is, which is which?) I'm a bit confused with this one.
Thanks.
Paul
Paul,
Hook your red (+) lead to the Right Speaker + and your negative lead (-) to the Left Speaker + lead.
steve
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Paul,
Hook your red (+) lead to the Right Speaker + and your negative lead (-) to the Left Speaker + lead.
steve
Steve,
If I'm reading Paul correctly, it sounds like he has the wiring configuration down. I think he's asking how phase is affected in bridged mode, which is a question I have too.
Brett
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What I'm saying is there still is a + and - side. Right side + is + and left + is negative.
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What I'm saying is there still is a + and - side. Right side + is + and left + is negative.
Good info...thanks.
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Other than Steve's very first post, which mentions La Scalas, I haven't found anything about using this kit with high-efficiency speakers, with the supposed imperative that those first few watts be great--not that I've read every post, though I'm working on it. I currently use a moderately tweaked Sure TK2050 Tripath board, Klipsch Heresy's, and mostly listen to vinyl. I like the Sure amp in my system, but this kit might be better for my needs.
Any opinions/suggestions regarding the low-power sound of the Class D Audio amps for horn speaker aficionados? I'm especially curious to hear from those who've been able to compare an amp from Class D Audio to 2A3's and other tube classics or even well-regarded solid state/Class D stuff.
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Any opinions/suggestions regarding the low-power sound of the Class D Audio amps for horn speaker aficionados? I'm especially curious to hear from those who've been able to compare an amp from Class D Audio to 2A3's and other tube classics or even well-regarded solid state/Class D stuff.
I suggest you contact Blair from his website at Niteshade Audio.
http://sites.google.com/site/niteshadeaudio/ or check out his circle here on AC.
He uses Klipsch speakers and designs some very nice tube gear and has built/sells the ClassD amp as well. I know of no better person to answer your questions.
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Thanks, Steve.
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Hi All,
I ordered and have setup one of the new Super D Class D amps.
All arrived in excellent condition but no manual was included.
Does anyone with a Super D also have a manual with the hookup instructions?
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Grounding Question
How did people do grounding with this amp? Did you connect the power ground to anywhere of the amp board or power board? I did not realize grounding is important until building the Pass B1 preamp and was wondering how people do it.
On the power and amp board, I wasn't sure where I should connect the power gound to. Or simply connect the power ground to the metal chassis and have boards sit on it.
Thx!
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I asked Tom that awhile back. He said the amps really don't need to be grounded but if you still want to, he suggested grounding to one of the screws that mounts the heat sink to the board.
steve
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Hi All,
I ordered and have setup one of the new Super D Class D amps.
All arrived in excellent condition but no manual was included.
Does anyone with a Super D also have a manual with the hookup instructions?
I'd suggest emailing Tom about it. He told me he would have the Super D manuals on his website this weekend so maybe he has a file he can send you that's just not posted on his website yet.
steve
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I just checked there are four screws on the up-facing side of the board mounts the heat sink and there are two screws on the down-facing side of the board. Would any of these work?
I asked Tom that awhile back. He said the amps really don't need to be grounded but if you still want to, he suggested grounding to one of the screws that mounts the heat sink to the board.
steve
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The ones on the down facing side might be better. I'd use a crimp connector with a loop on it and put the screw through it.
steve
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Good idea. Thanks!
The ones on the down facing side might be better. I'd use a crimp connector with a loop on it and put the screw through it.
steve
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Steve, isn't your amp mounted in an all wood cab? I was also planning to build a wooden enclosure with no place to ground.
If it works ok laid out on a bread board, it should be fine in a wooded box. Right? :?
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Mine work fine in wooden boxes. I don't have a tuner or TV to worry about interference. Mine are dead quiet with your ear to the speaker.
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Mine work fine in wooden boxes. I don't have a tuner or TV to worry about interference. Mine are dead quiet with your ear to the speaker.
My experience was that it worked fine in a wood/MDF box. I did not notice any noise at listening distance. Until recently, b/c there is a big hum after connecting the unshielded Pass B1, I did a comparison of the "noise" level between HK 635 and Class D, and I found HK 635 is a bit "quieter" than Class D (When my ears are against the speakers). It's subtle. But again, some people have been fine with Pass B1 without metal enclosure. So it could be my environment issue. But now I'd like to do it the right way - using metal sheet to shield it and ground it through through the ground wire from the power switch module.
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Ok I was wondering if anyone is using the amps bridged?
I have the SDS-254, always wondered if amps sound any
worse when they are bridged?
It would be easy to add another amp to my case.
Would only cost coupl hundred.
The power goes form 120w to 500w, I do not need that
much power but when I did have a higher powered Wyred
4 Sound it did offer better headroom. I do not want to add
any more hardness etc.
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6SN7 is running two amps in bridged mode as monoblocks. You might PM him.
steve
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6SN7 is running two amps in bridged mode as monoblocks. You might PM him.
steve
Maybe he'll post here.
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thanks guys, I will ask 6sn7
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My ears are ringing--someone must be talking about me.
I'm running two CDA-224 amps, bridged, as mono blocs. I've done this to allow me the flexibility of either placing them directly behind my speakers or side-by-side inside my cabinet. I posted pictures of one of the amps a couple of weeks back, and as of yesterday, the enclosure for the second amp is now complete.
My enclosures are wood and ungrounded, but since the amps are currently sitting behind my speakers, I don't know if they would interfere with my other components or not. In their present positions, all they do is pump out music--no noise whatsoever.
And now that the amps are enclosed (rather tightly, I might add) and have been running for many hours, I can confirm that even though they are feeding my 4 ohm rated Magnepans, they run at a very comfortable temperature--warm, but not hot.
I can't say how these amps compare sonically, between running in stereo and mono mode, as I've had them hooked up only as mono blocs, but I can say I'm still happy I replaced my tube mono blocs with these. As I've mentioned previously, the only down side to what I'm hearing with Tom's amps is a lessening of depth to the sound stage compared to my tubes. Other than that, I love what I hear.
That's my experience in a nut shell.
Bob
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Thanks Bob,
I am going to order the other amp board and give it a try
what the heck, pretty cheap and cheerful
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The first experiment will be with 30k per rail (two pair of 15k, 60k total on board) and to use the third position for bypass and snubber parts. If that works well enough I'll clone it for the other amps, box 'em up and move on to serious listening. Apart from input coupling and power supply I haven't identified anything else that I want to change . . . yet . . . :icon_twisted: . . .
any news?
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Finally got my first amp up and running. I changed the layout and wiring a bit. As you can see with the extra stand-offs, this case is ready to take another amp to run 2 boards, with very minor wiring changes. I may throw another one in there and run 2 bridged amps.
Again, a big thanks to jtwrace (http://www.audiocircle.com/index.php?action=profile;u=41254) for his great cases! :thumb: If you're interested, you can get them here: http://www.audiocircle.com/index.php?topic=79902.msg772255#msg772255 (http://www.audiocircle.com/index.php?topic=79902.msg772255#msg772255)
Here are a some pics, along with the ICs I made for them. For more pics, click here (http://www.audiocircle.com/index.php?action=gallery;area=browse;album=3312).
(http://www.audiocircle.com/image.php?id=29646)
(http://www.audiocircle.com/image.php?id=29649)
(http://www.audiocircle.com/image.php?id=29655)
(http://www.audiocircle.com/image.php?id=29656)
(http://www.audiocircle.com/image.php?id=29657)
Paul
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Finally got my first amp up and running. I changed the layout and wiring a bit. As you can see with the extra stand-offs, this case is ready to take another amp to run 2 boards, with very minor wiring changes. I may throw another one in there and run 2 bridged amps.
Again, a big thanks to jtwrace (http://www.audiocircle.com/index.php?action=profile;u=41254) for his great cases! :thumb:
Here are a some pics, along with the ICs I made for them. For more pics, click here (http://www.audiocircle.com/index.php?action=gallery;area=browse;album=3312).
Paul
Paul
Looks great!
What do you think of the sound?
Thanks again. :thumb:
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Haven't had a chance to listen to it yet. Just got it together late last night.
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Well, armed with a little to much free time and an idle soldering iron I went to work on my power supply. After doing some research and following in the steps of Wushuliu I upgraded to 40,000uf with the Panasonic TS-HA series caps (4x10,000uf). These caps seem to be highly regarded as a best bang for the buck when building a power supply for chip amps or class d.
I wasnt to sure I would get the same results that Wushuliu got because I started with the larger power supply.
First I removed the Nichicons slowly heating each post and rocking back and forth until able to remove cap.
(http://i59.photobucket.com/albums/g295/mrnick_2006/Picture802.jpg)
Then I used solder wick to clean the holes for the new caps to fit in.
(http://i59.photobucket.com/albums/g295/mrnick_2006/Picture803.jpg)
I soldered in the four new caps and rewired supply, I have 2 open slots to hit 60,000uf if I decide to max it out.
(http://i59.photobucket.com/albums/g295/mrnick_2006/Picture805.jpg)
Fortunately my results completely mirror Wushului's comments on the upgrade. Probably a little more subtle than his but I have a more dynamic sound with improved lower and mid bass. Seem to be getting a little overall increase in seperation and imageing. Very pleased with results, of couse this is all system specific. My speakers are quite revealing so the upgrade was obvious on my behalf, your results may vary. SuperD @ 125wpc.
Of course you shouldnt consider doing this without proper supervision. :nono:
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any news?
No problems with 60k (total) on each supply board with 25A rectifiers. The lights dim at switchon :lol:, but maybe not bad enough to add soft-start. I've decided to put a third amp board in the box rather than keep using my 3886 tweeter amps . . . it's raising some "issues", but hopefully nothing that careful shielding and maybe down tuning the switching frequency on the woofer channels won't cure. One thing for sure . . . when I switch my center channel and subs over to Class D it will be in a bigger box . . . things are a bit crowded with three amp boards and two power supply boards (and the transformer) all in (what was once) an Adcom 535 box . . . .
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Hey Nick,
Where did you get the caps, why did you only replace
4 of them, could you do 6?
How about the resistors on the board, are they worth
messing with.
I am getting ready to order another board to run bridged
SDS254's
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Hey Nick,
Where did you get the caps, why did you only replace
4 of them, could you do 6?
How about the resistors on the board, are they worth
messing with.
I am getting ready to order another board to run bridged
SDS254's
I was under the impression 40,000uf was more than ample and didnt want to just waste capasitance. I may try adding a couple more lower value.
I dont know anything about the resistors but have heard a larger bridge rectifier is reccomended. Anyone know a source for a fast recovery ixys bridge?
I got the caps from diycable cause digikey was out of stock, they have them now.
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I was under the impression 40,000uf was more than ample and didnt want to just waste capacitance. I may try adding a couple more lower value.
I dont know anything about the resistors but have heard a larger bridge rectifier is reccomended. Anyone know a source for a fast recovery ixys bridge?
Blair, (Niteshade) has a unique power supply that may interest you. Give him a shout out. :thumb:
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There's a pic of Blair's Class D power supply mod in his gallery.
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I will look it up, wonder if he sells it seperatley
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I found this one but dont know if its drop in or not? Anyone know for sure?
I sent them an email, if I am going to replace I want something better than stock.
http://www.partsconnexion.com/product4793.html
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I found this one but dont know if its drop in or not? Anyone know for sure?
I sent them an email, if I am going to replace I want something better than stock.
http://www.partsconnexion.com/product4793.html
I remember reading that the Paul Hynes is the "best".
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I remember reading that the Paul Hynes is the "best".
Whenever I need to use a well designed regulator for a critical audio application (i.e. not a filament supply) , be it for solid state or tube, I only use Paul Hynes.
Anand.
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Im looking for a drop in replacemnet bridge rectifier not an entire power supply. Wouldnd Paul just be for the whole supply?
edit: I was under the impression most perfer the IXYS products.
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Im looking for a drop in replacemnet bridge rectifier not an entire power supply. Wouldnd Paul just be for the whole supply?
Nope. He has them..
http://www.paulhynesdesign.com/page6.html
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Nope. He has them..
I think he is looking for a bridge rectifier, not a regulator.
Steve
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I think he is looking for a bridge rectifier, not a regulator.
Steve
:cry: I'd ask him then.
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Wanted to follow up with my experiment. So I finished my Pass Buffer in a Hammond metal box. I connected the buffer to Class D amp - to my surprise - it's now "dead silent". When I used HK 635 as preamp, I can hear small hum when I press my ears against speakers. Now it's gone.
Before, I didn't ground the Pass Buffer and the hum noise was horrible. Now inside a metal box - wow - the combination is awesome! Never though a preamp would make such a difference. ;)
My experience was that it worked fine in a wood/MDF box. I did not notice any noise at listening distance. Until recently, b/c there is a big hum after connecting the unshielded Pass B1, I did a comparison of the "noise" level between HK 635 and Class D, and I found HK 635 is a bit "quieter" than Class D (When my ears are against the speakers). It's subtle. But again, some people have been fine with Pass B1 without metal enclosure. So it could be my environment issue. But now I'd like to do it the right way - using metal sheet to shield it and ground it through through the ground wire from the power switch module.
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thats good you figured it out!
I would really like to try when of those buffers, this one or the Dodd
battery one. I f anyone near MD wouldlet me try one send me a PM
I have alot of gain in my system so I turned down the gain on the
SDS254 amp to allow for greater volume control range
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One long thread!
Anyone built the CDA-254S for use as a monoblock for subs?
Assuming I need also to purchase:
PC, PC receptacle with fuse, RCA inputs, speaker outputs, and any case I want to use.
Missed anything?
Hinging on building this for sub use, or just biting the bullet and buying a BASH 300 to replace the one that died.
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Okay, how about this. Could you use the 12v switching power supply from Classdaudio to make a battery powered amp for home use? Sort of like the Dodd products. How many amp hours would battery need? How would power supply compare to the large power supply with the kits? Would a battery power kit appeal to you? I plan to build the Dodd DIY tube buffer that is battery powered so why not see if the “D” can be made that way also. I would not want a big honkin’ truck battery setting in my system rack, however, if you built a custom battery enclosure……….mmmm must think
Robert
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Anyone built the CDA-254S for use as a monoblock for subs?
Assuming I need also to purchase:
PC, PC receptacle with fuse, RCA inputs, speaker outputs, and any case I want to use.
Missed anything?
I am using a pair of these amps for my subs. I didn't need the extra power, so I'm just using one amp in stereo mode for now, actually. I am thinking of adding another sub or two in the future. Bridged mode would also work fine. They are quiet, have lots of power and make great sub amps. You will also need an 8A fuse, switch, and wire.
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Are these Class D amps good enough for you to use as your main amplifier in your system?
I know lots of guys have enjoyed building them and trying them out. I'm just wondering how many are currently using them as their main amp? :thumb:
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The OP sold off his $3500 monoblock tube amps in place of the ClassD and also favorable compared them to some very pricey Ice amps.
I think people using these amps for sub use is the exception not the rule.
Drive to Austin and demo the Super. :eyebrows:
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Are these Class D amps good enough for you to use as your main amplifier in your system?
I know lots of guys have enjoyed building them and trying them out. I'm just wondering how many are currently using them as their main amp? :thumb:
I'm guessing you skipped, oh, the first 67 pages... :wink:
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I'm guessing you skipped, oh, the first 67 pages... :wink:
... ok, you got me! On that note, maybe I should withdraw my question before I get run out of here. :o
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... ok, you got me! On that note, maybe I should withdraw my question before I get run out of here. :o
:nono: You're welcome here! :thumb:
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Well, I sold enough old stuff in the AKFest swap room last weekend that I can now try out one of these amp kits. Looking at the SDS-224 but wondering what the extra $100 over the CDA-224 gets you besides balance inputs and adjustable gain. In other words, sound quality... is it better? I don't think I've seen much comparison in this regard on this thread (perhaps I missed it).
From classdaudio:
"Our Super D Series amps provide more life-like imaging and sound stage, along with the beautiful smooth tube-like sound we're known for. These amps are powerful, clean, quiet , and transparent"
Additionally, do you have to use the balanced inputs to achieve that improvement? That may not be an option for me in the near future, so no sense spending an extra 100 if I don't have to.
Thanks.
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Well, I sold enough old stuff in the AKFest swap room last weekend that I can now try out one of these amp kits. Looking at the SDS-224 but wondering what the extra $100 over the CDA-224 gets you besides balance inputs and adjustable gain. In other words, sound quality... is it better? I don't think I've seen much comparison in this regard on this thread (perhaps I missed it).
From classdaudio:
"Our Super D Series amps provide more life-like imaging and sound stage, along with the beautiful smooth tube-like sound we're known for. These amps are powerful, clean, quiet , and transparent"
Additionally, do you have to use the balanced inputs to achieve that improvement? That may not be an option for me in the near future, so no sense spending an extra 100 if I don't have to.
Thanks.
The beauty of the InGenus balanced input reciever is that the single ended user benifits from the technology also. Myself and a few others are using single ended inputs on the Super with great success. It is very transparent and worth the extra dough. :eyebrows:
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Help educate me please as I upgrade my system. I recently built a pair of GR Research transmission-line N3 speakers and they sound awesome, even though they are driven with my inexpensive Yamaha 5250 AV receiver. Enter Cheap and Cheerful 120W ClassD amp...Is it critical these amps are used with a preamp/buffer or can my source (Ipod, Cd player) feed them directly? The Dodd DIY buffer is on my wish list of upgrades, but it will need to patiently wait.
Pete
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Is it critical these amps are used with a preamp/buffer or can my source (Ipod, Cd player) feed them directly? The Dodd DIY buffer is on my wish list of upgrades, but it will need to patiently wait.
Pete
No sir. You can easily use your ipod / Cdp until you save up for the fantastic Dodd Buffer. You'll have no problems at all I don't think.
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Is it critical these amps are used with a preamp/buffer or can my source (Ipod, Cd player) feed them directly? The Dodd DIY buffer is on my wish list of upgrades, but it will need to patiently wait.
To connect your sources directly, your CD player would need to have its own internal volume control and the iPod would have to control the volume through its headphone output jack.
Your iPod will much sound better if you use its line out output available at the bottom dock connector, either with an iPod dock or an inexpensive dock to line out cable, than it will using the amplified headphone output.
Therefore I would recommend using your Yamaha AV receiver as a preamp (by connecting its Main L/R RCA preamp outputs to the Class D Audio amp), until you can afford a better preamp.
Steve
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Therefore I would recommend using your Yamaha AV receiver as a preamp (by connecting its Main L/R RCA preamp outputs to the Class D Audio amp), until you can afford a better preamp.
Steve
I agree, use the preamp section of your receiver or get a good passive volume control.
Blair Lamphear, a well respected AC sponsor, stated that this amp works great with a passive attenuator. The input impedance is 45K ohms which will work fine. I've also talked with Tom about this as well.
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Is it critical these amps are used with a preamp/buffer or can my source (Ipod, Cd player) feed them directly? The Dodd DIY buffer is on my wish list of upgrades, but it will need to patiently wait.
Pete
I ran my Havana DAC directly into my ClassD for a little over a month and it sounded very good, I used the MPD client software to control volume. I then added the Dodd Buffer and everything about the sound went up a number of notches! :thumb: You should be able to use your iPod directly into the amp for the time being (not sure of the output impedence of the iPod but my DAC is 800 ohms which is greater than recommended and it worked fine), when possible I heartliy recommend the Dodd Buffer, it is outstanding and works great with the ClassD.
Best,
Ed
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To connect your sources directly, your CD player would need to have its own internal volume control and the iPod would have to control the volume through its headphone output jack.
Your iPod will much sound better if you use its line out output available at the bottom dock connector, either with an iPod dock or an inexpensive dock to line out cable, than it will using the amplified headphone output.
Therefore I would recommend using your Yamaha AV receiver as a preamp (by connecting its Main L/R RCA preamp outputs to the Class D Audio amp), until you can afford a better preamp.
Steve
Thanks all for your answers. It looks like my plan going forward is to build the class D amp...my Yamaha receiver will be relegated to preamp status. I believe, as a preamp, this receiver could still facilitate its present job of 50/50 home theater and 2 channel listening. Then, when I build the Dodd buffer..?? I understand the Dodd buffer has no gain so possibly it could sit between the Yamaha and the class D.
Pete
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Thanks all for your answers. It looks like my plan going forward is to build the class D amp...my Yamaha receiver will be relegated to preamp status. I believe, as a preamp, this receiver could still facilitate its present job of 50/50 home theater and 2 channel listening. Then, when I build the Dodd buffer..?? I understand the Dodd buffer has no gain so possibly it could sit between the Yamaha and the class D.
Pete
If I have understood about these amps, the gain is set at about 32DB approximately 6DB higher than the "standard" amplifier gain. So you might either consider getting one of the Promitheus TVC with the latest generation of transformers, or just get the passive resistive type volume control. Of course, the other way to go is to ask Tom to put a toggle switch in there so you could just toggle from either the standard gain to max gain. It has two trimmers, and you would have to know for sure after turning each one if you have the channels matched successfully.
Ray
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....or just get a Super D amp and have adjustable gain. I use a Dodd Buffer and have no issues with any of the Class D amps. I have all three IR, TI & Super D.
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....or just get a Super D amp and have adjustable gain. I use a Dodd Buffer and have no issues with any of the Class D amps. I have all three IR, TI & Super D.
Hey Jason, do you have a favorite of the three? With or without the buffer?
Best,
Ed
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Hey Jason, do you have a favorite of the three? With or without the buffer?
Best,
Ed
In my opinion the IR and Super D are above the TI for full range speakers. I wouldn't hesitate to use the TI for a sub or for entertaining purposes. It's just a little harsh (top end) in my opinion.
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In my opinion the IR and Super D are above the TI for full range speakers. I wouldn't hesitate to use the TI for a sub or for entertaining purposes. It's just a little harsh (top end) in my opinion.
Cool, thanks! Looks like I picked the right one first try :wink:.
Best,
Ed
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In my opinion the IR and Super D are above the TI for full range speakers.
Jason, to your ears, is there a significant difference in the sound of the IR and Super D?
I ask this question as someone who won't be using the balanced inputs. I know this has been asked before, but I wanted your take on it. Thanks!
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Jason, to your ears, is there a significant difference in the sound of the IR and Super D?
I ask this question as someone who won't be using the balanced inputs. I know this has been asked before, but I wanted your take on it. Thanks!
Define significant.
In my terms of significant, no, in most audiophiles terms yes.
In my system using the Super D there is no change from using XLR or RCA. The adjustable gain is really nice though...
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Jason, all other things being equal, comparing the IR board to the Super D board, and using only the SET inputs, do you hear a significant difference?
I guess for me, significant means "enough difference to justify the additional expenditure." I know that both amp boards sound very good.
Thanks for the help. :thumb:
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In my system using the Super D there is no change from using XLR or RCA.
So does that mean that single ended inputs are equally as good as balanced, or that balanced inputs are no better than single ended?
Just trying to understand, not being picky or difficult. Let's try these options.
- too close to call, equally as good
- the difference is noticeable but not by much
- there's a significant difference
- no brainer
- other (your choice of words)
I appreciate your opinion, and for sharing your experience.
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So does that mean that single ended inputs are equally as good as balanced, or that balanced inputs are no better than single ended?
Just trying to understand, not being picky or difficult. Let's try these options.
- too close to call, equally as good
- the difference is noticeable but not by much
- there's a significant difference
- no brainer
- other (your choice of words)
I appreciate your opinion, and for sharing your experience.
Hi Roy,
Now that you have me slightly confused, lol, having the super D and the IR board side by side, if I were to walk in to the room, could I be able to pick out the Super D versus the IR board? Or is it just a matter of degrees here, like dusk to dark kinda thing. As far as balanced versus unbalanced goes, there would hardly be any real differences, so I would think, not enough to worry about.
Ray
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So does that mean that single ended inputs are equally as good as balanced, or that balanced inputs are no better than single ended?
Just trying to understand, not being picky or difficult. Let's try these options.
- too close to call, equally as good
- the difference is noticeable but not by much
- there's a significant difference
- no brainer
- other (your choice of words)
I appreciate your opinion, and for sharing your experience.
Since I've had both, I'll throw my 2 cents in here. I would vote for "the difference is noticeable but not by much". The biggest difference I noticed is the Super D seems to throw out a deep
er soundstage (at least in my system) whereas the ClassD tended to be flatter in depth (more on a plane between the speaker).
Steve
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So does that mean that single ended inputs are equally as good as balanced, or that balanced inputs are no better than single ended?
Just trying to understand, not being picky or difficult. Let's try these options.
- too close to call, equally as good
- the difference is noticeable but not by much
- there's a significant difference
- no brainer
- other (your choice of words)
I appreciate your opinion, and for sharing your experience.
Having owned both I also give the nod to the Super. I would have to say its between noticable and significant.
In my system the Super has much better control, a little better image and transparency.
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Thanks, guys... I really appreciate hearing from you since you all have both amp boards, IR and Super D.
Ray, sorry to be confusing. My wife says I'm that way most of the time. I found your observations helpful.
Steve, thanks for sharing your experience as well. I hear you saying that the Super D has depth of soundstage that the IR does not have. However, the width of soundstage should extend well beyond the speakers with either amp, right?
Keith, about the additional control, that could be difference between having an amp with 60 wpc and 125 wpc, especially driving those wonderful speakers you have.
In Tom's description of the Super D amp, the only difference between the two amps except the balanced input stage, different heat sink, molex connectors and adjustable gain is the following statement which supports what you all are saying...
"Our Super D Series amps provide more life-like imaging and sound stage."
Both are obviously very good performing amps. At the current prices, one can't go wrong either way, just depends on your needs. Thanks for all your input.
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Thanks, guys... I really appreciate hearing from you since you all have both amp boards, IR and Super D.
Ray, sorry to be confusing. My wife says I'm that way most of the time. I found your observations helpful.
Steve, thanks for sharing your experience as well. I hear you saying that the Super D has depth of soundstage that the IR does not have. However, the width of soundstage should extend well beyond the speakers with either amp, right?
Keith, about the additional control, that could be difference between having an amp with 60 wpc and 125 wpc, especially driving those wonderful speakers you have.
In Tom's description of the Super D amp, the only difference between the two amps except the balanced input stage, different heat sink, molex connectors and adjustable gain is the following statement which supports what you all are saying...
"Our Super D Series amps provide more life-like imaging and sound stage."
Both are obviously very good performing amps. At the current prices, one can't go wrong either way, just depends on your needs. Thanks for all your input.
Ok, here is what I'm hearing about these two amps, the "IR" and the "super D." The standard IR amp seems to lack depth of image. The "Super D" has that in spades, but also seems to be a bit more detailed. That is what I read from these pages. So for a full frequency response amp to use on my main system, I'd just be done with it and get the super D amp. You get the whole kit Minus case, RCA connectors, and switches fuse(s), and binding posts for $335, and depending on the casework involved, you could probably come out of this alive for about $450 to say $600. And it would do pretty well against what is out there on a commercial level. Now, there's the power supply which from what I read here from Keith, looks like that nees to be changed to somewheres between 40 MF to 60 MF for the value of the caps. Currently, it is about 28 MF. This is for both sides combined. I'd also upgrade to a higher current bridge rectifier. The reason for that is to handle the additional surge of the larger value caps. With those two mods, it would definitely be closer to the $600 range. Now, is this the last word in amplification you ask? Probably not, but you'd probably have to go a long way and spend much more bucks to get something a whole lot better. At least, that is what I am surmising from reading these pages.
Someone complained in previous pages back about hearing some subtle distortion. I suggest clean up that supply some more. Anyway, enough for the editorializing.
Ray Bronk
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I say unless it's money that can easily be parted or you need balanced, stick w/ the regular IR amps and use the cost difference on other upgrades. We spent 50 pages extolling the basic IR amps for a reason. Anyways, before long Tom will have Super Duper class d amps I'm sure or other improved product...
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I think if your looking for the absolute best bang for the buck, you nailed it. :thumb:
I only have about $400 into my Super with upgraded Panasonic caps in diy wood case. I am yet to swap out the bridge, i will report back on this one as it looks a little intimadating. The stock one isnt giving me any issues.
Edit: Dont forget Tom is giving 5% discount to AC.
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I say unless it's money that can easily be parted or you need balanced, stick w/ the regular IR amps and use the cost difference on other upgrades. We spent 50 pages extolling the basic IR amps for a reason. Anyways, before long Tom will have Super Duper class d amps I'm sure or other improved product...
Hi, Well, my summarization was given for those who were thinking about getting one of these amps. If the difference is fairly audible, especially if you are aware of imaging properties, then the SDS amp is for you. If you can't hear imaging, then get the less expensive CDA version. If Tom does indeed comes out with a super duper amp, well, lol, that's progress.
i'd probably get the SDS kit, and a case from Parmetal for about $80, and do all the metal drilling myself. I'll use some 16 gauge speaker wire for the power cord, get the 6A fuse? and the power switch I have as well as the fuse holder. I'll get some insolated binding posts for the speaker output. So just about $450 bucks, and I'm done. I can still use my TVC, or get the preamp from Aricaudio systems for about $400. Or I could get this other preamp that I see on Audiogon all the time for $330. That should work out fine.
How's that for cheap and cheerful? heheh
Ray
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I think if your looking for the absolute best bang for the buck, you nailed it. :thumb:
I only have about $400 into my Super with upgraded Panasonic caps in diy wood case. I am yet to swap out the bridge, i will report back on this one as it looks a little intimadating. The stock one isnt giving me any issues.
Hi, Well, if the bridge is holding up when you start/turn on the amp, then I'd leave it alone. It's just a thought. I'd probably fill out those other two positions with two more 10 UF and see what happens. Maybe nothing will. But then you know. Something is bound to be better with those caps. Maybe, slightly better imaging, a more relaxed presentation. Maybe a bit mor micro detail.
Ray
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If you can't hear imaging, then get the less expensive CDA version.
To be clear though, the imaging with the regular IR is great. It's not like it's lacking.
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well it all depends on the pre amp your using too. if you have a good tube pre or something like it the basic one will be great. if yur using the outs of yur surround receiver well the super might be the way to go i guess or im I wrong?
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So does that mean that single ended inputs are equally as good as balanced, or that balanced inputs are no better than single ended?
Just trying to understand, not being picky or difficult. Let's try these options.
- too close to call, equally as good
- the difference is noticeable but not by much
- there's a significant difference
- no brainer
- other (your choice of words)
I appreciate your opinion, and for sharing your experience.
In my system and my opinion I would say that option #2 would be best. I think rather then say the soundstage or imaging is so much better what sticks out to me is the micro detail. Again, all systems and ears are different. As for is it worth the extra money? That's only something that you can answer. If you can spend the extra money and it not effect you then yes. If not, go with the IR and I strongly believe that you'll be very happy. It's still a great amp. All three are still great amps. I think the proper selection of amp will depend on the sonic signature that you have now. That will dictate which way to sway.
Hope this makes sense.
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So are these amps still going to be featured in Affordable Audio?
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Hi guys,
I'm a newbie from India. I joined this forum some time ago but couldn't dedicate much time to go through various posts which I must admit are very very informative. BTW, I'm a member of www.hifivision.com, an India centric AV forum.
I had heard about Class D audio & have made a payment for IR based amp. However, Tom insists that I made payment for TI amp. Now I found a new dimension i.e. Super D amp. In addition there are SDS and CDA amps :?
I'm required to reply Tom immediately & may not have sufficient time to go through this thread immediately.
I understand that super D amp is the most expensive.
Can any of the audio experts advise me which one to go for if cost is not a limiting factor?
Which Amp costs eventually what i.e. including casing, transformer, power supply et al.
Sorry for bothering you but your advise will be a great help for me.
Regards
Rajesh
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Hi guys,
I'm a newbie from India. I joined this forum some time ago but couldn't dedicate much time to go through various posts which I must admit are very very informative. BTW, I'm a member of www.hifivision.com, an India centric AV forum.
I had heard about Class D audio & have made a payment for IR based amp. However, Tom insists that I made payment for TI amp. Now I found a new dimension i.e. Super D amp. In addition there are SDS and CDA amps :?
I'm required to reply Tom immediately & may not have sufficient time to go through this thread immediately.
I understand that super D amp is the most expensive.
Can any of the audio experts advise me which one to go for if cost is not a limiting factor?
Which Amp costs eventually what i.e. including casing, transformer, power supply et al.
Sorry for bothering you but your advise will be a great help for me.
Regards
Rajesh
Hi Rajesh,
Welcome to AC! There is a ton of great information in this thread but for what you are looking for simply review the last 2 pages. They cover a few members preferences with regard to the various amps available from Tom. Assuming they all have enough power for your application the last two pages should be able to give you an idea of what others hear in their systems. Of course how they work in your system is an unknown until you actually try one.
Best,
Ed
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Most of us have bought the kit from Tom that includes power supply and transformer. If money isnt an objection then the SuperD series is a great way to go. Depending on casing can run an extra $50-$250 for a finished product.
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Hi guys,
I'm a newbie from India. I joined this forum some time ago but couldn't dedicate much time to go through various posts which I must admit are very very informative. BTW, I'm a member of www.hifivision.com, an India centric AV forum.
I had heard about Class D audio & have made a payment for IR based amp. However, Tom insists that I made payment for TI amp. Now I found a new dimension i.e. Super D amp. In addition there are SDS and CDA amps :?
I'm required to reply Tom immediately & may not have sufficient time to go through this thread immediately.
I understand that super D amp is the most expensive.
Can any of the audio experts advise me which one to go for if cost is not a limiting factor?
Which Amp costs eventually what i.e. including casing, transformer, power supply et al.
Sorry for bothering you but your advise will be a great help for me.
Regards
Rajesh
Welcome Rajesh!
It might be easier to tell us what speakers you're going to drive. Also, what source(s) you may be using with what pre?
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Welcome Rajesh!
It might be easier to tell us what speakers you're going to drive. Also, what source(s) you may be using with what pre?
I agree 100% no one can really give you any good advise without more information. Do you know the impedance of your speakers and their efficiency?
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Hi everybody,
I'm really thrilled with the immediate voices of concerns & advices. So kind of you all.
I'm using the following equipment:-
Source: Marantz CD 6003 (Recently bought)
Amp: Denon PMA 520 (Very old may be a decade)
Speakers: DIY Full Rangers made using Kenwood drivers (Very Old)
The speakers have low sensitivity (85-86db or thereabouts)
So I'd say, I'm looking to change them too.
One of my friends Richie, who is much more experienced than me has suggested First Watt Bi Buffer Pre Amp (DIY) and GR Research N2X bookshelf speakers.
What is your take on the whole idea?
I can afford to buy the Super D kit.
Regards
Rajesh
I was looking to upgrade only my amp but considering all things, I'm in the process of thoroughly overhauling my system.
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If you're into DIY or have a friend who is able to help out in completion of these projects, I would say go for it.
GR speakers kit, Nelson Pass baffer or perhaps Dodd Audio tube, battery powered baffer.
You might also look into Single Driver/Horn designs as far as speakers are concern. These designs/drivers usually require much less power/headroom to sound their best.
Basicly, decision is yours and it depends on your application and budget.
Best
Mariusz
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Hi everybody,
I'm really thrilled with the immediate voices of concerns & advices. So kind of you all.
I'm using the following equipment:-
Source: Marantz CD 6003 (Recently bought)
Amp: Denon PMA 520 (Very old may be a decade)
Speakers: DIY Full Rangers made using Kenwood drivers (Very Old)
The speakers have low sensitivity (85-86db or thereabouts)
So I'd say, I'm looking to change them too.
One of my friends Richie, who is much more experienced than me has suggested First Watt Bi Buffer Pre Amp (DIY) and GR Research N2X bookshelf speakers.
What is your take on the whole idea?
I can afford to buy the Super D kit.
Regards
Rajesh
I was looking to upgrade only my amp but considering all things, I'm in the process of thoroughly overhauling my system.
I would say the Super D or the IR. If you can spend the extra money on the Super D go for it. I would really look into the Dodd Buffer
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First, welcome to Audio Circle... :thumb:
I agree that buying a kit is a good idea if that works for you.
Either the IR amp board or the Super D amp board would work well for you. Both are very good.
If you use speakers of low sensitivity, I'd recommend either the CDA-254 or the SDS-254. Either of these amp boards should give you sufficient output for those speakers.
This thread gets a little more active in the evening since lots of guys are working right now. Ask any questions you may have, and all the best. :wink:
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So does that mean that single ended inputs are equally as good as balanced, or that balanced inputs are no better than single ended?
Yes. When driven by a “single ended” output a “balanced input” has no inherent advantage. In the case of the CDA series amps, however, the implementation of the single ended input has some issues (corrected in the SDS series) that may have negative impact in some systems. If those issues do not apply to your system, or are correctable by you, then the addition of an input buffer, balanced or otherwise, will not provide any benefit. It all depends . . .
The CDA input impedance is quite low . . . typically 4000-5000 Ohms (depending on the built-in gain setting). Not all sources can drive that properly . . . so-called “passive pre-amps”, for example, cannot, producing interactions that can induce distortion and compromise frequency response. On the other hand if your source can handle the load it is not an issue.
The CDA amplifiers invert (at the output) the signal. This is generally not audible, and is easily corrected simply by reversing speaker leads, but in a bi-amped installation when used with other (non-inverting) amps it can, if not corrected for, cause significant dropouts in the frequency response (and may impact “imaging”, which almost always reflect a speaker/room problem, not an amplifier problem).
The CDA amps use a rather questionable input coupling capacitor. It is easily bypassed (and replaced), but some familiarity with circuit tracing and working with the (very small) smd used is necessary . . . it may not be a task for beginners.
The “stock” gain setting, especially of the higher power amps, is generally too high, resulting in amplification of noise from source devices. This also is easily fixed, but again requires some familiarity with working with smd components (one can also specify the gain desired when ordering the amp boards, or add a gain control).
The net result is that the CDA amps are great bargains for someone with a little familiarity with electronics who can properly match them to existing gear. What the SDS series brings to the table (for another $100) is an input buffer that resolves the above issues without the necessity of any board-level modifications by the end user. Input impedance is raised, polarity inversion is switchable, and a volume control is added. In systems where those things matter and have not been otherwise resolved by the builder the result may be “better” sound overall, and the greater ease of matching to a variety of “source” components may offer a worthwhile convenience.
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The CDA input impedance is quite low . . . typically 4000-5000 Ohms (depending on the built-in gain setting). Not all sources can drive that properly . . . so-called “passive pre-amps”, for example, cannot, producing interactions that can induce distortion and compromise frequency response. On the other hand if your source can handle the load it is not an issue.
Tom has assured me that the input impedance of their amps is 45k. I have the emails if anyone needs to see them. Just trying to help and limit any confusion.
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Tom has assured me that the input impedance of their amps is 45k. I have the emails if anyone needs to see them. Just trying to help and limit any confusion.
That is true of the new amps. It is not true of the "original" CDA amps . . .
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I'm sending a PM your way.
Previously, Blair Lamphear (Niteshade Audio), stated that the CDA-254 worked great with a passive attenuator and raved about the amp's performance. I don't believe that Blair would say that and market his own version of the amp using the CDA-254 amp board if it had so many issues.
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So are these amps still going to be featured in Affordable Audio?
The latest from Tom is it should be in the June issue.
steve
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I'm sending a PM your way.
Previously, Blair Lamphear (Niteshade Audio), stated that the CDA-254 worked great with a passive attenuator and raved about the amp's performance. I don't believe that Blair would say that and market his own version of the amp using the CDA-254 amp board if it had so many issues.
Deward is just emphasizing that *depending on your setup* you can potentially squeeze out more performance from the amp. He's obviously a big fan of these amps and is just presenting options, especially to those of us who like to wake up to the smell of solder in the mornin'. There's no question of them having great performance out of the box...
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The latest from Tom is it should be in the June issue.
steve
Awesome. Congrats to him.
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He's obviously a big fan of these amps and is just presenting options, especially to those of us who like to wake up to the smell of solder in the mornin'
Love it! Diy Rules! :eyebrows: :thumb: :thumb:
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Love it! Diy Rules! :eyebrows: :thumb: :thumb:
Have to be careful though. I just fried my classd amp this weekend :cry: Not quite sure what happened, but we had just finished moving to a new place and I started getting audio stuff set up. Probably something got jostled (actually I'm sure it's related to my first modding attempts back when I got the board in November which was sloppy *and* unncessary). I was too eager to get things going, was very tired, and I knew i should have given everything a once over and made sure the enclosure was ok, etc.
My new board should be arriving today... so be careful!
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Have to be careful though. I just fried my classd amp this weekend :cry: Not quite sure what happened, but we had just finished moving to a new place and I started getting audio stuff set up. Probably something got jostled (actually I'm sure it's related to my first modding attempts back when I got the board in November which was sloppy *and* unncessary). I was too eager to get things going, was very tired, and I knew i should have given everything a once over and made sure the enclosure was ok, etc.
My new board should be arriving today... so be careful!
Ouch! :duh: Sorry to hear that, is the power supply with the panasonic's ok?
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Should be. The sparks and smoke came from the amp :o. I'll find out tonight...
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Should be. The sparks and smoke came from the amp :o. I'll find out tonight...
Did you get the same board?
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Did you get the same board?
Yes. I was tempted to get the Super, but my will is strong, like my kung fu!
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Yes. I was tempted to get the Super, but my will is strong, like my kung fu!
Your will is strong Ninja-son, now fire that badboy up and report back!
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Here's a question for enclosure folk: My amp is housed in a wood enclosure. It's alright, but I'd like to step up to one of the ParMetal enclosures on ebay.
I have zero experience w/ metal enclosures. I live in an apartment and no access to major tools - just a basic drill. How do I go about making 3/8" and smaller holes for the rca/posts, etc? (rear panels are .06" thick aluminum). I've done searches all over, but surprisingly little info on these kinds of holes.
if this question should go somewhere else, lmk...
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Here's a question for enclosure folk: My amp is housed in a wood enclosure. It's alright, but I'd like to step up to one of the ParMetal enclosures on ebay.
I have zero experience w/ metal enclosures. I live in an apartment and no access to major tools - just a basic drill. How do I go about making 3/8" and smaller holes for the rca/posts, etc? (rear panels are .06" thick aluminum). I've done searches all over, but surprisingly little info on these kinds of holes.
if this question should go somewhere else, lmk...
Have you seen my gallery with my case? Take a look...it's right up your alley.
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Have you seen my gallery with my case? Take a look...it's right up your alley.
i know, but I am *way* broke. like post-move, post-flew to somebody's wedding far away, now post replaced dead amp broke...
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i know, but I am *way* broke. like post-move, post-flew to somebody's wedding far away, now post replaced dead amp broke...
:bawl:
If you can rig it up so it's safe, I would do that. Then when you save up the money, BAM you're good to go. This case is perfect for you as you don't need to use any power tools...
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Wushu
sorry to hear about your misfortune.
I'm sure you will be back on your feet before you know it.
As to your Q -
I am not the most knowledgable person but when it comes to drilling holes in metal, this is the easiest way that works for me:
step drill bit (http://6SN7 12SN7 Linestage preamp
100% Point to Point wired Vacuum Tube Linestage preamp)
(there are few versions out there- get the one that Ull need the most)
Best
Mariusz
P.S
there are some nicely made cases on eBay.(made here in US)
look here (http://iphone.ebay.com/Pages/ViewItem.aspx?aid=250628807454&ebayref=http://cgi.ebay.com:80/HiFi-DIY-Audio-amp-chassis-table-top-enclosure-20-16124-/250628807454?cmd=ViewItem&pt=BI_Electrical_Equipment_Tools&hash=item3a5aa41b1e&autoredirect=off&sflag=1)
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Thanks Mariusz. That's what happens when you rush things. but, hey, they're so cheap it's not that huge a deal. So I figure while I'm at it, might as well get it a proper enclosure. Make 'er respectable.
I've heard mention of the step drill bit. I'm guessing all I need is a center punch, step drill bit, maybe some lubricant. Yes, I've been eyeing those enclosures straight out of NJ for some time.
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Also know as Unibit...It works but is a crude way to drill a hole. You really need to file after to get all the burrs off.
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oh, excellent. I think I found a unibit that will work perfect. I'm pretty sure I have a file in my tool box, so should be good there. thanks much!
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oh, excellent. I think I found a unibit that will work perfect. I'm pretty sure I have a file in my tool box, so should be good there. thanks much!
:thumb: Measure twice or as many times as it takes to get it right the first time. Masking tape or painters tape works best. Tape the surface to be drilled then use a fine tip Sharpie to mark before drilling. Of course using a center punch then drill a small pilot hole ~1/8" then use the Unibit. This will keep the Unibit from "walking".
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I put some masking tape where I want to drill, mark it clearly, then use several small bits to work up to the hole size. Making a pilot hole is a must, and go slow. Good bits help a lot, worn bits don't work well.
But, that said, it's not hard to do... get 'er done!
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(http://www.northerntool.com/images/product/images/335325_lg.jpg)
(http://t0.gstatic.com/images?q=tbn%3A67uYrG6PpxC7iM%3A%3Awww.harderwoods.com%2Fgougejigdoc.html&t=1&usg=AFrqEzeFRo0RbKwwOSm8ZTaPW8OqrqKaMg)
Yeah, small half-round file might be needed.
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Looks like Jason and I had the same things to say while we were typing at the same time. :thumb:
This is just me, but I'd stick with regular drill bits to do this simple job. Don't really need a "step-up bit."
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Looks like Jason and I had the same things to say while we were typing at the same time. :thumb:
Great minds think a like. :lol:
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Terrific! Thanks guys. I'll probably take pics and write it up, of course... :rock:
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I'll second the step drill bit.
I've used regular drill bits, small one for pilot hole and 1/2" I think for the final hole for binding posts, and a stepped drill bit.
The stepped bit was much faster and cleaner,...just be sure to mark the bit where you want to stop, i wrap a piece of tape around the step just above the size I need.
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The par metal cases are very easy to drill,cut etc. I used a punch and regular drill bits. Smaller for pilot holes then stepped up to size needed. As already mentioned masking tape and draw everything out with a pencil or something else eraseable. For the IEC outlet you can use a skill saw with a metal cutting blade. Works like a champ. When your done cutting and or drilling you can clean up the holes with a file or sand paper as the metal is fairly soft.
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Well the new amp board is up and running and everything seems okay :D. I'll be ordering the Par-metal in a couple days...
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Well the new amp board is up and running and everything seems okay :D. I'll be ordering the Par-metal in a couple days...
Great news! Glad your PS survived the storm. :green:
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Earlier in this thread someone was asking for opinions of going with one of the linear PSU boards at connexelectronics.com over the one offered at classDaudio.com. I don't think anyone addressed this. Unfortunitely, I can find very little info about them on the website. Does anyone have an opinion about either of these modules with the SDS-254 or SDS-258? Would the combined 60,000uf capacitance of these be any sort of an upgrade?
http://connexelectronic.com/product_info.php/products_id/69?osCsid=3prbrltmu15kfebq69if854uf2
http://connexelectronic.com/product_info.php/cPath/25_45/products_id/87?osCsid=3prbrltmu15kfebq69if854uf2
wushuliu, what size of par-metal case would you be considering? 12x12x4 or 12x16x4?
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Hi guys,
OK, there has been some confusion about the input impedance of the CDA and SDS amp boards. I want to thank Deward for his technical help and Tom for giving me a more complete explanation as to why some boards measured differently than others. Here is the email I received earlier today. I'm posting it with Tom's permission.
Hi Roy,
I’m sure there is some confusion on the impedance of the CDA series amps. They have gone through changes since out first design. Our first amps worked well with most preamps and input devices, but they did have very low input impedance, and some with tube preamps had problems. Since that time, we have made several changes to try to make them more compatible and able to match up well to all available input devices. We have used up to 45K, but now we have settled on 7.5K input impedance for the CDA series. This seems to match up very well with all available audio equipment so far, and keeps the input noise down to a minimum. The SDS amps have an input impedance of 45K in balanced mode, and about 42K in single ended mode. This seems to work great with these amps and the balanced input stage. For some time now, we haven’t heard of any problems matching our amps to other input devices.
I hope this helps shed some light on this topic. Please let me know if I can be more help.
Thanks,
Tom
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Earlier in this thread someone was asking for opinions of going with one of the linear PSU boards at connexelectronics.com over the one offered at classDaudio.com. I don't think anyone addressed this. Unfortunitely, I can find very little info about them on the website. Does anyone have an opinion about either of these modules with the SDS-254 or SDS-258? Would the combined 60,000uf capacitance of these be any sort of an upgrade?
http://connexelectronic.com/product_info.php/products_id/69?osCsid=3prbrltmu15kfebq69if854uf2
http://connexelectronic.com/product_info.php/cPath/25_45/products_id/87?osCsid=3prbrltmu15kfebq69if854uf2
wushuliu, what size of par-metal case would you be considering? 12x12x4 or 12x16x4?
I dont have any advise on the supply in question but several of us have gone with just swapping out the stock Nichicons with Panasonic tsha series with positive results. It is not clear whether the increase in capasitance was the reason or the better caps. In both cases the increase was to 40,000uf and hasnt been confirmed if going higher is of any value or not.
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what happenned to the half dozen posts that were posted after this today?
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http://www.audiocircle.com/index.php?topic=81224.msg779312;topicseen#new
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what happenned to the half dozen posts that were posted after this today?
Split off this thread, for those feeling a little, er, Lost. No merging back. Whatever happened, happened. :wink:
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jtwrace
some members feel the need to expend on the topic and more techical side of it, including modifications etc. Ones we start moving away from the original topic and essence of this thread it will become more & more confusing for new readers.
We are already covering more then few versions of this amp and I see that it might look a bit "loose" for someone who just started fallowing this topic.
It will be also easier to refer future questions to coresponding thread in appropriate circle.
Mariusz
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I had been considering building one of these kits up as a sub amp, but the simplicity of the BASH 300 for $175 shipped to me in Canada won out in the end.
I will keep my eye on this thread though, as I may in time move away from my 96db efficient OB speakers, and look for affordable, good power - these appear to deliver that in spades!
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Well the new amp board is up and running and everything seems okay :D. I'll be ordering the Par-metal in a couple days...
If you change your mind re the enclosure, jtwrace's are well worth the money. You can just build the amp in a simple case or base (wood case or board) until you can swing it.
Paul
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If you change your mind re the enclosure, jtwrace's are well worth the money. You can just build the amp in a simple case or base (wood case or board) until you can swing it.
Paul
Just to get by until later, a simple 12"x12" (or whatever you choose) piece of mdf with a 4"x12" strip of peg board on the back side for your hardward. It's not attractive but it's functional... until you can do better. (cheap & cheerful) :green:
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Just to get by until later, a simple 12"x12" (or whatever you choose) piece of mdf with a 4"x12" strip of peg board on the back side for your hardward. It's not attractive but it's functional... until you can do better. (cheap & cheerful) :green:
The amp already has a decent diy wood enclosure (pics are in this thread somewhere).
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In the May issue of Affordable Audio, Lorin Elias wrote a review of the Virtue Audio ICEBLOCK M5001, a class d mono block amplifier. In it he made some comments about the use of cheap cables with class d amplifiers.
He said... "They are intolerant of cheap cables. You need clean power, good power cords, and good interconnects to get the best out of these amplifiers."
Could you guys share your experience with regard to the use of different cables and power cords with this Class D Audio amplifier? Thanks!
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In the May issue of Affordable Audio, Lorin Elias wrote a review of the Virtue Audio ICEBLOCK M5001, a class d mono block amplifier. In it he made some comments about the use of cheap cables with class d amplifiers.
He said... "They are intolerant of cheap cables. You need clean power, good power cords, and good interconnects to get the best out of these amplifiers."
Could you guys share your experience with regard to the use of different cables and power cords with this Class D Audio amplifier? Thanks!
Lots of variables but overall I found anything silver plated be it IC or PC came off harsh. I DIY mine fer cheap with upocc copper and ofc center pin RCA.
In fact I made a new pair last night to replace some uber cheap Chinese cables I use as temporary placeholder. The difference was apparent of course. However I think the classdaudio amps are more tolerant in general compared to say tripath or icepower (from what ive read of rheir sound). Transparent but More forgiving.
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In the May issue of Affordable Audio, Lorin Elias wrote a review of the Virtue Audio ICEBLOCK M5001, a class d mono block amplifier. In it he made some comments about the use of cheap cables with class d amplifiers.
He said... "They are intolerant of cheap cables. You need clean power, good power cords, and good interconnects to get the best out of these amplifiers."
Could you guys share your experience with regard to the use of different cables and power cords with this Class D Audio amplifier? Thanks!
I don't mean to open a can of worms - but I would take that comment, as they say, with a dose of salt
Sure, I can see how quality cables are important, especially when you are connecting a high quality source to a high quality amp, etc. But how could Class D amps possibly be inherently more susceptible to poor cables than class A or A/B? I suppose you could argue that they are more suspectible to signal degredation as they use the actual audio signal to generate the "clock" which switches the amplifier on and off, whereas a class A stage never switches off completely, but I'm a bit skeptical...
Anyone care to enlighten me?
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So I picked up a Superphon SP100 pre for my recently acquired used Bryston, problem is, I sent the Bryston back to be given 'the once over'.
But I still have loan of Pumpkinman's classD amp, so with wife out of town for weekend, I set up in front of the fireplace, (something I've always wanted to do but never did due to very low WAF), plus I can start burn in of recently acquired Luminous Audio Lynx II Rca ICs that had been still in blister pack.
First quick impression - not bad, not bad at all.
(http://www.audiocircle.com/image.php?id=30435)
(http://www.audiocircle.com/image.php?id=30436)
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This is my virgin post.
After reading this great thread, I bought 1 set of CDA-254L kit and housed in a chassis. It sounded warm, details and has powerful bass.
(http://i120.photobucket.com/albums/o181/dandondap/005-1.jpg)
I like the sound and bought another same amp to make it into a 4-channel amp.
(http://i120.photobucket.com/albums/o181/dandondap/038.jpg)
However, I'm surprised that it sounds bore and dead. The highs and dynamics are not there. Basically, no soundstage and flat. So I disconnect the DC supply to one of the amp and the music comes back alive. :D
Could the power supply does not have the enough power to drive 2 amps?
Would it help if I were to change the caps to higher capacitance and audio grade? If yes, any value and caps to recommend? Is the voltage of the caps important?
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This is my virgin post.
After reading this great thread, I bought 1 set of CDA-254L kit and housed in a chassis. It sounded warm, details and has powerful bass.
(http://i120.photobucket.com/albums/o181/dandondap/005-1.jpg)
I like the sound and bought another same amp to make it into a 4-channel amp.
(http://i120.photobucket.com/albums/o181/dandondap/038.jpg)
However, I'm surprised that it sounds bore and dead. The highs and dynamics are not there. Basically, no soundstage and flat. So I disconnect the DC supply to one of the amp and the music comes back alive. :D
Could the power supply does not have the enough power to drive 2 amps?
Would it help if I were to change the caps to higher capacitance and audio grade? If yes, any value and caps to recommend? Is the voltage of the caps important?
Probably so. You might change to 8200 or so per cap value. That would be a total of about a bit over 4800 UF, for both sides. You might also consult with Tom. I'd tell him your experience and see what he suggests. I'd ask him about upping the value of the "heavy duty" supply to something like 24/25 UF per side. It sure made a difference in Nic7 amp. Although he just brought his up to 40 UF per side.
Ray Bronk
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However, I'm surprised that it sounds bore and dead. The highs and dynamics are not there. Basically, no soundstage and flat. So I disconnect the DC supply to one of the amp and the music comes back alive.
Could the power supply does not have the enough power to drive 2 amps?
Would it help if I were to change the caps to higher capacitance and audio grade? If yes, any value and caps to recommend? Is the voltage of the caps important?
I have always been a little skeptial of the PS running two boards, now we know it comes with a price. I upgraded to Panasonic TSHA series caps with good results mostly in bottom end dynamics. I think you might contact Tom also and find out what he reccomends, not sure if cap upgrade will do the trick or if you might need a bigger transformer as well??
Welcome to the club! Nice work!
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I've run two boards and have no issues whatsoever. :scratch:
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I think the issue is that the CDA-254L kit comes with a 400Va transformer, however if you look at the CDA-2000 kit, it comes with a 600Va transformer. If you just added in the second board and didn't upgrade the transformer I would start here first.
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I've run two boards and have no issues whatsoever. :scratch:
What was your exact setup running two boards?
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What was your exact setup running two boards?
My aluminum case, 400VA with Super D and IR boards. Both using XLR inputs.
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So much for turning on the amp today and having a listen. Turn it on, no power :scratch:. Started checking all the connections making sure everything is wired up correctly. Finally decided to check the IEC fuse section, guess what no fuses :duh:. Will make a trip to home depot on my way home from work and pickup couple of 6amp slow blow fuse.
The adventure continues.
Just got myself a SDS258 kit. I powered up and no sound. I have to comb the whole thread again and upon checking my IEC, realize that a fuse is needed there. I have no training in anything electrical whatsoever and the most challenging thing I have done is change a light bulb. :eyebrows: I am assembling this step by step with all the pictures that were captured here.
Also there are two parts in the package, which I understand to be "potentiometers". What are these for? There are several strands of cables too. Are these for LED lights? :oops: I don't see these being used in the pictures posted so far..
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Yes those are the gain controls and they have to be hooked up to get any sound. Contact Tom for proper wireing. You dont have to have the leds hooked up, thats optional.
Your in for a real treat with that board! :eyebrows:
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For the potentiometers included, the black wire goes to the center pin on the pot, and if holding the pot with pins facing up, the yellow wire goes on the left, and the red wire on the right.
(http://www.audiocircle.com/image.php?id=28922)
Not the best picture but it kinda shows it.
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Thanks to those who have gave advices and opinions. Especially to wushuliu who PMed me with his suggestion on modding of the Power Supply and information on the caps. :wink: :thumb:
I'll change all the caps in the power supply to 10,000uF. Hopefully there would be improvement.
Now I'm also waiting patiently for SDS-258 to arrive. This would be used to drive front L/R speakers. :drool:
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For the potentiometers included, the black wire goes to the center pin on the pot, and if holding the pot with pins facing up, the yellow wire goes on the left, and the red wire on the right.
Indeed I can't see well... please help me... Is the picture below showing the pot with the pins downwards or upwards? The wires seem kind of tiny.. do you solder the tiny wires onto the pot? Thanks for the great help.
(http://www.audiocircle.com/image.php?id=30587)
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Indeed I can't see well... please help me... Is the picture below showing the pot with the pins downwards or upwards? The wires seem kind of tiny.. do you solder the tiny wires onto the pot? Thanks for the great help.
(http://www.audiocircle.com/image.php?id=30587)
Yes, you solder the tiny wires to the tabs.
As you're looking at your picture the black to the cente and the yellow to the left (bottom) and the red to the right (top).
make sense?
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My Par-metal enclosure just arrived. Pretty excited to break out the power tools. :D
(http://www.audiocircle.com/image.php?id=30602)
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Hi Wushu
Looks similar to NJ guy enclosure from eBay.... is that the source or....?
(if it is even cheaper then that please PM the source - THX)
Mariusz
Do not forget to snap few pix when finished.
:thumb:
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Hi Wushu
Looks similar to NJ guy enclosure from eBay.... is that the source or....?
(if it is even cheaper then that please PM the source - THX)
Mariusz
Do not forget to snap few pix when finished.
:thumb:
They're all from Par-Metal in NJ. Maybe that guy bought a bunch at discount and so sells them a little cheaper. I didn't see any of the gold models on his page. I think mine came to $10 more incl. shipping.
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Yes, I know they all come from Par-Metal..... just thought that you found even cheaper source (like a warehouse, B-stock or discontinue models) :wink:
Nevertheless, great value if you do not mind a tinny bit of DIY.
Cheers
Mariusz :thumb:
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Nevertheless, great value if you do not mind a tinny bit of DIY.
Cheers
Mariusz :thumb:
DIY, great value indeed. :D
What I really like about this kit is that you can assemble it for little $$, then listen to your hearts content before you make any decision about buying an enclosure.
Spend a little or a lot... it's DIY (you decide!) :thumb:
Wushuliu, looking forward to all those pics.
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A few questions:
Anyone tried the 600W mono? If so, anyone tried to drive a 12" or larger HT sub?
I'm going to pair it with a 800KVA Antek and upgrade the PSU with 27,000uf caps.
Anyone tried it at different rail voltages?
Thanks,
Greg
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Thanks to all who has helped, especially jtwrace, I have set up my SDS258. Very powerful bass indeed! As mentioned earlier, I am only capable of changing a light bulb before this project. So, hope that my success is an encouragement to all novices. While it may take an hour for the DIY enthusiasts here to assemble, it took me about four days to ask all the questions and buy the correct parts. But it can be done! Unfortunately, I am travelling tomorrow for 10 days and have to abandon it for 10 days! :duh:
(http://www.audiocircle.com/image.php?id=30646)
(http://www.audiocircle.com/image.php?id=30645)
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Nice work! Glad you are enjoying it, now get it into case. :eyebrows:
-
One question... the volume control pots (potentiometer)... if i am connecting via RCA, do you turn it all the way up, or half way, or... :?
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Ive found you should only turn them up as much as needed by listening tests. I think mine is set at about one o'clock. I had mine set to high and it was throwing off the balance of my sub output from the preamp and introduced a little brightness in my system.
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Nick77 is right. That pot controls the amplifier gain so the user can adjust it up or down depending on the load presented by the preamp. Turning it down will allow you more control via your preamp. Otherwise, you may be at full output by 10-12 o'clock on the preamp volume control. And, if that's what you like, then that's OK.
It just depends on the output of your preamp and how much control you want to have over the amplifier. I'd set it where you think it sounds best and works well with your preamp.
-
Also with the amp off you can use an ohm meter to set the pot
levels exactly, just put the leads on the yellow and black pins at
the pot and read the resistance, I have mine around 5 ohms.
Also kudos to jtwrace for his help and pictures, save up and buy
his case it makes a really nice package. :icon_lol:
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As mentioned in my earlier post, I commented about the sound after added another power module and made it into 4-channel. I discovered one of the RCA was loose and now the sound is back to what I have heard before. :duh:
Hope my previous encounter does not stop the rest from going into 4-channel. :D
While I'm writing this post, I'm listening to the music in bi-amping set-up. It brings the listening pleasure to another level. :thumb:
I have bought 6 Nippon Chemi-con 10,000uF, 100V, caps and scratching my head whether should I replace the stock caps. :scratch:
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Hi all,
I've been following this thread for some time and am unsure of 2 things:
1. For the SDS-258 Kit class D kit, can I replace the 2 dual mono pots that were provided with the kit with my own 50K stereo dual gang pot ?
2. If it is possible, can I connect my Samsung H1080 DVD player to the amp directly without the use of a pre-amp? Is this recommended ?
Kind Regards,
Dinny
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Hi all,
I've been following this thread for some time and am unsure of 2 things:
1. For the SDS-258 Kit class D kit, can I replace the 2 dual mono pots that were provided with the kit with my own 50K stereo dual gang pot ?
2. If it is possible, can I connect my Samsung H1080 DVD player to the amp directly without the use of a pre-amp? Is this recommended ?
Kind Regards,
Dinny
I assume what you're wanting to do is to use the two gain controls to control volume like a preamp does... since you also asked if you could plug your DVD player straight into the amp.
These two pots are not volume controls. The gain control is to match the output of the amplifier to the input of the preamp. Some preamps require more or less gain from the amplifier depending on their voltage.
That's just my understanding of your question. I apologize if I'm wrong about what you are asking. My suggestion is to send you questions to Tom at Class D Audio. He is very good about answering your questions.
Other members are FAR MORE KNOWLEDGEABLE than I am and can provide you with a better explanation than mine.
You can pick up a decent used preamp from Audiogon and give the Class D amp a try. I don't think you'll be disappointed. Good luck! :wink:
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I assume what you're wanting to do is to use the two gain controls to control volume like a preamp does... since you also asked if you could plug your DVD player straight into the amp.
These two pots are not volume controls. The gain control is to match the output of the amplifier to the input of the preamp. Some preamps require more or less gain from the amplifier depending on their voltage.
Yup exactly right. So basically if I hook the DVD player directly to the amp and play some source material through speakers, the loudness of the speakers cannot be controlled from the stereo pot unless I use an appropriate pre-amp? (assuming that I have rewired the dual mono pots into a dual gang stereo one)
Kind Regards,
Dinny
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The specs on the SDS-258 show an input impedance of 47K, so a 10K or 20K passive attenuator may work pretty well for you. Then you could adjust the gain using the amps pot as it's designed.
Short of buying an active preamp, using a good passive in the configuration I've described is the best I can think of right now.
If you have diy skills, take a look at the Nelson Pass B1 Buffer thread. This is one great performer! :eyebrows:
http://www.audiocircle.com/index.php?topic=78312.0
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Thanks for the great suggestions Roy =)
Im planning to get the SDS-258 Class-D amp to combo with a Dodd battery tube-buffer. Hopefully they will be a match made in heaven.
Anyone had the opportunity to compare the class D amps with Aussie amplifier NXv200 modules?
Kind Regards,
Dinny
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Thanks for the great suggestions Roy =)
Im planning to get the SDS-258 Class-D amp to combo with a Dodd battery tube-buffer. Hopefully they will be a match made in heaven.
Kind Regards,
Dinny
Should be an excellent match... good choice! :D
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I have bought 6 Nippon Chemi-con 10,000uF, 100V, caps and scratching my head whether should I replace the stock caps. :scratch:
Hi, I'd probably remove all 6 caps, and put in four of the 10 Kuf, two on each side, and see how it sounds. Then put in the remaining two and see if you notice any real difference. This would tell us DIYers whether to get 60 Kuf or something like 40 to almost 50 Kuf.
Inquiring minds like mine want to know. For right now, I will have to live out my thrills in what you guys do. Yeah, I know, that's sick, but then if noone did any experimentation, then we probably would still be back in the horse and buggy days.
Ray
-
Thanks to all who has helped, especially jtwrace, I have set up my SDS258. Very powerful bass indeed! As mentioned earlier, I am only capable of changing a light bulb before this project. So, hope that my success is an encouragement to all novices. While it may take an hour for the DIY enthusiasts here to assemble, it took me about four days to ask all the questions and buy the correct parts. But it can be done! Unfortunately, I am travelling tomorrow for 10 days and have to abandon it for 10 days! :duh:
(http://www.audiocircle.com/image.php?id=30646)
(http://www.audiocircle.com/image.php?id=30645)
Hi all,
I have a couple of ruler measurement questions for you.
How big is the SDS amps, with the RCA points at the rear and what is the diameter of the 400VA transformers? So Just trying to figure out the layout for less noise. I did see the SDS boards were about an inch longer, but what direction, hence the questions.
if I got a parmetal case, would the 12x12x3 be enough height? Thanks? Or would I be better to have an extra inch?
Ray
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Can someone post a pic of an external power switch used with their class d amps ?. From my understanding the SPST switch connected to the power cord is used to shut off the power supply and having an external power switch installed on the amp board allows me to leave the power supply switch on and allows the amp to be on standby mode if no signal is received?
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Can someone post a pic of an external power switch used with their class d amps ?. From my understanding the SPST switch connected to the power cord is used to shut off the power supply and having an external power switch installed on the amp board allows me to leave the power supply switch on and allows the amp to be on standby mode if no signal is received?
The manual says to leave the amp board's "on-off" switch in the "on" position, then wire directly from the amp board to an external power switch. This proceedure does not involve putting a power switch into the AC line as shown in the manual's diagram.
So does that leave the transformer on all the time? Would it be better to wire an external power switch into the AC line instead of involving the "power on-off" on the amp board?
Answers, please ...?
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I believe the onboard switch only turns off power to the FETS. While the tranny would remain on in standby mode, there would be no power drawn from it since the FETS are off.
steve
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Thanks, Steve. Which of the two would be the preferred way to wire the power switch?
It's a bit confusing since the manual describes wiring from the amp board to an external switch. But the wiring diagram shows a power switch integrated into the AC line.
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I don't understand why you wouldn't want to wire the way the instructions are...this way there is no power to the tranny > power board > amp board.
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I don't understand why you wouldn't want to wire the way the instructions are...this way there is no power to the tranny > power board > amp board.
This is probably the way most guys have routed AC to their amp, and the way I'll probably wire mine, too.
-
IMO the less parts that have high voltage when not in use, the better.
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I don't understand why you wouldn't want to wire the way the instructions are...this way there is no power to the tranny > power board > amp board.
Interesting. I was under the impresssion it just shut the FETs off. Why does my heatsink still get warm in standby mode then? Just curious.
steve
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Interesting. I was under the impresssion it just shut the FETs off. Why does my heatsink still get warm in standby mode then? Just curious.
steve
There are two sets of instructions now: the amp manual says to use the power switch on the amp board, but there is a separate diagram pdf on the site that says to switch from the tranny.
Mine is switched from the amp board because when I first got my amp there was no wiring diagram on the site, so I just followed the amp manual directions...
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Mine is switched from the amp board because when I first got my amp there was no wiring diagram on the site, so I just followed the amp manual directions...
Both ways must be acceptable since they are both recommended. AC, by switching from the amp board does the heat sink remain warm as Steve mentioned? What about the transformer?
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Both ways must be acceptable since they are both recommended. AC, by switching from the amp board does the heat sink remain warm as Steve mentioned? What about the transformer?
The heatsink and the transformer both remain warm to the touch, the transformer is barely warm though.
-
Both ways must be acceptable since they are both recommended. AC, by switching from the amp board does the heat sink remain warm as Steve mentioned? What about the transformer?
I think jtwrace is right about switching straight from the tranny as being the safest/best option. Maybe I'll do that when I put it in the new enclosure. The heatsink is not overly warm on standby, certainly nothing like when it's actually on. Transformer has never felt more than slightly warm to me, but I don't make a habit of playing w/ the amp while there's power running. Broke that rule once, 2 weeks ago, and we know how THAT turned out... :o
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The way I have setup everything is exactly as shown in this file
http://classdaudio.com/documents/transformer_115VAC_instructions.pdf
What I would like to do is to leave the AC switch on all the time so I don't have to keep turning it on.
My question is if I leave the small switch on the amp board on with the AC switch on, will this put the amp on standby mode if no signal is sent from the receiver/preamp?
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The way I have setup everything is exactly as shown in this file
http://classdaudio.com/documents/transformer_115VAC_instructions.pdf
What I would like to do is to leave the AC switch on all the time so I don't have to keep turning it on.
My question is if I leave the small switch on the amp board on with the AC switch on, will this put the amp on standby mode if no signal is sent from the receiver/preamp?
Yes, but you still have high voltage (120VAC) to the transformer which is outputing to the power board...
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Thank you Tom (to whom most of my questions went to) and to everyone for the very informative thread and for all the input and help that was provided here. Long story short, I bought the Class D amp (SDS-254) from Tom a month and a half ago, and designed and built a case around it. When I received the amp, I was able to run it on top of my little wodden table just for testing/burn-in purposes.
But last night, I completed my chassis and screwed everything in. I wanted to give this amp justice so I took my time building the chassis and voila. Forgive me for the not so encouraging photos, but I hope to take better shots when I get around to completing my light tent this weekend.
Unfinished Chassis:
(http://photos-edmar.gayao.net/photos/881742760_vMxmN-L.jpg)
Front Panel:
(http://photos-edmar.gayao.net/photos/881740481_t5gQK-L.jpg)
Rear Panel Unattached:
(http://photos-edmar.gayao.net/photos/881741828_qc5F5-L.jpg)
Laying out the components in the new chassis (Ready for marking drill holes):
(http://photos-edmar.gayao.net/photos/881720762_s3NEz-L.jpg)
Rear Panel Attached to Chassis:
(http://photos-edmar.gayao.net/photos/881714422_oUJ6r-L.jpg)
SDS-254 boards and Toroid screwed into chassis:
(http://photos-edmar.gayao.net/photos/881718319_Ku2Z5-L.jpg)
All wired up and ready to go w/ top case Off:
(http://photos-edmar.gayao.net/photos/881703109_uMCAM-L.jpg)
Happy Holidays Everyone.
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Yes, but you still have high voltage (120VAC) to the transformer which is outputing to the power board...
If in fact the amp board's on/off switch removes any load from the secondary side of the transformer, there shouldn't be any current flowing through the power supply board and only a small amount of no-load transformer primary current should be flowing, on the order of milliamps.
Does that sound more or less accurate?
Steve
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Jacko2x, nice work!
:thumb:
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Nice work Jacko, love the mounted gain pots. :thumb: :thumb:
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Beautiful! Simple, elegant, professional looking. Things have come a loooooonnnnnngg way in 1500 posts!!!! Most excellent.
steve k
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Jacko2X,
Front Panel Express is your friend.
Great work.
Anand.
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Front Panel Express is your friend.
Translation please? :? Never mind, got it from google, but for others, here you go...
http://www.frontpanelexpress.com/
Very nice job, Jacko2X.
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Front Panel Express it is ;)
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Beautiful! Simple, elegant, professional looking. Things have come a loooooonnnnnngg way in 1500 posts!!!! Most excellent.
steve k
Agreed. Really nice work.
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Front Panel Express it is ;)
Any chance you could make available your templates so I could order the same thing? Or did you cut all the openings yourself. I haven't quite gotten the hang of Front Panel's software. :? Nice case though. I like to get one in silver.
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Very nicely done Jacko! A clean, professional design perfectly executed.
Bob
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Thank you everyone for the kind words. I finally got around to get some better pictures to give the amp more justice. Please see below for the parts used and where to get them:
(http://photo-imprints.smugmug.com/photos/887120443_h2CTY-L.jpg)
(http://photo-imprints.smugmug.com/photos/887120299_LFMz7-L.jpg)
And since the chassis can only accomodate a single amp due to its 12x12 area, the insides look kinda cramped. It might be possible to fit in another amp module, but that would mean moving the toroid to one side and unevenly distributing the weight of the entire chassis.
(http://photo-imprints.smugmug.com/photos/887120600_ujzFj-L.jpg)
I take no credit for the chassis. That credit goes to someone who posted his build of his various headphone separates on head-case (Google: "context engineering 350dt forum"). The design of the rear panel is based on the idea that the power goes in through the center while binding posts are on the far left and right sides to give the chassis even weight distribution. The inputs are placed between the binding posts and IEC switch to avoid interconnects and speaker cables from crossing each other on a vertical rack. And also, the Toroid sits in the center: again for even weight distribution.
So I guess, my quest for an amp to replace my 15W hybrid tube speaker / headphone amp ends here. Next up Mini Statements to replace my Infinity 360's.
I owe a lot of my inspiration to this community, so it's time to give back:
Materials:
1. Chassis (Context Engineering Desktop Enclosure 350DT. It comes in Silver btw.) - Approx. $88 for the 12x12.
2. CNC cost w/ FPE - Approx. $130
3. IEC Switch - http://cgi.ebay.com/Tube-amp-IEC-AC-Switch-Fuse-Line-Phono-Preamp-Amp-DIY-/140353300866?cmd=ViewItem&pt=Vintage_Electronics_R2&hash=item20adb56982#ht_1009wt_1139
4. Binding posts - Cardas Patented Binding post (CPBP CRS). I would go for the rhodium plating since all you add is a couple of bucks.
5. Bulgin Latching Vandal Switch - Digikey: 708-1455-ND
6. RCA of your choice
7. Large IsoNodes for feet
8. Radioshack: RED & Orange LEDs, and Tie downs to keep wires in place.
PM me your email address for FPE templates if you're interested.
Cheers and happy listening everyone,
Ed
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Thanks Ed
great pics and
very nice of you to inclued the links
as well as tips regarding your build.
:thumb:
Mariusz :wink:
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Thank you everyone for the kind words. I finally got around to get some better pictures to give the amp more justice. Please see below for the parts used and where to get them:
(http://photo-imprints.smugmug.com/photos/887120443_h2CTY-L.jpg)
(http://photo-imprints.smugmug.com/photos/887120299_LFMz7-L.jpg)
And since the chassis can only accomodate a single amp due to its 12x12 area, the insides look kinda cramped. It might be possible to fit in another amp module, but that would mean moving the toroid to one side and unevenly distributing the weight of the entire chassis.
(http://photo-imprints.smugmug.com/photos/887120600_ujzFj-L.jpg)
I take no credit for the chassis. That credit goes to someone who posted his build of his various headphone separates on head-case (Google: "context engineering 350dt forum"). The design of the rear panel is based on the idea that the power goes in through the center while binding posts are on the far left and right sides to give the chassis even weight distribution. The inputs are placed between the binding posts and IEC switch to avoid interconnects and speaker cables from crossing each other on a vertical rack. And also, the Toroid sits in the center: again for even weight distribution.
So I guess, my quest for an amp to replace my 15W hybrid tube speaker / headphone amp ends here. Next up Mini Statements to replace my Infinity 360's.
I owe a lot of my inspiration to this community, so it's time to give back:
Materials:
1. Chassis (Context Engineering Desktop Enclosure 350DT. It comes in Silver btw.) - Approx. $88 for the 12x12.
2. CNC cost w/ FPE - Approx. $130
3. IEC Switch - http://cgi.ebay.com/Tube-amp-IEC-AC-Switch-Fuse-Line-Phono-Preamp-Amp-DIY-/140353300866?cmd=ViewItem&pt=Vintage_Electronics_R2&hash=item20adb56982#ht_1009wt_1139
4. Binding posts - Cardas Patented Binding post (CPBP CRS). I would go for the rhodium plating since all you add is a couple of bucks.
5. Bulgin Latching Vandal Switch - Digikey: 708-1455-ND
6. RCA of your choice
7. Large IsoNodes for feet
8. Radioshack: RED & Orange LEDs, and Tie downs to keep wires in place.
PM me your email address for FPE templates if you're interested.
Cheers and happy listening everyone,
Ed
Hi Ed,
pm me please with your template. I do have a question concerning the back panel layout.
If you are wiring so the Left and Right speaker connectors are on either left and right sides of the chassis respectively, then looking at the chassis from the backside, the right channel speaker wires would if I read this correctly, cross AC lines. If you are looking at the chasis from the back panel, I would think the speaker jacks would both go left of where the transformer is mounted in the center. Sorry, can't see your pics due to a slight blindness issue getting in the way. lol
Nevertheless, am interested in how the whole thing sounds. I am interested in your layout scheme too. TTYL
Ray Bronk
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Ed, thanks for the great pics and build information. Very helpful.
Will you share with us your thoughts on the performance of your Super D amp? :wink:
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Subjective feedback: http://www.audiocircle.com/index.php?topic=81176.msg787948#msg787948
I'm waiting on my friend to bring over his Von Schweikert VR1 speakers over so we can listen to my setup with those speakers.
Ed, thanks for the great pics and build information. Very helpful.
Will you share with us your thoughts on the performance of your Super D amp? :wink:
-
Looks like another positive review and satisfied CDA customer. Thanks, Ed. Nice to know it mates well with the LDR attenuator.
The Affordable Audio review should be out soon, too. :wink:
-
Yes, unfortunately the speaker line on one side does cross the AC line. Thanks for pointing this out. I should do something about this later. The rca-in does not cross at all since the wire towards the rear panel floats high up on the IEC switch. I just posted a link on how my whole setup sounds on the EVA2 thread. Link is in my previous post on this thread.
Hi Ed,
pm me please with your template. I do have a question concerning the back panel layout.
If you are wiring so the Left and Right speaker connectors are on either left and right sides of the chassis respectively, then looking at the chassis from the backside, the right channel speaker wires would if I read this correctly, cross AC lines. If you are looking at the chasis from the back panel, I would think the speaker jacks would both go left of where the transformer is mounted in the center. Sorry, can't see your pics due to a slight blindness issue getting in the way. lol
Nevertheless, am interested in how the whole thing sounds. I am interested in your layout scheme too. TTYL
Ray Bronk
-
I'm considering getting a tube buffer to place between the pre and amp to see if there are any sonic benefits, but I'll probably consider revisiting this after I build my Mini Statements.
This is my first foray into separates, and I'm really enjoying how the whole idea of separates sound.
Looks like another positive review and satisfied CDA customer. Thanks, Ed. Nice to know it mates well with the LDR attenuator.
The Affordable Audio review should be out soon, too. :wink:
-
Since the Eva LDR attenuator is passive, I'm curious to know how you set the gain on your SDS amp (32db max, 26db standard setting).
Is it max'd out or less? Thanks!
-
Less, but more than half way :D
Out of curiousity does anyone know what resistance values equate to the 26db standard setting? Tnx
Since the Eva LDR attenuator is passive, I'm curious to know how you set the gain on your SDS amp (32db max, 26db standard setting).
Is it max'd out or less? Thanks!
-
What type of drill bit would I need if I were to drill holes on a par metal case? Do you guys think a a battery powered drill will be good enough?
-
Yes, battery drill shall do it.
-
What type of drill bit would I need if I were to drill holes on a par metal case? Do you guys think a a battery powered drill will be good enough?
Sure, a cordless drill will work fine. Use some masking tape, and measure & mark where you want to drill. Start with a small drill bit first, then work up to the right size. Just go slow, and keep a firm hold on the item you're drilling so the bit doesn't grab it. :wink:
-
Par-Metal offers both steel and aluminum chassis options. The steel requires a bit more pressure (pun intended) to drill through, even with a petite bit. Still, if you've got a decent drill that will run at high speed and not run out of steam too quickly, I think you'll have no trouble working through any of their boxes. As was noted before, tape and measure and mark exactly where you want your holes, start small, and work your way up gradually. Bits made to pierce metal will work better than bits meant for wood. I just ordered a new chassis for my Class D (I originally tried it just mounted inside an old gutted Parasound amp chassis, so the fit is lousy), and I'm convinced those amps are worth the time and effort and money to mount in a decent looking chassis.
Neil
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I'm convinced those amps are worth the time and effort and money to mount in a decent looking chassis.
I am too! I'm just drawn into the music...
-
Would like to see pics of black Par Metal cases if anyone has them...
-
My Humble SDS 258...
(http://img.photobucket.com/albums/v241/joamonte/0e6ce05a.jpg)
(http://img.photobucket.com/albums/v241/joamonte/e333ffd7.jpg)
(http://img.photobucket.com/albums/v241/joamonte/7a10fd81.jpg)
(http://img.photobucket.com/albums/v241/joamonte/67acb612.jpg)
(http://img.photobucket.com/albums/v241/joamonte/ed5fdbdc.jpg)
(http://img.photobucket.com/albums/v241/joamonte/7d75a899.jpg)
Sorry for the Bad photo, taken with I-phone...
Have any one have experience suddenly shut off for a few second when playing fast transient music with your Super Class D?
My SDS 258 drive my Marten Coltrane(8 ohm) or Harberth LS 3/5a (11ohm) with ease no problem, but driving the Amphion Helium 510 will occasionally shut down a few second when playing music with lot of fast transient....could be due to the loudspeaker impedance? :(
-
That looks sweet! So is that a silver anodized enclosure from Par Metal?
-
Nice build joamonte, I'm really digging that case.
-
My SDS 258 drive my Marten Coltrane(8 ohm) or Harberth LS 3/5a (11ohm) with ease no problem, but driving the Amphion Helium 510 will occasionally shut down a few second when playing music with lot of fast transient....could be due to the loudspeaker impedance? :(
First, nice build! Mine is not a super, but it has occasionally gone into protection mode with speakers that are harder to drive. When I leave the cover off, it doesn't happen, so it seems to be a result of heat.
Tom suggested that I increase the amount of heat sink, which I just did this weekend so I'm optimistic.
You might try running it without the cover to see if that helps.
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It appears a number of people have had the amp go into protection mode with their 4 ohm speakers.
It is true that there are some speakers that present a very difficult load to an amplifier, and some of these 4 ohm "nominal" speakers may in fact spend some time down in the 2 ohm region. But a well-designed power amplifier should be able to drive 98% of the speakers out there.
Adding heat sinking or getting relief with the cover off really seems to point to the heat sink simply having too little area to begin with.
Steve
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Adding heat sinking or getting relief with the cover off really seems to point to the heat sink simply having too little area to begin with.
Tom has been pretty clear about the limitations of the heat sink in the original versions, which is too small for heavier loads. To overcome that limitation, I think, is part of the reason why he created his newer models with a different heat sink.
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I was originally looking at the CDA-258 amp. I was told in February that the heat sink had been upgraded and that the amp was rated for 375W/channel at 4 ohms.
Certainly having the consistency of all of the amplifier models rated at 4 ohm would allow for better comparison and an easier selection decision.
But 4 months later, the photo of the CDA-258 does not show the upgraded heat sink, the description still only lists power at 8 ohm, and the newer SDS-258 with the upgraded heatsink also only still lists power at 8 ohm.
That is why I did not pull the trigger. I am assuming that those that have had a shutdown problem did not have one with their previous amplifier that it replaced.
Steve
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I was originally looking at the CDA-258 amp. I was told in February that the heat sink had been upgraded and that the amp was rated for 375W/channel at 4 ohms.
Certainly having the consistency of all of the amplifier models rated at 4 ohm would allow for better comparison and an easier selection decision.
But 4 months later, the photo of the CDA-258 does not show the upgraded heat sink, the description still only lists power at 8 ohm, and the newer SDS-258 with the upgraded heatsink also only still lists power at 8 ohm.
That is why I did not pull the trigger. I am assuming that those that have had a shutdown problem did not have one with their previous amplifier that it replaced.
Steve
Hi Steve,
You might want to contact Tom about this. He wrote me that he is working on a module that will work in a 2 ohm configuration that is will handle difficult loads down to 2 ohm loads If I were buying one right now, I'd get the SDS254.
Ray Bronk
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I've decided to stick w/ my current wooden enclosure for my amp, so my unused Par-Metal enclosure is for sale. I will put up a proper post in the classified section this evening.
I just prefer wood (yes, I know, *that's what she said*)
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I've decided to stick w/ my current wooden enclosure for my amp, so my unused Par-Metal enclosure is for sale. I will put up a proper post in the classified section this evening.
I just prefer wood (yes, I know, *that's what she said*)
Those cases are very nice for the money.
I would buy it of you but unfortunately I've way too much wood laying around.
So yes, wood for me too. (and 1/8" aluminium plate -top/bottom)
P.S
Thanks for being considerate :thumb:
•edit for typo•
Cheers
Mariusz :wink:
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Those cases are very nice for the money.
I would buy it of you but unfortunately I've way too much wood laying around.
So yes, wood for me too. (and 1/8" aluminium plate -top/bottom)
P.S
Thanks for being considerate :thumb:
•edit for typo•
Cheers
Mariusz :wink:
Actually, I see that I'm still within my 30 days so I will try and return to them first. Sorry for the tease everyone :oops:...
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:nono: :lol:
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Pm sent Wush
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getting my cda-1000 soon... :)
:P
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Those cases are very nice for the money.
I would buy it of you but unfortunately I've way too much wood laying around.
So yes, wood for me too. (and 1/8" aluminium plate -top/bottom)
P.S
Thanks for being considerate :thumb:
•edit for typo•
Cheers
Mariusz :wink:
This might be a stupid question, but how do you ground a wooden case?
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This might be a stupid question, but how do you ground a wooden case?
You dont, Tom has said that grounding these amps is not an issue.
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Anyone tried the Car 12V power supply Tom offers to run it on a battery? I think I am going to so that it matches the DODD tube buffer 8)
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Praedet
(http://www.audiocircle.com/image.php?id=31413)
(http://www.audiocircle.com/image.php?id=31414)
(http://www.audiocircle.com/image.php?id=31415)
:thumb:
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Awesome! Any pictures of the inside when it is in the DODD box? That is what I am planning too!
Which amp is that, and why the HUGE heatsink?
Thanks,
Ted
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Praedet
Check your PM
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I wonder if one of these batteries will run both the amp and the buffer. I have one in the garage...
http://www.caraudiodeals.com/kinetik-hc1400-p-1872.html
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Hi guys, I just bought a Norcom IEC and need help installing it for the ClassD.
1) It says 6A on the tag so does that mean I have to use a 6 amp fuse?
2) There are two fuse slots on the left and right...do I insert 2 fuses? I thought the 2nd might be a fuse holder but it looks like there are contact leads on both insertion sides
3) If I need to insert 2 fuses, do I insert 2 6amp fuses or 2 3amp fuses?
4) Lastly, there are 4 leads at the back top portion and 1 lead at the back bottom portion, where do I connect the 2 black wires and 2 red wires from the transformer?
I'm so confused and don't want to mess anything up.
(http://photos.friendster.com/photos/80/09/72579008/2_782376369l.jpg)
(http://photos.friendster.com/photos/80/09/72579008/2_133029249l.jpg)
(http://photos.friendster.com/photos/80/09/72579008/2_490576374l.jpg)
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Hey Chill, 2 6amp fuses and yes you need both installed. Go to page 4 of this thread and you can see the wire set up for that IEC. It is at the bottom of the page. Easier than trying to explain.
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Thanks avionic! Last question, I can't quite make out the yellow wire from the bottom lead? Is that a ground to the chassis? This is optional right?
Hey Chill, 2 6amp fuses and yes you need both installed. Go to page 4 of this thread and you can see the wire set up for that IEC. It is at the bottom of the page. Easier than trying to explain.
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Yes that is a ground. Whether or not you use it is up to you. I certainly would and did. 2 minutes of your time to keep from getting the s_ _t shocked out of you :wink:
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My enclosure is made out of wood though. Can I just put it on a big screw?
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Sorry, didn't notice that you had a wood enclosure. I don't know what some of these guys have done. There are a few who have built these amps in wood enclosures. See if you can find some info in this giant thread.
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My enclosure is made out of wood though. Can I just put it on a big screw?
We have contacted Tom concerning grounding issues with a wood case and it has said that a ground isn't necessary with these amps. Of course if it was in a metal case it would be foolish not too. Myself and others have experienced no issues in a wood case with no ground. :green:
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That's nice to hear.
Does it matter what amp the spst switch is? I found a switch that says 3A. Am I tied to the 6A on the IEC?
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That's nice to hear.
Does it matter what amp the spst switch is? I found a switch that says 3A. Am I tied to the 6A on the IEC?
Should be 10-15 amp.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=060-670
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You can now order a custom aluminum enclosure direct from Classdaudio.
Looks familiar... :scratch: :lol:
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Good idea, Jason. You may want to have ClassDAudio correct a few misspellings in the Description.
1. this case is custom made to fin ... > to This and fit
2. This case is made and shipped directly from the manufacture. > manufacturer
Steve
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You can now order a custom aluminum enclosure direct from Classdaudio.
Looks familiar... :scratch: :lol:
Quick and good eye.
Good idea, Jason. You may want to have ClassDAudio correct a few misspellings in the Description.
1. this case is custom made to fin ... > to This and fit
2. This case is made and shipped directly from the manufacture. > manufacturer
Steve
Done. Thanks. :thumb:
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Quick and good eye.
Done. Thanks. :thumb:
Quick website editing response! Got the two misspelled words, just thought he might also want to start the second sentence with a capital letter (This). Or not.
Steve
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Jason, regarding the Class D website, the enlarged pics are HUGE.
They obviously need to be resized. Great idea to make them available through the Class D website.
Just trying to help. :thumb:
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Jason, regarding the Class D website, the enlarged pics are HUGE.
They obviously need to be resized. Great idea to make them available through the Class D website.
Yes! I hadn't clicked on them before, but they are 3872 X 2592!
Steve
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Pics should be done tonight...
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Congrats on the case deal Jason. That should make the classD's more marketable for sure!
steve
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Jason, perhaps someone here on AC has a light box and would volunteer to take some "professional looking photos" of your enclosure to post on the Class D Audio website.
I think your nice enclosure deserves some professional pics. Lots are work went into it, so you want to present it in the best possible light. (no pun intended) And, no offense to your photographic skills. :wink:
I'm just saying... :D
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What kind of screws/standoffs do you guys use to secure the amp/ps to the enclosure?
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What kind of screws/standoffs do you guys use to secure the amp/ps to the enclosure?
The ones that come with the kit. I believe they're 4-40.
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The ones that come with the kit. I believe they're 4-40.
Never mind. Amazon and Digikey saved the day. Hm, dont think I got standoffs w/ my kit last year.
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Congrats on the case deal.
I also think that if you showed a picture with an amp installed in your case it would also help with sales.
Scott
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So the case is only available from Class D?
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So the case is only available from Class D?
Nope. They all come from me. Class D is just showing them...
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Let's say I have 2 CDA-254 amp boards and one PS.
1) Does this mean I can vertical or horizontal bi-amp?
2) Are there any benefits to either ?
I have 2-way speakers.
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Let's say I have 2 CDA-254 amp boards and one PS.
1) Does this mean I can vertical or horizontal bi-amp?
2) Are there any benefits to either ?
I have 2-way speakers.
If you had two separate amps each with its own power supply, I would say to vertically biamp, driving each woofer with a separate amp/power supply, since the bass section would be the much greater draw of power/current.
Since you are sharing a common power supply, it might not make much of a sonic difference, but I would still vertically biamp to equally split the heat dissipation of the output transistors and heat sink between the amplifier boards.
If you are using a preamp with dual outputs you are good to go. If not, you would have to use a splitter to feed the signal into both inputs. Some amps don't respond well to having their inputs tied in parallel to another amps inputs. I don't know how the ClassDAudio amps would react to that scenario.
Steve
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Thanks Steve that seems to be the gist from what I have read. So I will put the spare amp board up for sale.
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Huh. So no review in Affordable Audio...
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Yeah, I noticed that last night... bummer! :o
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Hi All,
Looking for suggestion on which model/configuration to get. Currently have a Gallo 3.1 and also planning on acquiring the Magnepan 1.7 to switch back and forth so would want something with power and great sound. I haven't built anything like this before but willing to learn and can follow directions. I have an Audio Research LS1 and LS3 for preamps. Would love to get some suggestions since there are quite a selection. Thanks.
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Hi All,
Looking for suggestion on which model/configuration to get. Currently have a Gallo 3.1 and also planning on acquiring the Magnepan 1.7 to switch back and forth so would want something with power and great sound. I haven't built anything like this before but willing to learn and can follow directions. I have an Audio Research LS1 and LS3 for preamps. Would love to get some suggestions since there are quite a selection. Thanks.
Hi, To be honest, if I were buying right at this moment, I'd probably just spring for the SDS254 kit. It will do 8 ohms, and 4 ohms. I can't speak what will happen at 2 Ohms. But for a kit, case, RCA jacks, speaker terminals, and an On/off switch, for roughly about $500 to $600 with a metal case, I think you'd have to go a long way to do much better than that.
Ray Bronk
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Hi All,
Looking for suggestion on which model/configuration to get. Currently have a Gallo 3.1 and also planning on acquiring the Magnepan 1.7 to switch back and forth so would want something with power and great sound. I haven't built anything like this before but willing to learn and can follow directions. I have an Audio Research LS1 and LS3 for preamps. Would love to get some suggestions since there are quite a selection. Thanks.
Send an email to Tom at their website, he's really knowledgeable and can recommend the correct one.
Cheers,
Dan
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Funny , I have Email Tom 3 time and wait for 2 days but he did not give me a reply.
My question
"Hi Tom
Can I check with you, for 115V 60hz this kits need 6A slow blow fuse, what about 230V 50Hz area? 3A slow blow?
And if I connect 2 kits into one IEC inlet (with Fuse holder built in), how many "A" Fuse do I need?
Hope to get your reply soon, need to confirm with my parts supplier on how many amp of Hifi tuning fuse I am ordering, thank!
Regards
Lim"
What is wrong with my question? did I asked something stupid?? :roll:
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Ah....end out is my email block by his mail box, for some unknown reason...... :roll:
Anyway, Tom have confirm that for 230V it should be 4A , not 6A fuse to be used.
:D
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Could some of you provide some comparisons between the Classd Audio amps and commercial amps? I'm extremely intrigued with these amps, but I have now read the entire 79-page threat (Yes!) and did not see very many real comparisons. I know what the original poster said, and I respect it. But a few others have made more critical comparisons, even to a $1200 class AB integrated amp, and so I'd like to hear more. What amps did you replace? How do the Classd amps compare, sonically? (I have Nuforce mono's, a custom Don Allen tube pre, Vecteur transport + Altman Attraction battery-powered dac, Townshend Rock III turntable/Rega RB-300 arm, Grado Reference Sonata cart, Blacknoise power conditioning, GR-Research Paradox 3 floor-standers, etc.). I do not want to sound skeptical--but I do want to hear more before I order. Thank you.
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Could some of you provide some comparisons between the Classd Audio amps and commercial amps? I'm extremely intrigued with these amps, but I have now read the entire 79-page threat (Yes!) and did not see very many real comparisons. I know what the original poster said, and I respect it. But a few others have made more critical comparisons, even to a $1200 class AB integrated amp, and so I'd like to hear more. What amps did you replace? How do the Classd amps compare, sonically? (I have Nuforce mono's, a custom Don Allen tube pre, Vecteur transport + Altman Attraction battery-powered dac, Townshend Rock III turntable/Rega RB-300 arm, Grado Reference Sonata cart, Blacknoise power conditioning, GR-Research Paradox 3 floor-standers, etc.). I do not want to sound skeptical--but I do want to hear more before I order. Thank you.
Maybe after 79 pages your head is just spinning...the first post is a guy that replaced his amps with the Class D. There are also a few others in here. :thumb:
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Thank you, Jtwrace. But as I mentioned, I read the original poster's comments. I also read Pardales's post where he said he preferred the Miniwatt, and mjosef's post where he said he preferred the Exposure 2010S (a class AB solid state amp). The other comparisons, as I recall, were to mass-market receivers. Thus, I'd like to hear more, particularly comparisons to decent audiophile amps rather than mass-market stuff. My head may be spinning, but I'm still thinking clearly.
Thank you again for your reply, and I'm grateful for all of your work on the case--I may be getting one for this amp if I hear some more specifics.
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Thank you, Jtwrace. But as I mentioned, I read the original poster's comments. I also read Pardales's post where he said he preferred the Miniwatt, and mjosef's post where he said he preferred the Exposure 2010S (a class AB solid state amp). The other comparisons, as I recall, were to mass-market receivers. Thus, I'd like to hear more, particularly comparisons to decent audiophile amps rather than mass-market stuff. My head may be spinning, but I'm still thinking clearly.
Thank you again for your reply, and I'm grateful for all of your work on the case--I may be getting one for this amp if I hear some more specifics.
Proper comparisons to specific retail 'audiophile' amps are going to be hard produce. For one, specs would have to be comparable. The Miniwatt for instance has 3W vs. 250W for the CDA-254, so someone with a setup that can use the MiniWatt isn't likely to consider/need a classdaudio amp. And of course some people are going to prefer something else, we all have different tastes and setups. What IS important is that a large body of people familiar with good gear recognize the value of these $200 - $400 amp kits. The 2010S for instance retailed at 5x the CDA-254.
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Thank you, Wushuliu: when you say that lots of people who are familiar with good equipment are impressed with the Classd amps, that is exactly the sort of information I am looking for. I had the impression (perhaps mistaken) that most buyers of this amp were replacing mass-market receivers with the Classd amp. I'd be grateful if you (and other users) could provide some specifics--what other amps are you and other users familiar with? I'm only asking for simple comparisons. (And I would point out that while the Exposure initially sold for 5x the cost of the first generation Classd amp, it can be bought on the used market for only a hundred or so above the cost of the current generation Classd amp + associated case & parts.)
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I just bought one of these amps with the "enhanced" power supply( thanks to Wushuliu)...it might be a couple weeks before I put it together...hopefully mybuild would be better than the loaner I had, I will be using superior connectors, better layout and better ps filtration...I will be able to offer more long term impressions in comparison to my current amps, tube and SS.
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Adamay, I recall reading posts in this thread comparing the Class D Audio amps to Wyred4Sound, CherryJr, Clayton, VTL, some others I can't think of right now.
I'd say that's pretty good company. Not saying it's better or worse, but the Cherry Jr and Clayton were preferred. You can draw you're own conclusions.
In view of that, most guys around here figure the Class D amps are a steal. Reading the thread would be a good investment of your time. :wink:
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Looking for suggestion on which model/configuration to get. Currently have a Gallo 3.1 and also planning on acquiring the Magnepan 1.7...
Here's some information that might help. I asked about the SDS-258's ability to drive a four ohm load, and here's the response I received:
"The SDS-258 can run most 4 ohm speakers with no problems at all, but a few people have had trouble a few times with electrostatic types that drop to below 1 ohm. Most 4 ohm speakers do not drop this low and pose no problems for this amp. The power does not double into 4 ohms though due to current limiting and protection circuitry. The SDS-254 is better suited to speaker systems that prove a hard load to drive".
On the basis of this information I ordered the SDS-254 kit to drive my 2.5-way speakers that dip below four ohms. The rationale for this decision is 1) The SDS series are their best product, 2) The SDS-254 offers more versatility for driving a wide range of speakers, and 3) I save a few dollars by ordering the 254 instead of the 258.
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Here's some information that might help. I asked about the SDS-258's ability to drive a four ohm load, and here's the response I received:
"The SDS-258 can run most 4 ohm speakers with no problems at all, but a few people have had trouble a few times with electrostatic types that drop to below 1 ohm. Most 4 ohm speakers do not drop this low and pose no problems for this amp. The power does not double into 4 ohms though due to current limiting and protection circuitry. The SDS-254 is better suited to speaker systems that prove a hard load to drive".
On the basis of this information I ordered the SDS-254 kit to drive my 2.5-way speakers that dip below four ohms. The rationale for this decision is 1) The SDS series are their best product, 2) The SDS-254 offers more versatility for driving a wide range of speakers, and 3) I save a few dollars by ordering the 254 instead of the 258.
You'll be very happy with your choice. :thumb:
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Thanks, everybody! Mjosef, I'd be very grateful to hear your impressions and comparisons when you have your new unit up and running.
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Hello all,
First of all thank you Steve K and others for this thread.
Get ready for a long post :)
Why are ClassD Audio modules cheaper than IcePower and Hypex although they are made in USA by Team America, not China? IcePower and Hypex are made in Europe where labor costs more, maybe that's why? Or do they simply use better parts and material? Yes, IcePower has B&O behind them which has a big name (not necessarily in an audiophile way) and Hypex has the genius engineer behind them with his UCD invention, so they can charge as much as IcePower. Is this why?
I have read about ClassD audio when I decided to search for a Class D amps since they run cool, relatively cheap and put a lot of power. As most of us, I would like to get the best product for the money. I have looked for used Cary Audio CAI-1, Bel Canto S300iu and they are about $800-$1000 used. However, I feel like they do not have the power I look for. My speakers are Sonus Faber Extrema which is 88db @4 ohms and they are known to demand a lot of good power. I have never had a chance to use them with high powered amps, so I cannot tell this is true. My only Class D experience was with Panasonic XA-45 (I think) but the power was not enough for the speakers and I really could not enjoy/fairly test it.
The other day I came across Seymour AV 5001 monoblocks on Ebay which uses IcePower 500ASP modules. Unfortunately, the seller had them on two different auctions so I could not risk winning one and losing the other auction. I need a stereo amp. Each sold for $260 (MSRP $1100)! That was CHEAP considering Chris Seymour uses good parts on those amps and the 500ASP modules probably sell for $400 each (1000ASP sells for about $600 I think). I was kind of bummed out that I missed these but when I read this thread, I saw that maybe IcePower is not what I am looking for. Maybe I need the Class D audio because I like the tube amp sound. Steve K says that he does not like the Bel Canto which uses IcePower (though that model does not use the ASP version, I think) vs. Class D. (I wish Tom picked a different name) :)
I also talked to Tom who seems like a nice guy. He replied all my questions very quickly and I am leaning towards his modules the most at the moment. However, I still have questions in mind. According to him which I trust his opinions, there is no mods necessary for his amps which he recommended the SDS-258 for me. However, I have read some of you replace the caps with Panasonic, maybe a different PSU or SMPS, bigger transformer, etc. and get better results. I wonder what kind of mods really worth to perform.
I am NOT a DIYer but looks like with Tom's modules it is pretty much plug-and-play. I know if I want to do some mods, I need to have someone do it for me but I would not mind doing them if they would add better sonics to the amps. I know that SDS-258 is not doubling @4 ohms but it goes above 300wpc. However, the SDS-254, is 250wpc @4 ohms. I am not sure sonically which one would be a better choice. Stereophile's review/measurement of my speakers mentions this:
The impedance rating is a smooth 5 ohms with 4 ohm minima of low reactive content. Tube amplifiers rated over 150W, 8 ohms are advised, set to their 4 ohm taps if available. Solid-state models of good peak-current capacity (10A or more) will drive the Extrema well, given 8 ohm ratings of 75W or more. The 225W clip power of the KSA-150 caused no audible distress with high-quality program. The impedance curve (fig.C) shows that the Extrema's impedance holds within 4 and 9 ohms from 10Hz-2.5kHz before rising gently in the high frequencies.
http://www.stereophile.com/standloudspeakers/915/index6.html
The most important point for me is this though; there are some comparisons with some serious amps, VTL, Bel Canto. So, this tells me Class D maybe the choice but there are also other people who swear Hypex is the best one. I wonder if anybody could add to more amps to the list for comparison. I would love to hear a comparison with Hypex. Yes, Class D is the cheapest among them and I am after a good deal but if I choose to buy Hypex, I would probably pay $150-$200 more which is not too much more than Class D. If Hypex sounds better than Class D, it is worth the extra cost for me.
I am getting close to pull the trigger but do not know which exit should I take....
Thanks for reading :)
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Hi celo,
All I can say is I've always been attracted to amplifiers that create some excitement and emotion in the music. The VTL's had that magic in my system: great dynamics, great bass, warm enveloping mids, and snappy, extended highs that transmitted transients quickly and got the attack of acoustic instruments right. This is what floats my boat. Some would say this is colored, distorted, less true to the real thing and I respect that opinion.
With that said, of all the Class D amps I've heard, they tended to sound cooler, more detached, less emotional but accurate and detailed, that is until I heard Tom's amps. He gets the noise floor way down which brings out inner detail, gets the dynamics, bass and treble right, but the mids have the wonderful warmth of a good tube amp. THey get the wood sound out of a stand up bass or cello ,or acoustic guitar much more like a tube amp but in a cleaner, less noisy presentation of a tube amp. Most of the music I listen to is made by the human voice or acoustic instruments so the color and timbral presentation of instruments is very important to me. Call this colored or warm. I'll take it.
steve
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Hi Steve,
Thanks for the reply. I have heard many solid state amps. I heard some tube amps. The best amp among the ones I heard which I also owned many years, was the Pass Labs Aleph 3. I did not care too much of the bass being weak which was a negative point for some people. I think you are kinda describing the Aleph 3 when you talk about Tom's modules/amps plus with better bass handling. Obviously, Aleph 3 can cook an omelette when increasing my electric bill, heating the house and still cannot keep up with my Extremas :)
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I am NOT a DIYer but looks like with Tom's modules it is pretty much plug-and-play. But, it's not difficult to assemble, and you'll get plenty of help here.
However, the SDS-254, is 250wpc @4 ohms. I am not sure sonically which one would be a better choice.
As discussed previously, the Class D amp is in kit form and NOT plug & play. However, it's not difficult to assemble, and there's plenty of help available here.
The SDS-254 is a very popular choice and one I wouldn't hesitate to recommend.
Steve K knows what he's talking about from both his experience in the hobby and his personal use of Class D amps.
Once again, the Class D amp is an incredible buy, and the SDS-254 would be a good choice.
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As discussed previously, the Class D amp is in kit form and NOT plug & play.
The SDS-254 is a very popular choice and one I wouldn't hesitate to recommend.
Once again, the Class D amp is an incredible buy, and the SDS-254 would be a good choice.
I might have exaggerated a little :) I meant relatively easier than other available kits on the market. It is funny, Tom actually said SDS-258 first. Then after I sent my speakers info, he said SDS-254 but he said he meant the 258. Maybe he has his heart set on the 254.
Do you recommend the 254 because it sounds better than the 258 or you mean it would be enough for my speakers? Thanks Roy!
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I might have exaggerated a little :) I meant relatively easier than other available kits on the market. It is funny, Tom actually said SDS-258 first. Then after I sent my speakers info, he said SDS-254 but he said he meant the 258. Maybe he has his heart set on the 254.
Do you recommend the 254 because it sounds better than the 258 or you mean it would be enough for my speakers? Thanks Roy!
It's really not that difficult at all. We won't let you fail. :thumb:
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Thank you jtwrace, I have no doubt! Actually, it will be a looooong time till I build them. We are moving overseas in few months and we don't even have a house when we go back :) I will definitely ask your help. Let me decide which module I should buy first :)
I need a preamp too. Of course a cheap(er) one. Tom thinks an active preamp is a better choice. I asked him about passive amps.
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Many around here are partial to the Pass B1 buffer/preamp. :eyebrows:
Wushuliu has a great thread that walks you through the relatively simple build process.
Enjoy the Music has a nice write up on the B1 buffer.
http://www.enjoythemusic.com/magazine/equipment/0708/first_watt_b1_preamplifier.htm
You can assemble one for about $150. The B1 buffer and Class D audio amp are a great match especially for those like me who have champagne taste on a beer budget. :wink:
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Would I look stupid if I asked what is buffer? :) I have been seeing people talk about it but I am not sure if I know exactly what it does as opposed to preamp. Basically, it does the same thing as the preamp but in a different way?
I also asked Tom about the choice of a module. What do you think???
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Would I be better off buying two SDS-254 modules and bridge them for 500X1 @8 ohms or buying one SDS-258 would be a better choice?
I think 254 can do lower impedance better than 258, correct? Going with the 258 would give me only 50wpc more power vs. 254 @4 ohms, correct?
He responded:
Yes, the SDS-254 X 2 bridged is a great choice. This would be allot more power then you’ll ever need.
Tom
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I've got a Pass B1 buffer and just finished an SDS 254 amp, and I can vouch for the excellence of the combo. I used a Promitheus TVC (transformer based passive volume control) before switching to the B1, and although it was very transparent, and inserted no noise or hum into my system, it was not quite as musically involving as the B1 is.
Here is my take on a buffer: it is like a preamp, except it has no gain... so it provides a simple, easy load for your source components to drive (easier than most volume controls), and allows you to control the volume and switch from one source component to another (CD player, media player, DVD player, etc). Most amps can be driven to full power with 2 volts or less (the typical output of most source components) so a buffer (with no gain) offers the most simple and direct way to manage volume and source selection. Nelson Pass seems to heavily favor simple circuits and elegant solutions... and the B1 is just that.
The B1 requires some soldering skills, and requires you to be able to identify caps and resistors and such, but on the whole it is a fairly easy kit to build (although the Class D amps are even simpler). Hope this helps. Gary Dodd is also offering a battery powered tube buffer as a kit, just in case you'd prefer to add some tube magic ahead of your amp. There is also a thread about his goodies in the Lab area.
Neil W.
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Would I look stupid if I asked what is buffer? :) I have been seeing people talk about it but I am not sure if I know exactly what it does as opposed to preamp. Basically, it does the same thing as the preamp but in a different way?
I also asked Tom about the choice of a module. What do you think???
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Would I be better off buying two SDS-254 modules and bridge them for 500X1 @8 ohms or buying one SDS-258 would be a better choice?
I think 254 can do lower impedance better than 258, correct? Going with the 258 would give me only 50wpc more power vs. 254 @4 ohms, correct?
He responded:
Yes, the SDS-254 X 2 bridged is a great choice. This would be allot more power then you’ll ever need.
Tom
As an FYI if you use my case you can go with one amp board and add the second later if you wish. ALL the holes are already there. Just a thought.
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As an FYI if you use my case you can go with one amp board and add the second later if you wish. ALL the holes are already there. Just a thought.
I would but I cannot really take them with me when we are moving overseas. I will take the modules with me in the plane and the case would be too big :) Plus, my wife already told me that she has an idea for a case. She wants to use a wooden wine crate/case. She will stain them, wood burn them and will make them look like an art piece so she says :) She loves projects like that so, I am okay with it. She can probably help me with the electronics part as well, she is good :)
I would like to know if someone could give me an technical explanation about using two SDS-254 vs. one SDS-258 specifically with my speakers. I will keep them probably forever, so I want to get something exactly for them. I am not after TOO much power but I just want to make sure that I build something that will handle the speakers in best musical way possible. I lived with the Aleph 3 so, good power even though it is 30wpc is enough for me. I just don't want the amp fall short for the Extremas.
BTW, thanks Neil! Although I am not sure if I still understand it 100% or not but at least I know little more about it now. I will read Nelson Pass's take too.
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I have already assembled a SDS258 amp kit. Everything is going on fine. I am thinking of adding another amp board for additional 2 channels to power the surround. As this is for the surround only, I do not really need the 258. Is it OK to buy the cheapest amp from Class D audio to tap on the power supply from the SDS258 kit?
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OK I need help to hook up the Connex ps board I bought.
The connes board has a set of inputs from the tranny, they are AC1 GND AC2
On the ClassD ps board the center tap two wires are connected to
the CT center input, and the other green wire is hooked up to the
AC-L and the other blue wire is hooked up two the AC-N
So does the blue wire going to the AC-N hook up to the GND on the connex
Does the two CT wire hook up to the AC1
Does the green wire hook up to the AC2
(http://www.audiocircle.com/image.php?id=32187)
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Sorry this is the correct picture of the inputs
(http://www.audiocircle.com/image.php?id=32188)
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Sorry, I don't have an experienced opinion or definitive answer to your question. However, I suspect you join the two common wires in the center and the outside wires like the Class D power module. But wait for a more experienced opinion before doing anything.
When you get it all going, let us know if you think this setup is superior to the Class D audio heavy duty power board. Thanks! :D
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He reported in the modifications thread that he got it figured out...
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When you get it all going, let us know if you think this setup is superior to the Class D audio heavy duty power board. Thanks! :D
Did some reading on the modifications thread. I came away with the opinion that any differences will likely be subjective, subtle and dependant on the system's ability to resolve source material.
jtsnead, glad you got it going. :wink:
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Thanks Roy
Cheap and Cheerful is Fun!
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I have already assembled a SDS258 amp kit. Everything is going on fine. I am thinking of adding another amp board for additional 2 channels to power the surround. As this is for the surround only, I do not really need the 258. Is it OK to buy the cheapest amp from Class D audio to tap on the power supply from the SDS258 kit?
Anyone? Can I, for example, add a CDA224 amp to the SDS258 kit to build a 4 channel power amp?
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Anyone? Can I, for example, add a CDA224 amp to the SDS258 kit to build a 4 channel power amp?
You sure can! Heck, my case will take those two boards. :D
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You sure can! Heck, my case will take those two boards. :D
Thanks! I just want to make sure that the power supply will not go bonkers, powering two different types of amp.
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+1 On jt"s case, I was able to mount the above ps board in his case
just had to angle it to line up two holes, did not have to drill any,
easy as pie.
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Thanks! I just want to make sure that the power supply will not go bonkers, powering two different types of amp.
Shouldn't be an issue...just let Tom know what you're planning on.
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+1 On jt"s case, I was able to mount the above ps board in his case
just had to angle it to line up two holes, did not have to drill any,
easy as pie.
Thank you! :thumb:
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Just finished the kit with the ti-600. Another +1 on the case. I am so happy with the sound I ordered another amp to make it a dual-mono. I want to revise some of my connections and wire pathways, too, and I'll post pics when that's all done.
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Just finished the kit with the ti-600. Another +1 on the case. I am so happy with the sound I ordered another amp to make it a dual-mono. I want to revise some of my connections and wire pathways, too, and I'll post pics when that's all done.
Great! That was super quick too. Look forward to some pics. :thumb:
Thanks for nice comments on the case.
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Hi all,
After reading through half these threads, I'm interested in picking a CDA254 kit to drive a set of 4ohms Natalie P. I currently have the Onkyo RC180 which does 110w/ch x 7 and it does have pre-outs. If I were to pick up the cDA254 kit, would I still need to look for a pre-amp, or would the RC180 be adequate enough?
thanks
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Hi all,
After reading through half these threads, I'm interested in picking a CDA254 kit to drive a set of 4ohms Natalie P. I currently have the Onkyo RC180 which does 110w/ch x 7 and it does have pre-outs. If I were to pick up the cDA254 kit, would I still need to look for a pre-amp, or would the RC180 be adequate enough?
thanks
The RC180 will work fine.
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I have Pioneer VSX-21 that does 110w x7 supposedly. When I tried my SDS-254 I noticed much more clarity, control, and soundstage vs using just the Pioneer imo.
I'm sure the receiver will be adequate. But how adequate enough? That's up to you...
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Big #500 post. Yippie! :thumb: Okay now back to the action, I had the same response when i used my HK reciever and an SDS254. It totally blew away the HK in dynamics and was much much tighter sounding and a huge soundstage.
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I put together an integrated amp: Hot Rodded DC Coupled B1 Mezmerize board with 3 inputs, and my CDA-254.
I am a big believer in reducing connections as much as possible and this seemed the best way to do between the two components. Also GF will hopefully be less irritated with having to turn on this and turn off that. Messy wiring will be cleaned up later. May also get an extension rod for the volume pot.
(http://www.audiocircle.com/image.php?id=32482)
(http://www.audiocircle.com/image.php?id=32483)
Well I am just about wrapped up w/ big audio projects for a while. Time to enjoy the fruits of my labors.
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Wait what about that other girl? The Temptress 3020?
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Wait what about that other girl? The Temptress 3020?
On hold... I need to take some time and Actually listen to tunes. Also so I can make a proper comparison down the road.
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Sounding great: super-clear and effortless.
(http://www.audiocircle.com/image.php?id=32659)
(http://www.audiocircle.com/image.php?id=32660)
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Beautiful wiring!!! I'm jealous. :lol: What speaks are you driving?
steve
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Yeah, what kind of wires are those? They look so professional.
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Nice job!
Oh, and nice case. :D
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Gee, Thanks! I think the camera must have been too kind. The speaker wires are some left-over Acoustic Research "performance series" 16 ga. "oxygen-free" wire. I figured that would be plenty since I'm using two per channel. The mains wires are 12 ga. hook-up wire. The signal wires, I think are 22 ga.. I just braided them. The 12V wire is 16 ga. wire paired and colored black and red.
The case is all jtwrace.
I'm driving Magnepan 1.7. They seem to really love this amp.
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The case is all jtwrace.
:wave:
:D
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Gee, Thanks! I think the camera must have been too kind. The speaker wires are some left-over Acoustic Research "performance series" 16 ga. "oxygen-free" wire. I figured that would be plenty since I'm using two per channel. The mains wires are 12 ga. hook-up wire. The signal wires, I think are 22 ga.. I just braided them. The 12V wire is 16 ga. wire paired and colored black and red.
The case is all jtwrace.
I'm driving Magnepan 1.7. They seem to really love this amp.
It looks fantastic, great build!
What modules/kit are you running there, and what is the output into 8 ohms?
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Thanks! those are the Ti-600s: 600 W @ 8 ohms. http://classdaudio.com/index.php/600w-class-d-power-amplifier.html
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Sorry if this has been covered. Other than the TI boards are any of the class D amps stable at 4 ohms when bridged?
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Thanks! those are the Ti-600s: 600 W @ 8 ohms. http://classdaudio.com/index.php/600w-class-d-power-amplifier.html
Nice. So I'm guessing you purchased this kit (http://classdaudio.com/index.php/class-d-amplifier-kits/home-kits/600w-class-d-power-amplifier-and-power-supply.html) and a second amplifier board(?) Or did you buy the 2 amplifier boards, and power supply separately?
Would you give some details on the sound? Someone wrote on the class-d site, that the "Amp is definitley brighter than my trusty Yamaha M2". Though in my experience, Yamaha amps tend to lean toward sounding a bit dark anyway. I'm interested in hearing more impressions of it's sonic character.
I also wonder how it compares sonically with the CDA-1000 Kit (http://classdaudio.com/index.php/class-d-amplifier-kits/home-kits/1000-watt-class-d-amplifier-kit.html)(?)
Thanks
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Sorry if this has been covered. Other than the TI boards are any of the class D amps stable at 4 ohms when bridged?
I'd think this version would work:
http://classdaudio.com/index.php/class-d-audio-amplifiers/home-and-pro-class-d-audio-amplifiers/sds-254.html
I'm using this one into a 4 ohm load:
http://classdaudio.com/index.php/class-d-amplifier-kits/home-kits/250w-x2-500w-x1-amp-large-power-supply-transformer.html
It would overheat after 6-7 hours and go into protection for a few seconds, so Tom suggested that I add to the smallish heat sink. I did and it's been dandy ever since.
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I just corresponded yesterday with Tom at Class D, and both model 254 kits will drive 4 ohm speakers, no problem.
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Nice. So I'm guessing you purchased this kit (http://classdaudio.com/index.php/class-d-amplifier-kits/home-kits/600w-class-d-power-amplifier-and-power-supply.html) and a second amplifier board(?) Or did you buy the 2 amplifier boards, and power supply separately?
Would you give some details on the sound? Someone wrote on the class-d site, that the "Amp is definitley brighter than my trusty Yamaha M2". Though in my experience, Yamaha amps tend to lean toward sounding a bit dark anyway. I'm interested in hearing more impressions of it's sonic character.
I also wonder how it compares sonically with the CDA-1000 Kit (http://classdaudio.com/index.php/class-d-amplifier-kits/home-kits/1000-watt-class-d-amplifier-kit.html)(?)
Thanks
Yep, that's the kit! I wired it first in stereo, and then I ordered the second amp a few days later. My non-audiophile wife says it sounds "rich." I would say it gives a little needed "air" to the maggie 1.7; the percussion seems snappier, and clarity is a real strength. With the ACI Sapphire XL, the clarity remains, but for some reason most recordings sound a little more like they were made in an artificially non-reverberant room than I remember -- almost like there's some low-level dynamic expansion or something. It's subtle, so I don't want to overstate the effect, and it's not always a bad thing. Just different.
In my limited experience, I would say that this amp is a fantastic value with conventional dome and cone speakers, and with maggies, I would guess that you'd have to spend serious money to get better sound. That's my take so far, but remember my opinion is biased. Anything I wire together myself will sound better just because I did it. Sorry I'm not much of a reviewer. Hopefully one of the pros will publish a formal review on these kits. (Affordable$$Audio, I'm looking in your direction.) :)
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Yep, that's the kit! I wired it first in stereo, and then I ordered the second amp a few days later. My non-audiophile wife says it sounds "rich." I would say it gives a little needed "air" to the maggie 1.7; the percussion seems snappier, and clarity is a real strength. With the ACI Sapphire XL, the clarity remains, but for some reason most recordings sound a little more like they were made in an artificially non-reverberant room than I remember -- almost like there's some low-level dynamic expansion or something. It's subtle, so I don't want to overstate the effect, and it's not always a bad thing. Just different.
In my limited experience, I would say that this amp is a fantastic value with conventional dome and cone speakers, and with maggies, I would guess that you'd have to spend serious money to get better sound. That's my take so far, but remember my opinion is biased. Anything I wire together myself will sound better just because I did it. Sorry I'm not much of a reviewer. Hopefully one of the pros will publish a formal review on these kits. (Affordable$$Audio, I'm looking in your direction.) :)
Did you notice any difference going from stereo to two boards running bridged each?
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Great question. Not very much, actually. It seems like the sound emerges from the speakers into the room a little easier (I know that sounds a little dopey, but I can't think of a better way to say it), and the imaging might be marginally more focused. Overall, I would say it was a small difference. But, I've spent more to get less.
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Great question. Not very much, actually. It seems like the sound emerges from the speakers into the room a little easier (I know that sounds a little dopey, but I can't think of a better way to say it), and the imaging might be marginally more focused. Overall, I would say it was a small difference. But, I've spent more to get less.
I would say it's more effortless.
My personal opinion...I know what you're saying though.
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I went ahead and emailed him just for clarification.
Yes, the amps are stable at 4 ohms bridged but the power will not double from 8 to 4 ohm in bridged mode because the MOSFETS are not rated for so much current. We have protection circuitry built in to safeguard against this.
So, if you want to build monoblocks or have an odd number of channels it is no problem, however, you don't get twice as much power at 4 ohm.
Sorry if this has been covered. Other than the TI boards are any of the class D amps stable at 4 ohms when bridged?
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Guys,
I am getting the http://classdaudio.com/index.php/class-d-audio-amplifiers/home-and-pro-class-d-audio-amplifiers/sds-254.html (http://classdaudio.com/index.php/class-d-audio-amplifiers/home-and-pro-class-d-audio-amplifiers/sds-254.html) for my seas speaker build http://www.audioheuristics.org/projects_gallery/ER18DXT/ER18DXT.htm (http://www.audioheuristics.org/projects_gallery/ER18DXT/ER18DXT.htm)
I couldn't read the entire thread here but from whatever I did read these seem to be perfect for my needs and budget. I will be starting with stereo but plan on moving to a 5.1 system as time/budget permits. I am guessing I can add another stereo SDS amp and a mono in the future? I will using my PC as the source for now but will get a pre sometime in the future?
Please let me know if my assumptions are in order.
Thanks for all your help.
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Guys,
I am getting the http://classdaudio.com/index.php/class-d-audio-amplifiers/home-and-pro-class-d-audio-amplifiers/sds-254.html (http://classdaudio.com/index.php/class-d-audio-amplifiers/home-and-pro-class-d-audio-amplifiers/sds-254.html) for my seas speaker build http://www.audioheuristics.org/projects_gallery/ER18DXT/ER18DXT.htm (http://www.audioheuristics.org/projects_gallery/ER18DXT/ER18DXT.htm)
I couldn't read the entire thread here but from whatever I did read these seem to be perfect for my needs and budget. I will be starting with stereo but plan on moving to a 5.1 system as time/budget permits. I am guessing I can add another stereo SDS amp and a mono in the future? I will using my PC as the source for now but will get a pre sometime in the future?
Please let me know if my assumptions are in order.
Thanks for all your help.
That should all work.
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Thanks Jtwarce. One last question is the SDS worth the price difference over the CDA?
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Thanks Jtwarce. One last question is the SDS worth the price difference over the CDA?
I think so.
Don't forget to get a nice case. :)
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I think so.
Don't forget to get a nice case. :)
Planning to build one out of wood.. if not will get yours :) looks really nice need to save some more money for it though!
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I'm driving Magnepan 1.7.
This may be a little OT but how do you like the 1.7's? Did you upgrade from 1.6's? I'm curious because I haven't heard the 1.7's yet. Looking forward to Valin's review in TAS. Nice to hear another guy here using the Class D's with maggies.
cheers,
steve
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jtwrace-
Any chance in the future for silver colored case?
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jtwrace-
Any chance in the future for silver colored case?
Probably not anytime soon.
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jtwrace-
Any chance in the future for silver colored case?
Not quite as nice as jtwrace's cases, but if you're looking for silver...
http://cgi.ebay.com/HiFi-DIY-Audio-amp-chassis-table-top-enclosure-20-16124-/250666998653?cmd=ViewItem&pt=BI_Electrical_Equipment_Tools&hash=item3a5ceadb7d
they have their own web-site too...
http://par-metal.com/product.php
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Not quite as nice as jtwrace's cases, but if you're looking for silver...
http://cgi.ebay.com/HiFi-DIY-Audio-amp-chassis-table-top-enclosure-20-16124-/250666998653?cmd=ViewItem&pt=BI_Electrical_Equipment_Tools&hash=item3a5ceadb7d
they have their own web-site too...
http://par-metal.com/product.php
They definitely work. No doubt! Drill the holes....still not as finished as mine.
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I'll be starting my 500x2 along with my new loudspeakers this week.. it will be allot of fun..
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I'll be starting my 500x2 along with my new loudspeakers this week.. it will be allot of fun..
Sweet!
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Does anyone know the dimensions of the SDS module, will it fit/slide into a case like this?
(http://gkphotonics.com/images/gk4_drawing.jpg) (http://gkphotonics.com/ee.html)
I was thinking of putting the amplifier modules and power supply into separate enclosures.
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...still not as finished as mine.
Absolutely! That's why I'd started my post with...
"Not quite as nice as jtwrace's cases, but..."
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Absolutely! That's why I'd started my post with...
"Not quite as nice as jtwrace's cases, but..."
:lol: I know. All good. :thumb:
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Does anyone know the dimensions of the SDS module, will it fit/slide into a case like this?
(http://gkphotonics.com/images/gk4_drawing.jpg) (http://gkphotonics.com/ee.html)
I was thinking of putting the amplifier modules and power supply into separate enclosures.
I do but not now as the dimensions are in a different place then I am. I will say that I highly doubt you'll be able to find one large enough for the amp board, PS and tranny.
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I'll be starting my 500x2 along with my new loudspeakers this week.. it will be allot of fun..
Is that the SDS-1000 (http://classdaudio.com/index.php/class-d-amplifier-kits/home-kits/sds-245-x-2-kit-1000w-8-ohm.html) kit? It's what I'm considering.
I do but not now as the dimensions are in a different place then I am. I will say that I highly doubt you'll be able to find one large enough for the amp board, PS and tranny.
Hence... "I was thinking of putting the amplifier modules and power supply into separate enclosures." ;)
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Is that the SDS-1000 (http://classdaudio.com/index.php/class-d-amplifier-kits/home-kits/sds-245-x-2-kit-1000w-8-ohm.html) kit? It's what I'm considering.
Hence... "I was thinking of putting the amplifier modules and power supply into separate enclosures." ;)
:duh: Umm. OK. I'll stop responding now.
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I could only find dimensions for one of the amp boards but it is too large to fit that enclosure:
Features:
Stereo or Bridged Configuration
Power On / Off Switch
Power and Error LED’s
click and Pop Noise Reduction
Over Temperature Protection
Over / Under Voltage Protection
Over / Under Current Protection
MOSFET DC Protection
All Housekeeping Power Supplies
Small Size: 4.5” X 4.25” X 1.25”
Made in the USA by us... classDaudio.com
Best,
Ed
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Ha! It's all good!
I like the idea of keeping that big humming toroid and the ps board isolated from the audio signals.
I think that even if I were to use a single chassis I'd run a divider between the amp boards and ps stuff.
I'm just goofy that way ;)
Thanks Ed!
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Ha! It's all good!
I like the idea of keeping that big humming toroid and the ps board isolated from the audio signals.
I think that even if I were to use a single chassis I'd run a divider between the amp boards and ps stuff.
I'm just goofy that way ;)
Thanks Ed!
Yes, that's goofy. The tranny (in my amp that I built) doesn't hum at all. NOTHING. Personally IMO I think you're making it harder then it needs to be.
After seeing that you're from GSP Ex. 165 I understand. :lol: I'm originally from the same exit so I understand goofy. In fact, you probably drive by my parents house many times.
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After seeing that you're from GSP Ex. 165 I understand. :lol: I'm originally from the same exit so I understand goofy. In fact, you probably drive by my parents house many times.
Well if you're going to be in your old neighborhood shoot me a PM, and maybe we can have a listening/bs session :)
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Well if you're going to be in your old neighborhood shoot me a PM, and maybe we can have a listening/bs session :)
10-4
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One of these may be interesting for use as a case as well...
(http://www.audiocircle.com/image.php?id=32844)
(http://shop.ebay.com/gkphotonics/m.html?_nkw=GK8&_sacat=0&_odkw=&_osacat=0&bkBtn=&_trksid=p3911.m270.l1313)
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This may be a little OT but how do you like the 1.7's? Did you upgrade from 1.6's? I'm curious because I haven't heard the 1.7's yet. Looking forward to Valin's review in TAS. Nice to hear another guy here using the Class D's with maggies.
cheers,
steve
I had the 1.6 QR when it was first introduced. They were just too big for my hallway-sized living room I had at the time, so I sold them. I'm very glad to have them back in all their new-and-improved glory.
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Excellent!! I have a friend who's upgrading to the 1.7's. Can't wait to hear them.
Enjoy,
steve k
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Guys how do these compare to the UCD180 or Ska Audio's GB150? any one who has heard any two or all three comment?
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Here's a picture showing how the parts can be positioned in the $50 HiFi DIY Audio amp chassis table top enclosure 20-16124 from the Antek Ebay store. http://cgi.ebay.com/HiFi-DIY-Audio-amp-chassis-table-top-enclosure-20-16124-/250666998653?cmd=ViewItem&pt=BI_Electrical_Equipment_Tools&hash=item3a5ceadb7d
I'll be installing one SDS-254 amp board as shown, but the case is large enough to accommodate two.
(http://www.audiocircle.com/image.php?id=32965)
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Reading this thread has my head spinning! By page 70 I literally felt like all your guys' talk about input impedance and pots for gain but not for volume control and such has me totally confused (i'm not an electrician or engineer)
What I'm hoping for is someone in layman terms to help me out. This is my first electronic 'project' other than putting together a computer, which is really plug and play.
I talked with Tom, he suggested the SDS-254 kit for my speakers. I have a brother who can help me with soldering, but I need to know what to order to make this whole kit work.
I need a fuse, a switch, and a IEC connector. I need RCA jacks and a balanced inputs (my DAC does both, which is better? Do i need both?) and speaker binding posts... anything else?
I really don't know where to go to buy these parts. I'm not worried about a case, that's easy, just drill and mount the components, that's something I can do. I'll let future Joe worry about that, I just want the essentials to get this kit working.
What I'm hoping for is some help on what are some really good value components to buy that won't limit the sound of this amp but aren't snake oil at the same time. Please, any product recommendations and links would be really helpful! I want to order all the parts I need and have them on hand so when Tom ships the SDS254 I'm ready and have a full week to demo.
Here are my speakers and how hard they are to drive, I also wanted to verify that this is the right kit with you guys. I know these amps have a 'usable' power range before they distort to hell. I'm looking for power to really handle the big musical transients without going deaf and distorting.
(http://www.stereophile.com/images/archivesart/409Avofig1.jpg)
Thanks guys! If all goes well I hope to update you guys on my progress and i'll post pics!
-Joe
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Here's a picture showing how the parts can be positioned in the $50 HiFi DIY Audio amp chassis table top enclosure 20-16124 from the Antek Ebay store. http://cgi.ebay.com/HiFi-DIY-Audio-amp-chassis-table-top-enclosure-20-16124-/250666998653?cmd=ViewItem&pt=BI_Electrical_Equipment_Tools&hash=item3a5ceadb7d
I'll be installing one SDS-254 amp board as shown, but the case is large enough to accommodate two.
Nice, shoot us another picture when you a done.
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OK, I've actually gotten through this entire thread, though admittedly skimming some of the technical things that went over my head. Seems like a simple enough build for me to tackle, but I am curious as to how this thing compares to other respected class d amps.
I'm particularly curious as to how the super fares against the Virtue Audio TWO.2. I've got one on tour right now that is convincing me of the merit of digital audio and I'm considering buying the discounted loaner, but the price puts it to right about where this project plus a case would be.
My speakers are very efficent 101db and 16ohm (Zu Soul Superflys) and I would use a tube preamplifier (Eastern Electric Minimax w/ upgraded PSU) Can anyone chime in?
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My speakers are very efficent 101db and 16ohm (Zu Soul Superflys) and I would use a tube preamplifier (Eastern Electric Minimax w/ upgraded PSU) Can anyone chime in?
Since you have an EE Minimax, you could get a CDA series kit and save some $$. I'd recommend the 224 or 254 amp kit. If $$ is no problem, then spring for the SDS series which is their top of the line. But users say the CDA amps are very good to excellent.
Anyway, with Zu speakers of 101db efficiency, any of these amps you'll have gobs of power.
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Joe, you should be able to get all the help you need right here. Tom has suggested an excellent kit, the SDS-254. I'd recommend Digi-key and Parts Express as two places where you can pick up the parts you'll need. You could wire it together on a board for temporary trial listening. Ask Tom to tape the 2 common transformer wires together, they are the middle 2 blue and green wires. Let us know what else you need.
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My speakers are very efficient 101db and 16ohm (Zu Soul Superflys)
I built one of these Class D amps and I like it a lot; it's driving speakers that are ~84 db. But I'd think for speakers as efficient as yours, I would instead consider one of the many low power designs out there.
I am sure the Class D brand amps would work, but they are high power designs, so it might not be the best match of speakers to amp. Just my two cents...
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The power rating is irrelevant to me. Even 50wpc would be plenty. I'd have no problem with a lower power amp but would want the best SQ available in whatever wattage that was.
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I built one of these Class D amps and I like it a lot; it's driving speakers that are ~84 db. But I'd think for speakers as efficient as yours, I would instead consider one of the many low power designs out there.
I am sure the Class D brand amps would work, but they are high power designs, so it might not be the best match of speakers to amp. Just my two cents...
You could use a 2w tube if you wanted something different. The Decware tube amps are awesome for the money and would work great. The Class D although it has a lot of power available, it would work great as well. You will get a different sonic signature between them but one advantage with the Class D is that you'll more then likely always have enough power for future speaker changes (which are going to happen).
I would recommend the Super D or IR for your app and you'll be fine IMO. They are quiet with HF speakers too.
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Yeah, I'd like to stay in the two digit+ power ratings but I previously used 3.5wpc on my prior Fi 2a3 monoblocks with only 95db efficiency Abbys. Future speaker compatibility is not a consideration for me. I had my last pair for almost six years and expect to do the same or longer with these.
I've got a Firstwatt F1 (soon to be F1j) that will be my primary amplifier--I just love the idea of an inexpensive, excellent, cool running summer amp. Especially one I can leave on 24/7 (without going broke) so its always sounding its best.
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Hey Gopher, This may be an option for you: http://cgi.ebay.com/TK2050-TP2050-2-100W-CLASS-T-D-TRIPATH-T-AMP-Board-/130397808636?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item1e5c50a7fc
I have 2 of these as well as the class d audio amp and this little tk2050 sounds incredible. All you need is a power supply and you are up and running. Check his other listings as the seller has several different versions of the amp even one with the power supply. Sorry, I don't mean to step on this class d thread.
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I was thinking Tripath as well.
Gopher, you've owned some nice gear, so I'm sure you know what's what. It just seemed to me that building an amp that makes 200+ watts to use 4 seemed like it might be a mismatch, as so many argue that it's all downhill after the first watt.
But you know that, so I'll shut up. :)
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I didn't mean to come off as antagonistic or anything--just wanted to convey that I'm not thinking along those lines because I feel I NEED power, but if power is a side effect of the best SQ configuration, so be it--I don't think my Souls will argue nor will my amp be pushed.
You and avionic might be right with the tripath recommendation, I'm just trying to get a handle on how the presentations would differ with power taken out of equation.
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Gopher said:
I've got a Firstwatt F1 (soon to be F1j) that will be my primary amplifier
How would you describe is the sonic signature of that amp? And what you expect out of the F1j? I have the boards for the F3, I believe, but backed off of building it because it seemed to require a special type of preamp to run it.
Lyndon
My stereo mentor has built some of the monster diy Pass monoblocks, helped me with an AlephJ, and a Krell KSA-50clone. Although I liked the Aleph, the difference of the Krell through my Grounded Grid preamp was simply amazing. Back to my mentor, he built one of the Tripath amps, but is currently most happy with one of those Texas Instrument D amps, the 300W version. It really does punch the ticket on his Dynaudio towers. :o
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I didn't mean to come off as antagonistic or anything--just wanted to convey that I'm not thinking along those lines because I feel I NEED power, but if power is a side effect of the best SQ configuration, so be it--I don't think my Souls will argue nor will my amp be pushed.
You and avionic might be right with the tripath recommendation, I'm just trying to get a handle on how the presentations would differ with power taken out of equation.
From my brief experience with a TK2050 amp, I'd describe what I heard as a more 'precise' musical delivery, which as I understand it is a signature of Tripath sound. The TK2050/tripath has a distinct tonality, and I know some consider the TK2050 the best-sounding Tripath chip. Very very clear, clean, great instrument separation and imaging. Ultimately, though I found that I was listening to the amp itself than to the music. But this was a modified Sure board and I did not have a good power supply like the Meanwell SMPS that people use for those. I'd wager the CDAs lean more towards a lush, 'organic' presentation, imaging is not as precise as the TK2050 that I had, but the soundstage I believe is wider. It's been a while since I had the TK2050 though and the Virtue is a top-notch design so take this with a big grain of salt. I believe the presentation is different enough between the two that you would want to compare w/ your own ears if possible.
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Hi all, could I get some assistance please?
Just finished assembling my SDS258 but getting no sound.
The amp appears to be working ok - I have 2 blue lights on the amp board (and 2 on power supply) and am happy with all wiring.
My question - are there tests I can perform with a multi meter on the input and output terminals on the amp board to determine if it's working ok?
That way I will know if it's a problem with the amp or if I need to take another look at my connections to rca and binding posts.
Excellent thread by the way, thanks to the contributors.
Paul
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It's easier to post some nice clear detailed photos.
Make sure the little switch on the amp board is on. Also, if you're using XLR o RCA make sure the jumpers are correct.
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pics of amp and power board added. I haven't touched the jumpers so hopefully they are correct.
(http://www.audiocircle.com/image.php?id=33065)
(http://www.audiocircle.com/image.php?id=33066)
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Jumpers are on 2&3 which is for RCA input. Is that what you're using?
The amp is on right?
Are the gain pots soldered properly? Turn up midway?
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Yes I'm using RCA. Amp is on - 2 blue lights on power board, 2 yellows briefly on amp board then they turn off and 2 blue lights remain on.
I have turned the gain pots up all the way. Here they are pictured - I hope i have soldered the red & yellow the right way.
(http://www.audiocircle.com/image.php?id=33068)
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If your amp is setup for single ended input. The important thing to remember is… do not use the – on the input for single ended. Connect the + to + and the negative to G (ground). If you connect to -, it will damage the amp. For balanced input, just remove J1 and J2 jumpers completely. J1 and J2 have jumpers on pins 2 and 3… this is for single ended input. If you change the jumpers to pins 1 and 2, it will reverse the polarity… most situations this will probably not sound as good, so no need to mess with that.
For the potentiometers included, the black wire goes to the center pin on the pot, and if holding the pot with pins facing up, the yellow wire goes on the left, and the red wire on the right.
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I am using + and ground on inputs per instructions.
on the gain pots - the yellow should go on the left if holding the pot with pins facing down, but is that with the gain knob pointing towards you or away?
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My gain pot is seen here..
(http://www.audiocircle.com/image.php?id=33069)
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on the gain pots - the yellow should go on the left if holding the pot with pins facing down, but is that with the gain knob pointing towards you or away?
Pins up with the knob to your chest. See photo above. If I had my amp here, I'd take a better picture. If you wait until tomorrow, I can do just that. I'm trying to help you now so you can sleep tonight. :D
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ok thanks for that
My red & yellow wires need to be switched
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ok thanks for that
My red & yellow wires need to be switched
Couldn't you just turn the knob the other way?
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Couldn't you just turn the knob the other way?
I follow directions...
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may as well correct the pot wiring
but still no sound
I might look into how I can test the speaker terminals on the amp for a signal
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may as well correct the pot wiring
but still no sound
I might look into how I can test the speaker terminals on the amp for a signal
Hate to ask the obvious but are you sure your source is sending an audio signal to the amp?
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Yep the source works ok with another amp
It must be either the amp or my connections to RCA/binding posts
The soldering look fine to me, so I was wondering if there was a way to test the amp
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pics of amp and power board added. I haven't touched the jumpers so hopefully they are correct.
(http://www.audiocircle.com/image.php?id=33065)
(http://www.audiocircle.com/image.php?id=33066)
It looks like your connection from transformer to PS board is wrong. 2 Blues together and connect to Gnd. 2 Greens either connect to AC1 or AC2. Experts please confirm.
Thanks
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That's the correct 230v wiring per latest diagram from Tom.
I have been getting assistance from various sources and working through things slowly. Will get there eventually!
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Ok,
Hope things work out for you.
Thanks,
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What I discovered on my 254S was that the input level controls (the pots) worked the opposite of what I expected. When I turned them (what I thought was) all the way up, they were in fact turned all the way down. Turning them counter clockwise (in my experience) usually means you are turning things down, but I found these pots worked the opposite way. Turning things clockwise turned these down, and counter clockwise turned them up. So try setting the pot 'volume' in the middle instead of all the way in one direction or another and see if you get sound that way. Your connections from the transformer must be correct or you would not get blue LEDs lit up when you turn the amp on.
Best of luck,
Neil
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You might try turning the amp board switch off and a brisk turn back on??
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I will give these suggestions a try
Thanks guys
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Paul B, did you get your amp working properly? Did you contact Tom about it? I'm sure he can help in some way. Let us know.
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are you certain the input wiring and output wiring is correct?
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See if any of these help:
(http://www.audiocircle.com/image.php?id=33084)
(http://www.audiocircle.com/image.php?id=33085)
(http://www.audiocircle.com/image.php?id=33087)
(http://www.audiocircle.com/image.php?id=33088)
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Dear Class D Audio enthusiasts,
I was just lucky enough to have jtwrace (Jason) send me a Super D amp to listen to. My audition period lasted about 5 days while my family was out on R&R.
First and foremost, Jason is a gentleman and he promptly mailed the amp to me (we are only 60 miles from each other). The build quality is excellent and in fact, if you are even tempted to think about a case for the amplifier, I will say that his case is awesome. Remember he is in the racing industry (NASCAR was born in Charlotte), so all the hole punching, drilling and engraving/lasering of the nameplates are done. The case is also ready for any of Class D audio's amps, including the SDS series (Super D). Needless to say, I promptly purchased one from him.
The amp completely outclassed my dual mono gainclone which uses Peter Daniel's LM3875 souped up chip amplifiers with dual mono 400VA Plitron transformers and a pair of Lundahl 1676 input transformers (for balanced input and to adjust the gain between 24 dB/30dB). The commercial equivalent of this amp lists for about $2400. More open on top and tighter in the bass, but also more wider and deeper soundstaging. I had no listening fatigue with this amp and I could play it at even louder levels than I usually do. Microdetailing was about the same as my gainclone but definitely more macrodetails (of course the 125 watts helped!). My speakers are GedLee Abbeys so you know where I coming from. The amp is also DEAD QUIET on 95-96dB/2.83V/8 ohm speakers.
I'll be building mine soon, probably with Jensen 4 pole caps in the power supply just for kicks. Although I do have other chassis, I chose Jason's because my other chassis have heatsinks which you don't need for this amp (it would be a waste of a chassis).
Thanks Jason, and thanks Steve for bringing this amp to everybody's attention.
Anand.
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It's not working yet. Today I am going to take it apart and re-assemble outside the box. I am hoping that will fix whatever is not quite right, which must be something very minor as the wiring looks ok.
Will let you know when I get thing to sing.
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Paul, when you figure out the problem, and I'm betting it's something small like wiring something backwards, be sure to let us know. That should help others avoid making the same mistake.
Of course, that's assuming you did make a mistake. Not saying you did...:roll: hope you understand. Thanks!
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No problem. I'm relatively new to diy audio so it could happen.
I re-assembled the amp outside the chassis and de-soldered all RCA and binding post connections and re-attached with tape. I have around 21-22 mv DC at each input terminal. But I have zero AC reading at speaker terminal. Seems to be a problem here.
I will see what Tom has to say.
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Good luck Paul. Please keep us posted.
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I'm going to take the plunge and do the 120 watt kit along with the custom enclosure. I have a solid state NAD pre amp with a phono stage that I hope will be a nice fit. What I'm really hoping for is that this amp will "wake up" my GR Research NX2 speakers which have been rather unremarkable so far. My $1200 NAD amp is also rather unremarkable.
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I'm going to take the plunge and do the 120 watt kit along with the custom enclosure. I have a solid state NAD pre amp with a phono stage that I hope will be a nice fit. What I'm really hoping for is that this amp will "wake up" my GR Research NX2 speakers which have been rather unremarkable so far. My $1200 NAD amp is also rather unremarkable.
Very cool Which custom enclosure? It should work very well...
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That should be a nice combo. I had the demo version of the Neo 2X at my house and pairing them with the Virtue Two amp was just phenomenal.
I'm going to take the plunge and do the 120 watt kit along with the custom enclosure. I have a solid state NAD pre amp with a phono stage that I hope will be a nice fit. What I'm really hoping for is that this amp will "wake up" my GR Research NX2 speakers which have been rather unremarkable so far. My $1200 NAD amp is also rather unremarkable.
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I'm going to take the plunge and do the 120 watt kit along with the custom enclosure. I have a solid state NAD pre amp with a phono stage that I hope will be a nice fit. What I'm really hoping for is that this amp will "wake up" my GR Research NX2 speakers which have been rather unremarkable so far. My $1200 NAD amp is also rather unremarkable.
With those speakers, I'd recommend either the CDA-254 kit or the SDS-254 kit. The CDA-254 is only $15 more than the CDA-224 and double the output. No brainer! Let us know how it works with your setup.
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Paul B, what did Tom have to say about your situation? I'm sure he'll take care of you.
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Yep he sure did. I have a new amp board on the way. Hopefully by the weekend I will have good news to report.
The amp appeared to be wired correctly and I was seeing normal DC levels from the power supply. The problem was the amp board, where I was seeing normal DC readings on input side, but zero AC at speaker side.
I will report back when I found out what happened from Tom.
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Just placed my order for the sds-258 kit :eyebrows: Anand's comparison to his tricked out gainclone was what finally made me break down and order the amp. My initial venture into class d audio was 5 years ago and a huge disappointment so hoping for a better experience here. I'll make sure to post my feelings once I'm all wired up and running.
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Just placed my order for the sds-258 kit :eyebrows: Anand's comparison to his tricked out gainclone was what finally made me break down and order the amp. My initial venture into class d audio was 5 years ago and a huge disappointment so hoping for a better experience here. I'll make sure to post my feelings once I'm all wired up and running.
Great! Happy to be part of your re-introduction being that it was my amp that he used. :thumb:
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Great! Happy to be part of your re-introduction being that it was my amp that he used. :thumb:
I noticed your power supply has different capacitors than what's shown on the website. Care to share what you've replaced them with?
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I noticed your power supply has different capacitors than what's shown on the website. Care to share what you've replaced them with?
My power supply is bone stock.
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Panasonic caps seem to be the go to caps for power supplies.
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Jason, is the 258 a TI board or IR board? I was thinking the IR board sounded better. :scratch: Is that not true? Thanks!
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Jason, is the 258 a TI board or IR board? I was thinking the IR board sounded better. :scratch: Is that not true? Thanks!
The IR does sound better....
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The IR does sound better....
Thanks, so is the 258 an IR?
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Okay, quick and probably dumb question - what is the difference between the various SDS boards? Looking at the images on the site they all look the same. Voltage tolerances on the caps? Heatsinks? (though those all look the same). Maybe there are different driver chips hiding under the heatsinks? I'm just slightly puzzled as there isn't anything obvious to account for the 2x power handling diffence.
Also, is the gain control simply altering the R2 value (or is it R8 maybe?) in the feedback relationship? I'm wondering whether it's possible to just jumper a resistor in place rather than use the pot - I can't imagine having those long wires picking up stray EMI would be the best idea.
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Thanks, so is the 258 an IR?
Yes
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Okay, quick and probably dumb question - what is the difference between the various SDS boards? Looking at the images on the site they all look the same. Voltage tolerances on the caps? Heatsinks? (though those all look the same). Maybe there are different driver chips hiding under the heatsinks? I'm just slightly puzzled as there isn't anything obvious to account for the 2x power handling diffence.
Also, is the gain control simply altering the R2 value (or is it R8 maybe?) in the feedback relationship? I'm wondering whether it's possible to just jumper a resistor in place rather than use the pot - I can't imagine having those long wires picking up stray EMI would be the best idea.
Probably Tom at Class D Audio could answers these questions best.
However, steve k, wushuliu, jtwrace, gitarretyp, avionic, others who are more familiar with the boards can help, too. :)
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Yes
Thanks, AC. :thumb:
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I noticed your power supply has different capacitors than what's shown on the website. Care to share what you've replaced them with?
I changed my board th this one from connex, I noticed an improvement
at first but more later on I quess after the caps burned in more, the values
are 80 volt x 10000uf
(http://www.audiocircle.com/image.php?id=33248)
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I noticed your power supply has different capacitors than what's shown on the website. Care to share what you've replaced them with?
Another option is to replace the stock Nichicon caps with better caps, several of us have used Panasonic TSHA series caps with good results. Mostly improved dynamics in the lower end.
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Very cool Which custom enclosure? It should work very well...
Was thinking of one of your enclosures that is featured on the Class D website. It will be mid September before I order though because we are fleeing the left coast for chilly & cheerful Minnesota.
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Was thinking of one of your enclosures that is featured on the Class D website. It will be mid September before I order though because we are fleeing the left coast for chilly & cheerful Minnesota.
:thumb: :thumb:
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wow - ordered Tuesday arrived Friday. Pretty good service.
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wow - ordered Tuesday arrived Friday. Pretty good service.
Whatcha get?? :wink:
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Whatcha get?? :wink:
SDS-224 kit - just the little guy since I'm looking at it for a nearfield/desktop setup.
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:thumb: :thumb:
motosapien,
:singing: :hyper: :banana piano:
See my note here (http://www.audiocircle.com/index.php?topic=76400.msg812024#msg812024).
Anand.
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This is the site he is talking about:
http://connexelectronic.com/index.php/cPath/25_45?osCsid=e3nv7lugvcdhrhqnqj9taec2q2
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I don't know, but the owner (Christi) has a forum over at DiyAudio and he is knowledgeable and responsive.
http://www.diyaudio.com/forums/connexelectronic/
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Yep he sure did. I have a new amp board on the way. Hopefully by the weekend I will have good news to report.
The amp appeared to be wired correctly and I was seeing normal DC levels from the power supply. The problem was the amp board, where I was seeing normal DC readings on input side, but zero AC at speaker side.
I will report back when I found out what happened from Tom.
Any updates?
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For anyone interested, I'm selling 2 brand new CDA-254 amps for a discount. :thumb:
You can find my AC ad here: http://www.audiocircle.com/index.php?topic=84348.0 (http://www.audiocircle.com/index.php?topic=84348.0)
Paul
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Hi soundnoob,
I received a new amp board from Tom this week and it works fine. I offered to pay for any damage i caused to the old one but Tom said not to worry - 5 star customer service I would say.
I'm not sure what happened to the old board. The wiring is the same now as it was in the beginning. The only difference is that when I first set up the amp, I was short a little wire, so from the power board to amp board, on the "+" leg, i extended the copper wire with about 2 inches of silver wire. When i turned it on i saw a spark originate from near the yellow light for the right channel, and it was damaged from that point.
I don't know if it was the copper/silver combo wire that caused the damage. Regardless I have learned my lesson and I should be more patient with these things.
I can't comment on the sound just yet, my Dodd buffer is only working from one channel. I need to take a closer look at the RCA board.
Paul
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Paul
I'm glad you got the Class D amp running.
Please let me know if I can help.
:wink:
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Just a quick update. I fixed the buffer - there was a loose wire on the RCA board.
The SDS258 amp and Dodd buffer are running in now. It is sounding great and a big step up from my previous amp. I can't wait to hear it in a few weeks. I have a nice Amperex tube on the way as well.
Thanks to all for your help with advice, pictures etc.
Paul
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Paul
:thumb:
Which's Amperex ?
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Amperex 6DJ8, Orange globe logo
I know very little about tubes. this one had positive comments on Joe's tube lore.
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I created a small table of the different boards with the official printed specs. I can also work up an unofficial spec sheet if people will PM details of conversations with Tom regarding unpublished performance.
(http://www.audiocircle.com/image.php?id=33598)
Kind Regards,
Robert
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I created a small table of the different boards with the official printed specs. I can also work up an unofficial spec sheet if people will PM details of conversations with Tom regarding unpublished performance.
Kind Regards,
Robert
That's awesome Robert, thanks!!!
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I have a question why does the SDS254 put out 500w bridged?
I thought the power usually doubles when amps are bridged.
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That's awesome Robert, thanks!!!
Agreed! great post :)
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I just heard from Tom at Class D Audio that the review of one of his amps in Affordable Audio is due out next week. Film at 11.
steve
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I just heard from Tom at Class D Audio that the review of one of his amps in Affordable Audio is due out next week. Film at 11.
steve
That's what they said last month, but I hope you're right. Do you know which boards will be reviewed?
Steve, thanks for the update!
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I didn't ask Tom. I thought it would be better to be surprised.
steve
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I just finished reading all 88 or so pages of this thread,and even thou i dont need another amp im gitty like a school girl about doing a class d amp and custom making a box or platform to display
the amp. I love that a company can make it so simple to do!
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I am considering one of the Class D kits...but they are kind of silent on dimensions...will any of their stereo kits fit in an old Dynaco ST-120 chassis(13x10x4)...thanks
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I am considering one of the Class D kits...but they are kind of silent on dimensions...will any of their stereo kits fit in an old Dynaco ST-120 chassis(13x10x4)...thanks
If you go into the individual amp and power supply descriptions on the ClassD site the measurements are indicated.
Best,
Ed
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Hi, folks,
I'm just finishing up a SDS-258 contruction -- nothing fancy: no mods, just a plug and play. However a question: can I by-pass the supplied volume pots?
Tom at Class D Audio says, "Yes, you have to have the gain pots installed… you’ll like them, use them. It will let you adjust the gain of the amp to match the sweet spot of your preamp… usually between 9:00 and 2:00 position." He gave no further explanation.
Still, I think I'd rather by-pass them if possible. Can this be done easily, e.g. by jumping a couple of the header pins? If so, which ones? Or other simple options?
Your advice will be appreciated!
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I'm just finishing up a SDS-258 contruction -- nothing fancy: no mods, just a plug and play. However a question: can I by-pass the supplied volume pots?
Because these are gain pots and not actually volume controls, are they not just adjusting the gain multiplier of the amplifier, and are not actually part of the signal path?
Steve
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Because these are gain pots and not actually volume controls, are they not just adjusting the gain multiplier of the amplifier, and are not actually part of the signal path?
Steve
The gain vs. volume distinction is unfortunately lost on me, an electronics ignoramous. Note that there is, at the moment, no user manual for the SDS series amps.
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The gain vs. volume distinction is unfortunately lost on me, an electronics ignoramous. Note that there is, at the moment, no user manual for the SDS series amps.
I'm not sure you will actually gain much if anything. Personally, I like the ability to fine tune any amp.
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Because these are gain pots and not actually volume controls, are they not just adjusting the gain multiplier of the amplifier, and are not actually part of the signal path?
Steve
Steve,
You're correct! They are part of the signal path....I don't understand why one wouldn't want to use them as they are a very helpful add on to the Super D series.
just my opinion though.
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Steve,
You're correct! They are part of the signal path....
Okay Jason, don't try to confuse me! Did you leave out the NOT?
Steve
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No, I think he meant they *are* in the signal path. From the reference board schematics, gain on the amps is set via a pair of feedback resistors, similar to an op-amp. It's a reasonable assumption that the Pot is used to replace either 1 or both of these fixed resistors with a variable resistor to alter the gain.
So, they are most likely in the feedback loop, which is definitely 'in the signal path'
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No, I think he meant they *are* in the signal path. From the reference board schematics, gain on the amps is set via a pair of feedback resistors, similar to an op-amp. It's a reasonable assumption that the Pot is used to replace either 1 or both of these fixed resistors with a variable resistor to alter the gain.
So, they are most likely in the feedback loop, which is definitely 'in the signal path'
You are correct. If they are not soldered in, the amp is dead silent. In a bad way. :)
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No, I think he meant they *are* in the signal path. From the reference board schematics, gain on the amps is set via a pair of feedback resistors, similar to an op-amp. It's a reasonable assumption that the Pot is used to replace either 1 or both of these fixed resistors with a variable resistor to alter the gain.
So, they are most likely in the feedback loop, which is definitely 'in the signal path'
Then couldn't a jumper of some type be used to replace them?
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Gain adjustments are for matching the pre amp to the amp. Set it and forget it. Almost all car audio amplifiers have a gain adjustment due to the different output voltage of diff. head units.
My suggestion would be to read up on gain adj.(tons of info out there) and set the gain to match your pre. It really is a very nice feature to have. Also nice if you have more than one amp with gain adj. you could match the levels of the amps.
For me it is nice because I have hearing loss in my left ear( to much loud car audio) so I can adjust the left side up a little and get everything centered. My 2&1/2 cents.
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My pre-amp has volume and balance controls, why would I want a second set in my amp?
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My pre-amp has volume and balance controls, why would I want a second set in my amp?
By adjusting the gain of the amplifier, it can better match the output of the preamp so that the preamp's volume control can have a greater useable range.
A high gain amplifier used with a high output preamplifier can result in a narrow volume control range that can make fine volume adjustments difficult, for example if the combination results in maximum volume reached at a volume control position of only 9:00 o'clock.
Steve
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My pre-amp has volume and balance controls, why would I want a second set in my amp?
Then just get a CDA amp and have Tom set the gain at whatever you prefer.
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Then just get a CDA amp and have Tom set the gain at whatever you prefer.
But i thought the difference between the CDA and SDS amplifiers was more than just balanced inputs, gain controls, better cooling and LED headers. Posters in this thread have said that the SDS sounds better, and if I am not mistaken, you were among them?
Steve
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But i thought the difference between the CDA and SDS amplifiers was more than just balanced inputs, gain controls, better cooling and LED headers. Posters in this thread have said that the SDS sounds better, and if I am not mistaken, you were among them?
Steve
Don't think so. Haven't heard one! As for whether it's better regardless of those new features is a good question. Would be interesting to compare a CDA and SDS w/ equivalent input impedance and gain, etc (are the CDA still 7k input impedance?). - for those who don't need balanced inputs anayway...
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Sorry, I was mistaken. It was one of Steve K's posts I was thinking of:
I and my friends clearly hear a difference in the imaging of the Super D amp. Tom sent me one to verify this because he heard the difference and wanted some outside verifcation.
And from the Class D Audio website:
"Our Super D Series amps provide more life-like imaging and sound stage, along with the beautiful smooth tube-like sound we're known for. These amps are powerful, clean, quiet , and transparent"
It's probably a subtle difference, but with the additional features including larger heatsinking, I will probably go with the SDS version. I suppose one could always solder resistors to the gain control headers, once that perfect value for your particular system was determined by use of the gain controls.
Steve
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By adjusting the gain of the amplifier, it can better match the output of the preamp so that the preamp's volume control can have a greater useable range.
A high gain amplifier used with a high output preamplifier can result in a narrow volume control range that can make fine volume adjustments difficult, for example if the combination results in maximum volume reached at a volume control position of only 9:00 o'clock.
Steve
I realize the validity of this this despite my original question on about the pots -- but wouldn't it be nice if CDA actually provide a sensitivity specification for the product? Forgive me if I say the specifications in general are pretty scant.
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Direct your questions to Tom, he's very responsive and helpful. :D
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It's probably a subtle difference,
Its a little more than subtle, but system dependent. If you have a revealing system the difference is much better control.
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Tom will make the gain whatever you choose. I'm confused about all the fuss over gain pots (which are a good think IMO).
As for the Super D vs IR Board sonically this will be dependent on YOUR ears and YOUR system. There is no doubt (to me) that the adustable gain pots are a nice feature for initial system setup. Once they're set, they're set as long as you don't change components...the good thing is that you can change the gain if you so choose.
Then again, maybe I'm crazy! OK. I am. :thumb:
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Direct your questions to Tom, he's very responsive and helpful. :D
Tom is indeed very responsive and I thank him for it. On the other hand he only said I needed to use the gain pots and that I "will like them", (see above), which isn't has helpful as if he'd offer explanation and/or alternative suggestions.
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Tom will make the gain whatever you choose. I'm confused about all the fuss over gain pots (which are a good think IMO).
As for the Super D vs IR Board sonically this will be dependent on YOUR ears and YOUR system. There is no doubt (to me) that the adustable gain pots are a nice feature for initial system setup. Once they're set, they're set as long as you don't change components...the good thing is that you can change the gain if you so choose.
Then again, maybe I'm crazy! OK. I am. :thumb:
I'd like to keep the signal path as simple as possible. Also since there is a separate trim pot for each channel, how can you be sure they are set equally? If the gain really must be set, I'd prefer a choice of a few matched resistors that could be inserted/selected via a jumper.
My pre-amp has an adjustment range from -96 to +31.5 dB in half dB increments, so it should be no problem for me to find a usable setting for the volume without having an additional set of adjustments inside the amplifier.
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You guys are missing the point, the benefit of the Super is not having adjustable gain but the the rare Ingenus input receiver Tom is fitting the board with. Its super low noise gives the amp control that shines over the regular series even while using rca's.
I'd like to keep the signal path as simple as possible. Also since there is a separate trim pot for each channel, how can you be sure they are set equally? If the gain really must be set, I'd prefer a choice of a few matched resistors that could be inserted/selected via a jumper.
My pre-amp has an adjustment range from -96 to +31.5 dB in half dB increments, so it should be no problem for me to find a usable setting for the volume without having an additional set of adjustments inside the amplifier.
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You guys are missing the point, the benefit of the Super is not having adjustable gain but the the rare Ingenus input receiver Tom is fitting the board with. Its super low noise gives the amp control that shines over the regular series even while using rca's.
I don't think I'm missing the point...I've been futzing with the Super D for awhile now.
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I don't think I'm missing the point...I've been futzing with the Super D for awhile now.
Jason like you said it is system dependent. But my experience was equal to Steve K and Tom's thoughts about the Super having much better control. Adjustable gain is certainly a nice feature also.
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Jason like you said it is system dependent. But my experience was equal to Steve K and Tom's thoughts about the Super having much better control.
OK. and?
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The August issue of Affordable $$ Audio is out and shows a review of the Class D Audio CDA-254. However, I can't get it to load the article, it's showing the dreaded Error 404, in other words, it's not their yet.
Check back... :?
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The August issue of Affordable $$ Audio is out and shows a review of the Class D Audio CDA-254. However, I can't get it to load the article, it's showing the dreaded Error 404, in other words, it's not their yet.
Check back... :?
Congrats to Tom and Jason.
Anyone who has not purchased an amp by now better do so soon, because I see a price
jump comin'...
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OK, the new Affordable $$ Audio issue for August is now online. It has a very nice article about the Class D Audio CDA-254 amp and also a separate review of Jason's amp enclosure.
Congrats to both Tom and Jason, and thanks to Jeff for his interesting and positive articles about both products. :thumb:
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Instead of hiking up the price of kits in general it would be wiser to make the entry offering still attractively affordable while redesigning/improving top of the line SOTA boards/power supplies.
Even better way to capitalize on already popular product would be a customized options and
build/design alternatives.
- cases
- accessories
- PS / batteries
- possibly preamp/buffer option (integrated or separate
Class D amp kits became so popular due to its affordability 1st and performance 2nd and relatively easy build....., even for junior DIYer.
My 2c.
Mariusz
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Congratulations to Tom and Jason. Great sounding amps and a great looking case!! Hopefully, this is just the beginning of the kudos from reviewers. :rock:
steve k
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http://www.affordableaudio.org/aa2010-08.pdf
Congrats! Much deserved recognition!
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Anyone who has not purchased an amp by now better do so soon, because I see a price
jump comin'...
Here is Tom's response to that:
"You can tell them… no price increases for the near future… that wouldn’t be fair!" :thumb:
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:bowdown: :beer: :rock:
Even better!!!!
Mariusz
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Sweet! I got the CDA-254 and Jason's case. Congrats to both of you! :thumb:
Paul
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Thanks for all the compliments! I'm glad that I was able to do something that you guys would like. It's nice to know that I'm part of your enjoyment. :thumb:
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Congrats Jay and well deserved brother...
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Congrats to Tom and Jason.
Anyone who has not purchased an amp by now better do so soon, because I see a price
jump comin'...
:thumb: :thumb: :thumb:
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The deed is done, folks.
I've completed my SDS-258. Despite my earlier questions I just installed the gain pots as instructed; works fine admittedly.
The case is my own fabrication, mostly from 1/2" MDF with a Hammond aluminum case bottom for a back. This is basically the first time I've built a case and I made numerous small mistakes along the way but nothing major. The On/off switch kills the mains input; it's not the one on PC board -- any issue with that? Ons and offs are silent in any case.
Note that I'm using the XLR balanced connectors since my preamp has balanced outs.
(http://www.ody.ca/~wbailey/CDA_SDS-258_open(2).jpg)
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The On/off switch kills the mains input; it's not the one on PC board -- any issue with that?
The AC wiring between the IEC socket, fuse and power switch look a bit smaller than the AC primary wires from the transformer. They may be a sufficient size for the fused allowable current, but it was just something that caught my eye.
Steve
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Feanor,
If you turn your toroidal transformer counter-clockwise a bit, you'll be able to shorten some of your A/C primary and secondary wiring. And...it's a good habit to make twisted pairs of the A/C wiring. Try to keep output wiring away from the A/C wiring by a few more inches, you've done well with the input XLR wiring, which is the way this amp should be listened to imho.
Good work! Given the excellent input stage on this amp, its probably dead silent anyway. And...what Steve said.
Anand.
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The ground strap to the amp board isn't needed just as an FYI. I believe in grounds but that will not do anything IMO.
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Feanor,
If you turn your toroidal transformer counter-clockwise a bit, you'll be able to shorten some of your A/C primary and secondary wiring. And...it's a good habit to make twisted pairs of the A/C wiring. Try to keep output wiring away from the A/C wiring by a few more inches, you've done well with the input XLR wiring, which is the way this amp should be listened to imho.
Good work! Given the excellent input stage on this amp, its probably dead silent anyway. And...what Steve said.
Anand.
Thanks for your comments. I was loath to shorten the transformer leads right away this being my first project. However it is obvious that they could and, I guess, should be shortened. I'll probably do that and make the twisted pairs too.
Srb is correct that my added AC lines look a bit lighter than the transformer leads; they are 16 ga. The fuse is only 4 amp slow-blow but it hasn't blown with me playing as loud as I like.
The amp seems very quite. I have no transformer hum and none from the speakers, and start ups and shut downs are completely silent.
Any
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The ground strap to the amp board isn't needed just as an FYI. I believe in grounds but that will not do anything IMO.
Interesting point, thanks. The board itself has a little label there that says "chassis ground" so that's why I added it.
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Interesting point, thanks. The board itself has a little label there that says "chassis ground" so that's why I added it.
Gotcha. I would need to take a close look at the PCB and see how it's made there. Can't hurt though as long as it's dead silent. Have fun and enjoy!
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Feanor, thanks for posting the pic of your amp. Nice job.
Please give us your impressions of the SDS-258... all 250 wpc. Got headroom? :wink:
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The ground strap to the amp board isn't needed just as an FYI. I believe in grounds but that will not do anything IMO.
I'm no EE or anything but it's been taught to me that it's always a good idea to connect the box to ground. You just never know when something could go bad. It's a safety precaution and cheap protection from potential shocks.
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Here are some "first impressions" of the SDS-258 -- I feel it's still early to give a definitive review. For one thing, I'd like at least one swap back and forrth with my Monarchys. However I offer a few tentative remarks.
• Class D Audio says ... "Our Super D Series amps provide more life-like imaging and sound stage, along with the beautiful smooth tube-like sound we're known for. These amps are powerful, clean, quiet , and transparent." Mostly true.
• "Tube-like"? Well, there's a big variety of tube sound but I'd say not so much, especially if you mean "warm". There is some warmth in the 50-100 Hz bass region but the overall balance isn't especially warm. Versus my Monarchys, there is some prominence at the top of the midrange, but then again the Monarchys are a little reticent in that area.
• "Smooth"? Yes! The device, at least to my old and feeble ears, is basically free of solid state "nasties": no grain, no etching, no glare, and more generally, no harshness. This I say with the reservation that the SDS won't likey gloss over the shortcomings of up or downstream equipment.
• "Powerful, clear, quiet"? Definitely.
• "Transparent"? Yes, big time! Excellent resolution and "air" far exceeding anything I've heard in the price range; (kicks the heck out of Adcoms and NADs I've heard). Furthermore, the equal of the Monarchys and perhaps even my earlier Bel Canto eVo2i.
In my system a noticeable quality is excellent brass and percussion sound from things like bells and cymbals, including cymbals struck with steel brush -- I believe the best I've heard in this particular regard (-- does that make it "tube-like"?). Bass generally seems a bit more powerful and punchy than the Monarchys (which aren't bad either). Is this the slight additional bass warmth? And/or is it the extra power??
Another aspect I'm pleased with the sound of strings: violins, violas, cellos. Bowed and plucked, the amp delivers the full harmonic spectrum. No harshness is add, and -- equally important -- there is not artifical sweetening either. I suspect people who don't listen often to live classical strings have the impression that string ought always to sound silky & smooth. Well it just ain't so: depending to how and when they're played, and how they're recorded of course, the sound can be quite strident. If you want realism you've got to reproduce this the way it is. But again, I don't think the SDS is going is going to disguise poor up or downstream equipment -- or crappy recordings.
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Thanks for that evaluation. I'd be interested in what speakers it's feeding and their impedance. Nice job and much appreciated. 8)
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Thanks for that evaluation. I'd be interested in what speakers it's feeding and their impedance. Nice job and much appreciated. 8)
The speakers are Magneplanar 1.6QR whose impedance is 4 ohms. Have a look at my system via my signature link; everthing is the same as indicated except the amp is the SDS instead of the Monarchy Audios.
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The speakers are Magneplanar 1.6QR whose impedance is 4 ohms.
The SDS-258 was a good choice for the Maggies.
Another aspect I'm pleased with the sound of strings: violins, violas, cellos. Bowed and plucked, the amp delivers the full harmonic spectrum. No harshness is add, and -- equally important -- there is not artifical sweetening either. I suspect people who don't listen often to live classical strings have the impression that string ought always to sound silky & smooth. Well it just ain't so: depending to how and when they're played, and how they're recorded of course, the sound can be quite strident. If you want realism you've got to reproduce this the way it is. But again, I don't think the SDS is going is going to disguise poor up or downstream equipment -- or crappy recordings.
Reading your preference for classical chamber music, I better understand your comments about the real sound of violins and stringed instruments. I absolutely agree!
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O-M-G thought I'd never reach the end of the thread! I've been obsessed! Literally spent days getting here. :green:
But I need some advice, here's my deal. I want to drive relatively low efficiency speakers that drop to slightly less than 2 ohms at the top of the band, the Final Sound 1000i electrostatics (I see Jason jtwrace has, or had? these speakers). I'm still a bit confused if Tom is working on a 2 ohm version, and if so how it's progressing. I emailed him using the form page on his web site, but I wonder how often he checks for those...
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Folks,
My final review of the SDS-258 as posted at Audio Asylum ...
http://www.audioasylum.com/forums/amp/messages/15/157758.html (http://www.audioasylum.com/forums/amp/messages/15/157758.html)
I think its a positive review. :D
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Folks,
My final review of the SDS-258 as posted at Audio Asylum ...
http://www.audioasylum.com/forums/amp/messages/15/157758.html (http://www.audioasylum.com/forums/amp/messages/15/157758.html)
I think its a positive review. :D
Just a thought but that lower treble prominence I don't believe is endemic to these amps and may be related to synergy in your setup. In all the permutations of my gear I have only had that kind of issue if there is something up or down the chain causing it. I think the amps are very transparent that way. Nice review!
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That's a good review Feanor. One line says a lot IMO:
"the SDS' reproduction of steel-brushed cymbals is the best that I heard -- no spray can "pssst" in this case"
What I have been wondering is whether class D amplification (in general, not the company) is in the process of maturing into the first (maybe) truly transparent audio amplification technology.
If that's true, and with it's potential for a big linear power envelope, for less buckola, then boys we have a real game changer in the works here. And that is pretty exciting!
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I've had my sds-258 amplifier playing for the last 3 days. I have it paired with a pair of Ohm Walsh speakers and I'm really impressed at what I'm hearing :o
This thing is just a stupid good value.
I'm going to listen to this setup for the next couple hundred hours and then swap my Accuphase integrated back into the mix to see how the two compare.
Tempted to pick up a nice tube pre.
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I've had my sds-258 amplifier playing for the last 3 days. I have it paired with a pair of Ohm Walsh 3000 speakers and I'm really impressed at what I'm hearing :o
This thing is just a stupid good value.
I'm going to listen to this setup for the next couple hundred hours and then swap my Accuphase integrated back into the mix to see how the two compare.
Tempted to pick up a nice tube pre.
hi, Well, haven't heard the Ohm/Walch speakers in a long time. To really make them sing, they do require a lot of power. I don't remember the different models, but the one with the big Upside down woover was the best one.
Will be interested in your selection of the tube preamp. That too is my next decision, but gotta get the funds first.
Ray Bronk
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Anyone try the Grounded Grid preamp with these amps? I think I'm going to build one and try it out.
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Anyone try the Grounded Grid preamp with these amps? I think I'm going to build one and try it out.
http://www.audiocircle.com/index.php?topic=78312.480
Read several posts about the Grounded Grid starting with reply #484. You may want to consider other options.
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Other tube preamps worth looking into are the Bottlehead Foreplay III and battery-powered Quickie. You can't beat the Quickie for cheap and cheerful!
(http://i576.photobucket.com/albums/ss207/corndog642/Bottlehead%20Quickie/8f408d8e.jpg)
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Thanks for that.
What I want is something dead neutral since the amp already has a great balance of neutrality vs warmth. Maybe I'll try the b1 buffer first and go from there.
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Guys, I plan to hook up this amp to my PC for now and add a DAC/Pre-amp as budget permits. I am looking at the Buffalo II.
I have a couple of questions for you. What else do i need for a 5.1 setup? The source will be my PC I will be using the same setup for both Music and HT. Will I need a receiver as well? or will the DAC and Class D Amps suffice?
Thanks!
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Guys, I plan to hook up this amp to my PC for now and add a DAC/Pre-amp as budget permits. I am looking at the Buffalo II.
I have a couple of questions for you. What else do i need for a 5.1 setup? The source will be my PC I will be using the same setup for both Music and HT. Will I need a receiver as well? or will the DAC and Class D Amps suffice?
The external stereo DACs do not know how to decode multi-channel formats such as Dolby Digital, DTS, Dolby TrueHD or DTS-HD Master Audio, and if fed one of signals, they will either make a loud noise or no sound at all. You would think that external DACs should exist that can process multi-channel digital audio, but sadly, they do not.
How you configure your system will depend on your PC's audio card and playback software. Windows will only let you choose one audio device as default. It will treat the analog audio portion and the digital audio portion of the soundcard as two separate devices, and only one can be selected as default. However, if one of your playback applications has the ability to choose a playback source within the software, then you can utilize both the analog and digital side.
Here is an example:
I have a PC with an Realtek HD Audio chipset soundcard. It has analog 5.1 outputs which I could hook up to a 5-channel amplifier and listen to the 5.1 sources that it is able to decode (in my case only Dolby Digital and DTS). If I also have the digital audio output connected to an external stereo DAC, I will not get any sound using iTunes, because I have set the Windows default to analog speakers for my 5.1 output and iTunes has no way to select the digital output within the software, and must use the default.
However, if I playback my music with Foobar, a music player that has the ability within the software to select the digital audio output (even though the Windows default is set to analog speakers) I can utilize the digital audio output.
In my system, I have a 5.1 surround receiver that I use as a preamp, and I have both coaxial and optical digital outputs on the soundcard. One digital output goes to the receiver for 5.1 sound, and the other to an external DAC (and then into an analog bypass input on the receiver) for stereo sound.
So to start out, you can use the 5.1 analog outputs of a PC (if so equipped) into the Class D amplifiers and listen to both 5.1 and stereo. However, without some kind of preamp you would have to use the digital volume control on the computer.
If you later add a DAC, it gets a little more complicated and you will need some kind of multi-channel preamp or processor to tie it all together. Most who get serious about combining stereo and home theatre usually end up with a stereo DAC and a 5.1 surround processor or receiver, and those that want to take sound quality a step further will often add a stereo preamp with HT bypass or external processor loop.
Steve
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Guys, I plan to hook up this amp to my PC for now and add a DAC/Pre-amp as budget permits. I am looking at the Buffalo II.
I have a couple of questions for you. What else do i need for a 5.1 setup? The source will be my PC I will be using the same setup for both Music and HT. Will I need a receiver as well? or will the DAC and Class D Amps suffice?
Thanks!
I had been using an external DAC, the EMU0404-USB for 2 channel. It's amazing for the money. Now that we are setting up 5.1 I have installed a new Asus Essence ST Soundcard with their H6 daughter board. This gives very high quality and up to 7.1 analog output. We are using this in conjunction with JRiver MC15 as a media player. Crossover and equalization is done in MC, so we no longer need a receiver.
I'd be happy to further elaborate and suggest some forum links for this approach, but since it's OT we may want to go to another thread.
Good Luck,
Rod
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Wow thanks Steve and Rod.. am not sure I understand everything you guys said but will come back to you with more questions once I digest the information you posted :)
Thanks once again.
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I am thinking of taking the plunge on this amp. I am considering either the cda-258 or the sds-258 kit. If I want to only use the rca outs, is there any benefit to the the sds over the cda?
I remember reading in one of the posts that it may be better to get the power supply separately elsewhere since it may come with larger caps? Any ides what I should be looking for if I do this and where I can source it?
Also, If I want to try using a battery power supply, what more do I need to get?
Thanks in advance for any help.
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I am thinking of taking the plunge on this amp. I am considering either the cda-258 or the sds-258 kit. If I want to only use the rca outs, is there any benefit to the the sds over the cda?
- The SDS has a higher input impedance and may be a better match with some preamps and volume equipped sources
- The SDS has a larger heatsink for better cooling
- The SDS amps "provide more life-like imaging and sound stage" (per Class D Audio)
- The SDS has external gain controls
- The SDS has LED headers and supplied plug in cable sets
I remember reading in one of the posts that it may be better to get the power supply separately elsewhere since it may come with larger caps? Any ides what I should be looking for if I do this and where I can source it?
I'll let those who have actually purchased other supplies chime in.
Also, If I want to try using a battery power supply, what more do I need to get?
You would need the 12VDC Switching Power Supply that will take your 12V battery input and output +/- 50VDC
http://classdaudio.com/index.php/ac-dc-power-supplies/dc-12v-car-power-supplies/12v-dc-switching-power-supply-500-watt-car-audio.html (http://classdaudio.com/index.php/ac-dc-power-supplies/dc-12v-car-power-supplies/12v-dc-switching-power-supply-500-watt-car-audio.html)
or equivalent
Steve
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Steve beat me to the punch..........
The SDS254 will have a very high quality low noise balanced input receiver, nice thing is that the rca user will also benefit. If you can swing it, get the super. The stock supply isn't bad, it does seem to benefit from increasing the capacitance, panasonic tsha are nice..
Im not sure if the other supply has good caps on it. ??
I am thinking of taking the plunge on this amp. I am considering either the cda-258 or the sds-258 kit. If I want to only use the rca outs, is there any benefit to the the sds over the cda?
I remember reading in one of the posts that it may be better to get the power supply separately elsewhere since it may come with larger caps? Any ides what I should be looking for if I do this and where I can source it?
Also, If I want to try using a battery power supply, what more do I need to get?
Thanks in advance for any help.
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Thanks for the almost immediate help! So the sds seems to be the way to go. I have to decide if I want to go with the battery option now.
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I remember reading in one of the posts that it may be better to get the power supply separately elsewhere since it may come with larger caps? Any ides what I should be looking for if I do this and where I can source it?
If you're handy with a soldering iron, you can just swap out the caps in the stock supply with caps of larger value. This would be the simplest and most affordable way to upgrade the PS,
I've recently increased my PS (using the stock board) from 40k to 90k w/ TSHAs and it's a big thumbs up.
otherwise you're probably referring to the connexelectronic PS's:
http://connexelectronic.com/product_info.php/products_id/87?osCsid=o062fk0l52hb6g3p7jh89tr881
It's been a little while since I had the Connex, but in retrospect I don't think their 90k sounded as good as the 90k w/ stock board and TSHAs I have now.
my .02
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If you guys insist on changing the caps, I would ask Tom to leave the stock caps off the board and send you the board without caps. It will make a much nicer job and less stress on the PCB.
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If you guys insist on changing the caps, I would ask Tom to leave the stock caps off the board and send you the board without caps. It will make a much nicer job and less stress on the PCB.
Great idea!
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This would be the simplest and most affordable way to upgrade the PS,
I've recently increased my PS (using the stock board) from 40k to 90k w/ TSHAs and it's a big thumbs up.
No experience soldering onto a PCB so this may be a challenge. In any case, how much are the upgraded caps and where would I get them?
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http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=P7492-ND
If you dont have to desolder the old ones it will be a piece of cake.
Use whatever size uf to meet your target, these will give you 60k uf.
I just have 4 of them for 40k, think i will grab 2 more though.
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So I need the 63V caps? I could only find up to 10K...is there another source for higher value caps? Might as well go for a decent amount of capacitance if it does not cost much more.
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You have to go lower in voltage to get bigger caps. Tom told me to use a minimum of 63v, but a few other have used 50v.
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If you guys insist on changing the caps, I would ask Tom to leave the stock caps off the board and send you the board without caps. It will make a much nicer job and less stress on the PCB.
Yes, great idea. Thanks Jason.
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Soldering power supply caps into a circuit board:
Not the place you want to learn how to solder IMHO, even if you do not have to remove previously installed caps. But especially if you do.
Don't put the cart before the horse :lol:
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I hear you and very likely I will get someone to help me or look over my shoulder.
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I had been using an external DAC, the EMU0404-USB for 2 channel. It's amazing for the money. Now that we are setting up 5.1 I have installed a new Asus Essence ST Soundcard with their H6 daughter board. This gives very high quality and up to 7.1 analog output. We are using this in conjunction with JRiver MC15 as a media player. Crossover and equalization is done in MC, so we no longer need a receiver.
I'd be happy to further elaborate and suggest some forum links for this approach, but since it's OT we may want to go to another thread.
I'd be interested in hearing more about your adventures along these lines. Looked up the EMU DAC and yes it does look interesting, certainly cheap and cheerful! Amazing really if the mic and line level pre's are as good as the general comment out there. Might be a good way to rip vinyl!
Dave
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Well I took the plunge :thumb:
Jason's case came first, the dude is fast! Reading a monster thread I guess I missed the part about the lettering being engraved :drool: It's always nice to get more than you bargained for!
Beautiful job Jason - thanks.
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Reading a monster thread I guess I missed the part about the lettering being engraved :drool: It's always nice to get more than you bargained for!
Beautiful job Jason - thanks.
Can someone post a pic or two of the engraved front panel? Thanks.
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Well I took the plunge :thumb:
Jason's case came first, the dude is fast! It's always nice to get more than you bargained for!
Beautiful job Jason - thanks.
Yes, yes. . . and yes!!!
I've mentioned it before. I have 2 of his cases. They are pre-punched for the connectors, etc. and for ALL the different amp boards, PS and transformer. It can even be configured for 2 amp boards and with a little tweaking, dual mono.
IMO, Jason's case is a no-brainer, especially for those not big into DIY.
Paul
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Can someone post a pic or two of the engraved front panel? Thanks.
Only the back panel is engraved, the front panel is tastefully minimalist :eyebrows:
But the front panel is actually a frontispiece (thankyou spellcheck) that could be engraved as you wish. Come to think of it, that gives me ideas :green:
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Is it necessary for the PS caps to be matched? Or can one mix and match. My thought is that one could add to the caps on the PS board by connecting a bank of paralleled caps to one of the existing caps in parallel to add more impedance with minimal soldering on the board. Would that work?
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Is it necessary for the PS caps to be matched? Or can one mix and match. My thought is that one could add to the caps on the PS board by connecting a bank of paralleled caps to one of the existing caps in parallel to add more impedance with minimal soldering on the board. Would that work?
Not quite sure what you're suggesting, but if soldering is a put off you're probably better off going w/ the stock PS and maybe tinker down the road. The stock kit sounds terrific as it is, and I'm sure you want everything to go right the first time...
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I'd be interested in hearing more about your adventures along these lines. Looked up the EMU DAC and yes it does look interesting, certainly cheap and cheerful! Amazing really if the mic and line level pre's are as good as the general comment out there. Might be a good way to rip vinyl!
Dave
Hi Dave,
I started a new thread in the Cheap & Cheerful' forum on the 0404USB DAC.
Rod
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Not quite sure what you're suggesting, but if soldering is a put off you're probably better off going w/ the stock PS and maybe tinker down the road. The stock kit sounds terrific as it is, and I'm sure you want everything to go right the first time...
I am not explaining myself well. What I was thinking of was starting with the stock kit and adding an outboard bank of capacitors (the aforementioned Panasonic tsha) in addition to the on-board stock caps. My thought was that one could solder on leads from the outboard bank to (perhaps) the underside of the pcb.
I have not entirely given up on the idea of soldering an unpopulated board with panasonic caps. I could always buy an extra unpopulated PS board from Tom to see if I can do the soldering.
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I am not explaining myself well. What I was thinking of was starting with the stock kit and adding an outboard bank of capacitors (the aforementioned Panasonic tsha) in addition to the on-board stock caps. My thought was that one could solder on leads from the outboard bank to (perhaps) the underside of the pcb.
Why? Do you really think this amp requires it? Personally, If you feel the need to upgrade the caps then do that but adding more isn't necessarily going to give you more sonic performance.
I think it would be wise to put the kit together and listen to the unit first then if you still have the burning desire to DIY crazy, then have at it.
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OK...I will start with a basic kit and then move up from there. I was simply brainstorming.
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I was simply brainstorming.
Nothing wrong with that at all. I built an amp then before I knew it I had a bunch of cases. :duh:
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Why? Do you really think this amp requires it? Personally, If you feel the need to upgrade the caps then do that but adding more isn't necessarily going to give you more sonic performance.
I think it would be wise to put the kit together and listen to the unit first then if you still have the burning desire to DIY crazy, then have at it.
+100
I'm with jtwrace on this one. The version I auditioned was bone stock and sounded fantastic. The only reason I am building mine with 40,000 uf Mundorf E-lytics is because I have them on hand, not because I special ordered them for this project.
Anand.
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The version I auditioned was bone stock and sounded fantastic.
Anand.
That's because it was assembled by ME. :rotflmao:
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Ok this is my first post here on Audio Circle. Seems like a very informative & friendly place, specially for diy kit newbies like myself.
Pleasantries aside, I wish to purchase the SDS-254 kit but would really rather use it as an Integrated amp. How would I go about adding a volume pot (50k, 10k, Alps Blue???) to the mix & what additional components would I need and what are the pitfalls.
Couldn't I just wire the input directly to the volume pot & then on to the amp's input (Diagrams appreciated.)? Seems to easy to be correct...lol.....
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That kit already contains gain pots for both channels so you'll already have built in volume control.
steve
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That kit already contains gain pots for both channels so you'll already have built in volume control.
steve
My understanding was that the gain controls attenuate the gain within a limited range, i.e. not down to "0" volume. And if I am mistaken and they do, you would probably want to replace them with a ganged stereo pot so you wouldn't have to adjust two pots to change volume as well as fiddle to get equal balance.
Steve
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They do go down to zero but as you say, replacing them with a stereo pot would be more convenient.
steve
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They do go down to zero but as you say, replacing them with a stereo pot would be more convenient.
steve
Exactly!
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They do go down to zero but as you say, replacing them with a stereo pot would be more convenient.
steve
I had thought about that option, but you might want to check with Tom first. As I understand it, the purpose of those gain pots is to adjust the amp's gain to match your preamp, and not as a dedicated volume control. But what do I know? :roll:
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I had thought about that option, but you might want to check with Tom first. As I understand it, the purpose of those gain pots is to adjust the amp's gain to match your preamp, and not as a dedicated volume control. But what do I know? :roll:
Well the included gain pots can stay, but what I'm after is a volume pot.
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what's the difference between atenuating gain and volume of an amplifier?
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I would think reducing the gain of the amplifier would have an effect of limiting dynamic range as opposed to a volume attenuator on the input.
Steve
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Here is an email answer I got today from ClassDAudio regarding my request for info about adding a volume control. It seems that adding a volume control is very possible.
Question: Do the included gain controls manage each channel individually or does one affect balance only?
-------------------------------------------------------------------------------------
"Hi XXXXXXX,
Yes, it's possible to use a ganged volume pot on the amp. The SDS comes with 2 high quality gain controls you can use as volume control, so all you have to do is get a dual ganged pot... very easy.
I don't have time to draw up a diagram right now, but I can when I have more time.
Please let me know if I can be more help.
Thanks,
Tom"
---------------------------------------------------------------------------------------
Another question. Will the kit fit into this case? I love the case's dimensions and it is predrilled perfectly for my use.
http://cgi.ebay.com/DIY-Audio-Aluminium-Chassis-Power-AMP-Metal-case-03-/160469515048?pt=LH_DefaultDomain_0
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Another question. Will the kit fit into this case? I love the case's dimensions and it is predrilled perfectly for my use.
http://cgi.ebay.com/DIY-Audio-Aluminium-Chassis-Power-AMP-Metal-case-03-/160469515048?pt=LH_DefaultDomain_0
The amp module would fit, but I sincerely doubt it would hold the power supply.
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I would think reducing the gain of the amplifier would have an effect of limiting dynamic range as opposed to a volume attenuator on the input.
Steve
Interesting, I'd asked a similar question in the lab...
http://www.audiocircle.com/index.php?topic=83491.0
it was also addressed here earlier regarding the attenuator pots with the SDS kits. I figured I'd rather run without them, and use my pre-amp to control volume, but the general consensus was that they were needed to shelve down the amp. I figured more gain would give the impression of greater dynamics. I'm finding it somewhat confusing.
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That was the intended use for the gain controls, to be able to adjust the gain of the amp relative to the gain of the preamp. This was easier than having to modify the board with fixed resistors for 26dB gain or 32dB gain or whatever, particularly if it needed to be changed again for use with a different active preamp, passive preamp or buffer.
If the gain is turned down for low volume listening, say to 10dB gain, and a large dynamic peak of 10dB or 20dB comes along, it seems to me that the amplifier would not have the sufficient gain multiplier to be able to reproduce it.
At higher listening volumes, this is probably a moot point.
Steve
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That was the intended use for the gain controls, to be able to adjust the gain of the amp relative to the gain of the preamp. This was easier than having to modify the board with fixed resistors for 26dB gain or 32dB gain or whatever, particularly if it needed to be changed again for use with a different active preamp, passive preamp or buffer.
Steve
I agree with Steve. While the included pots may attenuate the volume, I don't believe that was their intended purpose, nor do I believe that will provide the best quality sound. Using a high quality preamp or buffered attenuator like the Pass B1 would be my preference.
However, it won't cost much to try, and you don't have to modify anything to do it. Who knows, you may like it.
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Ok, firstly please excuse my newbieness (New word).
I was thinking about how to add a volume control apart from messing with the gain. How about this setup?
Rca Inputs-->volume pot-->amp input
Is this feasible??
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If I'm understanding your idea correctly, that would make your volume control a passive attenuator. Nothing wrong with that as long as you use a quality VC like a Gold Point/Elma stepped attenuator. However, if you want to save some $$$, there is one sold on ebay for $15 that some really like. Also, the PEC pots are surprisingly good.
Given the SDS input impedance of 47K, I'd recommend you keep the attenuator's value at 10K, 20K, 25K. 50K would not be a good match.
Are you using a 2 volt source like a cd player? The SDS amp should provide plenty of clean output.
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Ok, firstly please excuse my newbieness (New word).
Excused, but as much as we would all like to coin a new word, newbieness is already a part of AudioCircle verbiage (if not yet added to the Urban Dictionary (http://www.urbandictionary.com/define.php?term=newbieness))!
nathanm - 6/26/2006
"I can fully appreciate Rob's opera newbieness."
http://www.audiocircle.com/index.php?topic=25121.msg223162#msg223162 (http://www.audiocircle.com/index.php?topic=25121.msg223162#msg223162)
MichaelHiFi - 3/24/2008
"Excuse my newbieness in this forum."
http://www.audiocircle.com/index.php?topic=52620.msg470355#msg470355 (http://www.audiocircle.com/index.php?topic=52620.msg470355#msg470355)
capace - 4/1/2009
"Sorry for my newbieness!"
http://www.audiocircle.com/index.php?topic=66676.msg613831#msg613831 (http://www.audiocircle.com/index.php?topic=66676.msg613831#msg613831)
As well as around the Internet (http://www.lmgtfy.com/?q=newbieness)
Steve
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Excused, but as much as we would all like to coin a new word, newbieness is already a part of AudioCircle verbiage (if not yet added to the Urban Dictionary (http://www.urbandictionary.com/define.php?term=newbieness))!
nathanm - 6/26/2006
"I can fully appreciate Rob's opera newbieness."
http://www.audiocircle.com/index.php?topic=25121.msg223162#msg223162 (http://www.audiocircle.com/index.php?topic=25121.msg223162#msg223162)
MichaelHiFi - 3/24/2008
"Excuse my newbieness in this forum."
http://www.audiocircle.com/index.php?topic=52620.msg470355#msg470355 (http://www.audiocircle.com/index.php?topic=52620.msg470355#msg470355)
capace - 4/1/2009
"Sorry for my newbieness!"
http://www.audiocircle.com/index.php?topic=66676.msg613831#msg613831 (http://www.audiocircle.com/index.php?topic=66676.msg613831#msg613831)
As well as around the Internet (http://www.lmgtfy.com/?q=newbieness)
Steve
Oops, my bad.......Didn't know........
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If I'm understanding your idea correctly, that would make your volume control a passive attenuator. Nothing wrong with that as long as you use a quality VC like a Gold Point/Elma stepped attenuator. However, if you want to save some $$$, there is one sold on ebay for $15 that some really like. Also, the PEC pots are surprisingly good.
Given the SDS input impedance of 47K, I'd recommend you keep the attenuator's value at 10K, 20K, 25K. 50K would not be a good match.
Are you using a 2 volt source like a cd player? The SDS amp should provide plenty of clean output.
This is very interesting news regarding getting a 10k passive VC. Please feel free to PM me details regarding the "Ebay" item & the PEC (Precision Electronics MIL 2RV7?) pots or feel free to post a followup please.
Btw, I found this item (http://cgi.ebay.ca/Valab-23-Step-Attenuator-Potentiometer-10K-Stereo-Log-/270617059671?pt=LH_DefaultDomain_0) Uses the highly regarded Vishay precision resistors. Comments??
A cd player will be the main source, initially at least. Down the road I may even ad a quality input selector, but that's getting away from myself for now. Need to stay focused.
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what's the difference between atenuating gain and volume of an amplifier?
In the context of the thread, its essentially the same( or the former is used to regulate the latter)...
An attenuator is effectively the opposite of an amplifier, though the two work by different methods. While an amplifier provides gain, an attenuator provides loss, or gain less than 1.
Attenuators are usually passive devices made from simple voltage divider networks. Switching between different resistances forms adjustable stepped attenuators and continuously adjustable ones using potentiometers. For higher frequencies precisely matched low VSWR resistance networks are used...http://en.wikipedia.org/wiki/Attenuator_%28electronics%29 (http://en.wikipedia.org/wiki/Attenuator_%28electronics%29)
the term can also apply to impedance matching, which is another thing altogether.
SO you can eliminate the pot(volume control), but you may need to substitute a resistor of equal value to maintain the input impedance (of the amp)...no need for two inline pots (pre & amp)...unless, you are biamping and wish to have an additional trim option per amp.
I have never heard of a pot being used to regulate the dynamics of a signal... :o
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While the included pots may attenuate the volume, I don't believe that was their intended purpose, nor do I believe that will provide the best quality sound. Using a high quality preamp or buffered attenuator like the Pass B1 would be my preference.
I believe using the included pots, or a ganged version, will produce the best sound, as the designer will have them in circuit optimally so as to provide the function of setting the amp gain for the sweet spot of the users pre-amp gain control. That implies the amp gain control will be transparent at any likely setting. Personally I wouldn't worry about using the gain controls in the amp as the main gain on the system, as there is no risk of sonic degradation.
The real problem is you have no input switching as you would with a pre-amp. If you only are going to use one source by all means use the amp gain, but using two mono pots day in and day out would be a royal pain, you would want to use a quality ganged stereo pot as opposed to the single channel pots that come with the amp kit.
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Hey guys, newb here. Found a link and have read much of this thread over the last few days. Very interesting.
My question is this. It seems that most of you are driving more "modern" type speakers with these amps. How do you think they would do with more vintage type speakers? Right now my mid life crisis has Bose 901 series II (please, no rock throwing) and JBL L100T's in the living room. I've also been playing with some Ewave stuff, much discussed over at AK, and will finish a build of them later.
Thanks for all the info here so far!
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Mmaxed
Welcome to AC :thumb:
I don't think you have any problem to drive the ClassD with vintage speakers.
Actually sound very nice with my Klipsch Forte'II and ADS L-810.
May give the 901, L100 a work-out :thumb:
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Here is the link to the GoldPoint page on choosing the value of your attenuator:
http://www.goldpt.com/info.html
If I'm understanding your idea correctly, that would make your volume control a passive attenuator. Nothing wrong with that as long as you use a quality VC like a Gold Point/Elma stepped attenuator. However, if you want to save some $$$, there is one sold on ebay for $15 that some really like. Also, the PEC pots are surprisingly good.
Given the SDS input impedance of 47K, I'd recommend you keep the attenuator's value at 10K, 20K, 25K. 50K would not be a good match.
Are you using a 2 volt source like a cd player? The SDS amp should provide plenty of clean output.
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Ok, firstly please excuse my newbieness (New word).
I was thinking about how to add a volume control apart from messing with the gain. How about this setup?
Rca Inputs-->volume pot-->amp input
Is this feasible??
Hi all,
I'll make the following suggestions for whom it may concern.
Well, first off, I'd be discussing with Tom on how to do this pot thing. Personally, I'd just get the two sets of resistors and plugs. One set for the standard 26DB and the other for the higher gain 32DB and leave it alone. These fixed resistors would replace the two pots. That's my opinion. Whatever pots you install will be compromising the amps. The present pots do play a part, but I don't know if they will achieve what it is you want. I would think that is something that Tom could elaborate mor with you.
secondly, on this capacitor upgrade for the supply, I'd buy whatever values and brands of the caps you want, and send all six of them to Tom, and he can then just solder them in to the board for you. If they are the Panasonics, then Tom can take a listen to see how the stock supply sounds versus the one you are upgrading. He says he has tried bigger supplies with no results. However, results from the various mods seem to indicate otherwise. All I know is for what it matters, is the cleaner the signal being fed from the wall, the better these amps sound. That's my take on it. it would probably be smart for now, just to get the stock supply and listen for awhile, and buy another supply, with no caps on the board, and add your caps. then you can find out just what the real deal here is. Then you can sell the stock supply, and get most of your money out of it.
That's my two sense worth.
Ray Bronk
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Well, first off, I'd be discussing with Tom on how to do this pot thing. Personally, I'd just get the two sets of resistors and plugs. One set for the standard 26DB and the other for the higher gain 32DB
Hi Ray,
Tom offers resistor sets and plugs for the SDS amps?
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My SDS-254 is coming Friday & after all the discussion with respect to adding a Volume control to the unit I've decided to try these two paths.
1) Add a high quality Input selector & Volume attenuator in the box. The input(s) would go to the selector switch then on to the volume control & finally on to the amp's signal input. The advantage of this approach is lower cable length (No Interconnects needed) & not having to go through an additional rca jack.
2) Build a high quality Passive preamp with the same selector & Volume attenuator. I'm also open to preamp kits like this one.
http://cgi.ebay.ca/6N3-5670-Tube-Buffer-Unit-Gain-Amplifier-DIY-Kit-/270480477544?pt=LH_DefaultDomain_0
Btw, here is the volume attenuator I'm loking at or at least something like it.
http://cgi.ebay.ca/Assembled-Dale-23-Step-Attenuator-Volume-Control-100k-/270311271326?pt=LH_DefaultDomain_0
I will naturally test all of this on a wood platform to see how feasible this setup will be.
Questions:
I was told that use of a 10k pot would be better matched to the SDS-254's input. Can anyone verify this?
Any pitfalls or issues that others can clearly see??
My music sources will be a cd player & the amp will also be hooked up to my Panasonic Vierra Plasma Television.
P.S. I need recommendations for a high quality input selector, 2-4 sources, that won't break the bank. I'm in Canada if that helps.
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My SDS-254 is coming Friday & after all the discussion with respect to adding a Volume control to the unit I've decided to try these two paths.
1) Add a high quality Input selector & Volume attenuator in the box. The input(s) would go to the selector switch then on to the volume control & finally on to the amp's signal input. The advantage of this approach is lower cable length (No Interconnects needed) & not having to go through an additional rca jack.
2) Build a high quality Passive preamp with the same selector & Volume attenuator. I'm also open to preamp kits like this one.
http://cgi.ebay.ca/6N3-5670-Tube-Buffer-Unit-Gain-Amplifier-DIY-Kit-/270480477544?pt=LH_DefaultDomain_0
Btw, here is the volume attenuator I'm loking at or at least something like it.
http://cgi.ebay.ca/Assembled-Dale-23-Step-Attenuator-Volume-Control-100k-/270311271326?pt=LH_DefaultDomain_0
I will naturally test all of this on a wood platform to see how feasible this setup will be.
Questions:
I was told that use of a 10k pot would be better matched to the SDS-254's input. Can anyone verify this?
Any pitfalls or issues that others can clearly see??
My music sources will be a cd player & the amp will also be hooked up to my Panasonic Vierra Plasma Television.
P.S. I need recommendations for a high quality input selector, 2-4 sources, that won't break the bank. I'm in Canada if that helps.
http://cgi.ebay.com/Input-Source-Selector-DIY-Kit-4-channels-/220651819871?pt=LH_DefaultDomain_0
http://cgi.ebay.com/Remote-Volume-Control-Input-Selector-DIY-KIT-MV04-/260461954935?pt=LH_DefaultDomain_0
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Oops, my bad.......Didn't know........
newbian-ness?... :D
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The attenuator that you linked is the 100K version, here is the link to the 10K version.
http://cgi.ebay.ca/Assembled-Dale-23-Step-Attenuator-Volume-Control-10k-/270311271534?pt=LH_DefaultDomain_0#ht_2175wt_781
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http://cgi.ebay.com/Input-Source-Selector-DIY-Kit-4-channels-/220651819871?pt=LH_DefaultDomain_0
http://cgi.ebay.com/Remote-Volume-Control-Input-Selector-DIY-KIT-MV04-/260461954935?pt=LH_DefaultDomain_0
That first input selector looks great!
How is the build & sound quality? Any issues with it being part of a Passive Preamp?
I've heard rumblings about relay based selectors vs rotary and being a relay based unit I just would like some insight as to where this will be with respect to sound quality. The relays used are well thought of, at least according to some Google searches I looked at.
I'll combine it with this:
http://cgi.ebay.ca/Assembled-Dale-23-Step-Attenuator-Volume-Control-10k-/270311271534?pt=LH_DefaultDomain_0#ht_2175wt_781
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How would the $175 kit shown here compare with say an Emotiva UPA-2?
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How would the $175 kit shown here compare with say an Emotiva UPA-2?
I've never heard the Emotiva UPA-2 but I think from a dollar to :D factor you'll be ahead with the Class D.
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How would the $175 kit shown here compare with say an Emotiva UPA-2?
From the Affordable Audio review:
"There are better amps out there, but you aren’t going to touch this sound quality
for under a grand even on the used market."
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From the Affordable Audio review:
"There are better amps out there, but you aren’t going to touch this sound quality
for under a grand even on the used market."
And I think that number is being conservative.
looking forward to hearing what my sds-258 sounds like after being paired with either the DCB1 and Lighter Note LDR kit I'm building.
Cheap and cheerful is right :thumb:
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How would the $175 kit shown here compare with say an Emotiva UPA-2?
I think if you read my review here (http://classdaudio.com/index.php/review/product/list/id/186/category/42/), any residual audiophile nervosa will just drift away. However, bear in mind that my review was based on the SDS254 which is the SuperD version for amp module alone is about $235.
Anand.
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How would the $175 kit shown here compare with say an Emotiva UPA-2?
I think if you read my review here (http://classdaudio.com/index.php/review/product/list/id/186/category/42/), any residual audiophile nervosa will just drift away. However, bear in mind that my review was based on the SDS254 which is the SuperD version and is about $235.
The SDS-254 is $235 for the amplifier module only, and $310 for the kit (with power supply board and transformer).
Steve
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The SDS-254 is $235 for the amplifier module only, and $310 for the kit (with power supply board and transformer).
Steve
Yup, thanks for the clarification.
Anand.
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is it possible run these on batteries? How does the SDS compare to the virtue one.2?
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is it possible run these on batteries? How does the SDS compare to the virtue one.2?
Yes. See here (http://www.audiocircle.com/index.php?topic=84285.msg818265#msg818265).
Anand.
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Where can I get the PS board from? Is it possible to do a DIY one?
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Where can I get the PS board from? Is it possible to do a DIY one?
http://classdaudio.com/index.php/products/power-supplies/12v-dc-switching-power-supply-500-watt-car-audio.html (http://classdaudio.com/index.php/products/power-supplies/12v-dc-switching-power-supply-500-watt-car-audio.html)
This one takes a 12VDC input and outputs +/- 50VDC. You could search on eBay for alternatives or kits that have similar specs.
Steve
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I just built an amp using the CDA254 PCB. It sounded a bit thin and nasty at first due to it's low input impedance so I built a unity gain buffer using a pair of LME49710 op-amps and added a 12V regulated PS to drive this. I am feeding it from a home brewed stepped attenuator balance control and a 100K (cheap) log pot. It sounds magnificent!!! It is probably the best sounding amp I've heard in my system and I've had a lot. It is not tube-like in that I don't find it very warm, but it is sweet and extended at the top, extended at the bottom, and probably a bit lean in the midbass. The only issue is that the class D amp really needs a gain stage rather than a unity gain buffer, so I'm looking for ideas for a great sounding tube circuit with a gain of 3. I want 50K - 100K input impedance and an output impedance of 200 ohms or less. I would prefer to use 12AU7 tubes or 5670's as I have a stock of those.
Any ideas for me?
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This last post begs the question, what is everybody using for a preamp with their Class D power amps. I would love to hear from as many people as possible who are using the Class D amp, as to what preamp they are using. I'll start off by saying I'm using the Audio GD P2 solid state preamp and its a pretty darn good combo, but I have the itch to try a tube preamp... Thanks, Martin.
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Many are using the Pass B1 buffer/pre which is zero gain, and I've have not read any complaints about needing more gain. I'm sure others will jump in here to comment.
Are you aware that the gain can be increased on the CDA series amps from 26db (standard) to 32db (high gain). That is twice the amount of gain increase you mentioned. If you don't know already, email Tom to find out which gain setting your amp board has.
Let us know.
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I got into class D stuff with the Virtue line of amps a One-2 this led me to build an SDS-254 which I used both the Virtue and ClassD with my Modwright
SWL 9.0SE tube preamp.
Both systems sounding great, I liked the ClassD a little better, but was
intriqued about how good a low price amp could sound in my system.
With the ClassD amp I had so much gain that I adjusted the pots lower
to 5 ohm setting to allow better range of volume control, which made me
wonder do I need a preamp at all, but I have always really liked tube preamps.
So I started reading the threads on Dodd battery powered buffer, this might be the way to go as far as the cleanest signal to the amp. Well in the mean time
I sold mt 9.0SE and bought a Signature version of the 9.0SE with tube power supply, definite upgrade mainly in lower bass. The difference in cost was not that much so I fiqured I could not loose.
Which brings me back to what if the preamp was less of influence on the signal
ie: the difference between the tube rectified 9.0 and the standard version?
I have been following the Virtue threads because the tripath amp is a really good sounding amplifier. Virtue had a sale on their Model 901 with a Dodd buffer installed, which also can be ordered with a battery power supply, had to order it to see how it will compare to my preamp with the SDS-254, I have a feeling that it will be a close match. I do not need the gain with the ClassD amp, so trying the 901 with it on battery is a promising situation, plus I get a tripath amp along with it to compare to the ClassD.
The bottom line is that I think a tube preamp is the best match with any type
class D amp, if you do not need alot of gain than a buffer might be the best
match. Stay tuned I will post my thoughts once I receive the Sensation 901
which I will use a battery powered tube buffer preamp first before I compare the amp sections. Fun Fun Fun!!
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I'm using a VTL 5.5 tube preamp with my Class D amps. I used to have an all tube system so now only my preamp is tubed. I love the combination with the Class D. The VTL is a very neutral sounding preamp for tubes but still adds the holographic imaging of tubes and brings out the sweetness in the mids where most of the sweetness in the music is--strings, vocals, piano, horns etc.
steve
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The Classic Two with auricaps and Two.2 with sonicaps sound much better than Classic One with VirtueCaps and Two.2 with virtuecaps. If you ordered the M901 with either auricaps or sonicaps I think you will be surprised at how much nicer it sounds. Looking forward to hearing your comparison.
I got into class D stuff with the Virtue line of amps a One-2 this led me to build an SDS-254 which I used both the Virtue and ClassD with my Modwright
SWL 9.0SE tube preamp.
Both systems sounding great, I liked the ClassD a little better, but was
intriqued about how good a low price amp could sound in my system.
With the ClassD amp I had so much gain that I adjusted the pots lower
to 5 ohm setting to allow better range of volume control, which made me
wonder do I need a preamp at all, but I have always really liked tube preamps.
So I started reading the threads on Dodd battery powered buffer, this might be the way to go as far as the cleanest signal to the amp. Well in the mean time
I sold mt 9.0SE and bought a Signature version of the 9.0SE with tube power supply, definite upgrade mainly in lower bass. The difference in cost was not that much so I fiqured I could not loose.
Which brings me back to what if the preamp was less of influence on the signal
ie: the difference between the tube rectified 9.0 and the standard version?
I have been following the Virtue threads because the tripath amp is a really good sounding amplifier. Virtue had a sale on their Model 901 with a Dodd buffer installed, which also can be ordered with a battery power supply, had to order it to see how it will compare to my preamp with the SDS-254, I have a feeling that it will be a close match. I do not need the gain with the ClassD amp, so trying the 901 with it on battery is a promising situation, plus I get a tripath amp along with it to compare to the ClassD.
The bottom line is that I think a tube preamp is the best match with any type
class D amp, if you do not need alot of gain than a buffer might be the best
match. Stay tuned I will post my thoughts once I receive the Sensation 901
which I will use a battery powered tube buffer preamp first before I compare the amp sections. Fun Fun Fun!!
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dvenardos: Do you have the SDS and the Virtue? which one do you like better?
Thanks! I just received the SDS-254 and the Virtue was something I was thinking about before going with the SDS.
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I'm using an AMC CVT1030 tube preamp. It's been modded over the years, and with the latest addition of PIO coupling caps, it's sounding better than ever. I've enjoyed the way it sounds with various solid state and tube amps (mostly tube), but it's at it's best with my bridged CDA-224's.
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After hearing my newly born sds-258 amplifier a couple weeks back my initial impression was that it would benefit from being paired with a good tube linestage. At that early stage the sound was very smooth but tonally dense in the midband. It wasn't bright in any way, just thick for lack of a better word, and I wanted to hear it open up the way it so effortlessly does with my class A Accuphase integrated.
The sound has changed since my initial impressions, namely that the midband is far more refined and everything has spread out a bit. The transparency is superb. With the sound I'm achieving now I've decided to abandon the idea of pairing the amplifier with a tube linestage, opting instead for either the Pass inspired DCB1 or the Lighter Note light dependent resistor volume control, both of which are on the bench for assembly.
Regarding the change in sound of my amp, I'm not sure what to attribute it to. The only difference is the amp has had additional time to play and also about two weeks ago I changed the magnet wire I was using to 10 gauge Belden and replaced the stock AC cord to a Pangea AC-9 power cord.
It's not the equal of my Accuphase, not yet anyway, but it is close enough that I'll likely sell the Accuphase and have a vinyl shopping bonanza with all the money I pocket. For my high current needs, I have a hard time imagining a more satisfying purchase.
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I've decided to abandon the idea of pairing the amplifier with a tube linestage, opting instead for either the Pass inspired DCB1 or the Lighter Note light dependent resistor volume control, both of which are on the bench for assembly.
Thanks for the report. You must feel that there is no need for an additional gain stage since both the Pass and LDR volume control provide no added gain. How sensitive are your speakers?
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Thanks for the report. You must feel that there is no need for an additional gain stage since both the Pass and LDR volume control provide no added gain. How sensitive are your speakers?
We'll see about the gain once I'm finished with the DCB1. Right now I'm using the preamp section of the Accuphase.
The speakers I have the amp paired with are Ohm Walsh 4.3000's. Essentially vintage Ohm Walsh 4's fitted with Ohm's most current drivers. Even with their 90db rating(need to check on this) Ohm's are notorious for requiring lots of current to sound their best.
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No, I don't have the SDS just commenting on the differences in sound between the Virtue units. I really like the tripath sound and curious how they would compare side to side.
Don
dvenardos: Do you have the SDS and the Virtue? which one do you like better?
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No, I don't have the SDS just commenting on the differences in sound between the Virtue units. I really like the tripath sound and curious how they would compare side to side.
Don
"Side by side"? No, but I did own a Bel Canto eVo2i which is Tripath-based. That was a couple of years ago so I can't A-B the Bel with my SDS-258, but based on my recollection of the sound, I prefer the latter: less bright in the mid-range, solider low bass (40-100 Hz), more accurate instrument harmonics.
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I finished putting my SDS-4 kit into Jason's chassis this weekend. This is the "two ohm" version of the SDS board. Took a week longer than I'd hoped, but now I have an impression and a few photos.
first some background about my approach since I'm new here. I have a passel of amps. But I don't have a single "super amp" because I have two systems that are tri-amped, and I have found it's easier (and cheaper!) to "amp roll" instead of getting three great (and expensive!) amps to do the job. An example might be Adcom GFA-565 monos for bass, Adcom GFA-555II's for mid, and Monarchy SM70Pro for tweets.
Another wrinkle, I'm not home at the moment, I'm in Florida using a 6.5" 2-way with subs, and the amps I have on hand are the SM70Pro and Adcom GFA555II. The Adcom drives the monitors well at the crossover (85Hz) handing off bass to subs beautifully, and is dynamic and big sounding, but grainy. The SM70Pro sounds smoother and more musical, but no cojones :lol: The SDS equals or betters the 555 in dynamics and bass, and betters the SM70 in soundstage and overall clarity. I think it might be the best sounding amplifier I own!
But the acid test for me will be using it with my Final Sound 1000i's. Can't tri-amp these babies, and I haven't had a good enough amp for them, so they have been mostly unused. I have heard them with a great amp, and know what they can do. So that's the test for the SDS-4, coming up hopefully in another few weeks (I wanted the 2 ohm version for the electrostatic impedance dip at high frequencies). I was going to run up to New Jersey for a few weeks this weekend, but hurricane Earl had other ideas.
A niggle, the power here is dirty and I have a slight 60Hz hum, low enough that music at low levels masks it. I have to get a cheap n cheerful power conditioner and have found some ideas here, interested in the Blue Circle Thingee so far, wondering what you guys think. I may go to shielded input cables too, can't hurt.
I'll see if I can post a pic of the board too, here goes :roll:
(http://www.audiocircle.com/image.php?id=34977)
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...
first some background about my approach since I'm new here. I have a passel of amps. But I don't have a single "super amp" because I have two systems that are tri-amped, and I have found it's easier (and cheaper!) to "amp roll" instead of getting three great (and expensive!) amps to do the job. An example might be Adcom GFA-565 monos for bass, Adcom GFA-555II's for mid, and Monarchy SM70Pro for tweets.
Another wrinkle, I'm not home at the moment, I'm in Florida using a 6.5" 2-way with subs, and the amps I have on hand are the SM70Pro and Adcom GFA555II. The Adcom drives the monitors well at the crossover (85Hz) handing off bass to subs beautifully, and is dynamic and big sounding, but grainy. The SM70Pro sounds smoother and more musical, but no cojones :lol: The SDS equals or betters the 555 in dynamics and bass, and betters the SM70 in soundstage and overall clarity. I think it might be the best sounding amplifier I own!
...
This is interesting because I currently own a pair of Monarchy SM-70 Pros and have, in the past, owned the Adcom GFA-555II. I pretty much agree with your relative assessments except, perhaps, on one critical point.
IMO, neither the Monarchy nor the Adcom compare for resolution & transparency with the SDS. The Monarchy is certainly a mellower sound that many people will prefer; it is maybe a little dark in the low treble. I agree that the SDS has more bass power and is generally more realistic in the mid-low bass, say 40-100 Hz. Most importantly, the SDS is a more accurate overall. It more accurately conveys instrument harmonics through my Magneplanar MG 1.6s and produces their sounds more realistically, notably brass, percussion (e.g. cymbals), and strings. The Monarchy is smoother, yes, but I would definitely not say more "musical" if we're talking about authentic reproduction of individual instruments.
The Adcom 555II is, IMO, a pleasant but rather dark sounding amp by comparison; it doesn't remotely approach the SDS for instrumental realism nor transparency. The 555II has good dynamic bass punch, but the SDS is at least it's equal.
The amp I've owned that is closest to the SDS was the Bel Canto eVo2i which is a Tripath-based amp. I dont' have the Bel around now but I think I'd give the nod to the SDS.
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I pretty much agree with your relative assessments except, perhaps, on one critical point.
The Monarchy is smoother, yes, but I would definitely not say more "musical" if we're talking about authentic reproduction of individual instruments.
We agree, the problem is I wasn't clear enough. :duh: What I meant to say is the SM70 is more musical than the Adcom, but the SDS betters the SM70 for "soundstage and overall clarity" (ie musicality).
Anyway, still getting a fix on the SDS, but my early impression is that it does everything right. I just have to track down the source of the 60Hz. When I lift the ground and disconnect the input cables it gets pretty loud. Makes me wonder if I have mis-wired something.
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I just have to track down the source of the 60Hz. When I lift the ground and disconnect the input cables it gets pretty loud. Makes me wonder if I have mis-wired something.
This is something that Wushuliu posted awhile back for noise suppression on a budget. I'd recommend you contact him, or maybe he'll jump in here with some advice.
(http://)
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This is something that Wushuliu posted awhile back for noise suppression on a budget. I'd recommend you contact him, or maybe he'll jump in here with some advice.
That's more of a conditioning device. Double checking the wiring is a good idea.
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Double checking the wiring is a good idea.
I measured the impedance across the signal inputs on the amp board, do these numbers sound right?
100 ohm across ground and minus, 22k ohm across ground and plus.
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Many are using the Pass B1 buffer/pre which is zero gain, and I've have not read any complaints about needing more gain. I'm sure others will jump in here to comment.
Are you aware that the gain can be increased on the CDA series amps from 26db (standard) to 32db (high gain). That is twice the amount of gain increase you mentioned. If you don't know already, email Tom to find out which gain setting your amp board has.
Let us know.
Explain how 26dB to 32dB (a 6dB change) is more than the gain of 3 I mentioned?
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snip...
The only issue is that the class D amp really needs a gain stage rather than a unity gain buffer, so I'm looking for ideas for a great sounding tube circuit with a gain of 3.
...snip
Explain how 26dB to 32dB (a 6dB change) is more than the gain of 3 I mentioned?
Ummm... How are you measuring 'Gain'? Last I checked 6 is more than 3...
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Ummm... How are you measuring 'Gain'? Last I checked 6 is more than 3...
A 6dB gain is equal to a power ratio of 4X. A 4X power ratio is still more gain than 3X, if that is what is being referred to.
Steve
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We are talking voltage gain not power. A voltage gain of 3 is 9.5dB.
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Well since hurricane Earl was down to a cat 2 Friday morning I drove to NJ this weekend after all. Of course I was anxious to hear the new amp on the Final Sound 1000i stats, and the first impression is (drum roll please) - the amp is superb with them, the stats are really on song. I don't have a lot of experience yet with the Finals, but I have never managed to get great sound with them at my house. I knew the problem was I did not have a good enough amp because I schlepped them over to a buddy's house who has an amazing Quad 57 set-up, and the Finals sounded wonderful at the end of his chain. Well now they are sounding wonderful at my house too :thumb: and doing that thing stats do when all it right with set-up, that soft enveloping sound but with amazing levels of detail and staging precision. Dynamics are also very real sounding with excellent bass extension (for stats) but I haven't pushed too hard, going to take some time to find the edges of the envelope, and play with subs too. They are in a smallish extra bedroom at the moment, and good levels are easy to achieve. In this room I wouldn't really need a sub, they get loud enough running full range. I can't say if the Final's sound as good as they did at my buddy's place, it was a very different room for one thing, but I would say "same ball park", except for price of amplification of course!
Yeah, I'm a happy camper right now :green:
Still have that pesky low level 60 Hz hum, but I have some ideas to try out that I think will work.
Speaking of pre-amps, of the ones I have on hand at the moment the Van Alstine Insight is the best lock. I have never heard this pre sound this good either, I guess I didn't know how good it was!
And speaking of subs I will put my two bits in and say check out Epik Empires, a true cheap n cheerful bargain if there ever was one. I've had a lot of subs, a pair of these are easily the best.
Did I say I was a happy camper right now? :lol:
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Show us some pics of that Class D.
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Show us some pics of that Class D.
Hey Jason,
they are in my gallery.
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Hey Jason,
they are in my gallery.
Nice job and nice case. :thumb:
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I finished putting my SDS-4 kit into Jason's chassis this weekend. This is the "two ohm" version of the SDS board. Took a week longer than I'd hoped, but now I have an impression and a few photos.
... snip...
I'll see if I can post a pic of the board too, here goes :roll:
(http://www.audiocircle.com/image.php?id=34977)
Odd, I couldn't find a SDS-4 amp board on the Class-D Audio web site :scratch:
I even just looked for a board with 6 out-put devices and didn't see one.
Could you give us a hint as to some of its specs?
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Nice job and nice case. :thumb:
The case is gorgeous, I love it! Thank you for making it. I'm thinking I may get another amp in case I want to bi-amp something. Better do it before you run out of cases!!!
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The case is gorgeous, I love it! Thank you for making it. I'm thinking I may get another amp in case I want to bi-amp something. Better do it before you run out of cases!!!
Now is the time iwth the case sale!!!
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Odd, I couldn't find a SDS-4 amp board on the Class-D Audio web site :scratch:
I even just looked for a board with 6 out-put devices and didn't see one.
Could you give us a hint as to some of its specs?
It's the 2 ohm version, and stable with 1 ohm also if I'm not mistaken. I specifically asked Tom about it since stats typically dip to 1 ohm at high frequencies. On the other hand there is very little energy at those frequencies, so it not so much a question of enough power as stability.
Other than that I don't know too much about it, for example one thing I am curious about is whether all the SDS variations would sound the same on an easy load (all loafing). Tom also said certain parts for the SDS-4 are in tight supply, which may be why it's not on the site.
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Now is the time iwth the case sale!!!
Sale? You mean the break for 50 quantity? :lol:
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Sale? You mean the break for 50 quantity? :lol:
PM Sent about the sale...
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PM Sent about the sale...
Jason wasn't kidding about the sale - 150 clams, I snapped up another one! sweet!
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Just got my SDS-254 (2ohm version) hooked up for a quick test. It's been a while already and I'm still "Quick Testing". :-)
I pulled out my dusty & trusty HK HD7500 cd player which fortunately has a variable out so no preamp needed...................for now my B1 build is coming.
It looks pretty hacked together right now but it's not going to stay like that for long.
I'm desperately looking for preferably someone local (Montreal) to drill & mill the front /rear of my chassis. I'm Looking hard at HiFi2000 case but at 30 Euro's per panel for customizations I need to find an alternative.
The SDS-254 is going to replace a Mission Cyrus 1 (2nd or 3rd gen designed & built in the U.K. not the newer ones built anywhere but the U.K.). I love that Cyrus Integrated (Now in the shop) but the SDS-254 off the bat grabbed my attention with it's clarity even if it is being fed by an old HK cd player. Very impressive!
(http://www.audiocircle.com/image.php?id=35273)
(http://www.audiocircle.com/image.php?id=35274)
Seems the hardest thing to nail down with my build is going to be the chassis...............
[Update 16h later]
Music to many is that flow of notes & sounds but equally important is the Silence in between. This is one silent amp & that combined with it's speed really highlights the all important silence between notes & sounds.
I'm presently listening to some Marcus Johnson & really loving it.
More to come!
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I have been searching for an SMPS for the Class D audio amps for a while and finally found one. http://connexelectronic.com/product_info.php/products_id/118?osCsid=b0fbhen2sto5c1euaf4vrp4h02
Hooked it up to my CDA-254 and it sounds amazing. Even better than my modded linear power supply with 6x6800uf 63volt caps. The main reason I wanted the SMPS500R was because of the size. It is about 4"x4" , so now a reasonably sized 5 or 7 channel Class D audio amp is possible. Cristi the owner of connexelectronics is very helpful and makes a great product. Highly recommend :thumb:
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OK, so I followed avionic's link for a power-supply, and surfing around that site came across this...
Class-D Amplifier Module 300w x 2 into 8 Ohms $85.99 (http://connexelectronic.com/product_info.php/cPath/39_41/products_id/55?osCsid=b0fbhen2sto5c1euaf4vrp4h02)
and also this...
Class D Power Audio Amplifier Module, scaleable from 2x50W up to 2x500W for $88.88 +/- depending on wattage (http://connexelectronic.com/product_info.php/cPath/39_41/products_id/103?osCsid=b0fbhen2sto5c1euaf4vrp4h02).
Anyone heard either of them?
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The DA-1 is discussed in the class d forum as is the irs amplifier here: http://www.diyaudio.com/forums/connexelectronic/
The IRS amplifier is very similar to the Class D Audio amp I believe. Please correct me if I am wrong. I don't have any experience with either.
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I have been searching for an SMPS for the Class D audio amps for a while and finally found one. http://connexelectronic.com/product_info.php/products_id/118?osCsid=b0fbhen2sto5c1euaf4vrp4h02
Hooked it up to my CDA-254 and it sounds amazing. Even better than my modded linear power supply with 6x6800uf 63volt caps. The main reason I wanted the SMPS500R was because of the size. It is about 4"x4" , so now a reasonably sized 5 or 7 channel Class D audio amp is possible. Cristi the owner of connexelectronics is very helpful and makes a great product. Highly recommend :thumb:
That is a good looking board.
I read on one of these threads (somewhere) that Tom's 12 v switching supply will only work with CDA-254, but I don't understand why that would be the case. The SMPS500R will work with any of Tom's amp boards?
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The DA-1 is discussed in the class d forum as is the irs amplifier here: http://www.diyaudio.com/forums/connexelectronic/
The IRS amplifier is very similar to the Class D Audio amp I believe. Please correct me if I am wrong. I don't have any experience with either.
Well, I read all 8 pages of that thread last night, and while there was much talk about dealing with one little issue or another, there was little to no discussion about the sound quality of the amp. So...
OK, so I followed avionic's link for a power-supply, and surfing around that site came across this...
Class-D Amplifier Module 300w x 2 into 8 Ohms $85.99 (http://connexelectronic.com/product_info.php/cPath/39_41/products_id/55?osCsid=b0fbhen2sto5c1euaf4vrp4h02)
and also this...
Class D Power Audio Amplifier Module, scaleable from 2x50W up to 2x500W for $88.88 +/- depending on wattage (http://connexelectronic.com/product_info.php/cPath/39_41/products_id/103?osCsid=b0fbhen2sto5c1euaf4vrp4h02).
Anyone heard either of them?
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Just got my SDS-254 (2ohm version) hooked up for a quick test. It's been a while already and I'm still "Quick Testing". :-)
I pulled out my dusty & trusty HK HD7500 cd player which fortunately has a variable out so no preamp needed...................for now my B1 build is coming.
It looks pretty hacked together right now but it's not going to stay like that for long.
I'm desperately looking for preferably someone local (Montreal) to drill & mill the front /rear of my chassis. I'm Looking hard at HiFi2000 case but at 30 Euro's per panel for customizations I need to find an alternative.
The SDS-254 is going to replace a Mission Cyrus 1 (2nd or 3rd gen designed & built in the U.K. not the newer ones built anywhere but the U.K.). I love that Cyrus Integrated (Now in the shop) but the SDS-254 off the bat grabbed my attention with it's clarity even if it is being fed by an old HK cd player. Very impressive!
(http://www.audiocircle.com/image.php?id=35273)
(http://www.audiocircle.com/image.php?id=35274)
Seems the hardest thing to nail down with my build is going to be the chassis...............
[Update 16h later]
Music to many is that flow of notes & sounds but equally important is the Silence in between. This is one silent amp & that combined with it's speed really highlights the all important silence between notes & sounds.
I'm presently listening to some Marcus Johnson & really loving it.
More to come!
Is that a laptop ac adapter that you are using for the power supply?
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Is that a laptop ac adapter that you are using for the power supply?
I think the Laptop PS and Amp are both plugged into the same AC off to the left of the image ;)
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Hooked up the new to me Class D amp and was wondering if folks are using any kind of power conditioner with these. the amp sounds great but, it is located in the garage that has only one power outlet and when the mini fridge turns on and off there is a loud "pop" from both speakers when the system is playing. the fridge is plugged into the top outlet and the power strip to the bottom outlet...thoughts??
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Mine is plugged into a conditioner. :wink:
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Hi All,
I have had the SDS258 in my system for awhile and felt some observations were in order.
System components for reference are as follows:
Speakers - Custom GR Research MTM towers
Source - Logitech Squeezebox Receiver
DAC - W4S - DAC-2
Preamp - W4S - STP-SE
Amplifier - Class D Audio SDS258
I am presently using a toslink connection between the Squeezebox Receiver and DAC-2 and all line-level interconnects are single ended.
Initially the sound with this setup was rather mechanical and unmusical.
That all changed when the DAC-2 settings were changed from the factory defaults to the following:
IIR Bandwidth - 70k
Roll-Off Slope - Slow
With these settings, the whole system changed dramatically.
With respect to the SDS258, I can only say that the amp is smooth, accurate, and musical.
No listener fatigue to speak of - mind all that I have owned, and still own, some tube equipment.
In this system it is bargain and half.
Highly recommended.
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Is that a laptop ac adapter that you are using for the power supply?
The laptop adapter & amp power cord are plugged into the same place. In the pic it does look like the adapter is plugged into the amp but this isn't the case.
I am very interested in adding this protection/filtering board to the final build.
http://shop.41hz.com/shop/item.asp?itemid=697&catid=9
With respect to my choice of chassis I came across these:
http://hifi4sale.fullboards.com/audio-video-equipment-for-sale-f1/diy-hifi-chassis-casing-new-t8587.htm
I'm interested in the A28A (Amp & Preamp) or a combination of A28A (Amp) and AV21 (Preamp). Has anyone had any dealings with this retailer?
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Hooked up the new to me Class D amp and was wondering if folks are using any kind of power conditioner with these. the amp sounds great but, it is located in the garage that has only one power outlet and when the mini fridge turns on and off there is a loud "pop" from both speakers when the system is playing. the fridge is plugged into the top outlet and the power strip to the bottom outlet...thoughts??
What kind of power strip? Is it one of those cheap computer ones?
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Nope, heavy duty one...an update, the amp pops through the speakers when not connected to preamp, also swapped out IEC cords, and plugged the unit straight into the wall...no change...all pops :(
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Is the outlet properly grounded? Maybe the fridge is poorly designed.
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none of the other equipment pops when turning on....
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Here's a few general, but related questions...
How did you go about buying your Class-D Audio amplifier?
Did you just go to the web-site, load your cart and check-out?
Or was there an email or telephone exchange before you decided which amp to purchase?
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Here's a few general, but related questions...
How did you go about buying your Class-D Audio amplifier?
Did you just go to the web-site, load your cart and check-out?
Or was there an email or telephone exchange before you decided which amp to purchase?
Buying a Class-D amp really IMHO involves two initial steps, reading & purchasing. Audiocircle is an amazing resource for Class-D info as is DiyAudio and will be very valuable as you gather more information leading up to your purchase.
In my case I "lurked" in forums for weeks soaking up as much info as possible on what was available finally officially joining a few. I settled on the SDS-254 from ClasDaudio.com and after that the purchase was just like any online purchase that I've ever made. Add to the cart & checkout. I did ask a few questions from the people from ClassDaudio.com but after all the reading I had done, my questions were mostly answered in advance.
If you finally decide to purchase a kit or completed product from the likes of 41hz, ClassDaudio, Hifimediy, Connex or whoever it's really a simple process.
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Same as Kingnubian, got as much info as I could from diff. forums and then emailed Tom at ClassDaudio several times with any questions. Tom responds very quickly and is a straight shooter.
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Well I've been reading here, and at DIYAudio for quite some time. I've even had a CDA-224 that someone else had assembled to try for a bit, but it had a pretty bad hum in my system so I didn't really get a good feel for its sound, and I didn't want to disassemble and reassemble my friends amp to see if I could eliminate the hum. But I think I'm getting closer to finally pulling the trigger on one of these.
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I have been searching for an SMPS for the Class D audio amps for a while and finally found one. http://connexelectronic.com/product_info.php/products_id/118?osCsid=b0fbhen2sto5c1euaf4vrp4h02
Hooked it up to my CDA-254 and it sounds amazing. Even better than my modded linear power supply with 6x6800uf 63volt caps. The main reason I wanted the SMPS500R was because of the size. It is about 4"x4" , so now a reasonably sized 5 or 7 channel Class D audio amp is possible. Cristi the owner of connexelectronics is very helpful and makes a great product. Highly recommend :thumb:
Hi Avionic
I am about to order a couple of the SDS-254 boards from ClassDAudio and had planned to power them from a pair of connexectronic A1000SMPS modules. I plan to run the boards in bridged mode and have contacted both Tom and at ClassD and Cristi at connex and both have confirmed that the modules will work well together. I wonder if you could comment a little more on how/why you chose the SMPS500R and how easy (or hard) it was to setup and wire up the modules. Did you have to make any special requests to either Tom or Cristi when you ordered the modules? Also if you have any experience with a linear supply with these modules, can you offer any further sound quality comparison between the two. Finally, I wonder if you could post some pictures of your implementation (especially of the wiring!).
Thanks very much for any help or advice you can offer.
Regards,Dave.
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If you know which amp to get it's as easy as loading your cart, and if you have a special request, I believe there is a "message to seller" field before confirming your purchase. Tom got mine out within 2 days.
Here's a few general, but related questions...
How did you go about buying your Class-D Audio amplifier?
Did you just go to the web-site, load your cart and check-out?
Or was there an email or telephone exchange before you decided which amp to purchase?
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I want to add an On/Off switch to my SDS-254 (Front panel mounted).
I've looked over ClassDAudio's manual and know that a simple external SPST type switch can be added. My question is what spec of switch is supported with respect to voltage ratings, ect?
I'm looking at something like these:
http://www.surplustraders.net/specs/gd261.php
http://www.frozencpu.com/products/8735/ele-397/Blue_Illuminated_Bulgin_Style_Latching_Vandal_Switch_-_16mm_-_Black_Housing_-_Ring_Illumination.html?tl=g52c343s894#blank
http://www.frozencpu.com/cat/l3/g52/c343/s894/list/p1/Switches-16mm_Bulgin_Style_Switches-16mm_Latching_Bulgin_Switches-Page1.html?id=g8LV4JFH
Can these type of switches be used?
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Hey Dave(atterbud) I sent you a PM.
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I want to add an On/Off switch to my SDS-254 (Front panel mounted).
I've looked over ClassDAudio's manual and know that a simple external SPST type switch can be added. My question is what spec of switch is supported with respect to voltage ratings, ect?
I'm looking at something like these:
http://www.surplustraders.net/specs/gd261.php
http://www.frozencpu.com/products/8735/ele-397/Blue_Illuminated_Bulgin_Style_Latching_Vandal_Switch_-_16mm_-_Black_Housing_-_Ring_Illumination.html?tl=g52c343s894#blank
http://www.frozencpu.com/cat/l3/g52/c343/s894/list/p1/Switches-16mm_Bulgin_Style_Switches-16mm_Latching_Bulgin_Switches-Page1.html?id=g8LV4JFH
Can these type of switches be used?
The switch is telling the housekeeping circuit to turn the amp on, so it doesn't need to handle high voltage or current. Any single pole single throw switch will work provided it is latching. Also, the amp turns on when the switch is in the "off" position, which some may find odd. :smoke:
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Hey Dave(atterbud) I sent you a PM.
I second atterbud's curiosity. I would like to hear your thinking too :|
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The switch is telling the housekeeping circuit to turn the amp on, so it doesn't need to handle high voltage or current. Any single pole single throw switch will work provided it is latching. Also, the amp turns on when the switch is in the "off" position, which some may find odd. :smoke:
Thanks for the info!
And yes I find that odd. For a lighted switch it would mean that the led would be off for the amp to be on................very odd for sure.
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For power indication you'll need to add the external LED's that are provided for on the amp board. Don't rely on a lighted switch.
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For power indication you'll need to add the external LED's that are provided for on the amp board. Don't rely on a lighted switch.
Do you happen to know the specification for the LEDs? Do they need a resistor in series or anything like that?
Personally at the moment I'm just using a simple, 115V SPST ahead of the transfomer.
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For power indication you'll need to add the external LED's that are provided for on the amp board. Don't rely on a lighted switch.
Thanks again.
Could I not just wire the switch's LED to the LED headers on the amp board?
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On my board and in the manual there are pads allocated for external LED's. I assume there are current limiting resistors in place already, but found it confusing that the manual specified colors for the LED's... Personally I am going to use red and amber (red for housekeeping circuit powered and amber for amps powered. Once I get this done I'll be able to say whether the connections are current limited or not.
I also have a power switch for the AC before the transformer, but prefer to let the housekeeping cicuit start up before applying power to the amp section so that I'm sure the unit is stable before it connects to my speakers. So I have two stage power. "Standby" and "On" from the front panel only, mains switching on the rear panel. THis also helps because I have an op-amp buffer that needs to charge it's output cap before the power amp comes online to avoid destroying my speakers. The same would happen (only worse) with a tube buffer. :smoke:
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Would someone please post the measurements of the Power-Supply and SDS boards.
The CDA board is listed as 4.25" x 4.5" on the Class-D Audio web site, but I couldn't find measurements for the other boards.
Thanks, Barry
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Email Tom. He is very responsive.
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Would someone please post the measurements of the Power-Supply and SDS boards.
The CDA board is listed as 4.25" x 4.5" on the Class-D Audio web site, but I couldn't find measurements for the other boards.
I can't figure out why all of the board and transformer dimensions as well as the SDS manuals are not on the website. Is it really more time efficient to individually and repeatedly answer the same email inquiries over and over again than to post the missing information on the website?
I'll answer my own question. No, it's not. It's a lot more time consuming.
Steve
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...or you can do what I did...purchase one of each and make a solid CAD model. :duh:
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If you can wait for the weekend, I'll take some measurements on mine and put them on here. I'll take some photos too.
I've heard a few people have grounding issues, so I'll also post some detail on grounding.
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If you can wait for the weekend, I'll take some measurements on mine and put them on here. I'll take some photos too.
I've heard a few people have grounding issues, so I'll also post some detail on grounding.
Excellent, thanks!
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OK, some pictures. I've built the CDA254 kit with the low profile power supply into a chassis from a ghastly Chinese preamp that has finally found a good use... I changed the fuse on the power module to a 6.3A slow blow to allow for toroid inrush. I added a heavy duty mains power switch at the rear to ensure that back emf from the toroid didn't destroy it on turn off. I added two LME49710 buffer stages to transform the input impedance to something usable (50K) and added a home brew shunt balance control (currently mounted at the rear) that works great although it looks a bit scruffy while I optimize resistor values to suit my requirements. Volume is currently a cheap 100K dual log pot, but I have a motorized Alps with input selection relays on the way. Other controls on the front of the preamp are for decoration only... Volume and power are the only controls that work right now. Power controls the housekeeping circuit only. The tube in the front window is for show and I am powering its heater.
Please note I used a partial center point grounding scheme and have the mains ground connected at the inlet. Details are in the photos. This grounding scheme gives me zero hum.
I am driving Vandersteen 2CE's with it - check out "my system" gallery. It is a match made in heaven with the Vandersteens.
Oh, dimensions: (1) transformer 5" x 3-1/4" including mounting bolt.
(2) PSU board 4-1/2" x 4-1/2" x 1-3/4".
(3) CDA 254 amp board 4-1/2" x 4-1/2" x 1-3/4".
Board dimensions INCLUDE stand-offs as supplied.
My chassis is 16-3/4" x 11-1/4" x 4" (including feet) to give an idea of space requirements. It looks OK now, but once I have the remote volume pot, input relays and logic board installed, plus a tube preamp stage, this is going to be packed. I'm not even sure I want to add the tube stage any more as I'm enjoying the quietness of the amp so much. We'll see, I'm always trying to squeeze a bit more out of everything.
(http://www.audiocircle.com/image.php?id=35539)
(http://www.audiocircle.com/image.php?id=35540)
(http://www.audiocircle.com/image.php?id=35541)
(http://www.audiocircle.com/image.php?id=35542)
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raindance, looking forward to your info on grounding.
OK I've got another WOW experience to report. last night I spent the evening setting up a pair of Acoustat 1+1's in my living room, running full range bringing a sub in to match. I spent a lot of the time dialing in the sub and room mode notch, got it sorted out pretty good, with a known decent amp. This morning I stuck the SDS-4 in and jaysus I never heard 1+1's sound like this. That famous Acoustat coloration and the "too big to be a tweeter" sibilants - gone. I don't want to go all hyperbolic, but dang it's pretty close to perfect.
So combined with what I heard with the Final 1000i, I'm beginning to think the SDS-4 is *the* amp for stats. But of course I wonder if the other SDS boards are just as good with stats - or does the SDS-4 1 ohm stability have anything to do with it? Don't know, but curious.
The 60 Hz is not as bad in this room for whatever reason, but I have some ideas about the chassis wiring routing I will try soon. And whenever I have my laptop plugged into the wall I hear "crickets chirping" in the speakers, but not when running on battery, in all three rooms I've had the class D in so far. What's up with that?
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raindance, looking forward to your info on grounding.
OK I've got another WOW experience to report. last night I spent the evening setting up a pair of Acoustat 1+1's in my living room, running full range bringing a sub in to match. I spent a lot of the time dialing in the sub and room mode notch, got it sorted out pretty good, with a known decent amp. This morning I stuck the SDS-4 in and jaysus I never heard 1+1's sound like this. That famous Acoustat coloration and the "too big to be a tweeter" sibilants - gone. I don't want to go all hyperbolic, but dang it's pretty close to perfect.
So combined with what I heard with the Final 1000i, I'm beginning to think the SDS-4 is *the* amp for stats. But of course I wonder if the other SDS boards are just as good with stats - or does the SDS-4 1 ohm stability have anything to do with it? Don't know, but curious.
The 60 Hz is not as bad in this room for whatever reason, but I have some ideas about the chassis wiring routing I will try soon. And whenever I have my laptop plugged into the wall I hear "crickets chirping" in the speakers, but not when running on battery, in all three rooms I've had the class D in so far. What's up with that?
Please post pictures of your wiring scheme for me to review.
Crickets chirping are EMC/EMI from the crappy SMPS that the laptop runs on. I got so tired of this I bought a cheap device to give me an optical out:
(http://www.audiocircle.com/image.php?id=35544)
It is a Behringer UCA202. Now I can use my computer with my DAC and the optical isolation gets rid of the crickets...
Let me help by viewing your grounding scheme as 60Hz hum really muddies bass, so without it you are in for a treat.
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thanks for the offer to help, have a look at the pics in my gallery, if there isn't enough resolution I can post bigger files.
also thanks for the tip in killing the crickets (not the girl band, I like them) :lol:
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Thanks for the measurements raindance, your amp looks good!
Would someone please post the SDS board measurements, I'm not sure they're the same.
Thanks, Barry
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thanks for the offer to help, have a look at the pics in my gallery, if there isn't enough resolution I can post bigger files.
also thanks for the tip in killing the crickets (not the girl band, I like them) :lol:
OK, first observation - you have no grounding scheme. Second - you are trying to have the RCA connectors and XLR's connected to the board at the same time. You can't do this as the RCA input requires the "-" and ground to be shorted to make the input single ended. Usually you would add a switch to select between the two inputs, like B&K does. Are you driving the unit via the XLR input? If so, then you need to try dropping the shield at the amp end and let me know if the hum goes away. The shield does not carry signal in a balanced system, but can cause a ground loop.
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You can have the XLR and RCA inputs connected to the board at the same time you just can't use them at the same time.
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You can have the XLR and RCA inputs connected to the board at the same time you just can't use them at the same time.
Explain how it stays balanced when you do this?
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OK, looked at the manual and - does not need to short to ground. I was wrong !!! So you can have both.
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raindance I don't think the optical isolation of the Beringer thingy will fix the crickets in my case because they are chirping even using analog output from cd player to pre. It seems the nasties are being fed into the ac then back into the class D. But I was looking at your DAC (which looks quite good BTW, first time I'm seeing Keces), and found this, maybe this is what I kneed
http://www.audiocircle.com/index.php?topic=62587.0
appreciate your comments on grounding I'm posting this mid stream and not sure where it ends yet, but yes one of the things I was wondering was "grounding scheme".
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Keces makes good stuff. But an isolation transformer doesn't filter anything so it won't fix your issue. I'm going to add one of these to my amp to filter the AC:
(http://www.audiocircle.com/image.php?id=35548)
It is an inlet filter made by Schurter and these work well. My reason for adding it is to stop the classd amp polluting the mains.
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Oh and I'm using single ended only so far - on deck have a balanced pre to try to see what happens to hum then.
A few more notes about it: when I disconnect audio inputs (single ended) the hum gets pretty loud, then lift ground it goes back to not so bad. I have ground pin on IEC inlet grounded to chassis using one of the IEC mounting bolts.
The level of the hum is low, masked by music, but it's easy to hear with ear to speaker.
Was wondering if one of the stand offs was not reaching ground causing some kind of eddy, haven't tested that yet, and Tom suggested try flipping the xformer. Also thought I would then run power hook-up on chassis bottom and fly audio hook-ups closer to chassis top, and reduce audio trace lengths to as short as possible. If all else fails use coax for audio inputs.
But not sure how to implement a star ground scheme. Thanks again.
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First thing to try is take the 0V from the power supply and connect it to the chassis. Does that make a difference?
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I would also run shielded cable from input jacks to the board - bear in mind the SDS series is more sensitive to hum pickup with its 50K input impedance. But I'm not sure this is your problem as you have done a nice job of twisting the cables, which adds some shielding effect. I think its grounding.
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It is an inlet filter made by Schurter and these work well. My reason for adding it is to stop the classd amp polluting the mains.
Hummm (60Hz) looks like the 5120 is the ticket
http://www.schurterinc.com/en/New-Products/EMC-Products
where are you buying it?
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Mouser has 'em. But it will NOT cure 60Hz, just EMI/EMC issues such as your crickets. Only grounding and shielding can solve 60Hz issues.
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PS: filtering requires excellent grounding to be effective. In the case of the Schurter unit, it needs to be well grounded to the case and to the mains ground.
I'll also be experimenting with simple RC filters on the audio inputs on my amp to remove hash above 50KHz or so. This would not be audible, but it is ultrasonic stuff that can cause the amp to work harder and messes with harmonics.
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First thing to try is take the 0V from the power supply and connect it to the chassis. Does that make a difference?
OK want to make sure I understand - take one of the two ground taps off power supply board (I could use the empty one) and tie it to chassis?
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Yup.
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If it helps, let me know & I'll put up a drawing that should help to revamp your grounding.
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Yup.
OK this may be interesting - I get more hum, but then with audio inputs disconnected I get NO hum, and usually that give me more hum.
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well it was a nice try raindancer, appreciated. As I said it's not bad as is, but still a puzzle. I'm going to try revamping the lead routing as noted within a few days and see what that does, and I'll post an update. Meanwhile better get outside, it's a nice day.
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OK this may be interesting - I get more hum, but then with audio inputs disconnected I get NO hum, and usually that give me more hum.
Well sounds like that may be the culprit. Maybe try separating/disconnectng rca and xlr, then only connect one of them at a time to the amp board inputs and compare.
Also not sure if that long rca/xlr wiring running by the PS and then by the toroid is the best idea.
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I would check that there is no ground leak from the input connectors to the chassis and use only shielded cable to connect to the inputs. It is fine for the amps and power supply to be isolated from the chassis ground (as you have it). That's the way mine are, and they are dead quiet. If starting from scratch, I would try to keep the 120V AC stuff away from the inputs and outputs. In your case, you could add some aluminum channel (screwed to the base) to isolate the 120V wires.
One other thing I noticed with my case... the paint coating was precluding a good ground connection between the top, bottom, sides, front and back. After I added some countersinks (which removed the coating and enabled a clean look with flat head screws instead of the round heads that came with the case) I got a good connection. A picture of my amp is posted somewhere in this thread, I think.
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A picture of my amp is posted somewhere in this thread, I think.
Doug,
It wasn't in this thread but in the Lab when you were discussing your cool bandpass subs using the 12BX100. But anyway, here it is again for all to see:
(http://www.dougsmith.lisalandy.com/myalbum/IMGP3906.jpg)
Notice the cleanliness of Doug's work. Notice how you can draw a circle starting from the power supply all the way to the input/outputs. Notice how the AC lines are very far away from anything DC. This is the sign of a pro builder.
Anand.
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Actually, I'm no pro - just built a few Heathkit things in the old days. I appreciate the compliment, though.
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well it was a nice try raindancer, appreciated. As I said it's not bad as is, but still a puzzle. I'm going to try revamping the lead routing as noted within a few days and see what that does, and I'll post an update. Meanwhile better get outside, it's a nice day.
Actually you are now halfway there> You have narrowed down the problem for me. It is a ground loop (as we suspected all along). Leave the added ground wire in place. Now verify for me which of the other components connected to the amp are grounded? I suspect you'll need to add a cheater plug to your preamp or the power amp to break the loop. Once you go balanced, you can re-ground and simply drop one end of the shield on each XLR cable.
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(http://www.dougsmith.lisalandy.com/myalbum/IMGP3906.jpg)
Notice the cleanliness of Doug's work. Notice how you can draw a circle starting from the power supply all the way to the input/outputs. Notice how the AC lines are very far away from anything DC. This is the sign of a pro builder.
Anand.
And, notice the symmetry of the wiring. Beautifully done, Doug!
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(http://www.dougsmith.lisalandy.com/myalbum/IMGP3906.jpg)
Doug, your wiring looks very clean. But I'm not sure what I'm looking at as the grey cables from the rear panel RCA jacks connect to the amplifier boards. It looks like they terminate into some kind of right angle RCA plugs and are plugged into RCA jacks on the boards.
If so, wouldn't it be better to eliminate a 2nd RCA plug/jack connection and solder the cables directly to the pads on the boards?
Steve
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[quote author=srb link=topic=76400.msg834892#msg834892 date=1284245827
Doug, your wiring looks very clean. But I'm not sure what I'm looking at as the grey cables from the rear panel RCA jacks connect to the amplifier boards. It looks like they terminate into some kind of right angle RCA plugs and are plugged into RCA jacks on the boards.
If so, wouldn't it be better to eliminate a 2nd RCA plug/jack connection and solder the cables directly to the pads on the boards?
Steve
[/quote]
The 1st gen CDAs came with those RCA jack inputs, so I'm guessing they're older boards.
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Doug,
It wasn't in this thread but in the Lab when you were discussing your cool bandpass subs using the 12BX100. But anyway, here it is again for all to see:
(http://www.dougsmith.lisalandy.com/myalbum/IMGP3906.jpg)
Notice the cleanliness of Doug's work. Notice how you can draw a circle starting from the power supply all the way to the input/outputs. Notice how the AC lines are very far away from anything DC. This is the sign of a pro builder.
Anand.
Absolutely gorgeous work! I used to design and build industrial control panels and always prided our group on its good workmanship. I would have tried to hire you!
Only one question. If the two amp boards were rotated 180 would that have not kept the sig leads shorter and further from the supply? Not familiar with this amps layout, but I would assume that the low level stages would be on the side with the inputs. That would also keep that portion of the amp further away. Not trying to criticize - just wondering as I may soon build one of these. It would be my first amp since a tube amp from scratch in 1958.
Rod
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Absolutely gorgeous work! I used to design and build industrial control panels and always prided our group on its good workmanship. I would have tried to hire you!
Only one question. If the two amp boards were rotated 180 would that have not kept the sig leads shorter and further from the supply? Not familiar with this amps layout, but I would assume that the low level stages would be on the side with the inputs. That would also keep that portion of the amp further away. Not trying to criticize - just wondering as I may soon build one of these. It would be my first amp since a tube amp from scratch in 1958.
Rod
It'll sound fine either way given the design of the input stage (on the SDS version, not sure of the CDA version that Doug used), however, yes, in my build the input side of the amp will be facing closer to the XLR/RCA jacks as it is a low level signal. But do notice that Doug used shielded cables to the RCA inputs (the grey wiring) due to the distance involved.
You just have to choose the right methodology depending on how you are going to orient the board. YMMV, JMHO, etc...
Anand.
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....and yes done properly I HIGHLY doubt you could hear a sonic difference between the two.
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Yes, those are the older unbalanced amps. I could have turned the boards the other way, but I thought it would be good to keep the speaker wires short and since I planned to use shielded cable for the inputs I figured that didn't matter. I also thought the convective cooling would work better in the configuration I used because of the layout of holes in my chassis. I also could have removed the RCA jacks, but didn't want to in case there was a problem with one of the boards and I had to return it or in case I decided to do something different with them in the future. It works fine in any case (by the way, that little board near AC-in has a 12V relay that can be used to trigger the amp on from my receiver). The nice thing about isolating the signal ground from the chassis is that ground loops are not possible.
I have been using these for around 8 months now for my subs. I drive them with a DCX2496 (unmodified), which gets its input from the sub-out on my receiver. This combination works quite well even though I am going from single ended to balanced and back again. The refinements on the new boards are nice, but I think the less expensive ones are sufficient for use as sub amps.
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The refinements on the new boards are nice, but I think the less expensive ones are sufficient for use as sub amps.
Wholeheartedly agree. And therein lies the answer to why we don't need to mess with replacing the integrated RCA jacks, etc...its for a sub amp for god's sake :duh:
Anand.
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raindance - made the power supply ground lead a permanent addition and now understand the simplicity of it: if the amp is only connected to AC and speakers it should be dead quiet, and now it is (almost - see below). Problem solved with increased understanding of ground loops - thanks for both.
Also great info on routing by other regulars of this thread. I put the Class D back on the Finals since they are more revealing than the 1+1's, and I do hear a tiny smidge of noise on right channel (ear smack on speaker), sounds like white noise I guess, and left channel dead quiet (amp connected to speakers only). Honestly it's so low in level I never would have noticed it without the other problem leading me to it. Based on the comments here my guess is the right channel input leads being longer, not shielded, and next to xformer are picking up some radiation and feeding that to amp board input. I might be imagining it, but it seems even pushing the leads away from xformer a bit makes a small improvement. So now I know what to do next, thanks for all the help guys! :thumb:
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hottuner - you might find these links helpful on grounding and how to avoid ground loops:
http://www.rane.com/note110.html (http://www.rane.com/note110.html)
http://www.rane.com/note151.html (http://www.rane.com/note151.html)
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Hi Everyone
I received a SDS 4 kit from Tom about a week and a half ago. First off I'd like to congratulate Tom on a very fine product especially at this price point. The kit is stock with the optional heavy duty power supply at the moment. Power rating for the SDS-4 is 150 WPC @ 8ohms /300 wpc @ 4 ohms and 600 @ 2 ohms.
It is working fairly well but seems to be taking a good bit of time to settle in. It also takes about 30 to 45 minutes to really get into it's own from start up. What has your experience been as far as these go?
Sonically, some things I have found, is it is lacking a bit on very low level resolution. The tone is very good and the bass is adiquate and very similar to my tube amps. The highs are rolled off but nothing dramatic. Has anyone else noticed these things?
My speakers are a very tough load - 2.8 ohms through the 30s and a very hard phase angle of 55 degrees at 70 hz. so this may have some bearing on my outcome as they will really tax an amp. The speaker measurements were why Tom suggested the SDS4 rather than the SDS 258 I had originally enquired about. I had wanted a very high power unit as I had tried an old SS amp with the ability to generate 450 WPC into 4 ohms and this really took the woofers under control. The rest of the frequency spectrum of the SS amp wasn't done as nicely and my big tube amps were much better everywhere else.
To the guys who have done the power supply upgrades, do you think either the Connex power supply board ( 6 x 10,000 uF@ 80 volts) or the Connex SMPS supply will be better than the stock heavy duty one and address the short commings above? (This power amp module has +/-35 volt rails so it APPEARS like I could use the SMPS500 )
Just some other observations thus far.
These things do respond to power cord and footer changes. So far I tried the following power cables: Stealth M5000 (1st place) Stealth Cloud 9 ( 2nd place) Virtual Dynamics Master Series (3rd place) and Black Sand Statement 1 ( last) Yes, these cords are all multiples in price of the amp but they do make a nice difference.
For footers, I have tried Symposium Roller Block Jrs ( 1st) Solid Tech Feet of Silence (a very, very close second) , Black Diamond Racing #4 cones ( 3rd) and Herbies Audio feet (last) none of these were anywhere as large a change as the power cords but still worth while.
I haven't gotten around to interconnects and speaker cables yet- once things settle in a bit more I'll do those. I'm currently trying out a set of Grover Huffman's latest speaker cable and this may be the source of the short comings as they are new to me. I have them on a 30 day trial so I'm using them as much as possible to give them a fair shot against my other cables.
Really, if this amp had just a bit more low level resolution it would have a long term home in my system. It cost less than a re-tube of my amps with a set of Gold Lion KT-88 re-issues. That was how I decided to even try this out.
Thanks for any insights you can give me
Kevin
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Welcome to AC Kevin
.......and interesting 1st post.
Enjoy your new amp :thumb:
Mariusz :thumb:
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Kevin welcome to AC, i have not heard much a want to the bottom end with these amps but upgrading the caps and capasitance on the ps did give a nice bump in low end grunt. I agree these amps do respond very well to internal wiring and power cords. I just put a Wywire power cord on my SDS254 and the result was overwelming. Felt like going from mono to stereo with increased resolution and depth of soundstage. Highly reccomend experimenting.
Thanks for sharing your thoughts.
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Sonically, some things I have found, is it is lacking a bit on very low level resolution. The tone is very good and the bass is adiquate and very similar to my tube amps. The highs are rolled off but nothing dramatic. Has anyone else noticed these things?
Kevin
Hi Kevin,
That is exactly how I found the Class D amps. I have not heard Tom's boards but I own a Class D TK2050 100W into 4ohms . It has a tube like sound with warmish bass. Highs are not rolled but they are softer than a good class AB amp. I am using Aussie Amplifiers Nxv200 as a reference amp for comparison.
I think the great thing about the Class D amps is their ability to make any speaker sound good. They even made my Bose cubes sing. (these are my test speakers). Also they have superb value for money considering they can be driven by el cheapo chinese SMPS power supplies.
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hottuner - you might find these links helpful on grounding and how to avoid ground loops:
http://www.rane.com/note110.html (http://www.rane.com/note110.html)
http://www.rane.com/note151.html (http://www.rane.com/note151.html)
Thanks Doug. Just downloaded the PDF's available at those links, on first glance look excellent.
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Hi Everyone
I received a SDS 4 kit from Tom about a week and a half ago. First off I'd like to congratulate Tom on a very fine product especially at this price point. The kit is stock with the optional heavy duty power supply at the moment. Power rating for the SDS-4 is 150 WPC @ 8ohms /300 wpc @ 4 ohms and 600 @ 2 ohms.
It is working fairly well but seems to be taking a good bit of time to settle in. It also takes about 30 to 45 minutes to really get into it's own from start up. What has your experience been as far as these go?
Sonically, some things I have found, is it is lacking a bit on very low level resolution. The tone is very good and the bass is adiquate and very similar to my tube amps. The highs are rolled off but nothing dramatic. Has anyone else noticed these things?
My speakers are a very tough load - 2.8 ohms through the 30s and a very hard phase angle of 55 degrees at 70 hz. so this may have some bearing on my outcome as they will really tax an amp. The speaker measurements were why Tom suggested the SDS4 rather than the SDS 258 I had originally enquired about. I had wanted a very high power unit as I had tried an old SS amp with the ability to generate 450 WPC into 4 ohms and this really took the woofers under control. The rest of the frequency spectrum of the SS amp wasn't done as nicely and my big tube amps were much better everywhere else.
To the guys who have done the power supply upgrades, do you think either the Connex power supply board ( 6 x 10,000 uF@ 80 volts) or the Connex SMPS supply will be better than the stock heavy duty one and address the short commings above? (This power amp module has +/-35 volt rails so it APPEARS like I could use the SMPS500 )
Just some other observations thus far.
These things do respond to power cord and footer changes. So far I tried the following power cables: Stealth M5000 (1st place) Stealth Cloud 9 ( 2nd place) Virtual Dynamics Master Series (3rd place) and Black Sand Statement 1 ( last) Yes, these cords are all multiples in price of the amp but they do make a nice difference.
For footers, I have tried Symposium Roller Block Jrs ( 1st) Solid Tech Feet of Silence (a very, very close second) , Black Diamond Racing #4 cones ( 3rd) and Herbies Audio feet (last) none of these were anywhere as large a change as the power cords but still worth while.
I haven't gotten around to interconnects and speaker cables yet- once things settle in a bit more I'll do those. I'm currently trying out a set of Grover Huffman's latest speaker cable and this may be the source of the short comings as they are new to me. I have them on a 30 day trial so I'm using them as much as possible to give them a fair shot against my other cables.
Really, if this amp had just a bit more low level resolution it would have a long term home in my system. It cost less than a re-tube of my amps with a set of Gold Lion KT-88 re-issues. That was how I decided to even try this out.
Thanks for any insights you can give me
Kevin
These amps will put out whatever you put in, including low level resolution. Your experience w/ the power cords and footers are indicative of this transparency imho. I believe they excel at low level resolution and micro-details, depending on what's up and downstream.
As for the PS, increasing the amount will definitely improve the low end punch. If you are comfortable with the soldering iron, easiest thing to do is replace the caps that come w/ the stock board with higher values. Otherwise, one of the Connex should be fine. Can't vouch for their SMPS, but from all the research I've done just seems like more care has to be taken when implementing SMPS w/ any Class D/T amp.
The rolloff you're experiencing may be related to your speaker impedance. The IRAUDAMP design which the CDA and SDS amps are based on indicate a slight rolloff with 4 ohm speakers vs. 8. I am guessing this continues as the impedance lowers. But that's what the chip pdf says, I don't know if Tom compensated for that.
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Hi Wushuliu
Thanks for your comments.
I guess I should have prefaced my comments in that I'm comparing the sound to a pair of $5 K tube amps that have been fully tricked over. The low level resolution just isn't there with this unit so far, compared to them. As you say this may be from how hard a load my speakers are.
I'm reluctant to dump much more money into this amp as it may be better spent putting it towards a big power SS amp which will sort out the bass issues and still give me a reasonable mid and treble.
Soldering in new caps would not be any issue. I have a hand full or two of 0.47uF Auricaps and Multicaps I was thinking to try as bypass caps.
The internal wire I used is a combination of my favorite Mundorf silver /gold hook up wire for the input wiring and Vacuum State Audio pure silver ribbon for the speaker wiring. I used Kimber rhodium RCA jacks and Eichman speaker pods. The system is a Wadia 861 CD player to a Tom Evans Vibe Pre with the Pluse power supply and S.F. Cremona speakers so the rest of the gear is fairly good.
I'm going to give the amp about another week or so as it is right now for more burn in. Then I'll evaluate the amp with the various speaker cables and make a final descision as to it's long term survival in this system and whether to spend much more on it. The give or take 50 bucks for the Connex power supply seems like a good deal for the better bridge rectification and the additional filtration. We'll see how it all plays out I guess.
Best regards
Kevin
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Hi Wushuliu
Thanks for your comments.
I guess I should have prefaced my comments in that I'm comparing the sound to a pair of $5 K tube amps that have been fully tricked over. The low level resolution just isn't there with this unit so far, compared to them. As you say this may be from how hard a load my speakers are.
I'm reluctant to dump much more money into this amp as it may be better spent putting it towards a big power SS amp which will sort out the bass issues and still give me a reasonable mid and treble.
Soldering in new caps would not be any issue. I have a hand full or two of 0.47uF Auricaps and Multicaps I was thinking to try as bypass caps.
The internal wire I used is a combination of my favorite Mundorf silver /gold hook up wire for the input wiring and Vacuum State Audio pure silver ribbon for the speaker wiring. I used Kimber rhodium RCA jacks and Eichman speaker pods. The system is a Wadia 861 CD player to a Tom Evans Vibe Pre with the Pluse power supply and S.F. Cremona speakers so the rest of the gear is fairly good.
I'm going to give the amp about another week or so as it is right now for more burn in. Then I'll evaluate the amp with the various speaker cables and make a final descision as to it's long term survival in this system and whether to spend much more on it. The give or take 50 bucks for the Connex power supply seems like a good deal for the better bridge rectification and the additional filtration. We'll see how it all plays out I guess.
Best regards
Kevin
Gotcha. No doubt custom $5k amps certainly should have the edge. Are you using only 1 or 2? Seems like using one amp per channel might be better for those speakers.
Given the quality of your gear, Tom's amps would probably want a little more lovin' as far as PS caps (both in capacitance and quality), toroid, etc. to give you what you need (not sure what transformer comes w/ your amp). Some people here advocate 800VA toroid and 100+kuf for the PS to really bring out the best in the amps. For your gear I wouldn't be surprised if you also benefitted from the same investment.
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Hi Wushuliu
Humm that's an interesting thought and one Tom didn't present to me. I wonder if the SDS-4 could be bridged for my system. It would make massive power but might not cut it on the impedance side of things. If things don't improve, I'll see what Tom thinks of that idea.
I still think this is an amazing little amp for the money and one that doesn't need to appologize to very many much more expensive products. If a guy was a pure "music lover" rather than "audiophile", I could see someone being totally happy with one of these.
I was reading about the Ampino amp and family - the higher powered members of those might make a very good candidate for me as well.
Thanks for the feedback
Kevin
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Hi Wushuliu
Humm that's an interesting thought and one Tom didn't present to me. I wonder if the SDS-4 could be bridged for my system. It would make massive power but might not cut it on the impedance side of things. If things don't improve, I'll see what Tom thinks of that idea.
I still think this is an amazing little amp for the money and one that doesn't need to appologize to very many much more expensive products. If a guy was a pure "music lover" rather than "audiophile", I could see someone being totally happy with one of these.
I was reading about the Ampino amp and family - the higher powered members of those might make a very good candidate for me as well.
Thanks for the feedback
Kevin
Cool. Oops I added a little more to my post above, in case you missed that.
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Hi Everyone
I received a SDS 4 kit from Tom about a week and a half ago. First off I'd like to congratulate Tom on a very fine product especially at this price point. The kit is stock with the optional heavy duty power supply at the moment. Power rating for the SDS-4 is 150 WPC @ 8ohms /300 wpc @ 4 ohms and 600 @ 2 ohms.
It is working fairly well but seems to be taking a good bit of time to settle in. It also takes about 30 to 45 minutes to really get into it's own from start up. What has your experience been as far as these go?
Sonically, some things I have found, is it is lacking a bit on very low level resolution. The tone is very good and the bass is adiquate and very similar to my tube amps. The highs are rolled off but nothing dramatic. Has anyone else noticed these things?
My speakers are a very tough load - 2.8 ohms through the 30s and a very hard phase angle of 55 degrees at 70 hz. so this may have some bearing on my outcome as they will really tax an amp. The speaker measurements were why Tom suggested the SDS4 rather than the SDS 258 I had originally enquired about. I had wanted a very high power unit as I had tried an old SS amp with the ability to generate 450 WPC into 4 ohms and this really took the woofers under control. The rest of the frequency spectrum of the SS amp wasn't done as nicely and my big tube amps were much better everywhere else.
...
Just some other observations thus far.
...
Thanks for any insights you can give me
Kevin
Kevin, you must listen to some pretty fine amps to notice poor low-level resolution problems -- or have some pretty fine ears.
I have the impression that Tom often recommends the 254 rather than the 258; does anyone know why this is? I opted for the 258.
By low-level resolution, I presume you mean resolution at low volumes??? I haven't noticed this with my 258 and Magneplanar speakers; on the contrary. It beats my $2.3k Monarchy SM-70 Pro monoblocks and at least equals my $3k Bel Canto eVo2 for resolution at any level -- but then these aren't tube amps or $5k for that matter. I wonder if your experience is related to your particular speakers?
Good luck with your tweaking. Sometimes these measures make a difference, but in my experience much less than basic component upgrades such as to speakers or amps. In that regard the SDS amps are super high-value relative to, e.g., expensive interconnects.
I think we agree that the SDS amps are solid and pleasantly warm in the 40-100 bass range. I find them a tad bright in the lower treble, but I suspect this has reduced a bit with burn-in. In any case, for me, inserting the vendor-supplied 1 ohm resistors in series with my Magneplanar tweeters has substantially removed that brightness.
I don't hear the high frequency roll-off but then I'm deaf above 10 kHz so that might explain that.
- Bill
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Snip...
By low-level resolution, I presume you mean resolution at low volumes???
...Snip
- Bill
Hi Bill, I believe that 'low-level resolution' refers to the ability to hear little details in the signal, and differentiate those sounds from the more prominent ones in the signal, at any volume setting.
Best, Barry
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Hi Bill, I believe that 'low-level resolution' refers to the ability to hear little details in the signal, and differentiate those sounds from the more prominent ones in the signal, at any volume setting.
Best, Barry
Humm ... OK then. Strange though: to me the SDS-258 is exemplary in this respect, and I've heard some good amps over the years.
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I have the impression that Tom often recommends the 254 rather than the 258; does anyone know why this is?
Hi - I suspect that this is just because the 254 is more compatible with a wider range of speakers (impedance-wise) than the 258. I've not heard either altho I have a CDA-254 on the way (seemed like the best fit for my purposes).
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Humm ... OK then. Strange though: to me the SDS-258 is exemplary in this respect, and I've heard some good amps over the years.
Understood Bill. FWIW, please see, about mid-way down the page, here...
http://www.stereophile.com/reference/50/index5.html
You know you're a geeky audiophool when you start referring people to J. Gordon Holt's 'The Audio Glossary ' ;)
(speaking of myself obviously)
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I think there are a couple of things to keep in mind here.
The SDS-4 board must be fairly different from the SDS 25X series. Tom told me there are some parts on this board which are very hard to get presently and are in short supply. He only recommends these to customers with very difficult loads. Therefore, it seems entirely reasonable that this board may sound slightly different from the SDS 25x series.
Most of the low level resolution I find lacking/poorly reproduced is in the treble region which I have already stated is rolled off /shelved down in my system. This may be unique to my system or a character of this series of board. I have a pair of monitor speakers which have a 6 ohm norminal impedance. If I have time in the next couple days, I'll hook those up and see if the treble issue changes.
The other area of mild concern is the very low bass which is not as articulate as my other amps but I think from suggestions here this may be overcome/ameliorated with a higher uF capacity or better power supply.
When I get some results I'll post them here.
Kevin
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I think there are a couple of things to keep in mind here.
The SDS-4 board must be fairly different from the SDS 25X series. Tom told me there are some parts on this board which are very hard to get presently and are in short supply. He only recommends these to customers with very difficult loads. Therefore, it seems entirely reasonable that this board may sound slightly different from the SDS 25x series.
Most of the low level resolution I find lacking/poorly reproduced is in the treble region which I have already stated is rolled off /shelved down in my system. This may be unique to my system or a character of this series of board. I have a pair of monitor speakers which have a 6 ohm norminal impedance. If I have time in the next couple days, I'll hook those up and see if the treble issue changes.
The other area of mild concern is the very low bass which is not as articulate as my other amps but I think from suggestions here this may be overcome/ameliorated with a higher uF capacity or better power supply.
When I get some results I'll post them here.
Kevin
Thanks Kevin. I agree. Look forward to hearing about the 6 ohm speaker.
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Understood Bill. FWIW, please see, about mid-way down the page, here...
http://www.stereophile.com/reference/50/index5.html
You know you're a geeky audiophool when you start referring people to J. Gordon Holt's 'The Audio Glossary ' ;)
(speaking of myself obviously)
Thanks, yes, I guess I haven't looked at that in while. It's good to have a common vocabulary. :)
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Most of the low level resolution I find lacking/poorly reproduced is in the treble region which I have already stated is rolled off /shelved down in my system. This may be unique to my system or a character of this series of board. I have a pair of monitor speakers which have a 6 ohm norminal impedance. If I have time in the next couple days, I'll hook those up and see if the treble issue changes.
Kevin
Hi Kevin, well it's nice to see another SDS-4 at the party :green: I'm also curious about the Connexet SMPS 500R. With this board in particular (600 watts 2 ohm) it would seem desirable, except I find it hard to imagine these tiny mosfets and heatsinks delivering that kind of power without a nice fireworks display!
I'm sure you know this since you mentioned it specifically - the psycho-acoustic effect of high frequency response variation on perceived transparency, resolution, and imaging is pronounced. I wonder if you have ready access to a way to adjust that as you listen? And I must admit I'm curious about your speakers!
Dave
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Hi Everyone
OK, some progress.
I was going to set up the monitors but thought while I was messing about I might as well start with the speaker cable swaps. It had a high probablity to be one source of problems as I had never tried Grover's speaker cable before. This was also the easiest to do first and might save a few steps.
And it did- this was a good 50% of my problem. The Grover speaker cables just did not totally gel with my speakers. Now I have much better high frequency information and low level detail retrieval than with the Grovers. It is still a good bit less than with my tube amps but within what I can live with( especially for the price differential).
The bass is a little tighter and now it seems in the relm of possibility that a power supply board change will get the bass close to what I can live with long term.
The down side for me is the Grover cables had the better midrange than the cables I have in at the moment. I am going to miss that but the overall balance and detail recovery is much more critical to me.
Grover was excellent about the return. I would say if you are in the market for a $300 dollar speaker cable, they would be worth a try - just for that midrange. Maybe with a speaker that isn't so hard to drive they might be perfect. By the way, his $200 Interconnects are simply great. I use them with ICs that are over $1K a pair and it's just flavours with non being "better".
I didn't have time to do much more today. I'm going to just let the system play for a few days. I think things show enough promise to warrent ordering the higher uf Connex linear power supply board and see what that will do. I'm going to chicken out on the SMPS - at least for now.
Best regards
Kevin
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Hey guys,
wired up one bridged sds224 today!! :D blew 4 fuses in the process :duh: the fuse im using is 6a 125v. on the IEC/fuse holder it states to use 250v fuses. oops? rewired everything tried it without fuse and it plays music.
also, im going to be running 2 transformers, 2 power supply, 2 amps, through one IEC/fuse, any problems with this?
thanks for your help.
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Who's plugging their amp into a power conditioner? Just for shits and giggles I plugged my sds-258 amp into a newly acquired cheap & cheerful power conditioner and got a noticeable improvement in the sound. Much better bass, front to back depth and more 3 dimensional with improved harmonics. If you have a decent power conditioner give this a shot and see what it does for you.
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Who's plugging their amp into a power conditioner? Just for shits and giggles I plugged my sds-258 amp into a newly acquired cheap & cheerful power conditioner and got a noticeable improvement in the sound. Much better bass, front to back depth and more 3 dimensional with improved harmonics. If you have a decent power conditioner give this a shot and see what it does for you.
Yes, the cleaner the power the better the sound for these amps. Best bang for the buck is the DIY 193L choke conditioner I mentioned in the modifications thread. It's the one tweak I am a fanatic about. Once you try it you'll never go back (only forward, like with say, dbe's Buss's). You will poop your pants.
Ok maybe not. Like I said, it's the one thing I'm a fanatic about... :peek:
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You will poop your pants.
I'm pretty sure my wife has a rule about that, so I'll just stick with what I have for now.
I was debating trying those Hammond chokes but decided I would try a Grant Fidelity power conditioner, which may have a big choke in it anyway. Special AC accommodation price of $285 shipped which includes their $149 power cord, check it out - http://grantfidelity.com/site/RPF-120-Power-Conditioner
I'll write a more detailed description of what this power conditioner is doing in my set up, but for now let me just say everything is better. I'm pretty sure I have crumby power so don't know how this would work for someone else.
Fyi, for anyone who wants to try Wushuliu's suggestion, there's someone on the trading post that has a few 193L chokes for sale at a very good price.
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Yes, the cleaner the power the better the sound for these amps. Best bang for the buck is the DIY 193L choke conditioner I mentioned in the modifications thread. It's the one tweak I am a fanatic about. Once you try it you'll never go back (only forward, like with say, dbe's Buss's). You will poop your pants.
Ok maybe not. Like I said, it's the one thing I'm a fanatic about... :peek:
Had to do some searching to find the thread, but I believe this is the one. http://www.audiocircle.com/index.php?topic=81223.0 (http://www.audiocircle.com/index.php?topic=81223.0)
When I get one of these I'll wire a ground connection from outlet ground to the transformer case for safety. I don't believe it will have any audible effect. But it could save your bacon if a winding on the choke should ever short to the case (extremely unlikely!). If that did happen and you touch the choke and anything else grounded you are in for a good shock. The safety ground wire should prevent that potential (no pun intended) shocking experience.
Rod
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I had excellent results with the Felix conditioner (as described in the Lab) on the Class D amp I auditioned...parts cost will run you less than $30.
My build, when I get around to it :roll:, will incorporate a Felix as part of the power supply.
No need to go spending $$$... :thumb:
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I had excellent results with the Felix conditioner (as described in the Lab) on the Class D amp I auditioned...parts cost will run you less than $30.
My build, when I get around to it :roll:, will incorporate a Felix as part of the power supply.
No need to go spending $$$... :thumb:
I'd like to do a big Felix project down the road as well, to replace my APC H10. But there's a bit more care involved with a Felix than w/ the choke - wouldn't recommend it to a newb.
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Okay, back on topic: Let's say I have a CDA-224 and a CDA-254, each with their own power supplies. I can still do a bi-amp setup, 224 w/ tweeters and 254 w/ woofers, despite the difference in power (120 vs. 250), right?
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Had to do some searching to find the thread, but I believe this is the one. http://www.audiocircle.com/index.php?topic=81223.0 (http://www.audiocircle.com/index.php?topic=81223.0)
When I get one of these I'll wire a ground connection from outlet ground to the transformer case for safety. I don't believe it will have any audible effect. But it could save your bacon if a winding on the choke should ever short to the case (extremely unlikely!). If that did happen and you touch the choke and anything else grounded you are in for a good shock. The safety ground wire should prevent that potential (no pun intended) shocking experience.
Rod
Hey Rod, actually grounding the choke w/ have affect sound quality but not in a bad way, just different. Let us know your impressions...
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Okay, back on topic: Let's say I have a CDA-224 and a CDA-254, each with their own power supplies. I can still do a bi-amp setup, 224 w/ tweeters and 254 w/ woofers, despite the difference in power (120 vs. 250), right?
Sure..depending on your understanding of Bi-Amping, but you will still have to set (adjust)SPL levels (with pink noise or is it white?) for the two spectrum...
Currently I am biamping (using an active crossover) @320Hz, with the mid/hi using the stock passive crossover. On the mid/hi I am using a 20W tube amp and a 200W SS amp on the bass...level matched of course.
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I have been searching for an SMPS for the Class D audio amps for a while and finally found one. http://connexelectronic.com/product_info.php/products_id/118?osCsid=b0fbhen2sto5c1euaf4vrp4h02
Hooked it up to my CDA-254 and it sounds amazing. Even better than my modded linear power supply with 6x6800uf 63volt caps. The main reason I wanted the SMPS500R was because of the size. It is about 4"x4" , so now a reasonably sized 5 or 7 channel Class D audio amp is possible. Cristi the owner of connexelectronics is very helpful and makes a great product. Highly recommend :thumb:
ok, so with this Smps supply, I assume you don't need a regular power transformer? if that be the case, then this would be a whole lot lighter and maybe a thinner chassis (top to bottom)
Ray
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I have been searching for an SMPS for the Class D audio amps for a while and finally found one. http://connexelectronic.com/product_info.php/products_id/118?osCsid=b0fbhen2sto5c1euaf4vrp4h02
Hooked it up to my CDA-254 and it sounds amazing. Even better than my modded linear power supply with 6x6800uf 63volt caps. The main reason I wanted the SMPS500R was because of the size. It is about 4"x4" , so now a reasonably sized 5 or 7 channel Class D audio amp is possible. Cristi the owner of connexelectronics is very helpful and makes a great product. Highly recommend :thumb:
Hi again,
Hmmm, looked on the site on the SMPS supply, adjusting the voltage Plus/Minus 10% that would make it about just under 50V. That's if my calcs are right. So you used one supply for the one board?
Since I can't see either modules, on the SMPS, did you just solder to tabs, or just to the board? Are they clearly labeled as to what is what?
Thanks.
Ray
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raindance, looking forward to your info on grounding.
OK I've got another WOW experience to report. last night I spent the evening setting up a pair of Acoustat 1+1's in my living room, running full range bringing a sub in to match. I spent a lot of the time dialing in the sub and room mode notch, got it sorted out pretty good, with a known decent amp. This morning I stuck the SDS-4 in and jaysus I never heard 1+1's sound like this. That famous Acoustat coloration and the "too big to be a tweeter" sibilants - gone. I don't want to go all hyperbolic, but dang it's pretty close to perfect.
So combined with what I heard with the Final 1000i, I'm beginning to think the SDS-4 is *the* amp for stats. But of course I wonder if the other SDS boards are just as good with stats - or does the SDS-4 1 ohm stability have anything to do with it? Don't know, but curious.
The 60 Hz is not as bad in this room for whatever reason, but I have some ideas about the chassis wiring routing I will try soon. And whenever I have my laptop plugged into the wall I hear "crickets chirping" in the speakers, but not when running on battery, in all three rooms I've had the class D in so far. What's up with that?
A SDS4? Hmmm, didn't see it on the website. I went up there to look and didn't see it on the new arrival stuff. He's still showing the SDS254 board.
How much was the board? Did you bbuy this as a kit with Transformer and PS?
Ray
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Hi
Was just wondering if anyone knows if Tom gets on Audio Circle at all or has a phone. Mailed him my amp so he could check out the "pop" sound and he got it on monday and he emailed and said he would try and look at it that night. no other emails and no replies to my emails during the week. just would like a headsup on what's going on, if he's gotten to it etc.....
I guess I would call it "hand-holding" :D
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Hi
Was just wondering if anyone knows if Tom gets on Audio Circle at all or has a phone. Mailed him my amp so he could check out the "pop" sound and he got it on monday and he emailed and said he would try and look at it that night. no other emails and no replies to my emails during the week. just would like a headsup on what's going on, if he's gotten to it etc.....
I guess I would call it "hand-holding" :D
I don't think he montors these threads much if at all. He's usually very responsive, even after midnight (PT), so I would say shoot another email. I'm sure he'll come through.
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Well, I've sent 3 and I don't want to bother him, on the other hand it would be nice to have an update :)
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Well, I've sent 3 and I don't want to bother him, on the other hand it would be nice to have an update :)
Give him some time. There have been no complaints about lack of communication as far as I know and a week turnaround for repairs sounds about right. He's a one man operation...
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Ah, one man operation...I was not aware of that! I figured with how nice his website was and the number of products offered that it was him and some staff.
okey doke, I shall be patient...hopefully....:)
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Tom got in touch with me so all is well, i have to have another power added to the already present one, the power supply that the seller installed is adding in the "pop" sound i keep hearing on start up so need to have one switch for the amp and one switch for the power supply...funky, but i guess the cheapest way out....
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So... your amp is not set up with the standard kit parts and wired per manual?
I don't recall reading this complaint before. :scratch:
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I thought I remember that avatar. Alan bought this amp (http://www.audiocircle.com/index.php?topic=84392.0) from Martin. It had caught my attention, but the TI amp board hadn't been getting the rave reviews that the other modules had. The switching power supply also made me a bit leery.
That's quite a testament to Tom's customer service that he's willing to look at an amplifier that was not sold directly by him and that was assembled using parts that were not part of his kit.
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That's quite a testament to Tom's customer service that he's willing to look at an amplifier that was not sold directly by him and that was assembled using parts that were not part of his kit.
I agree 100%. :thumb: Tom knows how to build more than just amps!
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Where are the pictures of the amps that some of you bought cases for?
Let's see them!!!
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Where are the pictures of the amps that some of you bought cases for?
Let's see them!!!
Okie doke, here it goes....
I purchased a case from jtwrace to house two CDA 224 amps, a CDA heavy duty power supply and the standard transformer that CDA sends out with its kits. The amp had been sitting on a board for way too long and it was past time to put it in a decent case.
(http://www.audiocircle.com/image.php?id=36140)
The amp is powering a couple of open-baffle subs.
(http://www.audiocircle.com/image.php?id=36141)
The subs work like this: the signal comes from the line-level outs of my Red Wine Audio Signature 30, which is tied to an attenuator that also controls the volume of the mains. From the RWA the signal goes to a couple of crossovers constructed by Bolder Cable, then to a Reckhorn B-2, which serves as an attenuator and EQ. After the Reckhorn is a Burson Buffer and then the CDA amp. The subs are Hawthorne Audio Augies mounted on 3/4" MDF.
(http://www.audiocircle.com/image.php?id=36142)
I really love the sound of this set up. The bass is both driving and articulate. I don't have any of the problems with boominess like I did with my boxed sub. The CDA amp handles bass duty superbly IMHO. :thumb:
(http://www.audiocircle.com/image.php?id=36143)
Sorry for not snapping one of the inside. :oops:
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Barry
Tom did not sell these directly?? I thought it came from his web site?
If he didn't sell this direct then I really appreciate him taking the time to fix it, he's charging me for it of course but still, awfully nice :)
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Very nice!
Nice case man!
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:fishing: :no_see: :no_hear: :no_speak:
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Barry
Tom did not sell these directly?? I thought it came from his web site?
If he didn't sell this direct then I really appreciate him taking the time to fix it, he's charging me for it of course but still, awfully nice :)
Tom sold the amp module used in the amp you bought, but not the power-supply. You are also the third owner of that particular amp, so did not purchase it from Tom. The wording of my original post maybe a bit off(?)
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Yeah, I knew he didnt do the power supply as he told me that the one in there is not usually used for the application...wonder if the other owners had the "pop" problem and that is why i am the 3rd owner :)
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I've ordered the Connex SMPS500R power supply that avionic mentioned for my cda-254. If it performs well, it'll free up some space in the enclosure for me to maybe add a LDR kit to the dcb1...
http://connexelectronic.com/product_info.php/products_id/118?osCsid=5t1u9gs3oaj7fnjenmriiqv185 (http://connexelectronic.com/product_info.php/products_id/118?osCsid=5t1u9gs3oaj7fnjenmriiqv185)
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I've ordered the Connex SMPS500R power supply that avionic mentioned for my cda-254. If it performs well, it'll free up some space in the enclosure for me to maybe add a LDR kit to the dcb1...
http://connexelectronic.com/product_info.php/products_id/118?osCsid=5t1u9gs3oaj7fnjenmriiqv185 (http://connexelectronic.com/product_info.php/products_id/118?osCsid=5t1u9gs3oaj7fnjenmriiqv185)
I will be very interested in your observations. I'm also thinking of ditching the power supply that came with my SDS-254 and using one of these SMPS's.
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I have received a few PM's asking about the smps500r. Hopefully this answers your ?? if not feel free to shoot me another pm.The smps500r sounds great. I did notice when driving a certain set of monitor speakers that I built, that the 500r couldn't keep up. The speakers are Danny Ritchies (GR Research) anarchy design. Sensitivity is around 84db :|. Those anarchy mids really need some power to get playing loudly. Definitely not the easiest load for an amp and power supply. Matter of fact these speakers fried one of my nuforce 8b,s. Love these speakers by the way.
While playing at very loud levels I noticed that the left speaker would cut in and out. At first I thought it was maybe a bad solder joint of mine. Hooked up the linear power supply and no problems at any levels.
I plan on using the smps500r for a 5 channel class d audio amp that will be driving PSB Image speakers with 93db sensitivity. I really do not think I will have any issues. All in all I am very happy with the smps 500r. It is small 4"x4" and gets rid of both the transformer and power supply board of the linear PS.
Hook up is a breeze 3 wires in and 3 wires out. Just be aware if you are driving difficult loads at very loud levels you may run into some issues. Attatched is a diagram of the 500r circuit board for wiring reference.
(http://www.audiocircle.com/image.php?id=36264)
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I have received a few PM's asking about the smps500r. Hopefully this answers your ?? if not feel free to shoot me another pm.The smps500r sounds great. I did notice when driving a certain set of monitor speakers that I built, that the 500r couldn't keep up. The speakers are Danny Ritchies (GR Research) anarchy design. Sensitivity is around 84db :|. Those anarchy mids really need some power to get playing loudly. Definitely not the easiest load for an amp and power supply. Matter of fact these speakers fried one of my nuforce 8b,s. Love these speakers by the way.
While playing at very loud levels I noticed that the left speaker would cut in and out. At first I thought it was maybe a bad solder joint of mine. Hooked up the linear power supply and no problems at any levels.
I plan on using the smps500r for a 5 channel class d audio amp that will be driving PSB Image speakers with 93db sensitivity. I really do not think I will have any issues. All in all I am very happy with the smps 500r. It is small 4"x4" and gets rid of both the transformer and power supply board of the linear PS.
Hook up is a breeze 3 wires in and 3 wires out. Just be aware if you are driving difficult loads at very loud levels you may run into some issues. Attatched is a diagram of the 500r circuit board for wiring reference.
Excellent info & thanks for posting it here.
Just to confirm, for my SDS-254 I would have to order the "110 Mains supply (I'm in Canada)", "+-54v" version?
With all that free space freed up, maybe I can include the Pass B1 I'm building in the same enclosure as my sds-254! It would make a wicked integrated amp!
Here is the enclosure I'm thinking of getting except for my concern for the lack of apparent ventilation.
(http://www.diyhifisupply.com/files/pictures/projektFB600_0.JPG)
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I have received a few PM's asking about the smps500r. Hopefully this answers your ?? if not feel free to shoot me another pm.The smps500r sounds great. I did notice when driving a certain set of monitor speakers that I built, that the 500r couldn't keep up. The speakers are Danny Ritchies (GR Research) anarchy design. Sensitivity is around 84db :|. Those anarchy mids really need some power to get playing loudly. Definitely not the easiest load for an amp and power supply. Matter of fact these speakers fried one of my nuforce 8b,s. Love these speakers by the way.
While playing at very loud levels I noticed that the left speaker would cut in and out. At first I thought it was maybe a bad solder joint of mine. Hooked up the linear power supply and no problems at any levels.
I plan on using the smps500r for a 5 channel class d audio amp that will be driving PSB Image speakers with 93db sensitivity. I really do not think I will have any issues. All in all I am very happy with the smps 500r. It is small 4"x4" and gets rid of both the transformer and power supply board of the linear PS.
Hook up is a breeze 3 wires in and 3 wires out. Just be aware if you are driving difficult loads at very loud levels you may run into some issues. Attatched is a diagram of the 500r circuit board for wiring reference.
Hm, with its specs, the SMPS shouldn't have had an issue with the Anarchy...
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Hm, with its specs, the SMPS shouldn't have had an issue with the Anarchy...
It acted as if the smps just didn't have the capacitance to keep up. 2x63v 6800uf
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Hm, with its specs, the SMPS shouldn't have had an issue with the Anarchy...
It acted as if the smps just didn't have the capacitance to keep up. 2x63v 6800uf
That makes sense. Not a large enough cap bank. Damn.
EDIT: This makes sense in terms of Connex product line. Most of his amp offerings come with large value caps, so the SMPS reservoir would not be a limiting factor in those cases, however for the CDAs a different story. Oh well.
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Actually my CDA-254 with Tom's low profile power supply also runs out of reserves when driving my Vandersteen 2CE's hard. I'm thinking of doubling the capacitance on that PCB.
I also have found a 3-4dB gain discrepancy between the 2 channels on my CDA-254. Anyone else have this issue? It is a real bummer to have the entire soundstage shifted.
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I also have found a 3-4dB gain discrepancy between the 2 channels on my CDA-254. Anyone else have this issue? It is a real bummer to have the entire soundstage shifted.
Have you checked the gain pots between the two channels?
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Another question, which I have asked before: Has anyone come up with a tube buffer that can PROPERLY drive the CDA series amps? I'm not having a lot of success. Cathode followers and SRPP circuits mostly don't like loads under 20K and the result is a loss of extension at the extremes and some odd coloration.
The CDA series has an input impedance around 7K, or so I've been led to believe.
Input anyone? :scratch:
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@jwtrace - The CDA series does not have gain pots. :?
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@jwtrace - The CDA series does not have gain pots. :?
:duh: :duh:
As my buddy in the U.K would say...You're F---ed mate!
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:duh: :duh:
As my buddy in the U.K would say...You're F---ed mate!
As luck would have it I'm kind of from there too (UK by way of a colony)... I think I'll have to buy a sodding SDS series instead...
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Another question, which I have asked before: Has anyone come up with a tube buffer that can PROPERLY drive the CDA series amps? I'm not having a lot of success. Cathode followers and SRPP circuits mostly don't like loads under 20K and the result is a loss of extension at the extremes and some odd coloration.
The CDA series has an input impedance around 7K, or so I've been led to believe.
Input anyone? :scratch:
Dodd Buffer. Have you also checked Glassware kits?
First I've read of this gain imbalance. Assuming you've ruled out other compenents, like your potentiometer, etc. I'm sure you can just send your board to Tom to repair.
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As luck would have it I'm kind of from there too (UK by way of a colony)... I think I'll have to buy a sodding SDS series instead...
I like you more now. See this http://www.audiocircle.com/index.php?topic=86325.msg842177;topicseen#new
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As luck would have it I'm kind of from there too (UK by way of a colony)... I think I'll have to buy a sodding SDS series instead...
You can also ask Tom if it's possible to increase the input impedance of your board rather than shell out for the SDS.
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@wushuliu - actually it is possible to increase in the input impedance, and I'm going to send the board to Tom to do that and also get the gain matched. I have heard of a gain mismatch on another board somewhere, so I'm not the first. I originally had a balance control in my design (using a stepped attenuator), but decided to get rid of it as it affected transparency.
I want gain, so the Dodd buffer won't work. Especially if I raise the input impedance, the sensitivity will go way down. Glassware appears to have great products but nobody replies to my emails.
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I just answered my own question - the SRPP circuit I just put together should be optimal for a 5K load as-is, just needs a change of coupling cap.
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... Glassware appears to have great products but nobody replies to my emails.
There's a good possibility that the emails ended up in the spam bin. Try adding the terms "tube amp" and "valve" in the subject line...
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Thanks grubyhalo, I'll try that.
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I received my SDS-254 kit today. Unfortunately they forgot to include the wired molex connectors and gain controls. I would very much like to build this amp this weekend and I wonder if actually need the gain controls. I am feeding the amp from a pre-amp. Any help to get it running this weekend would be most appreciated.
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I received my SDS-254 kit today. Unfortunately they forgot to include the wired molex connectors and gain controls. I would very much like to build this amp this weekend and I wonder if actually need the gain controls. I am feeding the amp from a pre-amp. Any help to get it running this weekend would be most appreciated.
I asked Tom whether the pots could be just omitted or whether a couple of the headers could be jumped, but he insisted that the gain pots were necessary. Obviously some alternative to the supplied pots is possible but Tom offered no suggestions.
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I asked Tom whether the pots could be just omitted or whether a couple of the headers could be jumped, but he insisted that the gain pots were necessary. Obviously some alternative to the supplied pots is possible but Tom offered no suggestions.
Isn't a pot nothing more than a variable resistor? Couldn't a single value resistor be used in place of the pot?
The thing that confuses me though is that the pots appear to have 3 leads not just 2... Would someone please explain this...
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Isn't a pot nothing more than a variable resistor? Couldn't a single value resistor be used in place of the pot?
The thing that confuses me though is that the pots appear to have 3 leads not just 2... Would someone please explain this...
The leads are input, output, and ground. To put it simply, (which is the only way I know how to put it), the unit works by routing some input voltage to output while bleeding the rest to ground.
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The leads are input, output, and ground. To put it simply, (which is the only way I know how to put it), the unit works by routing some input voltage to output while bleeding the rest to ground.
So it's like 2 variable resistors, in parallel, that are the inverse of each-other(?)
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The following is a quote from Tom, I was looking for a fixed gain option, this is what he said
"You can put a resistor instead of the pots for fixed gain. It might be best to first run the amp with your other equipment and set the gain to the best match for your preamp and other equipment, and then take a measurement of resistance from the two pins (two pins on the left of side of the MOLEX connector… yellow and black wire). What the measurement is, you can just put a resistor of that value between the yellow and black wire and remove the pot"
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You can also ask Tom if it's possible to increase the input impedance of your board rather than shell out for the SDS.
Does anyone know if Tom can increase the input impedance of a CDA board to 47K or higher? Thanks :D
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Can someone with the SDS boards comment on switching between balanced and single ended inputs? Is it easy?
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I received my SDS-254 kit today. Unfortunately they forgot to include the wired molex connectors and gain controls. I would very much like to build this amp this weekend and I wonder if actually need the gain controls. I am feeding the amp from a pre-amp. Any help to get it running this weekend would be most appreciated.
I received a reply from Tom:
> It is possible to get sound by putting a 10 ohm resistor in place of the gain controls temporarily.
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Can someone with the SDS boards comment on switching between balanced and single ended inputs? Is it easy?
There is a header for each channel comprised of three pins. Remove the supplied jumpers for balanced operation, (or leave them for single-ended). I supposed it would be possible to have an external switch that would open/close the circuits if you wanted to switch between the two modes.
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I received a reply from Tom:
> It is possible to get sound by putting a 10 ohm resistor in place of the gain controls temporarily.
quote from Tom
"When bridged, you only use the left channel, change the jumper from Stereo to Bridged, and only use the right speaker + out and the left + speaker out"
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quote from Tom
"When bridged, you only use the left channel, change the jumper from Stereo to Bridged, and only use the right speaker + out and the left + speaker out"
jtsnead: Is this relevant to my temporary fix with the 10 ohm resistor?
Also, the male molex connector for the gain has 3 pins. Which pins should I connect the resistor to?
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jtsnead: Is this relevant to my temporary fix with the 10 ohm resistor?
Also, the male molex connector for the gain has 3 pins. Which pins should I connect the resistor to?
I think he meant to quote the message above yours, which I've put below...
Can someone with the SDS boards comment on switching between balanced and single ended inputs? Is it easy?
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Greetings Gents...I`ve been reading along with great interest !
I`d like to use an Adcom 555 MK II that i`ve had for years as a platform for an SDS-258 build.
I know the 555 it has an 800va torodial for a power supply.
I have a question...What all can I reuse/salvage from the 555 while building this project ?
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You need to know what voltage your power supply puts out and determine if it is compatible with any of the ClassD boards.
The VA rating refers to the power capability of the transformer and is similar to watts. It does not give a clue as to what the output voltage is.
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From what I`ve gathered...74.5 volts. Does that sound right ?
Thanks
Steve
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It's just a bit high...
SDS-258 Specifications:
· Output: 250 X 2 - 8 Ohm, RMS
· THD+N, 1W - 1KHz: Better than .02%
· Dynamic Range: 101 db
· Efficiency: Over 90%
· Required Power Supply: +/- 60 Volts DC to +/- 70 Volts DC
But your best bet is to send an email to Tom.
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Greetings Gents...I`ve been reading along with great interest !
I`d like to use an Adcom 555 MK II that i`ve had for years as a platform for an SDS-258 build.
I know the 555 it has an 800va torodial for a power supply.
I have a question...What all can I reuse/salvage from the 555 while building this project ?
SCM, personally I'd sell the Adcom 555II and buy Tom's or a Connex power supply & transformer and the case Tom provide.
First, Adcom 555II's can be sold on eBay for $400+. Secondly, that model Adcom is a classic vintage unit much valued by audiophiles and collectors and it would be shame to demolish a good copy.
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Tom responded with this as to wether or not the Torodial in the 555 MK II would work... "You should be able to get a + voltage and a – voltage. The SDS-258 uses between +/- 60 and 70 volts "
Can anybody help me find what Tom needs ?
Thanks
Steve
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SCM, personally I'd sell the Adcom 555II and buy Tom's or a Connex power supply & transformer and the case Tom provide.
First, Adcom 555II's can be sold on eBay for $400+. Secondly, that model Adcom is a classic vintage unit much valued by audiophiles and collectors and it would be shame to demolish a good copy.
Thanks..I would agree BUT...this one had the speaker leads crossed by my daughter and never worked again ( 8 years ago). Blows fuses including the main incoming fuse.
I did a COMPLETED LISTINGS search and a good one averages about $250.00. So by the time I got hosed by a repair shop I`d probably get stuck with it.
If I can work with the good parts I`d be ahead..Right ?
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If I can work with the good parts I`d be ahead..Right ?
You can certainly make use of the case, power cord, (or IEC receptacle if present), power switch, rear panel fuse holder, speaker binding posts and RCA input jacks (if not PC board mounted).
But you will have to disconnect the transformer secondary leads and measure the output voltages with a voltmeter. The voltage requirement of the SDS-258 is +/- 60-70V DC, which would mean you would need a transformer with +/- 42V-50V AC secondaries to connect to the required DC power supply board.
Steve
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Tom responded with this as to wether or not the Torodial in the 555 MK II would work... "You should be able to get a + voltage and a – voltage. The SDS-258 uses between +/- 60 and 70 volts "
Can anybody help me find what Tom needs ?
Thanks
Steve
Do you have any pictures of the inside of the amp? If the power-supply board isn't integrated into the amp board it should be pretty easy to tell where the voltage reading should be done. If the boards are integrated, you may be able to use just the transformer. if that's the case just get a read off the output leads of that and tell Tom what they are.
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Here`s some pics...
(http://www.audiocircle.com/image.php?id=36795)
(http://www.audiocircle.com/image.php?id=36796)
(http://www.audiocircle.com/image.php?id=36797)
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If it were me, I'd take all the stuff inside and toss it. Just save the IEC, fuse holder and input connectors (if you can). Replacing the transformer that will cost you ~$40 is well worth the investment. That amp is probably 20 yrs old anyway...
Use the case and be done!
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I agree with Jason. Gut it but save all the connectors you can. Buy the SDS-258 kit, it's well worth the cost. You should be very pleased with the outcome.
Why pay to get the 555 working again since you haven't used it in 8 years. Besides, an SDS-258 would mop the floor with the Adcom. No brainer to me. :D
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Well the consensus seems to feel you should scrap all but the case and connectors, but I believe the heavy Red and Yellow wires from the transformer can be measured to get the output voltage of the transformer.
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...
Why pay to get the 555 working again since you haven't used it in 8 years. Besides, an SDS-258 would mop the floor with the Adcom. No brainer to me. :D
I've owned the 555II. It was a powerful and pleasant sounding amp; OK into 2 ohms and slightly "dark" in tone. But it is nowhere as good as the SDS-258. The latter is far more transparent and is capable of more accurate intrument timbres.
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Well the consensus seems to feel you should scrap all but the case and connectors, but I believe the heavy Red and Yellow wires from the transformer can be measured to get the output voltage of the transformer.
Barry, I know absolutely nothing and have no meters at all, although a kit doesn`t scare me off !.
I was hoping that the info I needed would be readily available.
But too, as has been posted, maybe I`d be better off not using the old stuff after all.
Maybe the Adcom transfomer isn`t up to speed with what Tom sells anyway.
Feanor, I believe you on that !!! ....I`m looking forward to this build up (new territory for me).
Anybody have any suggestions for me on this project, upgraded parts and such ?
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Well if that's the case, you probably are better off just getting the full kit and the assembly instructions, and just using the case, connectors and switch from the Adcom. From what I've seen here, Tom's kits are pretty easy to assemble and well documented.
Best, Barry
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Update: I upgraded my stock PS from 40k uf to 60k uf with 2 more Panasonics tsha's just for giggles, but i got a really nice bump in dynamics and mico details. Highly reccomend taking the supply to 60k.
SDS254 w/60k uf Panasonics tsha. :thumb:
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Anybody have any suggestions for me on this project, upgraded parts and such ?
Get the kit installed and working first. Once you learn about the whole circuit and listen to it you can then decide if you want to continue.
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Barry, I know absolutely nothing and have no meters at all, although a kit doesn`t scare me off !.
I was hoping that the info I needed would be readily available.
But too, as has been posted, maybe I`d be better off not using the old stuff after all.
Maybe the Adcom transfomer isn`t up to speed with what Tom sells anyway.
The Adcom transformer is pretty beefy, it would have been more than enough for any of of the ClassDaudio amps, however the secondary voltage are too high, I measured about 85 to 90VDC after the 555II power supply. The Red-Black-Orange are the secondary leads, with black being the 0 point. The power caps in the Adcoms are 100VDC.
Afraid all you can use in there are what jtw posted save the IEC, fuse holder and input connectors (if you can).
You can also reuse the power switch, speaker terminals. The heat sinks are useless, dead weight. The power supply you can maybe reuse (if its not damaged) but you will have to know how to reconfigure it...
Perhaps you can just sell it as/is for parts only.
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Update: I upgraded my stock PS from 40k uf to 60k uf with 2 more Panasonics tsha's just for giggles, but i got a really nice bump in dynamics and mico details. Highly reccomend taking the supply to 60k.
SDS254 w/60k uf Panasonics tsha. :thumb:
Are these the caps you're referring to? http://www.diycable.com/main/product_info.php?products_id=602&Cid=d267424e09d9ab5452567d828ec78634
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Are these the caps you're referring to? http://www.diycable.com/main/product_info.php?products_id=602&Cid=d267424e09d9ab5452567d828ec78634
Yes thats who i bought them from, i purchased only 4 to start with thinking the amp would not respond beyond 40k but the bump to 60k was very favorable.
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Okay, one more 'to do' on my growing 'to do' list. Might as well take care of it now before I put the amp in the case.
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Digikey, $6.85
http://parts.digikey.com/1/parts/51788-capacitor-10000uf-63v-elect-tsha-eco-s1ja103ea.html (http://parts.digikey.com/1/parts/51788-capacitor-10000uf-63v-elect-tsha-eco-s1ja103ea.html)
Are these the caps you're referring to? http://www.diycable.com/main/product_info.php?products_id=602&Cid=d267424e09d9ab5452567d828ec78634
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My case came out pretty nice, by the way. It's a powder coated par metal case with stainless steel cap screws and a 1" thick faceplate of polished clear acrylic.
(http://i291.photobucket.com/albums/ll286/thehungryeye/photo-1.jpg)
Nice front bezel... who cut and polished that thick acrylic? Good job!
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Digikey, $6.85
http://parts.digikey.com/1/parts/51788-capacitor-10000uf-63v-elect-tsha-eco-s1ja103ea.html (http://parts.digikey.com/1/parts/51788-capacitor-10000uf-63v-elect-tsha-eco-s1ja103ea.html)
Yup, but out of stock until Feb 2011.
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Nice front bezel... who cut and polished that thick acrylic? Good job!
Thanks! Except for the drilling, everything was done at a Tap Plastics store near me. I was going for a modern Scandinavian look but think I ended up with a disco Scandinavian look instead. :lol:
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Yes thats who i bought them from, i purchased only 4 to start with thinking the amp would not respond beyond 40k but the bump to 60k was very favorable.
Well now, ... I knew my bugging you to get the 6 caps would pay off. lol.
So looks like what I need to do is to get the caps, and when I place the order, send Tom the caps, and he can just solder them in in place of the ones he currently uses in his present power supply.
Ray
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Well now, ... I knew my bugging you to get the 6 caps would pay off. lol.
So looks like what I need to do is to get the caps, and when I place the order, send Tom the caps, and he can just solder them in in place of the ones he currently uses in his present power supply.
Ray
Ray i knew you would be relieved. Hehe
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Hi Everyone
This is an update on the Class D SDS-4 amp saga in my system.
The ultra short answer is - it is out of the system.
I ran up the hours so I could feel comfortable it was "burned in"
I tried several speaker cables and didn't find a great deal of change.
The four main "issues" are:
1) There is a definate lack of bass depth and to a degree, deliniation of what bass was produced. The Tube gear simply ruled here.
2) This one will be very hard to describe. Through the midrange, it gives the impression that most of the sounds are appearing at the same volume level. For example a guitar solo or lead vocal will be mildly depressed nearly at the same level as a background instrument. To give a real world example of this - Dire Straits album "On Every Street" track 11 "Planet Of New Orleans" This track has lots of low level percussion going on in the back ground. With the Class D amp it gave the perception that the percussion was almost as loud as Mark Knopfler's vocal and lead guitar This gave the appearance of enhanced resolution at first but became bothersome after a while. For those questioning which is correct- I have compared this to 3 amps and two completely different sytems and the Class D definately is the different one. I'll allow you to decide as to which is "correct".
At the same time as the mids seem to have "leveled" the sounds the highs are still a bit rolled off as I previously noted. For another real world example, Eva Cassidy "Live at Blues Alley" there isn't the ambience of the hall and low level information that gives the feeling of being at the club listening through pro audio gear. The hum of the tube amps on stage are subdued and not nearly as apparent through the other amps I tried.
4) This one should be no surprise. Tube amps simply have more "presence" and feel more like listening to a living performer/performance. The tube sound stage is bigger , deeper and more detailed.
I really hadn't thought about #4 until I put the tube gear back in and went "Oh ya that's what was missing" My sister was visiting and she heard the Class D. She commented it sounds nice but not as real as my tube amps she heard the previous visit. That's when I decided to pop the tube gear back in to see if she was right and she was.
Now I still haven't managed to get the other linear power supply board in. I ordered it on Sept 17. Still haven't got it yet. At the end of the first week this month (Oct), I asked whether it was shipped yet, Connex said oh we shipped it a few days ago and I'll get you the tracking #. A week later, they came back with a tracking # (and I can't find a Hong Kong shipper which recognises that #) and said it's on it's way - you should have it in two weeks. DIY Hi Fi Supply also based in Hong Kong had stuff to me in 7 days from the time of order. So.......we wait - NOT impressed.
If / when the Power supply board ever shows up I'll put in a comment on how it sounds from the supplied heavy duty board.
I did put in a power conditioner ( Belkin Pure AV PF60) and as others found it really did help the sonics, especially in the sound stage department. It went from the sound hanging around the speakers to having real width and depth. For a $200 buck conditioner I was very impressed.
I never did put in the other monitor speakers so far. Some day when I'm bored I'll do it.
Before people get the wrong impression, this is in comparison to much more costly tube monoblocks with a complete re-build using premium parts. I still am amazed at what $400 will buy you today. Even two years ago you'd never get this quality for under a grand at the minimum.
Now it's out of the main system, I'm going to stick it in my set/high efficiency set up -300B amp and DIY Planet Ten Half Changs (Fostex FE207) speakers. Might be fun.
Kevin
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Thanks Kevin:
What tube amps and speakers are you running?
Rocket_Ronny
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Hi RR
Sonic Frontiers and Sonus Faber cremonas ( original style not the new MM)
KB
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Ray i knew you would be relieved. Hehe
Hi Nick77, Sounds like you'd better send your supply to Kevin. His amp seems to suffer from a lack of dynamics. Hmmm, not good. I'm also giving some thought as to whether to get either the ClassD or hugh's amp. Seems for just under a grand, might be a another steal. Not to hijax this thread. i do wonder if the S4 or is it the T4, isn't as good sounding as the s254 or s258 board.
Did you guys see the review of Blair's version of the amp? That too was really good.
So someone had asked if the caps that Kevin has are the same ones that you bought? Anyway, all done now.
Ray Bronk
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I am not at all familiar with the SDS 4 board but it has been mentioned the IR boards sound a little sweeter than the TI version.
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I believe the SDS-4 is first mentioned here...
http://www.audiocircle.com/index.php?topic=76400.msg831007#msg831007
After the above review, I'll be keeping the SDS-258 as my goal.
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Did you guys see the review of Blair's version of the amp?
Ray, do you have a link for that review? Thanks!
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Did you guys see the review of Blair's version of the amp? That too was really good.
Ray Bronk
Ray, do you have a link for that review? Thanks!
Second, please don't tease...
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Nothing really that earth shattering IMO.
http://www.stereomojo.com/Niteshade%20SS500%20Amplifier%20Review/NiteshadeSS500Amplifier.htm
of course lets not forget that you can build one from here www.classdaudio.com
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OK I did a very brief audition of the SDS4 amp with my high efficiency speakers using some of the
same disks used with the Cremonas. The brunt of the midrange problems seem to be ameliorated. It is still there to a small degree but this is now down to the sort of presentation variations you could expect from differing amplifier topologies. The highs are much better with this easier to drive speaker, oddly enough.
I still prefer the 300 B amp with the major reason being no fault of the SDS4. The designer of the speakers stated to me when I bought the drivers from him that this style of speaker works best with amps that have a low damping factor. He specifically did not recommend class d style amps as they have too much bass damping and this doesn't allow the bass to bloom with the Fostex drivers.
I'm simply going to conclude the SF speaker /SDS4 amp combination is not a good one.
It will be interesting to hear from others with the same board with different difficult to drive speakers.
This is likely a one of a kind situation or possibly the SDS4 doesn't play into difficult loads as well as Tom initially thought.
I guess I'll have to get the monitor speakers out now as my curiosity is up. The monitors have a
nominal 6 ohm impedence so they should split the difference nicely.
Kevin
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OK I did a very brief audition of the SDS4 amp with my high efficiency speakers using some of the
same disks used with the Cremonas. The brunt of the midrange problems seem to be ameliorated. It is still there to a small degree but this is now down to the sort of presentation variations you could expect from differing amplifier topologies. The highs are much better with this easier to drive speaker, oddly enough.
I still prefer the 300 B amp with the major reason being no fault of the SDS4. The designer of the speakers stated to me when I bought the drivers from him that this style of speaker works best with amps that have a low damping factor. He specifically did not recommend class d style amps as they have too much bass damping and this doesn't allow the bass to bloom with the Fostex drivers.
I'm simply going to conclude the SF speaker /SDS4 amp combination is not a good one.
It will be interesting to hear from others with the same board with different difficult to drive speakers.
This is likely a one of a kind situation or possibly the SDS4 doesn't play into difficult loads as well as Tom initially thought.
I guess I'll have to get the monitor speakers out now as my curiosity is up. The monitors have a
nominal 6 ohm impedence so they should split the difference nicely.
Kevin
Unless I missed something, you're still using the stock power supply, right? I think you need some real juice for those speakers. Hopefully the Connex will help. The difference in tonality though with your tube amp is a gap that probably can't be bridged, but as you said that should be expected given the near $4500 cost difference and differing amp topology. I think the top end improvement w/ the high efficiency is a clue. What's their impedance?
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Sonus Faber=one of the kings of low efficiency speakers, lovely sound but you need an elephant of a SS amp to run it well....Tubed PP/Sonic Frontiers, like the Power 2 I had, might produce something like 110 watts of PP power, much more powerful than the PA-7 200 watts/Nakamichi I had prior to the Power 2.
The ClassD audio amp board design produces watts but not the more high current type that things like the Sonus Faber demands.
I say try something like a regular, Class A/AB amp with large PS, like McCormack or if digital H2O...you will see a large difference in sound.
Have we been struck by the digital hollow watts syndrome?
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Sonus Faber=one of the kings of low efficiency speakers, lovely sound but you need an elephant of a SS amp to run it well....Tubed PP/Sonic Frontiers, like the Power 2 I had, might produce something like 110 watts of PP power, much more powerful than the PA-7 200 watts/Nakamichi I had prior to the Power 2.
The ClassD audio amp board design produces watts but not the more high current type that things like the Sonus Faber demands.
I say try something like a regular, Class A/AB amp with large PS, like McCormack or if digital H2O...you will see a large difference in sound.
Have we been struck by the digital hollow watts syndrome?
From all the feedback I've read on the CDA/SDS amps, the conclusion I come to is the true value lies in the amp boards, not the power supply. The stock PS is good enough for the majority of folks mind you, but when it comes to really getting the most out of them that's where you start - it's just as important as in any other amp design. I think that has been confirmed by some knowledgeable folks in different threads in regards to these amps. It's just that you can get away with less for the average user.
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Wushuliu
The high eff DIY Fostex speakers are a flat 8 ohms or higher. VERY easy load and a sensitivity of 97.
None the less, the kit was sold as the answer to hard to drive speakers - maybe not as hard as the cremmies though. The Connex board will answer that when it shows. All I know is this amp won't be getting much, if anymore, money spent on it.
Bemopti123
Been down that road with Sim Audio and Pass - I preferred the sound of the SF tube amps.
I don't play loud ( give or take max of mid to high 70's) and with the speaker's sensitivity of circa 91, I'm using about a whole watt, the tube gear shows no shortage of current in this situation.I'd have expected the Class d to be the same.
I have an pair of very early Nuforce 8.02 amps and they did just fine for speaker control. I just didn't like the turn on /off nonsense and the clinical presentation the early ones were famous for
KB
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I seem to recall someone considering a Paul Hynes power supply for their classdaudio amp. Does anyone know if anything became of that? I suspect Paul Hynes could sell a lot of power supplies if he had a customized module for the classdaudio amps.
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I preferred the sound of the SF tube amps.
KB
Although my current set up is in eternal flux, there is one thing to be said about those Sonic Frontiers Power 1, 2, 3 line of amps, while the bass was somewhat flabby in my own setup, perhaps an artifact of the speaker I was using then(Gershman X-1 monitors), the rest was divine. There has not been an amplifier that has given much such pleasure as the Power 2s. While I sold it back to someone in Canada, I still have fond memories of it. It was and still is an exquisite design. If and when I pare down my amp stable, which is quite ample, I might/WILL consider getting one of them again. What a bargain they are in today's $$$$.
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Bemopti123
I've heard the Gershwins tend to have a slightly wooly bass so the combination of tubes and those could get a little out of hand but that midrange is worth it.
In many respects, I'm not at all unhappy. I was thinking about a major component change either speakers or amps. For the price of a tube swap I figured I'd try and see what class d had evolved into since the early Nuforce stuff.
In the course of my messing around trying to hit on something that would work with the SDS4, I tried a cable combination I hadn't done before. I had left that set up in when I went back to the tube gear and much to my surprise, it solved the couple little niggles I had. So ultimately, to get a combination that I'm happy with for under $500 is a huge bonus as the speaker range I was looking at was $5k plus. Even if the amp never gets plugged in again it was a cheap solution. However, it doesn't sound that bad, especially if the new power supply board does anything at all. I think it may turn into my summer amp when I don't listen too critically and the thought of turning on a whole pile of hot glass isn't too appealing.
Kevin
KB
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Please keep it on topic guys.
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Hi Everyone
This is an update on the Class D SDS-4 amp saga in my system.
The ultra short answer is - it is out of the system.
...
The four main "issues" are:
...
4) This one should be no surprise. Tube amps simply have more "presence" and feel more like listening to a living performer/performance. The tube sound stage is bigger , deeper and more detailed.
I really hadn't thought about #4 until I put the tube gear back in and went "Oh ya that's what was missing" My sister was visiting and she heard the Class D. She commented it sounds nice but not as real as my tube amps she heard the previous visit. That's when I decided to pop the tube gear back in to see if she was right and she was.
...
Kevin
CDA's blurb says that their amps have a tube-like sound. Personally I don't agree with that. Anyway, tube sound is ultimately a preference. Whatever it is that tubes do, it's hard for solid state, whether class D, A/B, or even A, to duplicate it. My guess is that it is the largish amounts of low-order harmonic distortion that tubes produce that cause the euphonic effects associated with tubes, viz. "harmonic richness", "body", "depth", etc. The counter arguement is made that solid state, including class D, produce more higher-order and intermodular distortion. However, IMO, these arguements aren't balanced because while higher-order harmonic and IM distortion might be pyscho-acoustically more objectionable, overall distortion tends to be far lower in quality solid state gear. (Incidentally, I'm a tube user myself; I have and enjoy a Sonic Frontiers Line 1 preamp.)
So it come around whether quality s/s gear is more accurate. My guess is that it is and that, in a manner of speaking, tube enthusiasts really just "can't handle the truth". Anyway 90% of the equipment differences that I can hear are far outweighed by the differences inherent in the sound of the various recordings in my collection. And in my experience with the SDS-258, my best recordings sound better that ever with this amp.
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Has anyone compared the SDS-254 to the SDS-258? or a CDA to its SDS counterpart?
I know that I've read in this thread that Tom says the SDS board's sound is superior to its CDA counterpart, but I was wondering if any of the posters here have done some direct comparisons. I'm searching and reading, but it's a big/long thread :oops:
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Has anyone compared the SDS-254 to the SDS-258? or a CDA to its SDS counterpart?
I know that I've read in this thread that Tom says the SDS board's sound is superior to its CDA counterpart, but I was wondering if any of the posters here have done some direct comparisons. I'm searching and reading, but it's a big/long thread :oops:
No. No direct comparison has been done. Although I think Nick77(?) has owned both and stated he preferred the SDS.
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Thanks, I was just reading Steve K's comparison of the SDS-258 to the Wyred4Sound STI-500 integrated.
I'll search for Nick77's posts.
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I finish my initial build(regular cda) a couple nights ago, this is with a Connix(?) ps with beefed up caps, 40,000uF x 2...today I am comparing it to the Modwright KWA100 SE I have here on demo. Its not gettin' blown away is all I can say for now. More later. :thumb:
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I finish my initial build(regular cda) a couple nights ago, this is with a Connix(?) ps with beefed up caps, 40,000uF x 2...today I am comparing it to the Modwright KWA100 SE I have here on demo. Its not gettin' blown away is all I can say for now. More later. :thumb:
Martin, you gonna bring it to Mike's on Saturday? I'd love to give it a listen
P.S. I'm talking about your CDA Amp ;)
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Hey Barry, not sure I am making Mike's rave. But I am sure we can arrange a demo somewhere.
I do have to add additional heat-sinking to the stock slab, I have +/- 56.4V coming off the power supply which is still within the recommended +/- 8V @50V., but there is more heat generated of course.
My build incorporate a CLC filtering unit prior to the transformer, so its a little different than the norm. The sound is pretty warm compared to Deepak's build I had auditioned some months ago.
I am using a stock Harmon Kardon amp transformer which The PunkingMan was kind enough to strip and send the chassis. Have no idea on the specs of the transformer but the secondary had 40-0-40...this will be replaced with a massive 1kW. transformer I have in route...my destiny on this build is a stereo amp with two bridged cda 254 units to power my bass drivers.
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I built a dual SDS-254 amp (4 channels) a while back and have been happily using one of the two amps to power my pair of custom bandpass subs for the past 9 months or so. I was going to add a third sub for very low/infrasonic frequencies, but never got around to it because the first two work so well down to 20 Hz or so - which is just fine for most of what I listen to (music & movies). So, anyway - since one of the amps was going unused, I rewired them in bridged mode (500W) and then re-balanced the subs through my DCX. The drivers I am using are B&C 12TBX100s (rated at 1000W rms at 8 ohms). The overall timbre is similar, but the low end definitely sounds a bit clearer and more authoritative now as well. Just thought I'd relate that little bit of info. These really do make great sub amps... cool, quiet and powerful.
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Too much of a good thing... :lol:
Stock transformer:
(http://www.audiocircle.com/image.php?id=37345)
Massive attack: :duh:
(http://www.audiocircle.com/image.php?id=37346)
This arrived today; Will have to move the power supply to fit this big fella' :lol:
Update on the sound vs the Modwright KWA100 SE...in brief, not in the same league, falls short in just about every department. But it has potential...maybe with better coupling caps and power supply caps, better internal wiring (I used throw away IC wire for input leads, and regular 12ga. house wire for speaker wire and power supply).
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That is a hunk of iron Mjosef. Gosh. Massive.
Has anyone have any good experience with the different wiring types to be used? Although I am familiar with hook up wires, what gauge should it be used, as well as the gauge/type of wire to be used from PS to board?
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That is a hunk of iron Mjosef. Gosh. Massive.
Yah...1,000 KVA.
I'm heading towards a bridged pair @ 500w. per channel...don't want the transformer to get in the way. :thumb:
I have already swapped in double shielded coax wire(solid core) for the cheap stranded IC wire I had on the inputs. Haven't heard how it sounds yet...since I have to ship out the Modwright tomorrow, I want to get as much time as possible with it.
I will also experiment with 24ga. solid core silver wire on the inputs, and some other wire I already have on hand. More to come.
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:o
Holy Schnikes Batman!
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So I have two CDA amp boards - the 224 (120w) and 254 (250w). The 224 was requested with lower (26db) gain. I think the 254 was too, but I don't remember. The 224 was running with a linear power supply w/ 90kuf and a beefier toroid. The 254 is connected to a Connex SMPS500R SMPS. I've had the chance to compare the two somewhat and make some observations: first the 224 is louder than the 254. I am going to assume Tom did not reduce the gain after all, as the difference is by a wide margin. While swapping preamps as well as amp boards, I've found the 224 sounds a lot fuller and more dynamic. I'm guessing this also due to the gain and Aikido tube pre. I wonder if that's actually noise and distortion I'm hearing due to the increased gain. The 254 sounds leaner and possibly cleaner, but I need more listening time. I guess I'm just surprised a 6dB gain difference would be so pronounced (assuming that the stock are still at 32dB as mentioned near the beginning of the thread).
As for the SMPS500R, the jury is still out. I listened to it briefly a few weeks ago, and popped it back in yesterday. The first time around I just remembered thinking OMG where did all that bass come from. Like slamming bass. Real tight. Listening to it again last night and this morning, for sure the bass is strong in this one. I had to turn my sub way down. Beyond that I am not sure yet what to make of what I hear. My first thought is that there is actually less noise than w/ my linear. The music seems cleaner. But I am not sure how much of that is this gain issue or what have you w/ the 254. Definitely the music seems more 'controlled'. I think the audiphile term is 'attack' or whatever. I know the ideal thing to do would be to get an SMPS500R for the 224 as well to compare.
I guess I am just really surprised by the difference between the two. I just finished an Aikido preamp and w/ the 224 music was warm and fuzzy, but w/ the 254 it's leaner and clearer, and by a lot.
Edit: I cam across this post from on diyaudio from someone at Coldamp that sums up the SMPS500R in the low end: "About regulation: linear power supplies are almost never regulated, and this is specially true as power increases, due to efficiency and heat dissipaton issues. On the other hand, it is easy to make regulated SMPS, that will hold rails voltage up to full power with no problem. This translates in a deeper and more powerfull bass, mainly, although it has sonic impacts in the rest of the audio band."
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Interesting post wushuliu. I think the thing to do to really compare the boards would be to swap the amp boards in/out of the same chassis/power-supply. Did you solder the connections to the boards, or use the screw terminals? If the latter the swap would be pretty simple. Then you could compare, apples to apples, and oranges to oranges ;) Seeing how each board is effected by each power-supply. Your current comparison of different boards, with different power supplies, would for me, make it very difficult to determine what is causing what difference. It would also be important, IMHO, to get the gains matched between the boards.
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Interesting post wushuliu. I think the thing to do to really compare the boards would be to swap the amp boards in/out of the same chassis/power-supply. Did you solder the connections to the boards, or use the screw terminals? If the latter the swap would be pretty simple. Then you could compare, apples to apples, and oranges to oranges ;) Seeing how each board is effected by each power-supply. Your current comparison of different boards, with different power supplies, would for me, make it very difficult to determine what is causing what difference. It would also be important, IMHO, to get the gains matched between the boards.
Yeah, if I wanted track the cause down I would have to shell out more dough for the smps and then engage in back and forth shipping w/ Tom probably to have the gain matched (and unmatched again if I don't like it). So this is probably as far as I'll go. This is where having confirmed specs on these amps, like gain, impedance, etc. would be helpful.
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Upon further thought, I'm now realizing that the 2 boards likely have different voltage requirements, so you can't just swap them back and forth as I'd originally suggested.
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The 254 sounds leaner and possibly cleaner, but I need more listening time. I guess I'm just surprised a 6dB gain difference would be so pronounced (assuming that the stock are still at 32dB as mentioned near the beginning of the thread).
I guess I am just really surprised by the difference between the two. I just finished an Aikido preamp and w/ the 224 music was warm and fuzzy, but w/ the 254 it's leaner and clearer, and by a lot.
Edit: I cam across this post from on diyaudio from someone at Coldamp that sums up the SMPS500R in the low end: "About regulation: linear power supplies are almost never regulated, and this is specially true as power increases, due to efficiency and heat dissipaton issues. On the other hand, it is easy to make regulated SMPS, that will hold rails voltage up to full power with no problem. This translates in a deeper and more powerfull bass, mainly, although it has sonic impacts in the rest of the audio band."
What is the value of the output cap you are using on aikido? I have the CDA254 connected to an aikido and Iam trying to get the right value.
thanks,
Dinesh
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What is the value of the output cap you are using on aikido? I have the CDA254 connected to an aikido and Iam trying to get the right value.
thanks,
Dinesh
[/quote
As this off topic I will send pm
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I had some left over 3 pin Molex connectors and decided to try substituting a single resistor for each input level control on my SDS 254 amp. I tried 10 ohm Vishay metal film resistors first, and then switched to 4.7K ohm carbon film resistors so I would better match the volume control output characteristics of my Pass DCB1. The resistors both offered (a) a more 3D or holographic sound stage (2) more layering and extension both in front and to the rear of my speakers, and (c) a quieter background from which sound emerged (sounded much like adding good AC power conditioning). The Vishay metal film resistors clearly tipped up the treble balance, and initially sounded a bit gritty or spitty or splashy, and they also tightened up the bottom end a bit. The carbon film (generic... had 'em laying around from Radio Shack) resistors were smoother sounding with no emphasis in any particular region, but they did warm up the midbass a bit (fuller, but not bloated or tubby). All in all I would say the improvement is as great as the difference between the CDA amps and the SDS amps, and all for less than $10. The Molex connectors I used were not a perfect fit and had to be filed a bit (the locking system on them was different than Tom uses), but are snug and won't fall out. Mouser part number for them is: 538-10-11-2033, and you'd also need crimp terminals for them that will attach to the legs of the resistors (that must be soldered IMHO) - Mouser part number 538-08-50-0114.
Highly recommended cheap and cheerful tweak that won't void your warranty. I'm sure higher quality resistors would be worth trying. The 10 ohm value leaves the input impedance similar to having the control pots fully turned up. The 4.7K ohm value was equivalent to turning the control pots down by about 6 db.
Neil
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Highly recommended cheap and cheerful tweak that won't void your warranty. I'm sure higher quality resistors would be worth trying. The 10 ohm value leaves the input impedance similar to having the control pots fully turned up. The 4.7K ohm value was equivalent to turning the control pots down by about 6 db.
Neil
Thanks Neil, that's great info!
Would you mind posting a couple of pix of the mod in place?
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I'll shoot a couple of photos when I get home. Not much to look at... but at least you could see the Molex housings both in place, and free standing.
Neil
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I'll shoot a couple of photos when I get home. Not much to look at... but at least you could see the Molex housings both in place, and free standing.
Neil
Hey Neil,
How about just removing the molex connector from the amp board and solder the resistor to the board? What do you think? Great find for the SDS boards. Thanks!
Roy
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Hey Roy,
You could certainly just remove the female Molex connector and solder the resistors directly to the pins on the male end of the connector on the board. I opted to use Molex connectors so I could check to make sure that the 10 ohm resistor value would work, and to try out different types of resistors. Once you find the sound you are looking for (and the input level that works best with your system) then that would be an ideal time to solder those puppies in.
Here are a couple o' photos (the Vishays not currently installed, and the carbon film resistors installed).
(http://www.audiocircle.com/image.php?id=37550)
(http://www.audiocircle.com/image.php?id=37551)
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Earlier in the thread there was a pic posted of the blue block-shaped input caps being replaced. Has anyone else done this mod? Pics?
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Hi Everyone
I just finished doing the replacement of the gain controls with fixed resistors on my SDS-4. I just de-soldered gain controls and soldered the resistors (Caddock 220 ohm in a TO220 package) to the yellow/black wires from the molex connector.I didn't have any spare molex connectors and I just wanted to experiment to see if it made any difference.
Well, all I can say this should be a manditory mod.
It might be worthwhile to run the gain controls to ballpark the value of the resistor for a while. I just used Walkern's base line of 10 ohms and added a bit more resistance. My guess is for most, a value of around 500 to 1000 ohms would work out well to give that pre amp center of the volume pot positioning. My pre has pretty high gain and I can run it at around 9:00 for about low 70's spl output with the 220 ohm resistors.
I did this in my high eff system and these speakers have never had this much bass. The clarity has now popped up to close to the 300 B amp
Great stuff!
Thanks Walkern for the inspiration
Kevin
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Glad it wasn't just my imagination!
The 10 ohm resistor value suggestion came from Tom, and in my system it sounded like the level was comparable to the control levels when they were maxed out.
Thanks Kevin,
Neil
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Okay, FINE, I'll put in an order for an SDS amp.
You guys happy now?!
:finger:
:green:
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Okay, FINE, I'll put in an order for an SDS amp.
You guys happy now?!
Not until we see completed photos!
Steve
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I asked Tom to increase the SDS254 voltage to +/-54v to accomodate the SMPS; though the SMPS can be manually dialed down 10% with a screwdriver, it just makes things easier...
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Hi Everyone
I just finished doing the replacement of the gain controls with fixed resistors on my SDS-4. I just de-soldered gain controls and soldered the resistors (Caddock 220 ohm in a TO220 package) to the yellow/black wires from the molex connector.I didn't have any spare molex connectors and I just wanted to experiment to see if it made any difference.
Well, all I can say this should be a manditory mod.
It might be worthwhile to run the gain controls to ballpark the value of the resistor for a while. I just used Walkern's base line of 10 ohms and added a bit more resistance. My guess is for most, a value of around 500 to 1000 ohms would work out well to give that pre amp center of the volume pot positioning. My pre has pretty high gain and I can run it at around 9:00 for about low 70's spl output with the 220 ohm resistors.
I did this in my high eff system and these speakers have never had this much bass. The clarity has now popped up to close to the 300 B amp
Great stuff!
Thanks Walkern for the inspiration
Kevin
Ok, so to beg the question Kevin, did the dynamics go up too? You had mentioned that the dynamics were such that all of the stuff seemed to be on the same level. Did that improve?
To those who have the SDS boards, rather than just pull the pots, just use a meter and bring down the value to something like 500 to 1K listen first, and then once the right value has been found, remove the pots, and put in the fixed resistors. Then you have to allow the value differences of each resistors, 5% 10% ETC.
Ray
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Hi Ray
So far I've only run the SDS-4 with the new resistors in my second system with the high effciency Fostex based speakers.
This second system didn't suffer with the "dynamics" the Sonus Faber based rig did either before or after the fixed resistor replacement.
The changes to the high eff. system were a much stronger and more detailed bass and a much improved treble response.
After going back to the tube amps in the main set up with the cable changes and power conditioner in, I really like what I'm hearing there. The improvement to the second system is is well worth while so the SDS4 amp will stay with the Fostex based rig at least for a while.
I still haven't received the Connex board. When that comes and after it has burned in I may stick it in the main system again just to see if the issues I had have been resolved or ameliorated
Kevin
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Neil, sorry for the delayed reply. Thanks very much for the pix they're perfect.
When I finally do place my order, I'll likely ask Tom for some extra molex connectors in place of the pots.
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Glad it wasn't just my imagination!
The 10 ohm resistor value suggestion came from Tom, and in my system it sounded like the level was comparable to the control levels when they were maxed out.
Thanks Kevin,
Neil
Thanks for the tip Neil. My one grip with the CDA/SDS boards is that there's really nothing to tweak. But now there is! :icon_twisted:
Edit: I also give a big thumbs up to the SMPS500R. At best it sounds cleaner than my 90k linear (probably because of the poor wiring layout I had frankly), at worst it sounds the same. Except for the bass. Unbelievable mid/bass. Ease of use and space/weight-saving make it a winner for me. Just be prepared for the 2-3 week wait time for delivery...
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I got the SDS254 up and running with the SMPS500R last night. I only got about an hour's listening in, with the gain dialed in to roughly the same as my CDA254. The sound was a little leaner and clearer but overall sounded the same as the CDA to my ears. My guess is the leaner sound is due to the impedance matching of the SDS w/ my Aikido as the difference is similar to going from the stock 1k B1 buffer output impedance to a somewhat lower value. I'll swap out the gain pots w/ resistors tonight.
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I'll swap out the gain pots w/ resistors tonight.
I'll be curious to read what you think...
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I'll be curious to read what you think...
Me too! I'd really like to hear a solid critique/evaluation of the CDA vs. SDS boards. If there really isn't a big difference in the sound of the two I'd likely go with the less expensive option. IF however the SDS is superior, I'll spend the extra $95.
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In my system and to my ears the SDS sounds better. Yes, cleaner with more micro detail.
What I mean't was about the resistor instead of the pots. I'm still :scratch: over this one. :dunno:
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In my system and to my ears the SDS sounds better. Yes, cleaner with more micro detail.
What I mean't was about the resistor instead of the pots. I'm still :scratch: over this one. :dunno:
I felt the SDS board yielded more control and better detail also.
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As a side note, I'm betting for SDS resistor mod, using the naked Vishays would pay off huge - especially since you only need 2... 8)
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Many thanks Neil. The resistor mod is a must. Plain and simple. Before what I heard wasn't $95 better than the CDA. Using 3.3k PRPs, the gain roughly in the same place I had before, was a game changer. No one will be disappointed. I will most certainly be getting the naked Vishays for this...
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Wush so what your saying is the gain pots are holding back the amp and switching to a fixed gain using a resistor improves SQ? I have my gain set to about 1 oclock, what should i try? I guess it would be trial and error with cheap resistors to determine exact resistance for my setup?
Would the same be true switching to a better gain pot? Could one say that the cheap plastic pots degrade the sound?
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No trial and no error, just measure the resistance you've dialed in with the pot and get resistors of that value.
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No trial and no error, just measure the resistance you've dialed in with the pot and get resistors of that value.
Okay thanks, how does one do that?
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Nick and all,
Let's learn to walk before we run!
Anatomy of a potentiometer
(http://sound.westhost.com/pots-f5.jpg)
1 = ground.
2 = wiper or output.
3 = input.
Here is a picture of a 10K linear potentiometer. Notice where he put the leads, i.e. one lead on the input and the other on the output/wiper:
(http://www.ladyada.net/wiki/lib/exe/fetch.php?hash=bfae82&w=500&h=375&media=http%3A%2F%2Fwww.ladyada.net%2Fimages%2Fmetertutorial%2Flinpotmin_t.jpg)
The minimum resistance of the pot is obviously 0 ohms or a direct short.
(http://www.ladyada.net/wiki/lib/exe/fetch.php?hash=d7c481&w=500&h=375&media=http%3A%2F%2Fwww.ladyada.net%2Fimages%2Fmetertutorial%2Flinpotmid_t.jpg)
Here the pot is centered, so the resistance is about 5K.
(http://www.ladyada.net/wiki/lib/exe/fetch.php?hash=5cf427&w=500&h=375&media=http%3A%2F%2Fwww.ladyada.net%2Fimages%2Fmetertutorial%2Flinpotmax_t.jpg)
Here the resistance is about 10K, or maximum attenuation.
Get it? :wink:
This post probably belongs in the "Lab" as well.
Required reading right here. (http://sound.westhost.com/pots.htm)
Anand.
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Anand, thank you! Very informitive, i guess then another test would be to try a better pot, i like having the flexablility of adjustment.
Are the plastic one's 10K?
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Anand, thank you! Very informitive, i guess then another test would be to try a better pot, i like having the flexablility of adjustment.
Are the plastic one's 10K?
One of mine measures 10K and the other measures 9.95K so plenty close to 10K. I just set them where it approximates to about 26dB of gain, which is ~ 5K.
Anybody who has a good oscilloscope, please corroborate, it would be nice to know what resistance settings correspond to various levels of gain, either in dB or "X".
Anand.
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Anybody who has a good oscilloscope, please corroborate, it would be nice to know what resistance settings correspond to various levels of gain, either in dB or "X".
Anand.
I'll loan you my http://www.easysync-ltd.com/product/520/ds1m12.html It sits more than it gets used. :(
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Can anyone explain from a technical perspective why two resistors in a voltage divider configuration with resistances being the same as the original pot would cause the sound to be different? I am baffled!
Thanks,
Rod
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Can anyone explain from a technical perspective why two resistors in a voltage divider configuration with resistances being the same as the original pot would cause the sound to be different? I am baffled!
Thanks,
Rod
That makes two of us!
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Well, whenever you start discussion 'sound quality' there is a lot of speculation and subjective opinion involved, but.....
First, the fixed resistor is replacing not only the resistive element of the pot, but also a long wire that connects the pot to the board. Since this resistive element is in the feedback loop, it is rather sensitive to contamination from emi/rfi etc. Eliminating the wire is likely to be a large part of the improvement.
Of course, I think the original mod was simply to stick the resistor at the end of the same long wire and that was also reported to be an improvement, so it's possible that the quality of the resistive element is also a factor. I don't think it's too much of a stretch to think that a conductive plastic pot and the associated mechanical contact has a different noise/distortion signature than a fixed resistor. Whether this is enough to be an audible factor even in a feedback loop is a valid question, but it's not uncommon for people to report significant benefit when switching from a cheap pot to a stepped attenuator in a preamp - in fact it seems to almost be 'accepted wisdom' that stepped attenuators using fixed resistors are much better.
So, it's probably a collection of factors
- eliminating the long wire leads
- eliminating the mechanical contact in the pot
- replacing the conductive plastic element with a fixed resistor.
As always, YMMV.
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Well, whenever you start discussion 'sound quality' there is a lot of speculation and subjective opinion involved, but.....
First, the fixed resistor is replacing not only the resistive element of the pot, but also a long wire that connects the pot to the board. Since this resistive element is in the feedback loop, it is rather sensitive to contamination from emi/rfi etc. Eliminating the wire is likely to be a large part of the improvement.
Of course, I think the original mod was simply to stick the resistor at the end of the same long wire and that was also reported to be an improvement, so it's possible that the quality of the resistive element is also a factor. I don't think it's too much of a stretch to think that a conductive plastic pot and the associated mechanical contact has a different noise/distortion signature than a fixed resistor. Whether this is enough to be an audible factor even in a feedback loop is a valid question, but it's not uncommon for people to report significant benefit when switching from a cheap pot to a stepped attenuator in a preamp - in fact it seems to almost be 'accepted wisdom' that stepped attenuators using fixed resistors are much better.
So, it's probably a collection of factors
- eliminating the long wire leads
- eliminating the mechanical contact in the pot
- replacing the conductive plastic element with a fixed resistor.
As always, YMMV.
Unless I'm mistaken this is the appeal of the Lightspeed attenuator/passive pre, the assumption being that all pots degrade the signal to some degree.
Regardless, there's a big enough step in sound quality that anyone could hear.
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Nick and all,
Let's learn to walk before we run!
Anand.
Thanks for posting that Anand! :thumb:
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In my VERY limited experience, different types of resistors sound different as well. So there may be something to the notion that one type of resistor is a better 'match' to the sound of the amp than another, or than a conductive plastic attenuator. Certainly high quality resistors sound different (usually better) than lesser quality resistors as well... so I'm thinking that there are more factors to consider in addition to the ones noted by DWK.
In any case, it was pretty obvious to me that using resistors in place of the pots clearly improved the quality of the sound of the SDS amp I own. And I haven't even tried the really nice high quality types of resistors yet. Thanks to everyone who was willing to try out this tweak and report on their findings.
Neil
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In any case, it was pretty obvious to me that using resistors in place of the pots clearly improved the quality of the sound of the SDS amp I own.
Neil
That's all that matters. Thanks for your effort. When I get my second SDS built I will try it. In the meantime, I look forward to others comments on this possible tweak.
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Thanks all for your explanations. I'm still a little baffled, but do accept what you are hearing. It's a bit of a disappointment though as I'm using a 'receiver-less' system. I'm going from the soundcard in my HTPC straight to the power amps. Having individual amp gain controls is a plus. So if I get one, or more, of these amps I'll have to set the gains on the pots at the right place for system balance, then change to fixed resistors.
Rod
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How many Watts do these resistors need to be rated for: 1, 1/2, 1/4, or will 1/8th Watt resistors do?
Thanks, Barry
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How many Watts do these resistors need to be rated for: 1, 1/2, 1/4, or will 1/8th Watt resistors do?
Thanks, Barry
Hi Barry,
I would think no more than a half watt resistor. An 8th watt might be hard to handle. a quarter watt might be just fine. Just make sure they are say 1% or at most 5% difference in value between each other. I'd probably get tweaky, and get 1% values. But, that's just me.
Ray
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Thanks Ray, as far as % variation goes, I'd likely get a hand full and measure to get a matched pair ;)
One more question...
Would a simple jumper with no resistance cause problems?
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Thanks Ray, as far as % variation goes, I'd likely get a hand full and measure to get a matched pair ;)
One more question...
Would a simple jumper with no resistance cause problems?
You would be at max gain, and probably it would be as if you turned the pots all the way up. Nothing gained there. no puns intended. lol.
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so if I wanted max volume/gain I could disconnect the pot and solder together the yellow and black wires and that would be ok?
I guess the red wire does not need to be attached to the pot?
I use a tube buffer so max gain is fine.
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You would be at max gain, and probably it would be as if you turned the pots all the way up. Nothing gained there. no puns intended. lol.
Don't you mean nothing lost ;)
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Don't you mean nothing lost ;)
Yep, there's always one in every crowd. Actually, yeah, nothing lost. What I should have said, nothing gained sonically. It might be interesting though to try a 5K in there as a fixed resistor. I suppose if he just wanted to have the amp gain at max, he could just run some solder between the two points, or just have a piece of wire soldered between the two solder points on the board. Then all you'd have to do is to just cut the wire to restore it back to the original factory specs.
Ray
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For all of you using a balanced input on your SDS amps be sure you pull the J1/J2 jumper (it's located close to the stereo/bridge jumper). With this jumper in place you are running the amp single-ended.
My set-up is balanced and I was unwittingly running the amp in single-ended mode and I can tell you that when I removed the jumper I got a very audible improvement in resolution and soundstage width/depth.
I wonder if this means that balanced users should be using two fixed resistors per channel in place of the gain pots - one across the yellow/black pins (input/output) and one across the red/black pins (red is chassis ground). Anyone? Tom has been too busy selling amps to give me a definitive answer on this.
Also, when you go from SE to balanced you will pick up 3-6db.
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For all of you using a balanced input on your SDS amps be sure you pull the J1/J2 jumper (it's located close to the stereo/bridge jumper). With this jumper in place you are running the amp single-ended.
My set-up is balanced and I was unwittingly running the amp in single-ended mode and I can tell you that when I removed the jumper I got a very audible improvement in resolution and soundstage width/depth.
I wonder if this means that balanced users should be using two fixed resistors per channel in place of the gain pots - one across the yellow/black pins (input/output) and one across the red/black pins (red is chassis ground). Anyone? Tom has been too busy selling amps to give me a definitive answer on this.
Also, when you go from SE to balanced you will pick up 3-6db.
Thanks for the heads up. FWIW, this amp was designed with balanced inputs in mind. Running it single ended is compromising its performance. So even those fellas who have their entire system running with RCA's/unbalanced I would encourage you to build or buy a differential/balanced preamp or source so you can hear this unit in all its glory.
Best,
Anand.
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FWIW, this amp was designed with balanced inputs in mind.
Anand,
Is this coming from Tom? I asked him about this when I bought my kit and seem to recall from our conversation that going balanced offered no real sonic improvements over single ended.
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No, its purely subjective, and with some objectivity thrown in! The differential input stage is designed for excellent common mode rejection (as he states on his website), and as such can benefit single ended inputs as well. When I auditioned the SDS 254 that jtwrace had lent me, I had two Belden cables, one unbalanced and the other balanced. I then set the levels to be the same as the balanced input had as much as a 6 dB increase in gain. The balanced input sounded better, although the RCA was no slouch. From a purely subjective standpoint, I found the balanced connection to sound *cleaner* and imaging was sharper if that makes any sense. If you are going to try it, I wouldn't splurge on some fancy balanced cable just yet. Use something cheap and well designed (like Belden) and borrow a balanced preamp.
My little study wasn't double blinded so my results could be completely biased, I will admit that.
YMMV,
Anand.
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Cool. Are you still building the dc coupled B1 to pair with the ClassD? If you are, I'd like to see how you put a balanced version together...maybe post in the thread Wushuliu started a few weeks back.
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Hey Anand, thanks for the update the other day on your multi-sub set-up. I hope I can take advantage of your learning when I do the final set-up on my three subs which I hope to complete in the next month.
In my current set-up I run balanced from my Metric Halo LIO-8 DAC/Pre to the SDS-224. I had been listening to it for 2 weeks (since I put it in my system) effectively in single-ended mode with a 5kohm resistor across the yellow/black pins (replacing the standard gain pot). So I had a very established baseline for comparison. Pulling the J1/J2 jumpers, as Anand described, yielded a "cleaner", more resolute presentation - in comparison to single-ended mode the sound seems just a bit "smeared". The difference was immediately audible in my system. I had to dial the gain down in my pre by 6db to restore the balance.
There is no question in my mind that this amp is at its best in balanced mode.
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No, its purely subjective, and with some objectivity thrown in! The differential input stage is designed for excellent common mode rejection (as he states on his website), and as such can benefit single ended inputs as well. When I auditioned the SDS 254 that jtwrace had lent me, I had two Belden cables, one unbalanced and the other balanced. I then set the levels to be the same as the balanced input had as much as a 6 dB increase in gain. The balanced input sounded better, although the RCA was no slouch. From a purely subjective standpoint, I found the balanced connection to sound *cleaner* and imaging was sharper if that makes any sense. If you are going to try it, I wouldn't splurge on some fancy balanced cable just yet. Use something cheap and well designed (like Belden) and borrow a balanced preamp.
My little study wasn't double blinded so my results could be completely biased, I will admit that.
YMMV,
Anand.
So, what about building the amp balanced and using balanced (XLR) to RCA cables? Would that be more beneficial than using RCAs out of the amp?
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So, what about building the amp balanced and using balanced (XLR) to RCA cables? Would that be more beneficial than using RCAs out of the amp?
You mean RCA's into the amp. I haven't tried it so I can't tell.
For my *main* speakers, everything that runs it is designed to be balanced and runs with balanced cables only. In other words, I don't look for diy projects or designs that convert RCA to balanced or vice versa without the supporting circuitry, be it tubed or solid state.
Anand.
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Cool. Are you still building the dc coupled B1 to pair with the ClassD? If you are, I'd like to see how you put a balanced version together...maybe post in the thread Wushuliu started a few weeks back.
I am currently half way through the build on the circuit boards, taking my time. I still have to design the chassis, and get the encapsulated toroidal transformers. I will be building the 600mA hot rod version for those who are curious (that's 600mA per board or 1.2A for the entire unit!). Each toroid is 80-100VA, probably Plitron. I already have the remote for the volume control which is a K&K balanced attenuator. All the series resistors in the main part of the circuit are TX2575 type.
I want to build this buffer once and not tweak afterwards.
Anand.
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Yeah, sorry, I was thinking about the pre-amp as I was talking...
Balanced in from an RCA preamp (DODD Buffer)You mean RCA's into the amp. I haven't tried it so I can't tell.
For my *main* speakers, everything that runs it is designed to be balanced and runs with balanced cables only. In other words, I don't look for diy projects or designs that convert RCA to balanced or vice versa without the supporting circuitry, be it tubed or solid state.
Anand.
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For anyone interested in buying a kit, there's a guy on head-fi selling a new sds-258 kit and he's willing to hear offers.
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The TX2575 resistors finally arrived. Smaller than I thought, kind of fragile. They sound very, very good.
I have also finished an Optical Volume Control pre based on the Lightspeed circuit. It is also VERY good. :P They go well together. Music is Pure.
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Wush can you give us some details, you replaced your gain pots with fixed naked Vishays?
Pics??
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Wush can you give us some details, you replaced your gain pots with fixed naked Vishays?
Pics??
Nick, I too would like to see what Wushuliu has done, but in case you missed it, this started a few pages back...
http://www.audiocircle.com/index.php?topic=76400.msg852812#msg852812
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(http://www.audiocircle.com/image.php?id=38537)
(http://www.audiocircle.com/image.php?id=38538)
(http://www.audiocircle.com/image.php?id=38539)
Wush can you give us some details, you replaced your gain pots with fixed naked Vishays?
Pics??
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Hey A.C... thanks for the feedback on the naked Vishays. I've been playing with an assortment of resistors myself and have definitely noticed sonic differences. Takmans sounded relaxed, smooth and warm. Tantalums (to my surprise) sounded dry, cool and a bit analytical. Holcos were a dramatic step up in dynamics, clarity, articulation and speed, and also offered the widest soundstage and amazing bass extension and control. Rikens have been my favorite so far. Very even tonal balance (a tiny bit warm), excellent ambiance recovery, very 3D soundstage with excellent image focus, and almost as dynamic as the Holcos. If you are using a tube preamp, the Holcos would give you a little 'solid state' character, and if you are using a solid state preamp the Rikens offer up a little tube character. So now I'm thinking I've gotta try some naked Vishays and/or some of the top of the line Caddocks. Are we having fun yet? :)
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I am for sure ! :icon_twisted: I agree with all the above. Yes, I was surprised by the tantalum sound as well. Definitely not warm and fuzzy. Personal favorite now are the Takman Metal. Perfect combination of metal clarity and carbon warmth. Just a pain to get because I have to go through Partsconnexion.
For some perspective I would also add that the biggest leap was losing the supplied gain pots.
Neil, now that you've mentioned Rikens... hmmmm...
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How much do those resistors lessen or lower the output or volume? Thanks!
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How much do those resistors lessen or lower the output or volume? Thanks!
It would depend on the value of the resistor. The higher the value, the more it will attenuate the volume. The potentiometer being replaced is nothing more than a variable resistor ;)
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Hey A.C... thanks for the feedback on the naked Vishays. I've been playing with an assortment of resistors myself and have definitely noticed sonic differences. Takmans sounded relaxed, smooth and warm. Tantalums (to my surprise) sounded dry, cool and a bit analytical. Holcos were a dramatic step up in dynamics, clarity, articulation and speed, and also offered the widest soundstage and amazing bass extension and control. Rikens have been my favorite so far. Very even tonal balance (a tiny bit warm), excellent ambiance recovery, very 3D soundstage with excellent image focus, and almost as dynamic as the Holcos. If you are using a tube preamp, the Holcos would give you a little 'solid state' character, and if you are using a solid state preamp the Rikens offer up a little tube character. So now I'm thinking I've gotta try some naked Vishays and/or some of the top of the line Caddocks. Are we having fun yet? :)
Very interesting. So what value and wattage of resistor did you settle on?
Are you running balanced or unbalanced?
Ray
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Very interesting. So what value and wattage of resistor did you settle on?
+1
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What values are recommended for zero gain passives like the NP B1 or others?
That's why I was asking about resistors limiting the gain.
For those using active preamps, the resistor value would be greater to lower the output to balance with the pre.
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10 Ohms gives you basically as much input sensitivity as you'd get if you left the volume controls in place, and cranked them all the way up. I've been using values around 5K ohms, and that drops the input sensitivity by about 6 decibels (which works really well with my Pass DCB1). I've tried 1/2 watt and 3/4 watt and even one 1 watt rated resistor and that doesn't seem to make any difference at all. I guess I'd suggest using 1/2 watt resistors unless you can't find the impedance value you want at that rating, at which time I'd feel free to go up a bit.
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10 Ohms gives you basically as much input sensitivity as you'd get if you left the volume controls in place, and cranked them all the way up.
Thanks Neil, that's what I needed to know... great find! :thumb:
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Someone please explain to me the following:
1. Is the pot only used as a variable resistor in the SDS?
2. Why should I bother to use any resistor at all when I can use a piece of wire to get max gain?
I recently bought the SDS-254 to try in place of my CDA-254. The results were surprising: You can't run either amp directly from a 100K volume control. The input impedance on the CDA amp is way too low to do this without significant loss and the SDS amp ends up sounding really thick and with almost no highs. When I buffer the volume control with a pair of LME74910 and feed the CDA-254 I get wonderfully extended highs. I haven't tried this with the SDS yet. But what this seems to reveal to me is that the amps have a fairly high input capacitance. This would explain the spread of opinions on the top end extension / roll off that I have seen on this discussion - it all depends on what you feed it with. So far I like the CDA-254 best.
Also, in my opinion, the CDA-254 is not a good candidate for driving with a tube preamp. I have tried a few options and it is just not practical as it loads the last tube stage too much. The SDS, on the other hand, is perfect for driving with a tube preamp. Also, the CDA-254 is dead quiet, whereas the SDS-254 is most certainly not due to the added gain stage. Once I try the buffered volume on the SDS, I'll post findings.
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To expand on my post: I am trying to build an integrated using the ClassDaudio amp modules and using a diyclub.biz remote volume kit with input selection to feed it. Dead simple idea, but the 100K pot seems to be a deal breaker without adding additional circuitry.
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And to expand just a tad more: The gain pots behave like volume controls in that they adjust between nothing and full gain. I don't see how a single resistor in a feedback loop can set the amp to "not amplify" when its value increases to 10K as it does with the pot used on the SDS.
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To expand on my post: I am trying to build an integrated using the ClassDaudio amp modules and using a diyclub.biz remote volume kit with input selection to feed it. Dead simple idea, but the 100K pot seems to be a deal breaker without adding additional circuitry.
With an input impedance of 47K, I'd think a stepped attenuator of 10K or 20K should work well.
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I just finished a stock CDA-245S kit and all i can say is I am most disappointed. It is totally lifeless. no freq extension either way. This is supposed to be 250watts and my 50watt glass amp beats it in every way. whats going on?
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I just finished a stock CDA-245S kit and all i can say is I am most disappointed. It is totally lifeless. no freq extension either way. This is supposed to be 250watts and my 50watt glass amp beats it in every way. whats going on?
Wow, that's odd. I've got the CDA-254 that Bill built here for some auditioning, and I wouldn't call it lifeless at all. In my system there's more emphasis in the lower treble than with my Audio Alchemy OM150 amplifier, giving the impression of greater immediacy. But the sound-stage seems a bit larger over all, and I'd say it also sounds more dynamic, with greater difference in volume between soft and loud passages. I also notice no loss of extension at either of the frequency extremes.
The 'S' version you have does have less capacitance in the power supply, which could effect the sound. Why did you opt for the smaller power supply? There are discussions in this thread about he benefits of upgrading (adding capacitance to) the standard power supply, so I imagine that down-grading the PS, as you did, could have negative effects on the sound(?)
Regarding the out-put power, just to be clear, it's 250 wpc into 4 Ohms and only 125 wpc into 8 Ohms.
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I just finished a stock CDA-245S kit and all i can say is I am most disappointed. It is totally lifeless. no freq extension either way. This is supposed to be 250watts and my 50watt glass amp beats it in every way. whats going on?
I think Barry is certainly on to something concerning the PS, not only does the S model have the lower profile PS with less capactance but the kit comes with smaller transformer. I would contact Tom and see if its possible to get the L model.
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I just finished a stock CDA-245S kit and all i can say is I am most disappointed. It is totally lifeless. no freq extension either way. This is supposed to be 250watts and my 50watt glass amp beats it in every way. whats going on?
"It is totally lifeless. no freq extension either way."
I don't think using the smaller power supply would kill the performance of this amp, but the increased capacitance apparently steps up the dynamics.
There must be something else going on here. Contact Tom, he may need to take a look at it or advise you in some way.
An amp that is "totally lifeless with no frequency extension" would not garner over 100 pages of interest.
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I just finished a stock CDA-245S kit and all i can say is I am most disappointed. It is totally lifeless. no freq extension either way. This is supposed to be 250watts and my 50watt glass amp beats it in every way. whats going on?
Disregard the stuff about the power supply. That is not the problem. The problem is, what I have been talking about all along, impedance matching. What are you driving the amp with? The only way to get frequency extension and liveliness out of the CDA series is with a low impedance driving source, such as a solid state preamp or solid state buffered volume control. PM me if you need help.
Later on, when you want more slam at high volume, just add some more caps to the power supply.
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Come on, someone please take the time to answer my questions from yesterday. I really appreciate your input.
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You can't run either amp directly from a 100K volume control. The input impedance on the CDA amp is way too low to do this without significant loss and the SDS amp ends up sounding really thick and with almost no highs.
Your findings are not surprising. The CDA amp has an input impedance of approx 7.5K which is very low. That's why a buffered preamp is necessary for impedance matching like you said. The CDA series amps are just not candidates for most common volume controls. However, the SDS series amps, with their input impedance of 47K, should be fine with using 10K, 20K, 25K value attenuators. I prefer the 20K Goldpoint/Elma stepped attenator, and would not anticipate any impedance matching problems with the SDS amps.
Regarding your earlier 2 questions, I recommend that you send a PM to Walkern. He can answer those for you.
Hope his helps.
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I just finished a stock CDA-245S kit and all i can say is I am most disappointed. It is totally lifeless. no freq extension either way. This is supposed to be 250watts and my 50watt glass amp beats it in every way. whats going on?
I think raindance is probably right about the impedance matching. What preamp are you using?
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Also, in my opinion, the CDA-254 is not a good candidate for driving with a tube preamp. I have tried a few options and it is just not practical as it loads the last tube stage too much. The SDS, on the other hand, is perfect for driving with a tube preamp. Also, the CDA-254 is dead quiet, whereas the SDS-254 is most certainly not due to the added gain stage. Once I try the buffered volume on the SDS, I'll post findings.
My aikido pre worked fine with the CDA-254. The input caps should be visible on the bottom of the board if you want to know the value. Last I knew they were 22uf for the CDA-254, but this may have changed. And do you need max gain?
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Don't get me wrong, a tube pre will drive the CDA series, but the treble extension suffers and it loads the output tube heavily. I tried an SRPP specifically setup for a 7K load and it worked, but there was no air at the top end. With the LME74910 unity gain buffers, there is amazing extension top and bottom, but not enough gain when driven from my CD player or DAC.
This is not a coupling cap issue as the coupling cap governs the low frequency response.
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My tube preamp has 200ohm output impedance I tried the amp with a SS preamp and it was no different and the same with feeding my dac directly into the D amp. The DAC has extremly low output impedance. the Xformer measures 33.6 VAC and the PS measures 44.6VDC
(http://www.audiocircle.com/image.php?id=38641)
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My tube preamp has 200ohm output impedance I tried the amp with a SS preamp and it was no different and the same with feeding my dac directly into the D amp. The DAC has extremly low output impedance. the Xformer measures 33.6 VAC and the PS measures 44.6VDC
What speakers are you using? And which tube pre, if you don't mind me asking.
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Rebuilt Maggy IIIa's custom passive xover with 12ga coils and Solen /clarity caps.
Right now I am running bass panels with 150watt SS (db Systems) monoblocks and the mid/ribbons with a TAD-60 glass amp. All is nicely balanced, confirmed with TrueRTA and a Behringer mic. Bass is supplemented with a pair of Janis W-1's running 40hz on down
(http://www.audiocircle.com/image.php?id=38658)
The goal is to go four way active and using all new d amps. I was hoping that these class D audio kits would work. The bass panels are 5 ohms, mids are 2.5 ohms and the ribbons are 2 ohms native.
for the active xover I was thinking the mini DSP
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Rebuilt Maggy IIIa's custom passive xover with 12ga coils and Solen /clarity caps.
Right now I am running bass panels with 150watt SS (db Systems) monoblocks and the mid/ribbons with a TAD-60 glass amp. All is nicely balanced, confirmed with TrueRTA and a Behringer mic. Bass is supplemented with a pair of Janis W-1's running 40hz on down
The goal is to go four way active and using all new d amps. I was hoping that these class D audio kits would work. The bass panels are 5 ohms, mids are 2.5 ohms and the ribbons are 2 ohms native.
for the active xover I was thinking the mini DSP
I'm not sure the D amps are going to do such low impedance loads. They are half bridge designs and on the high power models even 4 ohms is pushing it. There is a custom model I read about - the SDS-4 that might do it. The CDA series would probably need additional heatsinking.
You are also driving multiple amps from a single preamp with the passive setup, so the CDA series input impedance would stack up poorly in this mode. When you change to active, the preamp only needs to drive the crossover and the crossover has to be able to drive the 7.5K input on the class D's.
Before you dimiss the class D amp, try my suggestion of buffering its input with an LME49710 op amp for each channel configured as a non-inverting buffer. You might even be able to power this from the aux winding on your existing transformer. PM me if you need more help. I found the amps really sparkly but smooth and refined with this buffer up front. All it is really doing is making the amp a light load and simplifying the input impedance.
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thanks for the reply and the help....sent you a e-mail
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I'm running a similar system: Maggie IIIA's with modified outboard passive crossovers (Alpha core/sonicaps/jensens bypass). I'm biamping with a ClassDAudio SDS 258 on the bass which runs around 400wpc/4 ohms and an SDS 224 on them mids/highs with no trouble at all. I run a tube preamp in front and get plenty of grip on the panels--clean, tight, punch bass, sweet mids and highs. I use a Dahlquist LP-1 crossover which is passive on the highs but adjustable on the lows. Very natural souding unit. Don't know that you need to go bridged monos to get what you want. I think they might have problems because each channel will be driving a 2 ohm load. Might be worth discussing with Tom at Class D though.
Best of luck,
steve
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Forgot to mention--beautiful frames!!
steve
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Hope you get it figured out. Fwiw, my cda-254 runs a 12" 3 way, 4 ohm/90db with no problems. Lots of power, clarity and very clean strong bass. You should be able to get similar results imo.
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Rebuilt Maggy IIIa's custom passive xover with 12ga coils and Solen /clarity caps.
Right now I am running bass panels with 150watt SS (db Systems) monoblocks and the mid/ribbons with a TAD-60 glass amp. All is nicely balanced, confirmed with TrueRTA and a Behringer mic. Bass is supplemented with a pair of Janis W-1's running 40hz on down. The goal is to go four way active and using all new d amps. I was hoping that these class D audio kits would work. The bass panels are 5 ohms, mids are 2.5 ohms and the ribbons are 2 ohms native.
for the active xover I was thinking the mini DSP
The TI-300/600 amps are stable down to 2 ohms, but the sound quality is probably not as good as the CDA/SDS amps that use the IR chips. http://focus.ti.com/lit/ds/symlink/tas5630.pdf (http://focus.ti.com/lit/ds/symlink/tas5630.pdf)
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Hope you get it figured out. Fwiw, my cda-254 runs a 12" 3 way, 4 ohm/90db with no problems. Lots of power, clarity and very clean strong bass. You should be able to get similar results imo.
BUT 4 ohms does not equal 2 ohms. If the ribbons are 2 ohms driven directly there is a problem. If you biamp using a passive X-over to the mids/highs that can offer a 4 ohm load to the amp, then you are in business.
I do not recommend running a half bridge amp into 2 ohms and DEFINITELY not a full bridge as it will see 1 ohm.
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Andy adds a 1ohm resistor to the 2ohm ribbon bringing it to 3ohm in his active system.
I really appreciate everybody's comments and I realize I jumped too soon with the CDA.
So I am stuck with it, it will go on the shelf until I need the PS for some other project.
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Thanks All But,
I just hooked up my cda 224 and I have a mismatch with gain or impedance or something. It doesn't play as loud as my Audio Research or Forte ams. I am going directly from a JVC XLZ1050 into the amp using the variable outputs of the player. I have plenty of volume using either of the other two amps. I love the volume control of the JVC player can anyone advise me what to do?
PS The amp seems to sound fine. I beefed up the power supply to 6800uf like was suggested. And by the way the Hammond choke 193L, you spoke of made a big difference with the ClassD not as dramatic with the other amps. Thanks for the tips Wushuliu
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Funny thing you just uncovered - I have mentioned this sensitivity thing before but no one else agrees - the CDA series amps need a preamp with a gain of 2 or 3 and the ability to drive a 7K load.
I have tried running an op amp buffer -> volume pot -> CDA amp and it sounds amazing, but I can't get much volume either.
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Hmmm... I don't doubt what you are saying at all, but just to give perspective. When I hook up the CDA-254 I have for evaluation, it seems to have about 3db more gain than my Audio Alchemy OM150 which has 29dB of gain and a 40k Ohm input impedance. I use an Audio Alchemy DLC1 pre-amp with a 220 Ohm output impedance, which, IIRC, runs passive until it gets above unity-gain, and 90% of my listening is done somewhere between 20 to 30db below unity-gain.
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I think the difference is I'm not using a preamp at all. I'm going directly to the amp from the cd player. The player has variable outputs which I control from the remote, very handy. I quess the question is. Can I increase the gain in the amp? I don't think a passive amp will work for me but I don't know that much about this stuff. I can't turn my volume past 12 with the Audio Research amp or I'll blow out the drivers it's so loud. The Forte Amp also plays very loud but not as loud. The input sensitivity on the tube amp is .55v and input impedance is 100k. I have no idea what those numbers mean. The speakers are quasi O-B 5 in drivers only from GR Research, pretty efficient, but I'm not using Dann'y crossover so mine can't compare, sound wise.
How can I up the volume? I got rid of my preamps because I could go direct to the amp and it sounded better than any pre I tried Thanks
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If you turn the CD player output up all the way and it is not loud enough, then you'll need a preamp. Same problem I have. I got myself an SDS-254 and it solves this problem nicely as it has variable input gain.
Most people here are running the CDA amps with active preamps.
Evidently you can send the amp back to Tom to get the gain changed but if you bump it up the input impedance drops. You don't need that, it is already really to low for practical purposes.
I've found that to really get the treble detail that these amps (CDA series) are capable of I have to at least buffer the input with an op amp.
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If you turn the CD player output up all the way and it is not loud enough, then you'll need a preamp. Same problem I have. I got myself an SDS-254 and it solves this problem nicely as it has variable input gain.
Most people here are running the CDA amps with active preamps.
Evidently you can send the amp back to Tom to get the gain changed but if you bump it up the input impedance drops. You don't need that, it is already really to low for practical purposes.
I've found that to really get the treble detail that these amps (CDA series) are capable of I have to at least buffer the input with an op amp.
This alone may justify the extra cost of the SDS series. Yes?
Rod
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Yes, I would think so. Although in my head the jury is still out on which sounds better. Right now, with my home made buffer with no gain, the CDA sounds much better but won't go loud enough. The SDS without my buffer sounds a bit thick and rolled off in comparison but goes plenty loud.
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The SDS without my buffer sounds a bit thick and rolled off in comparison but goes plenty loud.
Have you tried driving the SDS with a 10K or 20K stepped attenuator?
"Thick and rolled off" sounds like the value of the passive unbuffered volume control is 50K to 100K. I'd be interested to know if that's the case. :scratch:
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Yes, I would think so. Although in my head the jury is still out on which sounds better. Right now, with my home made buffer with no gain, the CDA sounds much better but won't go loud enough. The SDS without my buffer sounds a bit thick and rolled off in comparison but goes plenty loud.
Raindance,
Consider changing the feedback resistors on your LME49710 opamps to give you 6-12 db gain.
FWIW,
Paul
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Would bridging two CDA amps solve the volume issue by any chance?
Are you suggesting that by buying the SDS I would have sufficient gain? If so maybe I'll try selling the CDA and replace it with an SDS if it's sound is similar. I don't like the thought of thick and rolled off, however. If I get an SDS I should get a buffered passive too? Usually when adding something, a preamp for instance, doesn't that muddy the water?
I like the idea of building a preamp maybe with the above mentioned LME4970, if it sounds as good with additional gain. I would need guidence though. Anyone game? Thanks Walt
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OK everyone. My buffer was a non-inverting stage with 100% feedback. The only resistor in that circuit is between input and ground and it sets input impedance to a sane value. On the LME chip that sounded great. When I rewired to an inverting gain stage with a gain of 2 it did not sound good at all. Of course I reversed my speaker wires to keep things in phase when I tried this... This is possible a quirk of this chip. Also note I was running off a single supply and this is not the best way to reject power supply ripple, although my supply was regulated. Possibly you would get better results with a split supply, I just did not have a transformer lying around for that plus Ratshack doesn't know what negative regulators are :(
@Roymail: yes, I was trying to use a 100K motorized Alps black that I ordered for another project. Padding the value down with resistors would totally screw up the curve of the pot, so I don't really want to go there. Buffering it is the key to avoiding the "thick & rolled off" description.
So, regarding the CDA series: there is great benefit from buffering (no gain) the input to make it an easier load for your preamp. But you'll need a preamp with gain.
Regarding the SDS series: drive it with a low value pot, around 10K if you have to go passive, or use a preamp or buffer with gain or no gain, your choice - the gain pots help sort this out. Or use a no gain buffer like I suggest for the CDA if you have to drive it from a high resistance pot.
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10 Ohms gives you basically as much input sensitivity as you'd get if you left the volume controls in place, and cranked them all the way up. I've been using values around 5K ohms, and that drops the input sensitivity by about 6 decibels (which works really well with my Pass DCB1). I've tried 1/2 watt and 3/4 watt and even one 1 watt rated resistor and that doesn't seem to make any difference at all. I guess I'd suggest using 1/2 watt resistors unless you can't find the impedance value you want at that rating, at which time I'd feel free to go up a bit.
OK, I volunteered via a PM with another member to get some info from Tom (the amp designer) on the gain resistors/pot situation. Here is his response:
First, the amps are AC coupled (EDIT BY RAINDANCE - So you can try them with your Little Dot Mk III if you want). The gain is in the first stage of the amp.
I was very careful in selecting the pots that come with the amps. They feature high quality conductive elements and are pretty much dead quiet. Of course, you can use stepped attenuators for possibly a little better performance, but most could never be able to hear the difference. These do not come with the kits because as I’m sure you already know, you can spend allot more money on quality stepped attenuators than the cost of the amp kit. Fixed resistors are another and possibly the best choice as long as you know the correct gain to set the amp at to get the most out of your preamp or other input device. Without taking this into account and just changing to a fixed resistor, it is possible that you won’t achieve the optimum sound quality from your equipment if your preamp is not matched correctly to the amp and adjusted to find the maximum and optimum sweet spot of the preamps volume control. Distortion from the preamp can be a problem on many units if the volume control is turned up too high, and you also might not be getting the best from your preamp if the volume is turned too low… they are all different.
To put it simpler…
The gain controls are used to match the amplifier’s gain to the gain of the other amplifiers in the system as in active or passive preamps, DAC, iPod or mp3 players, etc. The gain controls allow you to match the amplifier to the input device. Not all input devices have the same maximum preamp output voltage. Some preamps are capable of producing 15 volts RMS out while others are only capable of 1.5 Volts RMS out. Most preamps or other input device will reach its maximum output level (clipping) well before the volume control reaches the upper end of its range, usually at a point of 75-90% of its maximum range.
For those who wish to change the pots for fixed resistors, here are resistor values to produce required gain. Gain is listed in dB: To change gain potentiometer to a fixed resistor, you would connect a fixed resistor between the yellow and black wires on the gain controls (of course, remove the gain pots). Leave the red wire disconnected.
Use high quality 1% resistors:
560 Ohm = 31 dB
1K = 30 dB
2.2K = 27 dB
5.2K = 23 dB
6.2K = 18 dB
7.5K = 16 dB
I hope this is of some help. Please feel free to post this on the forums if it will help others. On my personal systems here, I use the same pots that come with the kits.
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Buffer circuit, non-inverting, using any op amp WHERE THE SPEC SHEET SPECIFICALLY SAYS IT IS UNITY GAIN STABLE. Note that this uses a split supply and can be DC coupled both ends and I only show one channel. This circuit is the most simple circuit in the op amp world and works as an impedance transformer. The input resistor sets the input impedance. It is that simple. The output impedance is low and will drive the CDA series 7K load easily.
The decoupling caps have to go as close to the power supply pins on the op amp as possible and the power supplies must be regulated. Use cheap electrolytic or tantalum caps for the larger value (this is cheap & cheerful after all) and ceramic or other non-polarized small caps for the low value.
(http://www.audiocircle.com/image.php?id=38957)
If you want more info, I can add the power supply and also some detail on how to do this with a single supply. This is all basic electronics, nothing fancy. Always check for DC offset at the output before trying a home made buffer with your system! Also, make sure the buffer is on before the power amp to be safe (protect your speakers from turn on pops).
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Roymail just sent me a PM that reminded me of something:
With the SDS amp you can replace the two 10K "gain" pots with a 10K dual log volume control and you are DONE. You have an integrated amp with one input. This would probably be the best sounding configuration as well.
Don't do this if you are using a preamp that has gain, do it only if you want to run totally passive.
I'm betting this will be the BEST way to run these amps.
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Single supply version of the buffer (note that this works fine but has poor PSRR due to the fact that you can't place any significant size cap on the divider to bias the op amp halfway for single supply use - the cap forms a low pass filter).
Input impedance is 100K in parallel with 100K which is 50K. Don't go too high on the divider resistors as the biasing won't work.
(http://www.audiocircle.com/image.php?id=38962)
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there are no pots on the CDC so I this means they have to go back for the change?
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For those who wish to change the pots for fixed resistors, here are resistor values to produce required gain. Gain is listed in dB: To change gain potentiometer to a fixed resistor, you would connect a fixed resistor between the yellow and black wires on the gain controls (of course, remove the gain pots). Leave the red wire disconnected.
Use high quality 1% resistors:
560 Ohm = 31 dB
1K = 30 dB
2.2K = 27 dB
5.2K = 23 dB
6.2K = 18 dB
7.5K = 16 dB
I hope this is of some help. Please feel free to post this on the forums if it will help others. On my personal systems here, I use the same pots that come with the kits.
[/color]
Extremely helpful post. Muchos gracias Raindance.
Thanks!
Anand.
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there are no pots on the CDC so I this means they have to go back for the change?
What are you trying to find out?
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I had mentioned a few days back that I was disappointed with the CDA I just purchased in that it was very dull sounding and had no gain. The discussion centered on my tube preamp that has 700 ohm output impedance. I believe you suggested an input buffer and it was also mentioned that the importer can change the gain and that might be the solution so I just wanted to confirm that before I contact him
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It shouldn't be this hard. Once again I recommend that you contact Tom. He's very helpful. The problems you're having don't seem to be typical of these amps.
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According to Tom, he can change sensitivity on the CDA series. Decreasing sensitivity INCREASES input impedance, making the amp more tube friendly, but you'll have to be sure your preamp can swing enough volts to drive the amp properly. You already feel you have no gain, so I doubt this will help you. Going the other way will decrease input impedance and will probably not work with a tube preamp.
Also, which tube preamp do you have?
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I using the transcendent sound Grounded Grid
Specifications:
Harmonic Distortion: Less than .02% at 2 volts RMS out.
Signal to Noise Ratio: Greater than 93 dB.
Bandwidth: 1 dB down from 5 Hz to 300 kHz.
Gain: 12 dB.
Max Signal Out: 20 volts RMS.
Output Impedance: 200 ohms.
Input Impedance: 50 k Ohms.
Inputs: 3, Outputs: 1, all single-ended, RCA
Controls: Input Selector, Volume, Power
Tube Compliment: 3-12AU7
Dimensions Overall: 15'W by 11'D by 4 1/4'H. 100-120V, 200-240V, 50-60 Hz, 25 watts
Weight: 10 pounds.
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My SDS 254 build with pictures is here (http://www.audiocircle.com/index.php?topic=65332.msg867981#msg867981) for anybody interested. Questions/comments/criticisms welcome.
Anand.
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My SDS 254 build with pictures is here (http://www.audiocircle.com/index.php?topic=65332.msg867981#msg867981) for anybody interested. Questions/comments/criticisms welcome.
Anand.
Anand your build looks amazing. You certainly took some extra measures in regards to power, care to comment on your sonics compared to the stock unit you demo'ed?
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Anand your build looks amazing. You certainly took some extra measures in regards to power, care to comment on your sonics compared to the stock unit you demo'ed?
A review will come soon enough, but comparing to the stock version will be difficult as I don't trust my memory that much. In any case, I will compare it with another solid state amp I built, the Poseidon's Voice Anjali (pics available in my gallery). I try to compare the solid state amps to each other instead of my tube amps I have just cause they are quite different sounding and I may prefer one or the other depending on mood, appetite, type of music, etc...
If anybody has questions on the build itself, let me know.
Anand.
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I can confirm that changing the pots outs for some quality resistors on the sds amps has a very positive effect. I changed mine out for the naked Vishay's yesterday. Let's just say I can't wait to get the remaining resistors I have into my DC B1 board. Very satisfied.
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Just mailed my CDC 254 for tom to look at and maybe change the gain
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This is a great thread guys, I really appreciate all the info on how to mod them ... and not just by throwing darts and hoping for good results. I'm convinced, it's time to build one!
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I've got a question for bridged mode.
After changing all the jumpers and then connecting the outputs to (left + and Right +) and using the left input.
How do you connect speaker wires to the binding post.
Speaker Wire (-) to amp (left +) or (right +)
Speaker Wire (+) to amp (left +) or (right +)
Since both outputs are + I wasn't sure how to hookup the speaker wire so they are in phase properly for the speaker.
Hope this makes sense.
Joel
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In bridged mode (SDS-254) you use the left channel positve to the positve speaker output, and the right channel positve to the negative speaker output.
This is what Tom told me and it does sound like it is phase
JT
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JT,
Thanks for the advice.
Joel
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Can anybody help my with the wiring for a power supply using a dual bridge rectifier like the one used in the following link. http://www.tnt-audio.com/clinica/ssps2_e.html
I now have all the parts but I can't understand the bridge rectifier's wiring. In the diagram it seems that the upper bridge neg out is connected to the lower bridge positive out then both to ground. Otherwise how then can the neg be achieved in the diagram. Can this be correct? Nightshade used a dual rectifier power supply in a March 18th post, could you Nightshade, or anyone else help me out? Thanks Walt
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I have a question about the resistor mod.
If your running in bridged mode do you only need one resistor on the left input or do you still need resistors on both the left and right input. I was thinking of buying the naked vishays and was wondering if I could save a few bucks.
Joel
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I have a question about the resistor mod.
If your running in bridged mode do you only need one resistor on the left input or do you still need resistors on both the left and right input. I was thinking of buying the naked vishays and was wondering if I could save a few bucks.
Joel
Hi Joel,
Well, here's how you can know the answer. Assuming you haven't removed the two pots, do the bridge mode. Then while all is hooked up accordingly, then turn the knob on the right pot, and see if there is any affect. If there's no affect, then unplug that pot, and see if all is well. If again, no affect, you have your answer.
Now, if in turning the right pot, the volume drops, then you again have your answer. Let us all know what you find out.
Ray Bronk
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I am running a bridged SDS-254 and according to Tom you only need the left hand pot attatched, which is the way I have it. So you would only need one resistor per board, mine are on order.
(http://www.audiocircle.com/image.php?id=38630)
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Where are folks sourcing the naked Vishay resistors? And has anyone compared them with the top end Caddocks? Would like to try these, but Michael Percy is the only source I've found, and he has a minimum order of $25.
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mine are coming from Parts Connexion, they are having a 20% off sale right now, 1K naked - $15.95 each. but they charge $15 shipping cost me $41.00 shipped
so if you can get them less than that go for it
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JT Where did you get the power supply.
Is that from Connexelectric ?
How do you like it?
Joel
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You can get the naked vishay's directly from Texas Components. They were around $9 each plus shipping I think and about a two week lead time.
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JT Where did you get the power supply.
Is that from Connexelectric ?
How do you like it?
Joel
yes it is from Connex, it probably is a 20% improvement to the stock one, more open soundstage and deeper base, was not noticable at first but after about a week it opened up. Worth the investment for sure.
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yes it is from Connex, it probably is a 20% improvement to the stock one, more open soundstage and deeper base, was not noticable at first but after about a week it opened up. Worth the investment for sure.
Hi JT,
So did you get the dual diode situation set up? What other changes did you make?
Ray
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Hi JT,
So did you get the dual diode situation set up? What other changes did you make?
Ray
Hi Ray,
what do you mean by dual diode? I am getting ready to install vishay resistors
in place of the volume pots. Also am going to install a felix common-mode choke.
As you can see above I added another amp board so I am running bridged SDS-254's which made a big difference on the quanity and quality of the bass control.
If I new more about power supply construction I would look at improving that like bigger transformer, caps etc. This would have to be on the affordable side though. I looked at Paul Hynes stuff but that is expensive.
JT
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Well I've been auditioning Pumpkinman's CDA-254 build for a bit now, and he's built a nice amp. The wiring is nicely laid out and cleanly routed. The amp sounds pretty good, but I don't feel it's as good as my Audio Alchemy OM150 with a PSU150 and a PSU150M. FWIW the PSU units are nothing more than a transformer and diode, so the extra PSU doesn't add any capacitance to the amplifier. The CDA-254 does have an immediacy that I think the AA amp lacks, but the CDA is also pretty severely lacking in bloom and body. Listening to Johnny Cash, 'American IV - The Man Comes Around' via the two amplifiers really illuminated the differences. With the CDA the strings of the guitar were clearly audible, but the wooden body was pretty much absent, and Johnny's voice took on a slightly nasal characteristic. With the AA the strings were less evident, but the warmth and resonance of the guitar body was clearly there. Another thing that was interesting was the sound-stage presentation. While the CDA may have presented a slightly wider sound-stage, the AA was far deeper both in-front of and behind the plane of the speakers. This was pretty evident on most all recordings, but a favorite demo for this is Peter Gabriel's 'Growing Up' from his album 'Up'.
I'm still interested in the Class-D Audio amplifiers, but only if the SDS boards are closer to my Audio Alchemy, bringing back some of the warmth, resonance, and depth that I feel the CDA board is lacking in my system. Anyone care to comment?
Pumpkinman's amp (from his gallery)...
(http://www.audiocircle.com/image.php?id=28184)
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Barry, just to be sure - while you were auditioning the amps, everything else in your system remained constant?
I have a CDA-254 and have only had a NAD 1700 preamp so far. Next week should receive a simple tube pre to try, then hopefully later this month a B1. Expect either of these to have more air and space. Also in next few weeks a different solid state amp to try (Ampslab LM60).
I don't love or hate the CDA, thou it's obviously "good" in my system, especially in the bass. I enjoy the power (90db speakers) especially after a run of low power tube amps (with high eff speakers). But for me so far without a better pre can't make any legit comments on it.
Also just rearranged my room to have 5' behind speakers and a 6 foot opening to an adjoining room between them. This above anything else brought wide and deep soundstage and much diminished reflection problems (as always the room rules).
Don
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The power supply will have a huge effect on the end sound. Gary Dodd recommended a bigger transformer than the ones that come in Tom's kit. He also recommended for the best sound to power them with batteries. When I get around to building one that's the route I'll take. The cost isn't much different between transformer vs. battery builds.
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Barry, just to be sure - while you were auditioning the amps, everything else in your system remained constant?
Don
Oh absolutely Don, same interconnects, same speaker cables, same power cord, the same everything.The only difference in the system during auditioning was the amplifier.
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Thanks Barry. It's good to hear of these comparisons. I enjoying the music from my cda, and don't hear any big problems or lack of abilities with it, but I haven't compared it to other amps yet. My big mistake in the amp search over last few years was in selling an AVA Omega III amp which would've been perfect to compare to everything else I tried.
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I am new to the hole DIY amps and I ordered the CDA-254L Kit. Now I need to order all the miscellaneous stuff to complete the amp. One thing I noticed is that some people use the IEC inputs with filters in them. What is the purpose of that and/or is it recommended? Sorry is this is a pretty basic question.
Thanks,
Topp
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Anyone manage to contact Tom for the past few days? I received the SDS-4 kit but I had a problem with the left channel where there is cracking and distortion. Right channel is working fine and I like the ClassD amp sound signature compare to Jungson Class A amp. After further troubleshoot, I no longer getting any sound from the amp. I use a multimeter to check the power supply module and found out the power supply unit output is 98v. I believe the voltage is wrong. I check the transformer output and it is correct at 72v. Also when I turn off the main power, I can hear some noise from the speaker like the capacitor is discharging.
I'm thinking to build a 8 channel amp using 4 SDS-4 kit. As mention earlier, is the SMPS500R recommended compare to Transformer + power supply module? If I get SMPS500R, do I still need the power supply module (the board with rows of capacitor)? Also, which version should I get, the SMPS500R single rail or dual?
Thanks in advance.
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I received back my CDA-254 from Tom. He changed the gain and now it is a more usable amp. It sounds pretty good, decent extensions either way. It definitely is an in your face amp, very upfront but not very involving. It does not suck you into the music like my other amps. I would like to work on the PS. What is the maximum capacitance I can add.
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I am running 60kuf with no problems on the stock PS with Panasonic 10k TSHA caps, i think Wushiliu went even higher. I ran 40k for a while and bumped up to 60k with nice results, dont know if there is any benifit to going higher.
Digikey has these back in stock for a killer price.
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=P7492-ND
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I returned a cda224 for credit and purchased a sds254. No problem with the cda but with me not using a preamp exactly as raindance described. I changed out the supplied pots with PRP 2.2k ohm 1% resistors. I will try other resistors and will post if anything beneficial results.
I originally purchased the small power supply and changed caps to Panasonics 6800uf 63 volt so I couldn't return it. So I bought a 800va Antek transformer, changer the bridge rectifier to a 35 amp model and heavily heat sinked it for protection. Don't know if I had to do that but it works. I bypassed before the bridge with .1uf polypropylene caps and after the Panasonics too, and added all poly bypass poly caps following this link. http://www.tnt-audio.com/clinica/ssps2_e.html
I don't know if all this was necessary because I did not do it in stages, but I would certainly do it again. This amp has very deep base with control, reasonably good stage depth, lots of air around the musicians a sweet extended high, and it is quick. For me it's just wonderful and I would recommend it to all.
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Can someone please explain to me the concept of changing the gain of this amp? What is it about the stock unit that isn't so good?
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Can someone please explain to me the concept of changing the gain of this amp? What is it about the stock unit that isn't so good?
Hi, First of all, I don't know which model you have. From what I understand the units come with approximately 32DB of gain. Now, that's ok if you have a buffer, or passive Pre-amp which has no gain. if you have the CD units, before you buy, you should ask tom to make it approximately 27DB of gain, which is about standard in the industry for amplifiers. Now if you have a SDS unit, it has a buffer built in, as well as providing a volume pot for each channel. At max the gain is
32DB. Rather than dial it down and guess if you have the gain set correctly, you can just sub these pots out for resistors of specific values. It appears that certain brands of resistors do make a difference in sound. If you are using a pre-amplifier, then you want to have at least the lower 27DB of gain, which means you need a 2.2 K-ohm resistor.
This DB gain factor is from 0 at input to 27DB at output. I'll let the more technically minded give you a further explanation.
So to answer your question, as a summary, if you are using a buffer, then leave the gain at max 32DB. if you are using an active pre-amplifier, SolidState or Tube, then you need to lower the gain to at least the standard 27DB. Hope this helps.
Now, some have lowered the gain anyway even though they had a buffer, and the sound improved.
Ray Bronk
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Uh, resistors? I thnk I remember what those are from my Vietnam War protest days.
I bought an SDS254 amp. From a photo of the finished amp in a chassis it didn't look like it had volume controls for each channel. I just don't understand the meaning and concept of gain. Isn't it all relative?
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Ha ha, I too was in that era of the Vietnam war.
I probably misused the word gain in my post. I don't use a passive or active preamp but go directly from my cd player to the amp, so my speakers would not play loud enough for me. That is not a problem with the amp but my peculiar situation where a mismatch existed. Not so with the SDS254 where by using resistors or the supplied potentiometers you can adjust how loud the amp plays in relation to where the preamp volume level sounds best. It balances this using the input of the amp I believe.
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Uh, resistors? I thnk I remember what those are from my Vietnam War protest days.
I bought an SDS254 amp. From a photo of the finished amp in a chassis it didn't look like it had volume controls for each channel. I just don't understand the meaning and concept of gain. Isn't it all relative?
Hi, Well as far as relativity goes, yes, sorta. However, it does come with two separate for each channel volume pots. these can be used to raise and lower the gain of the amplifier. It really depends on your setup. If you are just going to your source item, like a CD/DVD Player, Well, you could use it directly. Personally, I think a preamp is in order. But that's my opinion. The preamp helps to balance out the source components electrically, so they will in theory sound there best.
As far as the gain issue goes, well like I said that depends on your setup. If you are not using an active component, then you might consider getting something like a TVC, which is a passive device. Well, this really needs to go in to another thread. Tell me your setup.
Ray Bronk
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Thanks, everyone. My system is pretty basic.
Arcam CD-72 player
Morrissey ELAD (active) preamp
Silverline Minuet speakers
When the ClassD arrives I'm going to install a Beresford TC-7520 DAC into the mix just to evaluate what it does.
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Thanks, everyone. My system is pretty basic.
Arcam CD-72 player
Morrissey ELAD (active) preamp
Silverline Minuet speakers
When the ClassD arrives I'm going to install a Beresford TC-7520 DAC into the mix just to evaluate what it does.
Then you might want to get some 2.2 K-ohm resistors and not use those pots at all. It would be 2 less holes in your case that you would have to punch. look further up this thread in which wires you use for the two resistors.
Ray Bronk
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It would be 2 less holes in your case that you would have to punch.
Ray, you would think that, but the majority of builds I have seen in this topic have left the pots and their signal-carrying wires coiled up in the case like antenna inductors.
Steve
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I'm afraid that I am totally inept when it comes to performing any kind of mechanical or electrical work. I'll just see how the unit fits in.
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I'm afraid that I am totally inept when it comes to performing any kind of mechanical or electrical work. I'll just see how the unit fits in.
Hi, Well, since this is a kit, and I'm not sure, but I think there is a bit of soldering to do. Not to bad though. you will have to mount the Transformer to the case, and mount the board to the case. If you don't know how to do this, then you will have to find someone locally to do the work for you. I myself have not had the chance to play with one.
Ray
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I bought the amp from someone on our own Trading Post.It's all built, in a chassis and ready to go.
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I bought the amp from someone on our own Trading Post.It's all built, in a chassis and ready to go.
Hi, That's cool. Ok, so if the two volume pots are not mounted, then I would just replace them with fixed resistors of 2.2 K-ohms. You have an active pre-amp, which has gain. From the read I read from the previous pages, fixed resistors do make a difference in sound. Happy listening.
Ray
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Anyone added a volume pot to CDA-254? If so would really appreciate pics to help with wiring.
I have 10K Bourns and 25K from ebay (used for B1).
Don
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The amp arrived yesterday and I hooked it up with a Beresford 7520 DAC in the mix. I'm going to remove it to see how things sound without it. I need to do a lot more listening before I judge this amp completely. It images very well, good sound stage. I'm not positive that I like the overall sound as well as with my Adcom 535, but this is a very tentative observation.
I also have a hum since installing the amp. A cheater plug did not remove it.
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The amp arrived yesterday and I hooked it up with a Beresford 7520 DAC in the mix. I'm going to remove it to see how things sound without it. I need to do a lot more listening before I judge this amp completely. It images very well, good sound stage. I'm not positive that I like the overall sound as well as with my Adcom 535, but this is a very tentative observation.
I also have a hum since installing the amp. A cheater plug did not remove it.
Are you using it with XLR or RCA inputs? Are the jumpers installed accordingly?
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I'm using RCA connections. Jumpers?
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MWG
Shoot some picture.
:wink:
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I'm using RCA connections. Jumpers?
Did the previous owner use RCA's? If so, then you should be all set. If not, you do need to install the jumpers for RCA operation.
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From Class D:
The important thing to remember is… do not use the – on the input for single ended. Connect the + to + and the negative to G (ground). If you connect to -, it will damage the amp. For balanced input, just remove J1 and J2 jumpers completely. J1 and J2 have jumpers on pins 2 and 3… this is for single ended input. If you change the jumpers to pins 1 and 2, it will reverse the polarity… most situations this will probably not sound as good, so no need to mess with that.
For the potentiometers included, the black wire goes to the center pin on the pot, and if holding the pot with pins facing up, the yellow wire goes on the left, and the red wire on the right.
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Uh, resistors? I thnk I remember what those are from my Vietnam War protest days.
Ha. That gave me a good laugh...
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Wow, I didn't know about the input wiring importance. I must have gotten lucky and wired the negative to ground, properly. I received no instructions with the sds254, but did with cda224.
On quick note the Holcos provide a much smoother presentation, less grain, warmer with better image depth and resolution than with my PRP resistors, and surprisingly, easily discernible. I also have some Takmans and Rikens I'll report on if any different.
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Wow, I didn't know about the input wiring importance. I must have gotten lucky and wired the negative to ground, properly. I received no instructions with the sds254, but did with cda224.
On quick note the Holcos provide a much smoother presentation, less grain, warmer with better image depth and resolution than with my PRP resistors, and surprisingly, easily discernible. I also have some Takmans and Rikens I'll report on if any different.
Very curious to hear a report on the Rikens, one of my favorites. Thanks
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From Class D:
The important thing to remember is…
I do not understand this at all. The unit was built by the seller, who did use RCA cables. All I did was connect everything to the proper right/left or positive/negative.
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I do not understand this at all. The unit was built by the seller, who did use RCA cables. All I did was connect everything to the proper right/left or positive/negative.
Fine. Then start the troubleshooting process as you normall would. Shut off each component one by one going to the amp. Does the hum go away?
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Ok. I disconnected every thing except the preamp, amp and speakers. Hum still present. I've requested that the seller let me return the amp to him.
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Ok. I disconnected every thing except the preamp, amp and speakers. Hum still present. I've requested that the seller let me return the amp to him.
That's not what was recommmended above though. Shut off each component one at a time until you get to the amp, if it's still there then unplug the inputs and leave the amp on with the speakers connected.
This really isn't hard. We'll get it fixed with a little bit of patience. Worst case is that something took a shot in shipping. Everything is easily fixed though.
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I will be glad to do the troubleshooting steps again and try getting it right. Thanks.
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I have read most of this very long thread and have pulled the trigger on two SDS 224 amplifiers, large power supply and gigantic transformer. Ordered last Thursday night and it arrived today. Great service.
I have read most of this very long thread, but still have couple of simple questions: On the SDS board is it necessary to install the LEDs and the on/off switch using the molex connectors or can I just leave them off for the time being? I know that the gain pots are required but not sure about the rest.
i plan to install this in old Dynaco SCA80Q integrated amp case that I have as a first cut to see how it goes. I should be able to use the speaker terminals, RCA's, on/off switch and power cord.
Thanks,
Bill
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you do not have to install the leds and switch
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I have read most of this very long thread and have pulled the trigger on two SDS 224 amplifiers, large power supply and gigantic transformer. Ordered last Thursday night and it arrived today. Great service.
I have read most of this very long thread, but still have couple of simple questions: On the SDS board is it necessary to install the LEDs and the on/off switch using the molex connectors or can I just leave them off for the time being? I know that the gain pots are required but not sure about the rest.
...
No, it isn't necessary to connect the LED or On/Off cables. Just leave them unconnect as I did when I first put the amp together. In my case, I eventually added the On/Off and pairs of blue LEDs for Power On and amber LEDs for Standby -- but this is entirely optional.
I guess using Standby voids "in rush" (or whatever it's called) when the AC to the power supply is switched on and leaves the power supply capacitors fully charged -- not that the seems to cause noice or any other problem with the SDS.
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What are you guys using for your internal wires?
AC electrical runs?
Board to RCA input jacks?
Board to binding posts?
Thanks,
Topp
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has anyone in the houston texas area built one of these ? would like to build a cda-1000 and 2000 but this looks like a little over my head and i have no soldering abilities .
donc
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I am running 60kuf with no problems on the stock PS with Panasonic 10k TSHA caps, i think Wushiliu went even higher. I ran 40k for a while and bumped up to 60k with nice results, dont know if there is any benifit to going higher.
Digikey has these back in stock for a killer price.
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=P7492-ND
Aren't these caps rated too low for voltage? These are 63V - aren't the stock caps 80V?
THanks,
Lang
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Donc
I'm in the Houston area and think I could help you out in a few weeks after I finish up all my current projects. My solding skills have been getting better lately.
I soldered an in wall speaker while standing on a box holding the speaker in one hand, gun in the other, and solder in the speaker hand. It was a real Cat in the Hat moment. Lol
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Aren't these caps rated too low for voltage? These are 63V - aren't the stock caps 80V?
THanks,
Lang
224 amps you can go as low as 50v;254 amps 63v is fine. Also I think the connexelectronic amps are much better power supply and make for a smaller and even easier to build amp.
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Been rereading this thread for info, have a cda254.
I just wanted to link to an interesting thread that worked out a tube preamp impedance mismatch problem for someone with a cda254 and a PAS pre with Van Alstine mods. I notice Wushuliu is on that thread so this info may not be new here.
After reading Flounders post #2107 in this thread the symptoms seem similar.
Start on post #32. Easy read.
http://techtalk.parts-express.com/showthread.php?t=218374&page=2
Discussions like this are helpful. I'm going to be careful with preamp or buffer matching. I only had a NAD 1700 pre for awhile and it just sounded muffled. Working on Pass B1 soon as possible, and considering the Dodd buffer too. Seems they both mate well with cda254 at least.
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thanks My CDA 254 went back to tom for a gain change and it came back much better but still not up to par to what i am now using. I have ordered parts for a beefier PS based on whats on the parts express forum so we will see if the bigger caps and better diodes help
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I'm at the point where I'd like to upgrade the power supply on my sds-258. The only decent quality caps I can find in a larger value that will fit the board are Nichicon KG 6800uf 80v. Not much of an increase in capacitance but I'm willing to try them just to see if there's a difference between the basic and premium Nichicon caps. As an alternative I could just swap the whole board for one of the Connex boards but I'm not sold on that.
Is anyone aware of any other plug and play option out there for the power supply? Seems like an excellent opportunity for one of the commercial modder's on this site to step forward with a better solution.
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I'm at the point where I'd like to upgrade the power supply on my sds-258. The only decent quality caps I can find in a larger value that will fit the board are Nichicon KG 6800uf 80v. Not much of an increase in capacitance but I'm willing to try them just to see if there's a difference between the basic and premium Nichicon caps. As an alternative I could just swap the whole board for one of the Connex boards but I'm not sold on that.
Is anyone aware of any other plug and play option out there for the power supply? Seems like an excellent opportunity for one of the commercial modder's on this site to step forward with a better solution.
Just my .02 but I do think the Connex SMPS500R performs head and shoulders above the PS setups I had before, and it's pretty much plug and play to boot. Terrific bass control. Same size as the amp board, too. Certainly lighter (and cheaper) than the monster toroid and premium caps you'd probably have to buy if you want to really step up your game. Win-win. I know someone was asking about using a Paul Hynes PS in his forum, so that's a possibility. But again, not cheap I'm sure...
http://connexelectronic.com/product_info.php/cPath/25_46/products_id/118 (http://connexelectronic.com/product_info.php/cPath/25_46/products_id/118)
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I have a SDS-254 and eventually plan to add another 254 and a 258 for a 5.1 setup. Would you guys recommend getting a large transformer or changing the power supply to something like the Connex? how much power would i need?
Thanks!
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I dont know where on the scale of performance the Panasonic TSHA's are, but they did yield much better dynamics and detail. They are available in 10k uf and fit the stock supply just fine, i have 60k uf and no regrets.
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On the subject of increasing power supply, I'm intrigued by Gary Dodds post #65 in "monoblocks?" thread on GR Research forum. 800va transformer with 68,000 uf on each side, for his CDA254.
http://www.audiocircle.com/index.php?topic=84285.msg818985#msg818985
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Just my .02 but I do think the Connex SMPS500R performs head and shoulders above the PS setups I had before, and it's pretty much plug and play to boot. Terrific bass control. Same size as the amp board, too. Certainly lighter (and cheaper) than the monster toroid and premium caps you'd probably have to buy if you want to really step up your game. Win-win. I know someone was asking about using a Paul Hynes PS in his forum, so that's a possibility. But again, not cheap I'm sure...
http://connexelectronic.com/product_info.php/cPath/25_46/products_id/118 (http://connexelectronic.com/product_info.php/cPath/25_46/products_id/118)
Hi, can you kindly post your connection from SMPS to the ClassD Amp board? I'm thinking to build an 8 channel power amp with Connexelectronic 2000w SPMS with 2 x SDS-258 (for LCR) + 2 x CDA-258 (for 4 surround speakers). If I'm not wrong, both board should be running at 70v.
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8ch amp with 4 x CDA258 and a 2000w power supply would be awesome. Can the 2000w supply power 4 boards.
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(http://www.audiocircle.com/image.php?id=40773)
Pinout for the smps 500r. Someone pm'd me about this a while back and I couldn't get it to load. Works now :D
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Just my .02 but I do think the Connex SMPS500R performs head and shoulders above the PS setups I had before, and it's pretty much plug and play to boot. Terrific bass control. Same size as the amp board, too. Certainly lighter (and cheaper) than the monster toroid and premium caps you'd probably have to buy if you want to really step up your game. Win-win. I know someone was asking about using a Paul Hynes PS in his forum, so that's a possibility. But again, not cheap I'm sure...
http://connexelectronic.com/product_info.php/cPath/25_46/products_id/118 (http://connexelectronic.com/product_info.php/cPath/25_46/products_id/118)
That board is rated at +-54v which is ideal for the Class-D 254 boards, but the 258 boards need +-60 to 70.
The only SMPS Connex solution that offers that much voltage is quite pricey...
http://connexelectronic.com/product_info.php/cPath/25_46/products_id/120?osCsid=3kkel2uoqfdsc7r28v54p69fe7
P.S. further poking around turned up this option, at a more affordable price, but it seems to be at the low end of the required voltage or just over max recomended...
http://connexelectronic.com/product_info.php/cPath/25_46/products_id/124?osCsid=esalb5d1m7s390jauaqo28pvh5
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That board is rated at +-54v which is ideal for the Class-D 254 boards, but the 258 boards need +-60 to 70.
The only SMPS Connex solution that offers that much voltage is quite pricey...
http://connexelectronic.com/product_info.php/cPath/25_46/products_id/120?osCsid=3kkel2uoqfdsc7r28v54p69fe7
P.S. further poking around turned up this option, at a more affordable price, but it seems to be at the low end of the required voltage or just over max recomended...
http://connexelectronic.com/product_info.php/cPath/25_46/products_id/124?osCsid=esalb5d1m7s390jauaqo28pvh5
Cristi at Connex should be able to modify the voltage for the latter upon request. The 500R has that +/-10% range, so it may be worthwhile to ask if it can be set to 60v or so for that as well...
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8ch amp with 4 x CDA258 and a 2000w power supply would be awesome. Can the 2000w supply power 4 boards.
I check with Tom and he said no problem running 4 boards from a 2000w power supply. The voltage requirement recommended is 68v for CDA-258 and SDS-258.
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I find it utterly ridiculous that ebay is the only place to source 35mm wide 10000uf capacitors in the required 80v for my sds-258 :evil:. I have scoured every possible source with no luck. It looks like the 80v Nichicon KG 6800uf from partsconnexion is the best you can do with the power supply board from classdaudio unless you want to take your chances with what are more than likely fake capacitors on ebay.
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I find it utterly ridiculous that ebay is the only place to source 35mm wide 10000uf capacitors in the required 80v for my sds-258 :evil:. I have scoured every possible source with no luck. It looks like the 80v Nichicon KG 6800uf from partsconnexion is the best you can do with the power supply board from classdaudio unless you want to take your chances with what are more than likely fake capacitors on ebay.
I talked to Tom and he said minium of 63v is okay, that is what several of us are running no problems. The TSHA's are available from digikey.
Opps.......... sold out again, they go like hot cakes at only $6.85.
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=P7492-ND
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Thanks Nick. Did Tom say 63v capacitors would work well specifically with the 258 or was he speaking about the 254? 10000uf 63v snap-ins with a 35mm diameter will be much easier to find.
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Hello toxteth ogrady,
While I don't own a Class D Audio amp (yet I hope to some day), I've been looking closely at their offerings and it seems that it would be relatively easy to add additional capacitance to the PSU by adding external pairs of caps to either the DC output terminals of the PSU board or the DC input terminals of the Amp PCB. Of course this approach assumes you have room within your chassis to accommodate additional components.
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Thanks Nick. Did Tom say 63v capacitors would work well specifically with the 258 or was he speaking about the 254? 10000uf 63v snap-ins with a 35mm diameter will be much easier to find.
The conversation did revolve around the 254, might want to double check on the larger amp.
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Here's a more exotic option for the power supply. The boards are designed to take Jensen four-poles. Hubba hubba.
http://www.musicaldesign.com/MC_PS200.html
EDIT - I just got an email back from John Hillig saying that Class D Audio has actually sent them some customers. So this supply will work--very tempting :icon_twisted:
Also for anyone looking to add more capacitance to their 258's using the stock boards, I found a U.S. source for United Chemicon 80v 10000uf's for dirt cheap prices: http://www.futureelectronics.com/en/technologies/passives/capacitors/aluminum-electrolytic-capacitors/Pages/5585385-ESMH800VSN103MA50S.aspx
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Here's a more exotic option for the power supply. The boards are designed to take Jensen four-poles. Hubba hubba.
http://www.musicaldesign.com/MC_PS200.html
EDIT - I just got an email back from John Hillig saying that Class D Audio has actually sent them some customers. So this supply will work--very tempting :icon_twisted:
Also for anyone looking to add more capacitance to their 258's using the stock boards, I found a U.S. source for United Chemicon 80v 10000uf's for dirt cheap prices: http://www.futureelectronics.com/en/technologies/passives/capacitors/aluminum-electrolytic-capacitors/Pages/5585385-ESMH800VSN103MA50S.aspx
You can also get the Universal power supply board from Peter Daniel of Audiosector. It is also drilled for 4 pole capacitors if that's what you fancy. The price per board I think is $10.
Here is a link (http://www.audiocircle.com/index.php?topic=65332.msg886712#msg886712).
(http://www.diyaudio.com/forums/attachments/audio-sector/139294d1251300271-universal-power-supply-pcb-1.jpg)
Anand.
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Anyone know the actual specs for SDS-4? Is it 250w @ 8ohm and 500w @ 4 ohm? What's the input voltage requirement? I try to email Tom twice for past one week but didn't get an answer to above question. I email Christi from Connexelectronics and advice to go for separate SMPS for each board due to better channel separation. So now I had a flexibility to either get 2 x SDS-258 + 2 x CDA-258 or 2 x SDS-4 + 2 x CDA-258. I'm getting one SMPS800R for front channel, SMPS500R x 3 units for center channel, surround and back surround speaker.
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Wow did you guys see this thing? It even has the IEC socket! http://connexelectronic.com/product_info.php/cPath/25_46/products_id/124?osCsid=1ikvno4j5l4a85akd57lpui0c5
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Wow did you guys see this thing? It even has the IEC socket! http://connexelectronic.com/product_info.php/cPath/25_46/products_id/124?osCsid=1ikvno4j5l4a85akd57lpui0c5
Yes, about 2 pages back...
http://www.audiocircle.com/index.php?topic=76400.msg885116#msg885116
;)
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What fuses are y'all with 60,000uf capacitance using? I just blew an 8A slow-blow, undoubtedly due to the high inrush current caused by the large capacitance.
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The power supply I used had 10A fuses, after I had souped up the capacitance to 55K uF, I tried 8A fuses which promptly blew...so went back to 10A, and it was all good.
YMWV
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Okay, finally got my SDS-224 up and running over the weekend. I figured letting it sit around for ~6 months or whatever would allow it to age like fine wine.....
Impressions so far are very good even just using the gain pots - resistor mod coming as soon as I settle on my gain setting.
I'm headed towards a 3-way active setup though, so I need another amp module. (woofers will be taken care of by an existing amp). My chassis isn't big enough for 2 amp boards plus the PS board plus the xformer though. I have a 2nd matching chassis that I could make into a power supply unit, but I'm a bit concerned at having the PS board that far away from the amp units - the idea being that shorter leads from the PS to the amp boards will allow better power delivery. (Is this really a big concern in practice?)
What do people think of having the xformer and stock ClassD PS board in one chassis, and then a 2nd ps board w/ caps (maybe the musicaldesign jensen unit) in the main chassis next to the amp boards? This 2nd stage would just be fed the DC from the initial supply. Would this type of 2-stage PS setup be prone to oscillation or other problems? I guess the alternative would be to simply house the xformer in the 2nd chassis and run AC into the amp chassis, but it seems like a missed opportunity to have a separate box and still end up having the rectification happen in the main unit.
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My chassis isn't big enough for 2 amp boards plus the PS board plus the xformer though. I
using transformer covers, i mounted them on the outside of the enclosure.
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After blowing through 10 bucks worth of fuses I figured out that TA had taped the wrong two transformer secondary leads together for the center tap, d'oh! :duh:
Hopefully someone can benefit from my woes...
What fuses are y'all with 60,000uf capacitance using? I just blew an 8A slow-blow, undoubtedly due to the high inrush current caused by the large capacitance.
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Hi Guys,
Just came here to ask if anyone has had contact with Tom recently?
I've been trying to email him for the last couple of weeks concerning an issue with a board but have not had any response. This is somewhat surprising as I have always had very quick response in the past and have been very happy with the service he has given (I've now bought four different amps from him). Perhaps he is on holiday?
cheers,
Richard
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Hi Guys,
Just came here to ask if anyone has had contact with Tom recently?
I've been trying to email him for the last couple of weeks concerning an issue with a board but have not had any response. This is somewhat surprising as I have always had very quick response in the past and have been very happy with the service he has given (I've now bought four different amps from him). Perhaps he is on holiday?
cheers,
Richard
What issue is it? Perhaps we can help.
Anand.
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Thanks for the offer Anand, but it relates to a board which was DOA that I returned to him a number of weeks ago.
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I've just heard back from Tom so panic over and issue gone!! Tom was indeed having a break with family and getting ready for what is likely to be a busy 2011.
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Hi,
I have just purchased a SDS-254 and it come with no literature...
It is not a big problem since it could not be simpler to put together. But i have a little question about the supply.
If I what to fuse the input is a 2A slow blow fuse is ok???
Thank you
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Hi,
I have just purchased a SDS-254 and it come with no literature...
It is not a big problem since it could not be simpler to put together. But i have a little question about the supply.
If I what to fuse the input is a 2A slow blow fuse is ok???
Thank you
If your on 220/240v supply then 2A is probably just about enough but may blow due to in-rush current at switch on due to the supply caps charging. Probably safer to go for 3A. If your on a 110 Volt supply then use 5 or 6 Amp fuse.
Remember to keep some spares. There's nothing worse than a fuse blowing when you switch on and not having one to hand!
cheers, Richard.
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Hi,
I have just purchased a SDS-254 and it come with no literature...
Literature is available on-line here...
http://classdaudio.com/index.php/Manual/?___store=default
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Literature is available on-line here...
http://classdaudio.com/index.php/Manual/?___store=default
and the #2357 posts of literature. :lol:
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and the #2357 posts of literature. :lol:
So, with this said, this is going to seem a tad lazy..... :oops:
I'm looking at a Small Gigaworks High Grade 24bit/192khz DAC http://cgi.ebay.co.uk/High-Grade-24bit-192khz-DAC-fully-assembled-kits-/120551270004?pt=LH_DefaultDomain_0&hash=item1c116a6674 (http://cgi.ebay.co.uk/High-Grade-24bit-192khz-DAC-fully-assembled-kits-/120551270004?pt=LH_DefaultDomain_0&hash=item1c116a6674) seen there.
This is to run into a CDA-254 with gain adjusted to 35. There has been some thought over at diyaudio that I would possibly need a buffer built between these two. Would this be the case? From my limited understanding of this issue, the gigaworks DAC is 75ohms output impedance where as the amp likes 7-10k ohms impedance in? Am I going to notice a SQ problem because of this?
I'm looking at putting in a stepped attenuator or dual gang log pot (10k impedance as recommended by Tom) in just before the amp as a volume control. I also plan to have a analog input (prob RCA) these two inputs would run through a DPDT switch for input selection and then through the volume control then into the amp.
Most likely analog input will be an IPhone. SPDIF or coax input from both a computer and the TV through the DAC which will be by far the most common sources.
TL:DR -> Do I need a impedance buffer for this amp? Will I notice a SQ difference?
Thanks for all the help.
Mitch
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Just to add onto my last post,
This setup is being built from scratch. All I have at the moment is an SPDIF output from the computer waiting for something to make my music live. So I'm trying to take the time to make everything as simple, effective and matching as possible. The only item I have bought is the CDA-254L kit from Class D Audio, because I managed to score the free shipping back in decemeber. I live in Australia so $80 less for shipping was a bargain. I'm working on building a 2.1 System using very efficient speakers and sub-woofer. These will be DIY as well, and I can choose to make them 4 or 8 ohm. I am leaning towards 4 obviously for more head room. I will be doing EQ on the computer and just have to work on an effective method of getting a sub out into the system, while cutting <100Hz frequencies from the speakers. Preferably with an adjustable cross over.
Since last night I have been reading through this post and find myself getting lost again and again (I know very little about electronics, I have been teaching myself for the purpose of this build + the speaker build lol). But anyways, I'll probably be keeping the kit close to stock, instead of swapping out caps and this and that.
Sorry for ramble but sometimes context helps.
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I have a SDS-254 and eventually plan to add another 254 and a 258 for a 5.1 setup. Would you guys recommend getting a large transformer or changing the power supply to something like the Connex? how much power would i need?
Thanks!
Anyone?
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I'm building 8 channel amp using 2 x SDS-258 + 2 x CDA-258. After emailing Christi from Connexelectronics, he advice me to get separate SMPS for each module. So, instead of my plan to get a 2000w SMPS to drive all 4 modules, I get 800w SMPS for Front L/R speaker, 500w SMPS for center speaker and 500w for surround and back surround speaker.
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Thanks a ton rjyap
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Hey guys, I have quite possibly, a very stupid question for you...... :oops: Well, I have been eagerly following this thread for months and have finally decided to jump in to the Class D pool to see if I can swim. I'm very much a beginner when it comes to this, but I think I can follow the wiring diagram. My question is this. I received my CDA-254L a couple of days ago, but haven't had time to do anything with it. Anyway, today was a day off and I decided to break it open and start the build. I already had my amp box assembled with all of the speaker and rca jacks installed, so I thought I could knock this out pretty quickly. Like a kid at Christmas, I busted open the box to check out the cool parts. Everything made the journey through the U.S. Postal service A-OK. I busted open the box that held the AnTek Toroidal Transformer. It looked real cool, but was wrapped in all kinds of plastic, so I continued to unwrap it. Well, I removed the plastic from the top and bottom, exposing the copper coils, only on the top and bottom of the coil. The white wrap with the AnTek label is still firmly intact around coil. At This point, I became concerned that I should not have removed the plastic. :duh: I went back to this thread and examined other member's builds. All still have the wrapping on the transformer. My question for all of you.....Have I screwed up? Have I ruined or damaged this transformer? What should I do. I appreciate any and all advise. :thumb:
Thanks, Tom
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Hey guys, I have quite possibly, a very stupid question for you...... :oops: Well, I have been eagerly following this thread for months and have finally decided to jump in to the Class D pool to see if I can swim. I'm very much a beginner when it comes to this, but I think I can follow the wiring diagram. My question is this. I received my CDA-254L a couple of days ago, but haven't had time to do anything with it. Anyway, today was a day off and I decided to break it open and start the build. I already had my amp box assembled with all of the speaker and rca jacks installed, so I thought I could knock this out pretty quickly. Like a kid at Christmas, I busted open the box to check out the cool parts. Everything made the journey through the U.S. Postal service A-OK. I busted open the box that held the AnTek Toroidal Transformer. It looked real cool, but was wrapped in all kinds of plastic, so I continued to unwrap it. Well, I removed the plastic from the top and bottom, exposing the copper coils, only on the top and bottom of the coil. The white wrap with the AnTek label is still firmly intact around coil. At This point, I became concerned that I should not have removed the plastic. :duh: I went back to this thread and examined other member's builds. All still have the wrapping on the transformer. My question for all of you.....Have I screwed up? Have I ruined or damaged this transformer? What should I do. I appreciate any and all advise. :thumb:
Thanks, Tom
You could try contacting the manufacturer here:
Antek contact link (http://www.antekinc.com/contact.php)
He's a nice guy, and is located in NJ. I don't think you 'ruined' the transformer, but your safety now is my concern. You've got live copper wires exposed and when you switch your amp on, you need to be extremely cautious when measuring voltages. So check in with the manufacturer first with the above link.
Anand.
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Yes, very good advice from Anand.
DO NOT USE THAT TRANSFORMER UNTIL YOU SPEAK WITH ANTEK.
Feel free to post pictures too.
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Thanks for the heads up guys. I'm pretty good at screwing things up. I'll give AnTek a call in the morning. I do have lots of electrical tape! :D
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I just finished a 2 x sds 224. I am very pleased. Worked the first time :green:
(http://www.audiocircle.com/image.php?id=42310)
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I just finished a 2 x sds 224. I am very pleased. Worked the first time :green:
Nice work!
What size is that case?
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Too big! Its 17"x17"x5.5". It's a standard ParMetal case. Never did this before so I wanted a lot of room. Kind of got carried away :green:
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Too big! Its 17"x17"x5.5". It's a standard ParMetal case. Never did this before so I wanted a lot of room. Kind of got carried away :green:
I think I bought the same case, and my plan is to eventually fill it with two full amps, including power supplies, running in mono.
Looking at what you've done I think it'll be tight, but I think I can get it all in there.
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I think I bought the same case, and my plan is to eventually fill it with two full amps, including power supplies, running in mono.
Looking at what you've done I think it'll be tight, but I think I can get it all in there.
I'd say there is plenty of room. You could even add dividers and it would work.
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I'd say there is plenty of room. You could even add dividers and it would work.
Two toroids too ;)
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Two toroids too ;)
Yep. If I had time to model it I would but cardboard will work just fine. :wink:
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Yep. If I had time to model it I would but cardboard will work just fine. :wink:
Hi all,
I've never been to sure how I ask a question without replying to someone. Anyway, was thinking of either getting two SDS224, and bridging each module or getting one SDS254. So which would sound better. Was also thinking of getting one or two MPS supplies, depending on which config I'd go with. Lastly, if I go with the bridged monos, do I hook the 110AC lines together in Parallel or Series? This way, I would only need one power cord.
Ray Bronk
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Hi Ray,
I would get the SDS-254 (which I did) for the $35 difference it is worth it, also comes with a 400va transfornmer which is better if you want to bridge. First I replaced the PS supply board which improved the sound, then I added another amp board and bridged them and the increase of headroom bridging the two amp boards really allowed my speakers to open up.
Next I will install the nude vishay resistors and a Felix in line conditioner,
I think a bigger transformer would help also (if anyone knows what I should use please chime in!) case is not big enough for two.
(http://www.audiocircle.com/image.php?id=38630)
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Class D amps have no business in any real hi-fi system. Might as well run a corded drill while you are listening. :duh:
cityjim
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Interesting post cityjim, care to share your personal experience with Class D or other digital amps that lead you to have this opinion?
I have owned many, and find them good for certain applications.
I don't currently run one in my main system, but retain a hybrid digital JVC for a high WAF living room system.
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Class D amps have no business in any real hi-fi system. Might as well run a corded drill while you are listening
Not all Class D amps are created equal. What manufacturer's have you heard? Do you prefer tubes or SS?
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Class D amps have no business in any real hi-fi system. Might as well run a corded drill while you are listening. :duh:
cityjim
I don't know, same could be said for blanket statements... :wink:
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Class D amps have no business in any real hi-fi system. Might as well run a corded drill while you are listening. :duh:
cityjim
Wasn't the same thing once said about solid state amps some years ago?
Seems to me there now a heck of a lot of high quality SS amps available, no?
Might that not also be true of class D?
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Interesting post cityjim, care to share your personal experience with Class D or other digital amps that lead you to have this opinion?
I have owned many, and find them good for certain applications.
I don't currently run one in my main system, but retain a hybrid digital JVC for a high WAF living room system.
Not all Class D amps are created equal. What manufacturer's have you heard? Do you prefer tubes or SS?
I don't know, same could be said for blanket statements... :wink:
Wasn't the same thing once said about solid state amps some years ago?
Seems to me there now a heck of a lot of high quality SS amps available, no?
Might that not also be true of class D?
Come on guys, don't feed the troll :nono: :wink:
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I received the SMPS800R and SMPS500R from connexelectronics and work nicely with the SDS-258. However, I had a below problem. When I turn on the amp without turning on the DAC (with volume control), I had white noise from the speaker even with the volume turn to min. Turning on the DAC and the amp become dead silence. I disconnect the RCA cable from the amp and it is silence too. But once I connect the + of the input without connecting the ground, the noise is back even the RCA end is not connected to the DAC. Christi advice to add a parallel resistor with a value 4.7kohm to 10kohm. Any other ideas to solve this problem?
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Hi,
I bought a SDS-254 kit It sound good, but I have a 60Hz hum coming from my speaker. It is not very loud but loud enough to be disturbing. I tried to move the tranfo away from the boards with no success... I just can't find the source of this "hum"
Also, when played loud it some time make some weird noise, almost like a white noise. I wonder if the amplification board is
desajuste. I read a lot of reviews of this amp and I am a little bit deceived by the sound. It sound good but not great....
I post a photo of how I wired everything. Feel free to comment....
Thank's
J-P
(http://www.audiocircle.com/image.php?id=42818)
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I post a photo of how I wired everything. Feel free to comment....
Thank's
J-P
I'd flip the toroid and the PS Board, keeping all AC lines as far from signal as possible.
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I'd flip the toroid and the PS Board, keeping all AC lines as far from signal as possible.
It's in fact one of the first thing that I tried... I unscrewed the transfo from the board and stretch it of the board as far as I could with no result.
On my transfo there is a shield wire should I plug it in to the ground ???
Thank's
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Maybe you should call Tom at classdaudio.
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Hi,
I bought a SDS-254 kit It sound good, but I have a 60Hz hum coming from my speaker. It is not very loud but loud enough to be disturbing. I tried to move the tranfo away from the boards with no success... I just can't find the source of this "hum"
Also, when played loud it some time make some weird noise, almost like a white noise. I wonder if the amplification board is
desajuste. I read a lot of reviews of this amp and I am a little bit deceived by the sound. It sound good but not great....
I post a photo of how I wired everything. Feel free to comment....
Thank's
J-P
zoula, I notice that you do not have your board grounded. Several pictures posted in this thread show a ground wire attached to a standoff screw, labeled Chassis Ground. If you do talk to CDA, please ask if this is necessary and, if so, how it should be accomplished. I suspect several here would like to know - I would. Enjoy, John.
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My previous reply got caught up in the quote. Here it is again:
zoula, I notice that you do not have your board grounded. Several pictures posted in this thread show a ground wire attached to a standoff screw, labeled Chassis Ground. If you do talk to CDA, please ask if this is necessary and, if so, how it should be accomplished. I suspect several here would like to know - I would. Enjoy, John.
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Does anyone know how these amps compare to the modified Shure Tripath TK2050 boards?
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Has anybody compared the sound of these to nuforce power amps? Did a search and didn't find anything.
Interested b/c I have someone who wants to sell me used nuforce at a good price.
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Does anyone know how these amps compare to the modified Shure Tripath TK2050 boards?
For starters, modifying a Sure board is a lot of work to get good performance. I speak from experience. You'd be better of either buying a Hifimediy board from ebay or just get a Virtue amp. Second, Tripath have a different sound to the classdaudio. Up to you whether you prefer one or the other. I'd put my money on the classdaudio vs. any Sure board any day.
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I post a photo of how I wired everything. Feel free to comment....
Thank's
J-P
Are you using the 2 gain potentiometers for volume control?
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I suspect that zoula's problem is that the unbalanced inputs appear to be connected to the + and - inputs, which I think are for balanced inputs. zoula should try using the + and G inputs. The information available from CDA is certainly not clear. Enjoy, John.
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OK.... Thank you all!!!!
I just find what I was doing wrong. There is no official documentention about the SDS series, so you need to use the CDA series instructions.
They are mostly the same to assemble with the exeption of the Potentiometers and the option of using balance input.
And gess what!!! Like an amateur I wire the gound to the (-) insted. I'm just lucky that I did not fried the amp. It seems ok now..
Tom shoud realy post the new SDS manual so that mistake like this won't happen in the futur.
Again, Thank's all
J-P
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Now that you've got it working properly, what's your opinion of the SDS amp?
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Hi,
I really can't give a final opinion on the sound of the SDS amp. My preamp is not working properly so I'm now using the amp direct from my Sugden DAC. For the volume control I use the digital volume control from the Squeezebox device that I use. To achieve a decent volume I need to use my volume at around 30% witch is not very good... The Squeezebox trash too much data...
Also I don't use any buffer before my amp so....
I'm now in the process of building my self a preamp with a kit for this guy
http://electronics.dantimax.dk/Kits/Control_boards/index.html
So it will probably be a integrated amp in it's final form.
I'll keep in touch and also post some photos and final comments
J-P
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For starters, modifying a Sure board is a lot of work to get good performance. I speak from experience. You'd be better of either buying a Hifimediy board from ebay or just get a Virtue amp. Second, Tripath have a different sound to the classdaudio. Up to you whether you prefer one or the other. I'd put my money on the classdaudio vs. any Sure board any day.
Thank you!
I understand that you have/had a Sure board so could you please compare the Tripath sound to the ClassD sound? How are these different?
Did you also test Virtue amps?
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Thank you!
I understand that you have/had a Sure board so could you please compare the Tripath sound to the ClassD sound? How are these different?
Did you also test Virtue amps?
And have you listened to any of the Hifimediy amps? How do they fit in the mix to you?
Thanks,
Rod
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I have the Sure Board/Meanwell PS and tube pre driving a pair of Zu's. Haven't heard the Class D but it must be dang good if it beats the TK2050.
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I finally pulled the trigger and ordered the cda-224. I have read this thread it seams like a hundread times and looking forward to building my first amp.
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I finally pulled the trigger and ordered the cda-224. I have read this thread it seams like a hundread times and looking forward to building my first amp.
Congrats........ :thumb: :thumb:
Post your build.
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Thanks Steve. The rca connections has the positive going to the center post and the negative going to the ring. Hopefully, that is correct.
(http://www.audiocircle.com/image.php?id=27069)
(http://www.audiocircle.com/image.php?id=27070)
One thing i have a question about is the ground ring,does it go behind the white spacer or does it right against the nut?
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One thing i have a question about is the ground ring,does it go behind the white spacer or does it right against the nut?
Between the spacer and the nut, not the spacer and the chassis, otherwise there is no need for the spacer ;)
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One thing i have a question about is the ground ring,does it go behind the white spacer or does it right against the nut?
It goes behind the white spacer between it and the nut. You want each channel RCA floating. Otherwise you will definitely have a ground loop.
Ray Bronk
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ok thanks guys
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I recieved the amp today and i have a question
there is a purple wire coming off of the transformer what is that?
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there is a purple wire coming off of the transformer what is that?
It's a purple wire! :P
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lol i set myself up for that
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(http://[IMG]http://i902.photobucket.com/albums/ac225/scodo68/class%20d%20build/Classdampbuild002.jpg)[/img]
(http://[IMG]http://i902.photobucket.com/albums/ac225/scodo68/class%20d%20build/Classdampbuild001.jpg)[/img]
Just a couple of quick pics to make sure everything works
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I recieved the amp today and i have a question
there is a purple wire coming off of the transformer what is that?
You will need to contact Tom, but some of the transformers have secondaries that just get taped off.
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(http://www.audiocircle.com/image.php?id=43832)
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(http://www.audiocircle.com/image.php?id=43833)
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yea i went back and read that it gets taped off. soo far so good we have tunes
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Is that your phone as the source?
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Its my ipod touch
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Been spinning vinyl sence last night and all i can say is wow! Im very inpressed with the sound of this thing.
The tightness of the bass is right there well worth the $175!
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boomer68, great to hear you're enjoying the Class D amp. :green:
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You guys are not going o like this.......
(http://www.audiocircle.com/image.php?id=43932)
I bought one of these, sent it back for gain change, upgraded the PS by more than doubling the capacity and did a bypass with high audio quality cap, burned in for over 200 hours and I still thinkg it sounds most lacking. No life, no envolvement. I keep visiting this thread hoping to read that someone has found the magic bullet to make this thing sound like what you guys are whistling.
As it is its barely worth what I paid for it
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No life....
Bummer. What speakers are you driving? What pre-amp and source? Just curious...
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As it is its barely worth what I paid for it
Well, there are a lot of descriptions a lot positive some negative in this thread but I don't recall no life or involvement type of remarks. Certainly not the above statement, even by the disenchanted. Maybe you've already done this, but if you could give a run down on your setup as requested above that would help.
That said, could be you just don't care for it. If *everyone* said they loved these amps, I'd be worried.
EDIT: looking back your previous posts you mention dull sounding and 'upfront' as well and I do think there is some bad synergy. Something isn't right.
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sorry I did not mean to come across that harshly and I did get a person flame from a member
(http://www.audiocircle.com/image.php?id=43962)
I was hoping to use these amps in an 3 way active xover system. This was going to be the mid panel amp, but when I listen to this amp compared with the TAD 60 tube amp (55watts per channel) or even the dbSystems 150watt monos I use for the bass panels (which is known for being dark sounding which is why I use for the bass), the Damp just sounds dead. It improved with the doubling of the PS caps with a wondercap bypass. Its is listenable and if I did not have anything to compare it to I would say its fine, but its not
If any one has another suggestion for pumping some more air in this thing I will give it a try otherwise its a boat anchor and not a very good one at that
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The version of the Class D amp (http://classdaudio.com/products/class-d-amplifiers/class-d-power-amplifier-250w-x-2-500w-x-1.html) you have (which isn't the SDS254-the upgraded balanced/differential version (http://classdaudio.com/products/sds-254.html)) would probably not have the bloom of a tube amplifier-sorry. You might want to try another TAD 60 (http://www.angelfire.com/biz/bizzyb/TAD-60.html) for your midrange amplifier. The other option is the SDS254 which is what I have.
Maggies are nice speakers but they are very power hungry, active crossover or not. Active crossovers really do help though. Although they advertise sensitivities of 85dB/2.83V/1m, the ones I have seen actually measured are about 81-82dB/2.83V/1m. They drink wattage.
Where do you live? Do you have anybody nearby that can lend you the SDS 254?
Anand.
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if I did not have anything to compare it to I would say its fine, but its not
Surely you've tried other gear that you didn't like as well as what you already own -- heck, I sure have, and those usually cost me a lot more than what this unit costs.
Clearly, this amp doesn't work for you in your rig, despite it working well for others. Cut your losses and move on, life's too short.
8)
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Impedance matching is critical with these amps. What you're describing sounds like an impedance mismatch. Your photo doesn't show what your source or preamp is and that's the first place I would start looking. That said in my experience Class D in general does not convey 'emotion' the same way that tubes or even solid state can. Again, I state this as my experience, but it is simply one of the areas that I believe class d can't compete with tubes or good solid state. In other areas it can run circles around tubes and solid state.
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Can anyone tell me the dimensions of the SDS-258 and Heavy Duty DC Power Supply PCB's?
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Impedance matching is critical with these amps. What you're describing sounds like an impedance mismatch. Your photo doesn't show what your source or preamp is and that's the first place I would start looking. That said in my experience Class D in general does not convey 'emotion' the same way that tubes or even solid state can. Again, I state this as my experience, but it is simply one of the areas that I believe class d can't compete with tubes or good solid state. In other areas it can run circles around tubes and solid state.
That's a good point. The input impedance of the CDA-254 is a very low 3K (or maybe 7K if its one of the newer iterations-see website) which was a design oversight in my opinion. The input impedance of the SDS254 on the other hand is 47K! This can make a massive difference, if your preamp is not up to the task.
Anand.
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output impedance on my preamp is less than 200ohms
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Anand, i really do not understand you comments about active xovers.
At least what I am thinking about is what sits between pre-amp and amp. It would have three channels per side controlling the the lowpass, bandpass and high pass to the bass amp, mid amp and ribbon amp. I am looking at two possibilities. Building the linkwitz 4way on Paul Elliotts (esp) site or the easy way minidsp. I might go with minidsp because its cheap and easy to see if this will ork and if so then build the analogue way
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Anand, i really do not understand you comments about active xovers....
You don't have to. It's just my opinion (which isn't worth much to anybody but myself!). Expanding on it would go off topic, so if you would like to know, you can pm me, that's okay.
All the best in your search for audio nirvana,
Anand.
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Long time listener, first time caller:
I've been following this thread for a while b/c I've been thinking about adding external aps for the front two or three channels of my system. I run Strata Minis (and a Ref 100 center) off of a Pioneer SC-05. It has pre outs. I've always thought I could use some more headroom and last week I blew some internal fuses during a particularly raucous movie scene so now I really think I could really use more headroom.
I'm not too technical but I can follow instructions. It looks like the SDS amps are preferred. I've been thinking of making mono blocks because I've always dug the idea. I'm also leaning towards those connectix switching power supplies that wishuliu tried for simplicity - although if linear really is the way to go, I could probably be talked into it.
So,is this plan reasonable/feasible, or am I missing something? Would the pre-outs work on the SC-05? How sensitive are these amps to connectors/internal wires? Any other suggestions - I'm all ears.
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A few questions:
Would the sds 1000 kit, or dual 254's work as biamped monoblocks?
Would I need two cases for that?
referring to the new kit that has dual 254's, to be clear.
Is that one guy still building cases for these things?
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mmm hi
i have this buffalo II and want to use the balanced output section using the XLR output connectors to connect to a SDS-258 balanced XLR input .
I have a SE preamp only using the + and GND , . it' of no use if i want balanced output to the SDS-258 ! ?
My guess is i need to find a balanced preamp with in/out XLR's . , to keep the stereo balance philosophy optimized ?
Output on this will be appreciated
regards
rolie.
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Is that one guy still building cases for these things?
I don't think he is.
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HI Folks
i have this buffalo II and want to use the balanced output section using the XLR output connectors to connect to a SDS-258 balanced XLR input .
I have a SE preamp that i want to add so i can use use the volume pot on it . By doing so ....will it annul my setup of the buffalo II and SDS-258 balanced topology ?
some feedback will be appreciated
regards
rolie.
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Hey Rclark.If you are looking for a reasonable case you might want to look at a Techical Pro PA1000 which I used for my build as it has all the hard work done for you.Rear panel has rca,1/4 inch and xlr for inputs,also for outputs it has speakon jacks as well as 5 way binding posts.For power it has a fused IEC jack.I removed the 1/4 inch input jacks for Cardas GRFA rca jacks and Cardas CCGR binding posts.One more feature this amp has that is note worthy is that it has gain control on the front panel which I modified to accept the SDS254 gain controls.Amp was purchased at Amazon real cheap,and all other jacks purchased at Sonic Craft on line.Front knobs I got aluminum ones at Rat Shack.
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Hi all,
I have read all the pages from first to here, and something caught my interest - Gain. Can anyone please explain to me :
1. does preamp's gain be a match to the Class D amp's gain? Saw an add on a preamp stating Gain = 12db. Then what should I set the gain for Class D amp if I am in this situation?
2. technically, why must the preamp's gain be the same as power amp?
3. If a buffer is used, which is no gain, must the power amp's gain be max out?
4. What is the difference or disadvantage if the gain of preamp does not match up with Class D amp?
Thanks for helping. I bought 2 SDS-224 and was hoping to make them into a monoblock. Still waiting for the amp since last week. Hope that I can get my hands on the the next week
cheers
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I am using my mono sds-254 amps witha Dodd Audio Buffer with out any problems and it sounds great!
I would leave the gain pots all the way up or do as others have and install Vishay resistors for the pot's to full/fixed gain.
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For those that have bought an SMPS from connexelectronic, how was the experience? I ask because I placed an order for a 500VA unit 2 weeks ago and it still shows as 'processing' on their site. Aside from the auto-responder when I placed the order, I've heard nothing from them despite sending them a contact email via the form on the site.
I did ask for a 32v version of the unit so it's possible that there is some work needed to process the order, but 2 weeks with no contact or feedback starts to get a bit concerning even for a smaller internet vendor.
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Shipping seems to take some time from connex. You can go to this link and ask Cristi directly http://www.diyaudio.com/forums/connexelectronic/
He seems to monitor that board fairly closely and should get back to you soon.
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For those that have bought an SMPS from connexelectronic, how was the experience? I ask because I placed an order for a 500VA unit 2 weeks ago and it still shows as 'processing' on their site. Aside from the auto-responder when I placed the order, I've heard nothing from them despite sending them a contact email via the form on the site.
I did ask for a 32v version of the unit so it's possible that there is some work needed to process the order, but 2 weeks with no contact or feedback starts to get a bit concerning even for a smaller internet vendor.
Yes it's a bit frustrating buying from him (Cristi). My first experience was very irritating and I had to learn to go with the flow. It's a one-man part-time operation and he never tells you if he's out of town or backed up. Still, I've ordered multiple times and all items came through. If you ordered regular air mail and not express it will take about 3-4 weeks. Looks like he hasn't posted on diyaudio for about 2 weeks as well.
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Thanks for the feedback. If this is somewhat typical, then I'm not going to freak out about it at this point.
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I want to build the 250x2@8ohms amp which calls for 60-70v transformer.
I see Antek has a 1000VA transformer that's rated 64v / 7.8A
So my question to anyone who can answer is what size fuse should I use?
8amp?
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If you want 60-70VAC that transformer is not correct. That will give you closer to 90VAC with a standard bridge.
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:o
Seriously?
... :scratch:
Are you sure?
So would something like this be more suitable?
http://www.antekinc.com/details.php?p=132 (http://www.antekinc.com/details.php?p=132)
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If you want 60-70VAC that transformer is not correct. That will give you closer to 90VAC with a standard bridge.
You meant to say "DC" in both cases?
The power supply requirements for the amplifier boards are in DC volts (i.e. +/- 60VDC to +/- 70VDC). The transformer specifications are in AC volts. After rectification the DC output will be 1.414 X the transformer secondary AC voltage.
60VAC input X 1.414 = ~ 85VDC
70VAC input X 1.414 = ~ 99VDC
Decide on your target DC voltage then either multiply that by .707 (or divide by 1.414) to determine the proper transformer secondary AC voltage.
Example: 65VDC X .707 = 46VAC transformer secondary voltage
Steve
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You meant to say "DC" in both cases?
The power supply requirements for the amplifier boards are in DC volts (i.e. +/- 60VDC to +/- 70VDC). The transformer specifications are in AC volts. After rectification the DC output will be 1.414 X the transformer secondary AC voltage.
60VAC input X 1.414 = ~ 85VDC
70VAC input X 1.414 = ~ 99VDC
Decide on your target DC voltage then either multiply that by .707 (or divide by 1.414) to determine the proper transformer secondary AC voltage.
Example: 65VDC X .707 = 46VAC transformer secondary voltage
Steve
Thanks, Steve. I'm still learning.
So would this be suitable? http://www.antekinc.com/details.php?p=139 (http://www.antekinc.com/details.php?p=139)
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So would this be suitable? http://www.antekinc.com/details.php?p=139 (http://www.antekinc.com/details.php?p=139)
Yes, the 45VAC secondaries would give you ~ 64VDC after rectification by the power supply. I always like to operate components at less than the maximum permitted voltages (but I have also been known to underclock my computers!).
I don't know which modules you are using, so the 1000VA transformer could be a little overkill, but I like big transformers, and what's an extra 2 pounds, .3"D and $16 among friends? (vs. the 800VA model AN-8445).
Have fun with the build. I know some prefer SMPS power supplies vs traditional linear supplies, but I have not built one of these and can't comment on the difference with the Class D Audio modules.
Steve
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You guys are not going o like this.......
(http://www.audiocircle.com/image.php?id=43932)
I bought one of these, sent it back for gain change, upgraded the PS by more than doubling the capacity and did a bypass with high audio quality cap, burned in for over 200 hours and I still thinkg it sounds most lacking. No life, no envolvement. I keep visiting this thread hoping to read that someone has found the magic bullet to make this thing sound like what you guys are whistling.
As it is its barely worth what I paid for it
You want the SDS-254 unit that can handle lower ohm speakers. Really for your setup you need SDS-254 run bridged. I'd also consider the DPS-500-s SMPS from audio power. Only then will the IR PWM really perform on those Maggies!!!
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Yes, the 45VAC secondaries would give you ~ 64VDC after rectification by the power supply. I always like to operate components at less than the maximum permitted voltages (but I have also been known to underclock my computers!).
........
Have fun with the build. I know some prefer SMPS power supplies vs traditional linear supplies, but I have not built one of these and can't comment on the difference with the Class D Audio modules.
Steve
I have one SDS 258 and run it stereo using +-72vdc from a connex SMPS with classDaudio approval.
It runs HOT! I will eventually get a PS with 60-65vdc for longer life.
The SMPS generates less heat but more than I expected.
I soldered the inputs on to the circuit board for improved sound.
Biggest improvement was getting rid of the gain control and soldering in vishays I had used in other projects. Those pots suck.
Sounds clean and clear, better than the icepower 1000 I was using. Great value.
It'll end up on the back of a speaker bi amping it and I'll get another later for the other channel.
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I have one SDS 258 and run it stereo using +-72vdc from a connex SMPS with classDaudio approval.
It runs HOT! I will eventually get a PS with 60-65vdc for longer life.
The SMPS generates less heat but more than I expected.
I soldered the inputs on to the circuit board for improved sound.
Biggest improvement was getting rid of the gain control and soldering in vishays I had used in other projects. Those pots suck.
Sounds clean and clear, better than the icepower 1000 I was using. Great value.
It'll end up on the back of a speaker bi amping it and I'll get another later for the other channel.
What value resistors did you use?
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What value resistors did you use?
I used 10K to match my subwoofer level.
Speakers are a Geddes Nathan clone that I've built.
10" B&C driver and B&C de250 tweeter on a 10" DDS waveguide.
Fairly efficient speakers. Around 94-95dB
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You want the SDS-254 unit that can handle lower ohm speakers. Really for your setup you need SDS-254 run bridged. I'd also consider the DPS-500-s SMPS from audio power. Only then will the IR PWM really perform on those Maggies!!!
pelliott321 !!!!
Those Maggies would sound amazing with this transport proposition using ClassDAudio.com
PC-->Halide Design SP/DIF USB BRIDGE-->Audio-gd NFB-10WM DAC-->ClassDAudio.com SDS-254 AMP bridged with dedicated Audio Power DPS-500-S SMPS per module.
Now then and only then could you really make judgement using your expensive Magnepans regarding the IR PWM performance. It really doesn't matter how much capacitance you add to the reserves when the amp module it's self can't drive the speakers properly. Also the input section of the non SDS units are known to cause impedance issues. To be fair please do contact Tom and swap that amp for the SDS-254 and do consider a decent SMPS.
SDS-254 2 x $235 + DPS-500-S 2 x $225 plus the chassis you already have...
It's gunna take a grand of class D investment to drive those maggies properly!!! They eat current for breakfast and so does your xover I bet!!! You've never heard 20.1 with GB ribbon etc/mods until you've driven it with HIGH CURRENT!!! With a lot of loudspeakers it wouldn't pay off spending extra money on the SDS series bridged and that SMPS but your speakers most certainly would gain from the investment!!!
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Just ordered one of the new ti-600 kits.. i needed more power to my woofers which dip down to 2 ohm.... Will post results soon.
peace. Beat
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Thanks HiroPro
I hear you. I only want to drive the bass panel which is 4ohms. I have 150watt SS driving them now and a 55 watt KT88 driving the mids and ribbon. I am in the decision process of which active xover I am going to get/DIY and then try the Damp on the bass panel my 150watt SS on the mids and the kt88 amp on the ribbon.
When I listen to the 254 full range on another (standard box speaker) of the maggy is when I hear this amp lacking. There is plenty of power, its just lifeless, non-envolving, compared to my other amps. It will be fine running the bass panel
(http://www.audiocircle.com/image.php?id=45189)
I also run a pair of subs that go from 40hz on down and I cut off the maggy bass panels just above that. My room gives me a bass bump from 40 to 60hz
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You don't have SDS-254 I believe. That unit in your pictures looks like CDA-224. The PSU you have looks to small to have enough current even for the 224. I'd get a bigger linear or SMPS. This is what's affecting the SQ IMHO.
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sorry I miss spoke I have CDA-224, which is irrelevant. It works fine for the bass panels. I just could not tolerate it as a main amp on any speaker.
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I had purchased the CDA 254 in March 2010. Lovely mids and crisp highs but it is very lean in the bass department. Moreover, it heats up where I've marked in the pic.
(http://www.audiocircle.com/image.php?id=45483)
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I've have a CDA-254 (built by Gary Dodd) that I got to run a sub, but as I have't built the sub yet I thought I'd try the amp on my OB 7s, WOW. So now I have a SDS-254 on its way and I would like to up grade both amps as much as I can and as I've gotten some good tips off this site so far , figured this would be the place to ask. I also have a Dodd tube buffer kit coming and want to put both on the same chassis. The amp/buffer will have 1 set of inputs and I will not use any of the pots or switches . My system is battery powered and I'm using the 12 volt power supplies from Class D, any suggestion on up grades for them would also be appreciated. If this works out I plan to build a second amp/tube buffer and bi amp either a set of GR Super Vs or some other OB speakers. As I'm new to this, pics and diagrams would be very helpful. Thanks in advance for what I know will be some great advice.
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I run the SDS254 on my ob/7's too, with a Pass B1 buffer. Wonderful combo, i am using upgraded linear supply so dont have any input on battery power. I will say the unit responds well to upgrades in internal wireing and pc's.
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(http://www.audiocircle.com/image.php?id=45779)
Here is tentative layout for my SDS 254 amp and Dodd tube buffer, how is spacing and layout? Chassis will be 17"wide 10" deep and 4 1/2" high, made of wood and stone and lined with copper sheeting. I want to upgrade as much as I can. The buffer will use platinum caps and 6H30DR tube. What type and size of wire, (was thinking about silver or silver plated copper?) what size and make of resisters to replace gain pots, should they get soldered straight to board or to the pins? Using 12v power supply, any suggestion on caps? size and make. Any suggestion on grounding or any other upgrades? I'm new to all of this so don't assume I know anything, but I do have fairly good solder skills.
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^^^I would love to know what to upgrade the caps on the Battery power supply with. I have the same one!
What resistors did you go with for getting rid of the pots on the amp? I have mine paired with a Dodd Battery buff as well and would like to change them out!
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I recommend www.homegrownaudio.com for internal wiring. Their 22awg solid core copper and silver wire is very easy to work with and sounds great.
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^^^I am using that for signal lines, do you recommend that for power as well? I have 16 AWG copper solid I am using for power right now...
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^^^I am using that for signal lines, do you recommend that for power as well? I have 16 AWG copper solid I am using for power right now...
Yeah, I meant to say the HGA stuff is for signal wiring. 16awg solid core is fine for power. That's what I'll be using for mine as well.
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^^^I would love to know what to upgrade the caps on the Battery power supply with. I have the same one!
What resistors did you go with for getting rid of the pots on the amp? I have mine paired with a Dodd Battery buff as well and would like to change them out!
see page 113 post 2247, I used 1Kohm vishay nude resistors, just cut the
wires down and soldered resistors to the end of the wires
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I finally have all of the pieces. Now comes the fun part! :bounce:
(http://i576.photobucket.com/albums/ss207/corndog642/classdaudio%20amp/dacecf19.jpg)
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I would think after all the comparison to tubes, and adding a Dodd tube buffer, don't know what that is but suspect I will be seeing Gary soon at the Lone Star Audio Fest here in Dallas that you would want to stay away from silver wire and stick with copper. Even tinned copper should be better since everyone listens to tin because of solder joints anyway. Siver does change the sound and if you are looking for a tube sound with a SS device I would think the silver a strange choice since it might reverse some of the positive things about this kit.
Of course it is your ears and wallet, so do what you want, but I think silver can make things too bright, copper is almost always mellow. I kinda doubt getting a few more electrons through are worth the price anyway. I like the old WE copper for most stuff, make cables out of the 26 guage for my tube amps and use Vampire CCOFC for signal.
That is just me though. I don't like metal dome tweeters either, unless of corse there is enough silver to make my ears bleed and thus muffle the hat pins. It just seems a bit counter intuitive to me.
What is the tube that goes in this? Russian version of the 6DJ8? I heard they are good.
Thatch
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I haven't had any problems with HGA silver wire. I find it to be transparent but not bright. I've used it in several tube projects to good effect. Their copper wire is very good as well and a lot cheaper. It's not as warm as say Monster cable but then I find those cables tend to obscure details.
I have heard too bright systems but wouldn't blame it on the cables as much as the actual components. I've heard plenty of gear that no cable was gonna "fix". They were either cheaply made or made very well but tuned for older folks (with natural hearing loss up top).
The caps and resistors in speaker crossovers also have a big effect on the overall sound.
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Thanks to all that have responded so far very much appreciated, keep it coming, with pics if possible.
Mike
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Speaking of wire, I'm embarrassed to say that I originally wired my kit together using what I had laying around (Radio Shack solid core copper speaker wire) and liked it so much that I haven't reinstalled it with the good stuff. My amp is pulling duty as a bass amp crossed over at 60 Hz. It's one of those thoughts that keeps reoccurring - would the bass sound even better, if I rewired my amp with more appropriate wire?
For bass application what type of wire would you guys recommend?
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If you like the way it sounds then why mess with it? Sure there is probably better quality wire out there but if you're only talking a few inches then any differences you hear will be minimal.
What about the rest of your speaker cable? If it isn't as good as your internal wiring then you're just taking 2 steps back.
I think of wire as seasoning. It enhances the sound to a small degree but it won't make or break it.
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What about the rest of your speaker cable? If it isn't as good as your internal wiring then you're just taking 2 steps back.
I suppose the same could also be said about your speaker's internal wiring.
Steve
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If you like the way it sounds then why mess with it? Sure there is probably better quality wire out there but if you're only talking a few inches then any differences you hear will be minimal.
What about the rest of your speaker cable? If it isn't as good as your internal wiring then you're just taking 2 steps back.
I think of wire as seasoning. It enhances the sound to a small degree but it won't make or break it.
I think you either misread my question or I did not communicate it very well.
I'm asking what you kind folks would suggest as internal wiring for my Class D Audio amplifier, which is being used for the sole purpose of driving open baffle subs.
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I think you either misread my question or I did not communicate it very well.
I'm asking what you kind folks would suggest as internal wiring for my Class D Audio amplifier, which is being used for the sole purpose of driving open baffle subs.
http://silversonic.com/docs/products/
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http://silversonic.com/docs/products/
Nice one...the topic of speaker cables was going to be my next question, but thought I'd ask it in a more appropriate circle.
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Nice one...the topic of speaker cables was going to be my next question, but thought I'd ask it in a more appropriate circle.
They have everything. I use their internal wiring for equipment and also all the interconnect and speaker wire. He also has the speaker cable for inside the speakers if you want to use unshielded. It's all available and really great stuff.
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I suppose the same could also be said about your speaker's internal wiring.
Steve
I would agree with that.
Say you have 6" of good wire in the amp, 10' of 16awg zip cord for speaker wires, and maybe 20" of low quality 18awg wire inside your speakers.
That 6" won't make much of a difference.
The main misunderstanding about wire is it won't make the sound better but it can make it worse. The "better" wire just does less damage to the signal than the cheap crap.
I'm not saying don't use the good wire. Just don't expect miracles.
Also, I recommend Kimber Kable 4VS or 4TC for speaker cables and TCSS for internal wire (TCSS is the individual wire in 4TC).
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They have everything. I use their internal wiring for equipment and also all the interconnect and speaker wire. He also has the speaker cable for inside the speakers if you want to use unshielded. It's all available and really great stuff.
Sorry, I thought you were being facetious when I saw the the external wiring in the link you shared. I'll check out the rest of their wares. Thanks.
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Has anyone done a 5.1 system using these amp modules? What is the cheapest way to feed these amps home theater? (DTS/Dolby/etc)
What is gained by using the dodd audio preamp? What type of input does the dodd audio preamp take?
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Since you need a Dolby/DTS decoder, beyond a few rare stand-alone decoder units, you are basically talking about one with a preamp built-in, either a surround processor/preamp or a surround receiver with preamp outputs. The cheapest solution would be probably be a surround receiver with preamp outputs (and having the latest codecs and features) or an older used surround preamp/processor that only does Dolby/DTS 5.1, and therefore has taken quite a hit on resale price in the used market.
The Dodd Tube Buffer is a two channel unit, and while it could be used on the main front L/R channels, you would not need it's impedance matching buffering ability with a preamp, and I imagine that any "tubiness" flavor that might be added to the two front channels would not be of too much use for HT.
Steve
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Since you need a Dolby/DTS decoder, beyond a few rare stand-alone decoder units, you are basically talking about one with a preamp built-in, either a surround processor/preamp or a surround receiver with preamp outputs. The cheapest solution would be probably be a surround receiver with preamp outputs (and having the latest codecs and features) or an older used surround preamp/processor that only does Dolby/DTS 5.1, and therefore has taken quite a hit on resale price in the used market.
The Dodd Tube Buffer is a two channel unit, and while it could be used on the main front L/R channels, you would not need it's impedance matching buffering ability with a preamp, and I imagine that any "tubiness" flavor that might be added to the two front channels would not be of too much use for HT.
Steve
Would it be possible, or laughable, to connect this up to your HTPC and have that do the decoding? Heck, if you had a large enough metal PC case you could mount a small mATX board and the amp in the same case, and have a PC fan or two blow on it.
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Would it be possible, or laughable, to connect this up to your HTPC and have that do the decoding? Heck, if you had a large enough metal PC case you could mount a small mATX board and the amp in the same case, and have a PC fan or two blow on it.
You may want to check out Pete Schumacher's PCeiver build...
http://techtalk.parts-express.com/showthread.php?t=218374&page=7 (http://techtalk.parts-express.com/showthread.php?t=218374&page=7)
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Sorry, I thought you were being facetious when I saw the the external wiring in the link you shared. I'll check out the rest of their wares. Thanks.
http://www.partsconnexion.com/wire_hookup_dhlabs.html
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Would it be possible, or laughable, to connect this up to your HTPC and have that do the decoding? Heck, if you had a large enough metal PC case you could mount a small mATX board and the amp in the same case, and have a PC fan or two blow on it.
I use an HTPC for encrypted cable HDTV recording, playback and DVD playback. But I choose to use an external AVR for audio decoding and preamplification. There don't seem to be too many high quality 5.1 analog audio soundcards, as opposed to high quality 2 channel analog audio soundcards.
If you want to keep additional heat and size down, a surround processor may be a better choice than a receiver if you don't plan to use any of the receiver's internal amplifier channels.
Again, if 5.1 Dolby/DTS is all you need, you may be able to find a surround processor known for better than mainstream receiver audio quality in an older used unit from manufacturers like Anthem, B&K, Rotel, etc. in the $300 - $500 range.
Steve
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You may want to check out Pete Schumacher's PCeiver build...
http://techtalk.parts-express.com/showthread.php?t=218374&page=7 (http://techtalk.parts-express.com/showthread.php?t=218374&page=7)
Sweet, that's what I thinking about. They have some HTPC cases that are very receiver-ish looking, too.
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Where are you guys buying your enclosures for your amps? Any suggestions would be appreciated.
Thanks,
Topp
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Where are you guys buying your enclosures for your amps? Any suggestions would be appreciated.
Thanks,
Topp
Here's where I got mine.
http://cgi.ebay.com/3U-Audio-Steel-Aluminum-Rackmount-DIY-Case-10-19085B-/370238950878?pt=BI_Electrical_Equipment_Tools&hash=item5633f60dde (http://cgi.ebay.com/3U-Audio-Steel-Aluminum-Rackmount-DIY-Case-10-19085B-/370238950878?pt=BI_Electrical_Equipment_Tools&hash=item5633f60dde)
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Where are you guys buying your enclosures for your amps? Any suggestions would be appreciated.
Thanks,
Topp
I just bought an enclosure for my Dodd buffer from these guys.
http://www.circuitspecialists.com/level.itml/icOid/4158
TrungT hooked me up.
Neil
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see page 113 post 2247, I used 1Kohm vishay nude resistors, just cut the
wires down and soldered resistors to the end of the wires
Any idea where to get these resistors? What power rating? I have been searching and have found LOTS of choices...
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the resistors I got from here
http://www.partsconnexion.com/resistors_vishay_var.html (http://www.partsconnexion.com/resistors_vishay_var.html)
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What is the difference between 1K, 1K2, and 1K5?
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What is the difference between 1K, 1K2, and 1K5?
jtsnead, 1K2=1,200 Ohm, 1K5=1,500 Ohm. See here http://en.wikibooks.org/wiki/Practical_Electronics/Resistors (http://en.wikibooks.org/wiki/Practical_Electronics/Resistors) Enjoy, John.
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SDS-258 Done! Now I just have to remember to buy the little fuses and not the big ones.
(http://i576.photobucket.com/albums/ss207/corndog642/classdaudio%20amp/b711d1b1.jpg)
Success!!!
(http://i576.photobucket.com/albums/ss207/corndog642/classdaudio%20amp/fce23314.jpg)
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How does it sound?
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So far it sounds good. I just had it driving a pair of AV123 X-LS bookshelf speakers. Over the next few days I'll be pairing it with X-Omnis and X-Statiks.
I've done a couple of tweaks right off the bat. I swapped out the PS caps for Panasonic 6800uF giving me 40,800uF total. I also swapped out the stock bridge rectifier for a 25 amp version. I've read many times over the years that you can't go too big on the power supply so I got an Antek 1000VA / 45V transformer. This whole thing has to weigh around 20 pounds!
Input wire is Homegrownaudio copper wire. I also used it for the gain control wires. PS and output wires are Electra Cable 16awg solid core copper. Connectors were sourced from Parts Express.
I've read this giant thread a dozen times and have learned a lot. This is my first solid state kit build. I've previously built several tube preamps and amps as well as rebuilt a few Dynaco amps. I'm pretty happy with it so far. I've been wanting a big amp for a long time and for the ~$600 investment the classdaudio amp is working nicely.
I'll post more thoughts later. Thanks to all of you guys for sharing your work and experience. :rock:
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I have a question about fusing. There are hi end fuses some fairly expensive but I don't see hi end fuse holders. Seems silly to put a $50 fuse in a $2 fuse holder.
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I have a question about fusing. There are hi end fuses some fairly expensive but I don't see hi end fuse holders. Seems silly to put a $50 fuse in a $2 fuse holder.
Here you go.
http://www.acmeaudiolabs.com/ (http://www.acmeaudiolabs.com/)
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Thanks, exactly what I was looking for.
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I'm in. My SDS-254 kit (http://classdaudio.com/products/class-d-audio-kits/sds-254-kit.html) is on the way, and I've ordered what I hope are all the needed ancillary parts from PartsExpress. I worry I am in over my head, but hope you will permit me to ask for advice when the time comes.
My aim is to use this with my Peachtree Nova, which I think might benefit from a bit more power in the amp department. If it sounds better, great. If for some reason it does not, I guess I can always hook up some outdoor speakers or something.
As for the chassis, I've gone back and forth on the various options. I'm now thinking if I can get a matching Nova outer chassis shell, it would look quite nice, and then get some custom front and back plates from Front Panel Express (http://www.frontpanelexpress.com/index.html) to try to match the style of the Nova. I know this isn't the cheapest option, but the potential for the coolness factor is worth a few more dollars. Maybe I could even put a little window in there, like the Nova has for the tube and blue LED, to peak in at the solid-state components...
Now, the wait. I feel like the little kid in The Christmas Story waiting for the decoder.
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My SDS-254 is playing :P
First, the system as it currently sits.
PC Engine Alix Linux based Music Server (Currently on a AC Wall Wart, but will be moved to Battery soon)
MF V-link USB-S/PDIF
Modified Lite Audio DAC
DODD Audio Battery Buffer (Running on the Battery Power Supply I created)
SDS-254 w/ DC Power Supply (Running on the Battery Power Supply I created)
Skiing Ninja Modded Polk LSi9s
Oh yeah, most importantly it is sitting in a temporary chassis provided by Trung! :o
How does it sound? I'll get to that. First the only small "huh?"
For now I have the pots in place and no mods to the amp. I am very suprised at how small the window is for the difference between little to no sound, relatively loud, and then cut-out of the amp. Right now the R and L are at about 475 ohms of resistance. Higher resistance than that means I turn the Buffer up a LOT higher. Thoughts?
The sound? Very, very nice. REALLY quiet. I mean literally there is NOTHING in the speakers when there is no music. Could be the Battery supply, the amp, or the buffer, but I like it! Very wide and deep sound stage and good dynamics. I haven't really turned it up yet as everyone is at home :lol:
Oh yeah, in the interim before this amp I was using the R and L of an Outlaw 7700.
Overall, I am very happy. This was made with stuff I had on hand due to the temporary chassis, so the components will be better when it is moved. Also, the speaker cable is crap :oops: Pics? I'll get to those ;)
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Sorry for the crappy cell phone pics...
(http://i41.photobucket.com/albums/e257/praedet/DIY%20Audio/a388117a.jpg)
(http://i41.photobucket.com/albums/e257/praedet/DIY%20Audio/418c19f5.jpg)
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^^^^^
:thumb:
I'm glad you have a good use for the bamboo chassis. :wink:
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It wouldn't be running without it!
Any insight on the gain control? If I am measuring correctly it seems like I want about 250 ohms of resistance...
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Another nice thing about those gain controls:
I'm using a tube preamp that uses a single tube per channel. It's hard to get matching tubes (3S4) without buying a lot of tubes. Also it has a single volume control. At the lower end of the volume pot the left channel cuts out before the right side.
The gain controls bring the music back into balance. :thumb:
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So, looking at the Amp board so that the left input is on the left, and the right on the right, the wires coming out of the board to the gain are red, white, black from left to right. If I now look at the gain pot with the connections going down, what color should go where? The directions referenced yellow instead of white, and the pictures a lot of folks have taken look like I wired different than others...
Ted
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The directions referenced yellow instead of white
Really? There are directions? That would definitely help.
Apart from what is wired to the transformer, I think you supply the other wires, if I understand correctly.
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I went by this pic as a reference.
(http://i576.photobucket.com/albums/ss207/corndog642/classdaudio%20amp/4aad770c.jpg)
The wires supplied were so thin and fragile I had a hell of a time stripping them. I ended up yanking them out of the connector and replacing them with HGA wire I had on hand.
(http://i576.photobucket.com/albums/ss207/corndog642/classdaudio%20amp/b2b2fd8e.jpg)
I wonder if the person who posted the first pic got it backwards though because turning the pots clockwise reduces the volume. It was such a pain rewiring those connectors I didn't feel like messing with them anymore. I guess it doesn't matter which way you need to turn them.
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^^^Thanks! Tom e-mailed me the following, apply it if you have the same color as me, or follow the picture above or the one after Tom's directions
"Thank you for pointing that out to me. I forget we just got in new wires and they’re different color than the last. Now, with the pot shaft facing toward you and the pins of the pot facing up, the black wire goes to the right pot pin, the white to the center pin, and the red to the left pin."
(http://i41.photobucket.com/albums/e257/praedet/DIY%20Audio/f5b2c7de.jpg)
If you have little to no volume with an SDS, the pot is probably the problem...
Now I figure out what resistor is best for the Buffer!
I also thought I would post up a few better pics of the amp in Trung's bamboo box.
(http://i41.photobucket.com/albums/e257/praedet/DIY%20Audio/0def038c.jpg)
(http://i41.photobucket.com/albums/e257/praedet/DIY%20Audio/8f91bd08.jpg)
(http://i41.photobucket.com/albums/e257/praedet/DIY%20Audio/2647fdf6.jpg)
Here is the cord I just built for my Alix Music Server so that it runs on the same Battery supply as the Amp and buffer...
(http://i41.photobucket.com/albums/e257/praedet/DIY%20Audio/7df00251.jpg)
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Nice clean work! :thumb:
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^^^Thanks!
This is the power supply...
(http://i41.photobucket.com/albums/e257/praedet/DIY%20Audio/08e57161.jpg)
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I'm amazed that after 15 months and 125 pages, this thread is still alive and kicking! It's a tribute to an affordable, quality product and a lot of ingenious work by DIY'rs. My hat's off to all of you. :thumb:
steve
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Go Steve!! Hats off to the original thread starter, thanks again. :thumb:
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Go Steve!! Hats off to the original thread starter, thanks again. :thumb:
:thumb:
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This is why pics are so important. I'll give it to Tom for putting out a great product but knock him back a few points for lack of proper installation pictures. I could create a proper instruction manual with nice, clear pics in a few hours.
And it looks like my gain control wiring is all wrong. :duh:
For those still unclear on the transformer wiring let's hope I got this right. It measured right and seems to work well so I think I got it right. Mind you I bought the tranny from Antek and not from Tom.
(http://i576.photobucket.com/albums/ss207/corndog642/classdaudio%20amp/b1b28d96.jpg)
My taped CT leads.
(http://i576.photobucket.com/albums/ss207/corndog642/classdaudio%20amp/0dfe8fa8.jpg)
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Transformer wiring looks correct. :thumb:
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I've got everything but the transformer now. Usually I avoid going to the mail box, because it is just filled with bills and death threats and biopsy results and letters from the IRS and that sort of thing. But now I actually look forward to the arrival of the transformer. Yet it eludes me. Such is my existential angst.
While I wait, I have been worrying about the connection between the amp board and the RCA jacks I plan to attach to the cabinet. Presumably EM interference is going to be worst inside the box. Does anyone use shielded wires between the RCA jacks and the amp board? Would it help?
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If I remember correctly those toroidal transformers don't emit the same kind of em field as tradional transformers do. I doubt you'll need to resort to shielded wire. A simple twisted pair should be fine. I used a 3-wire braid partly because it allows me to double up on the signal wire and partly because I just like the way it looks. Plus my interconnects are the same 3 wire braid of HGA copper wire.
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Speaker wire in the chassis, guage? Solid or Stranded? What about the power wire in the chassis. Same questions...
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I made my class D amp CDA254. Here. is the pic
(http://www.audiocircle.com/image.php?id=45994)
Sad part is, there is not much gain. Also, the amp sounds thin and lean. LF content is very low. Moreover, the PCB area directly above the chips heats up quite a bit. Looking forward to comments and advices from the gurus here.
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You are using the linear power supply - it looks like you are powering it with a somewhat smaller transformer than the larger, more robust standard toroidal transformer.
The recommended transformer VA rating is 300VA and the required DC supply voltages for the CDA-254 are +/- 42 VDC to +/- 52 VDC, which would require a transformer with AC secondaries in the range of ~ 30 VAC to 36 VAC.
What is the VA rating and secondary voltages of your transformer?
Beyond that, although it's hard to tell from the photo, some of the wiring looks a bit on the small side, i.e. the transformer secondaries and wiring from power supply board to amp board. The speaker wires also look a bit lean, I would recommend no smaller than 16 gauge, but again, hard to tell from the photo as well as not knowing what length they are or what speaker load you're driving.
Steve
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it looks like you are powering it with a somewhat smaller transformer than the larger, more robust standard toroidal transformer.
The recommended transformer VA rating is 300VA and the required DC supply voltages for the CDA-254 are +/- 42 VDC to +/- 52 VDC, which would require a transformer with AC secondaries in the range of ~ 30 VAC to 36 VAC.
What is the VA rating and secondary voltages of your transformer?
Thank you for the reply Steve. It is a EI core transformer, 35-0-35 & 400 VA. I'm posting some closeup pics which may give you a better view.
(http://www.audiocircle.com/image.php?id=45998)
(http://www.audiocircle.com/image.php?id=45999)
some of the wiring looks a bit on the small side, i.e. the transformer secondaries and wiring from power supply board to amp board. The speaker wires also look a bit lean, I would recommend no smaller than 16 gauge, but again, hard to tell from the photo as well as not knowing what length they are or what speaker load you're driving.
Actually, I took the help of a guy who runs a AV repair workshop. The speaker cables are 14 gauge, the thickest possible which can fit into the slot. I tried 12 gauge but they won't fit in.
Are you saying that replacing the wires supplying current from power supply board to the amp with thicker ones would help in increasing the slam? Will try that for sure.
But what is the reason for generation of considerable heat on the PCB area just above the IR chips? Looking forward to your views.
Regards
Rajesh
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If the 400VA sticker on the transformer is correct and the secondaries are 35V-0-35V, that's certainly within spec. I assume you got the 35V figure checking with a voltmeter?
As far as the supply to amp wiring, I would at least try to match the gauge of the transformer output wires, but they may already be of the same gauge. (I didn't really do a great job of visually assessing wire sizes from the photo earlier).
I know this is just a test board hookup, but the RCA input wiring should probably be separated. I would think the effect might just be some channel crosstalk, but maybe there is some kind of signal cancellation occuring? Also, I'm not sure what I'm seeing at the elbow of that wire bundle.
None of this really explains why you may have higher than normal temperatures. The heatsink is not quite as large or finned like the SDS series, so I don't know if it is somewhat normal. Perhaps some owner's of the CDA-254 could report what level of heat they're experiencing.
Steve
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I would also recommend cutting those input wires down as short as possible and unbundled. It should just be 2 nice, clean twisted pairs.
You might consider also upping the capacitance.
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The things you guys are suggesting about the cabling are useful, but are likely not going to make a real dramatic change.
Like Steve, I'd start by making sure that transformer is within spec.
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Today has been a great day for listening to music!
The stereo:
Rega P25 with Shure V15VxMR, Cambridge Audio 640P phono preamp, Bottlehead Quickie battery-powered tube preamp, Classdaudio SDS-258 driving my AV123 X-LS'.
Been spinning vinyl all day and it just sounds fantastic!
I may have to build another one of these amps for my other system.
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How hot is hot? The heatsinks of my CDA amps were all too hot to touch, which is normal.
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Thanks for the suggestions guys. The wires from PSU Board to Amp are a little thinner than those from the trafo. The elbow of wires that you guys are talking is a pot which I inserted in the chain to control the gain into the amp's input to control volume. That photo was taken a while ago. The speaker cable is now of 16 gauge.
I've since made use of the kit as power amp. I've removed that pot and cut open a monster cable and am using it to connect to the source. Result is the same; lean bass.
Also, the heat I'm talking of is not on the heat sink but on the PCB which I've roughly marked.
This being my standby amp, I'm using it only once a while.
(http://www.audiocircle.com/image.php?id=46015)
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I noticed that you have only a single lead going to the center tap on the power supply board; the toroids I've seen used all have two leads going to the center tap.
I don't know enough about transformers to know if how you have it is correct for your transformer, but I thought I'd point it out.
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I cannot comment on the xformer either. I built mine from the full kit with the big toroidal supplied by TOM.
I still had the same problem, no gain, thin, lifeless sound. I had to send the board back for a gain adjustment which Tom did cheerfully and quickly. It mad a big difference in the gain but the amp still did not sound great. I doubled the six PS electrolytics and by passed with a poly and this helped but the just sounds totally non-involving and is now collecting dust at the bottom of a closet, hoping that some day I will find a use for the PS.
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I noticed that you have only a single lead going to the center tap on the power supply board; the toroids I've seen used all have two leads going to the center tap.
Don't know about that. I made another kit amp (based on LM 3886 designed by one Mr. Mauro Penasa and modified by one Mr. Shivchander) where I used a toroid. Even that had one wire for ground, one for + and one for -
I also do not understand the 2 taps each for the +, - & Gnd from the PSU whereas the amp has only 3 connectors.
I built mine from the full kit with the big toroidal supplied by TOM.
I still had the same problem, no gain, thin, lifeless sound. I had to send the board back for a gain adjustment which Tom did cheerfully and quickly. It made a big difference in the gain but the amp still did not sound great. I doubled the six PS electrolytics and by passed with a poly and this helped but the just sounds totally non-involving
The amp sound in mids is fantastic and highs are crisp; only lows are lean. I did a one-to-one comparison with the following setups.
Common components in the setup are Marantz CDP, 2-way Accoustic Portrait bokshelf speakers having Vifa drivers; 6.25 PP cone mid-woofer and 1" Aluminum tweeter and Cardas I/C.
1. The amp driving the speakers directly with pot controlling the gain
and
2. The amp receiving signal from Parasound P/LD 2000 Pre-Amp.
and
3. A vintage Luxman L80V SS Integrated Amp.
In the first setup, sound was thin and lean with negligible bass. Sound stage was not very wide.
In the second setup, Parasound improved the sound greatly, imparting it a lot of body but the bass was better but still lean. Sound stage was wider.
The third setup sounded superb with a wide and deep sound stage, oodles of bass and fantastic sound.
I think it is the case of amp-speaker mismatch. The speakers require a powerful AB Amp to sing I guess.
I also played the amp with Fostex single driver based speakers from Audere. Nice sound but sound stage was very narrow with razor sharp sweet spot; an inch here or there and the magic vanishes.
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I also do not understand the 2 taps each for the +, - & Gnd from the PSU whereas the amp has only 3 connectors.
The extra terminals are just for convenience if you are powering 2 amp modules.
I think it is the case of amp-speaker mismatch. The speakers require a powerful AB Amp to sing I guess.
It certainly could be a synergy thing with the speakers. Maybe not even a Class A/B vs Class D thing. Maybe a different Class D amp would drive them better.
I also played the amp with Fostex single driver based speakers from Audere. Nice sound but sound stage was very narrow with razor sharp sweet spot; an inch here or there and the magic vanishes.
Do you have any other 2-way speakers with passive crossover you can try it with? It's just kind of surprising seeing how many people are thrilled with the amps.
Steve
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I'm driving my AV123 X-LS, a 2-way 6.5" ported bookshelf speaker, with my amp and getting unbelievable bass.
(http://i576.photobucket.com/albums/ss207/corndog642/classdaudio%20amp/20f17c0f.jpg)
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My transformer arrived today.
It has a lot of wires on it. I'd be grateful for a reality check, since the instructions are kind of vague to non-existant. I've mostly pieced this together from the first 126 pages of this thread, so maybe it will be a good summary, if I got it right:
Input:
There are two red, two black and one purple wire. From the diagram on the class D audio website, it indicates the two red wires connect to the AC hot wire (along with fuse and switch), and the two black wires connect to the AC neutral. I hope I have that right. {Edit: Yes, it is correct.} The purple wire says it connects to the internal shield. Should this go to the ground? {Edit: Tom verified it should.}
Output:
Do I ignore/cap off the orange and brown wires? {Yes}
I see two blue and two black wires. Since mine came with no wires taped together, I am assuming the wires in the #2 and #3 positions go to CT? {Yes}
Covering:
Am I supposed to remove the clear plastic wrapping? {No!}
Sorry if all of this is obvious to everyone but me...
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I don't know about the purple wire but it may not be a bad idea to ground it if your instructions say it's a shield wire.
As for the brown and orange wires, I clipped off the exposed wire and wrapped each end with a little piece of electrical tape. Then I taped them together for neatness.
You got the black and red primary leads correct.
Did you get this from classdaudio?
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Thanks. Yes, but they drop-shipped it.
Should I leave the clear plastic wrap on it or take it off?
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Don't suppose you can post a pic?
Is it a bag? Or is it tight like mine.
(http://i576.photobucket.com/albums/ss207/corndog642/classdaudio%20amp/0dfe8fa8.jpg)
If it looks like mine I would leave it alone. You can always email Tom to be sure.
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Looks identical to yours. Thanks.
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You may want to check out Pete Schumacher's PCeiver build...
http://techtalk.parts-express.com/showthread.php?t=218374&page=7 (http://techtalk.parts-express.com/showthread.php?t=218374&page=7)
Would the volume be controled by the "PCeiver" in this case?
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Well, I haven't managed to get mine to work yet. I have the SDS 254 kit. I believe I have it wired correctly. The blue LEDs on the power supply come on, and when I flip the amp board power switch to "on", the yellow LEDs turn to blue. However, I get no sound. I can hear it turn on through the speakers, very faintly. Because I am impatient, while waiting for the proper connections to ship, I rigged up my iPod to test the signal. I can verify the iPod puts out sound via RCA inputs on my TV soundbar, so that much is working. I have RCA (unbalanced) female inputs to + and G on each channel, and verified that the contacts are good with a multimeter.
I haven't yet attached the gain control pots. Is the gain by any chance turned down or effectively off if I haven't connected those controls up?
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yeah, the incoming signal passes through those pots.
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Good. I have to go to work to get some solder* (my British wife keeps busting my arse for how I mispronounce it).
* and to do some work.
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Looking for some input on whether this is a good idea or not. I have an Outlaw 200 Monoblock that's developed a heat-related noise issue. It was a fairly inexpensive amp to start with, and I'm not sure it's worth sending out for repair.
The class D amp is interesting, and I was considering using the power section and case with one of the boards mentioned in this thread.
(http://www.audiocircle.com/image.php?id=46053)
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Outlaw makes very good amps. I think it would be worthwhile getting it repaired.
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I have an Outlaw 200 Monoblock .....
The class D amp is interesting, and I was considering using the power section and case with one of the boards mentioned in this thread.
It will depend on the DC output of the power supply. The Class D Audio amps will require
+/- 30VDC to +/- 40VDC (SDS-224)
+/- 32VDC to +/- 42VDC (CDA-224)
+/- 40VDC to +/- 50VDC (SDS-254)
+/- 42VDC to +/- 52VDC (CDA-254)
+/- 60VDC to +/- 70VDC (SDS-258)
+/- 62VDC to +/- 72VDC (CDA-258)
Then, the 1U case is 1-3/4"H, so I don't know if the amp boards will fit or not. A couple of the models specify 1.25" height, so they may all be that height. They also mention 9/16" standoffs, but I think you would need to use a shorter standoff closer to 1/4" or 3/8".
Steve
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I was wondering about the power supply (among other issues). And you're right that the 1U enclosure is snug.
I'll do a bit more research and also see what a local shop would charge for a diagnostic. The fix might be fairly simple, and these amps are great for home theater front channels. (I have two more.)
Thanks for the quick and helpful feedback.
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Still haven't managed to get it to work. :oops: Doubtless I am doing something stupid. Is there any reason in principle an iPod touch won't work as a test source? I'm pretty much at a loss, apart from this, as to where to start trouble-shooting.
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Still haven't managed to get it to work. :oops: Doubtless I am doing something stupid.
So this means you have either connected the gain control pots or installed fixed resistors in their place, and it still doesn't work?
Steve
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Yeah, I found some solder and installed the gain control pots, fiddled with them, etc. I was kind of rushed since I had to go to work, so I easily could have overlooked something, but nothing obvious having just re-read the first 40 or so pages here during a boring meeting....
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did you turn your ipod's volume all the way up?
Alternatively, you could get one of these
http://www.amazon.com/FiiO-L7-Line-Dock-Cable/dp/B004QVNS0S/ref=sr_1_16?s=electronics&ie=UTF8&qid=1303866087&sr=1-16
which bypasses the built-in volume and just passes a standard line level output. You would need a preamp which isn't necessarily a bad thing. It just takes you further down the rabbit hole.
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Works now. Naive Luser error. :icon_lol:
The iPod using the mini-jack to RCA definitely gives a very weak signal. But I also found if I turned the gain all the way up (all the way counter-clockwise, counter-intuitively), it cuts out, but if I dial it back maybe a degree or two, it works. Is that normal, or have I fscked it up somehow?
I'm planning to use this with the pre-Amp stage of my Peachtree Nova, btw. The iPod was basically a test to make sure everything works and doesn't burn down my house or more importantly, destroy the pre-Amp and speakers.
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Ultimately, what I want to do is use the new Class D amp in this system (http://www.audiocircle.com/index.php?action=systems;area=browse;system=1568). The Peachtree Nova has a pre-Amp (RCA) out, so I want to use this instead of its built-in Class A Amp. If this sounds significantly better, I may add a second amp board and do (passive) bi-amping.
I was able to buy an extra Nova case, so I can make something that matches for the Class D amp, and order customized front and back plates.
This is my first DYI audio project (in case it isn't obvious), so I am always in need of help in suggestions.
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I haven't tried mine straight from the ipod. I would think you would get enough of a signal from it. I have my gain controls open all of the way as I prefer to get those cheap pots out of the way as much as possible. I have to remember to look for some higher quality ones like PEC.
As mentioned before a preamp is a good investment. If you can handle a soldering iron then I highly recommend Bottlehead's Quickie.
http://www.bottlehead.com/store.php?crn=220&rn=438&action=show_detail
Here's mine. :thumb:
(http://i576.photobucket.com/albums/ss207/corndog642/Bottlehead%20Quickie/7669d368.jpg)
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Cool. If this one goes ok, then I'll try that for my next project. I only have one tube in the current pre-Amp.
The nice thing about the Nova is that if you want to use a different amp, there is a pre-Amp out, and if you want to use a separate amp and a separate pre-amp, there is a line-level out from the DAC.
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Works now. Naive Luser error. :icon_lol:
The iPod using the mini-jack to RCA definitely gives a very weak signal. But I also found if I turned the gain all the way up (all the way counter-clockwise, counter-intuitively), it cuts out, but if I dial it back maybe a degree or two, it works. Is that normal, or have I fscked it up somehow?
I'm planning to use this with the pre-Amp stage of my Peachtree Nova, btw. The iPod was basically a test to make sure everything works and doesn't burn down my house or more importantly, destroy the pre-Amp and speakers.
I think you wired the gain pots wrong. That is what mine did when I had it messed up...
Check my picture up above. What color are the wires for your gain pot?
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Black in the middle, red on the right as the knob points away from you, white where the non-existent yellow wire is supposed to go.
I just found your picture:
(http://i41.photobucket.com/albums/e257/praedet/DIY%20Audio/f5b2c7de.jpg)
That is TOTALLY different from what I have, and the instructions I got with the amp. WTF? I am surprised mine works at all.
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Ignore the colors...
Point the pot with the "knob" towards you and the connections down. This next part is a little harder to understand, so bear with me and I might try to take a picture tomorrow. If you connect the platstic connector to the board and then look at the amp facing the inputs with the left input to the left and the right on the right. Now, disconnect that connector and spin it 180 degrees so that the part of the plastic connector that was away from you, is facing you. (The part that has the nub for the locking connector. Now, lay it down like that tieh the gain pot above it like I talked about and solder away.
To orient you with my connector, looking at the back of the amp my wires went red, white, black (1,2,3) from left to right. So with the pot facing towards you and down, the wires reverse and become black, white, red (3,2,1)...
Did this help or make it worse? :duh:
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This is one instance where a picture truly is worth a thousand words. :scratch: :| :o :P :green:
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:o
-
I know :oops: :lol:
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I'm thinking of getting potentiometers that are a little bit less cheesy than the supplied Honeywell ones.
Is this a reasonable option?
http://www.partsconnexion.com/controls_pot_connex.html
I don't want to spend megabucks (I would probably get 4 if I decide to bi-amp), but would like something slightly more confidence-inspiring than what came with the kit.
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I'm thinking of getting potentiometers that are a little bit less cheesy than the supplied Honeywell ones.
Is this a reasonable option?
http://www.partsconnexion.com/controls_pot_connex.html
I don't want to spend megabucks (I would probably get 4 if I decide to bi-amp), but would like something slightly more confidence-inspiring than what came with the kit.
I would recommend Precision Electronic pots from
http://www.tubesandmore.com (http://www.tubesandmore.com)
Only $9.95 ea.
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Black in the middle, red on the right as the knob points away from you, white where the non-existent yellow wire is supposed to go.
I just found your picture:
(http://i41.photobucket.com/albums/e257/praedet/DIY%20Audio/f5b2c7de.jpg)
That is TOTALLY different from what I have, and the instructions I got with the amp. WTF? I am surprised mine works at all.
I've re-connected it the way you have pictured above, and it works much better, not surprisingly. What does concern me is that Tom went to the trouble to print out an email giving very explicit directions to the contrary.
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I would recommend Precision Electronic pots from
http://www.tubesandmore.com (http://www.tubesandmore.com)
Only $9.95 ea.
Thanks. I'll do that as soon as I figure out what wattage and resistance I need.
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I've re-connected it the way you have pictured above, and it works much better, not surprisingly. What does concern me is that Tom went to the trouble to print out an email giving very explicit directions to the contrary.
Awesome! Yeah, when I e-mailed him about that he apologized because he had not thought about the change in wiring/e-mail...
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By the way, your verbal description is retrospectively pretty clear, but the photo really saved me.
-
srry guys, I was travelling and couldn't access the site from my mobile. Even now I'm doing it through my phone connected to my laptop. :|
It certainly could be a synergy thing with the speakers. Maybe not even a Class A/B vs Class D thing. Maybe a different Class D amp would drive them better.
You may well be right there Steve. I think a speaker with a sensitivity of 91dB or above should make things better.
Do you have any other 2-way speakers with passive crossover you can try it with? It's just kind of surprising seeing how many people are thrilled with the amps.
Actually, I played the amp with a couple of other speakers, one a professionally designed Tower speakers with drivers cannibalised from my old Kenwood monitors and a smallish bookshelf with 4" Kevlar mid-woofer and 3/4" PP Tweeter. The bookshelf does not have the SQ to dig out the full music details. The towers had 12" woofer and the amp has tough time controlling the same. The result was, there was some bass overhang. I posting the pics of the speakers here.
(http://www.audiocircle.com/image.php?id=46102)
(http://www.audiocircle.com/image.php?id=46103)
Rgds
Rajesh
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Hey guys,
Building an SDS 254 kit. I have an email into Tom regarding fuse sizes but wanted to see if anyone else had spoken to him previously. I have a 7amp slow blow fuse. is that too big? My switch is rated for 10 or 15 amps. Hopefully, I'll be done today!!
Thanks
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I didn't get any instructions with my amp except how to change from single-ended to balanced inputs. The manual posted on the website is for the older CDA boards with instructions on how to install outboard leds and how to bridge the outputs. And that's it. No info on fuses. No helpful hints. I guess he just assumes the customer will email him. To be fair I bought the boards seperately and I got my transformer directly from Antek. I'm not sure if his complete kits are different.
I had to read this thread a lot to gather all of the needed info.
Product: A+
Instruction Manual: F
I'm still thinking about making a manual with full color pics for the forum just because one is needed so badly. When and if I build another classdaudio amp I'll do it.
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Hey guys,
Building an SDS 254 kit. I have an email into Tom regarding fuse sizes but wanted to see if anyone else had spoken to him previously. I have a 7amp slow blow fuse. is that too big? My switch is rated for 10 or 15 amps. Hopefully, I'll be done today!!
Thanks
Here is what he sent me:
Most of what you need you can get from places like www.parts-express.com.
Here are a few links to some items...
Fuse holder (http://www.parts-express.com/pe/showdetl.cfm?Partnumber=071-510)
for fuse (http://www.parts-express.com/pe/showdetl.cfm?Partnumber=071-710)
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I didn't get any instructions with my amp except how to change from single-ended to balanced inputs. The manual posted on the website is for the older CDA boards with instructions on how to install outboard leds and how to bridge the outputs. And that's it. No info on fuses. No helpful hints. I guess he just assumes the customer will email him. To be fair I bought the boards seperately and I got my transformer directly from Antek. I'm not sure if his complete kits are different.
I had to read this thread a lot to gather all of the needed info.
Product: A+
Instruction Manual: F
I'm still thinking about making a manual with full color pics for the forum just because one is needed so badly. When and if I build another classdaudio amp I'll do it.
I would most definitely be willing to add anything on running it on Battery power...
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Here is what he sent me:
7A should be fine.
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So, I have some solid silver RCAs that have been sitting for a while waiting to go in the final chassis. They are lightly tarnished. I ordered some DeOxIt, but it won't be here for a few days. Any ideas on what I can use to clean the connection so I can solder it?
Ted
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So, I have some solid silver RCAs that have been sitting for a while waiting to go in the final chassis. They are lightly tarnished. I ordered some DeOxIt, but it won't be here for a few days. Any ideas on what I can use to clean the connection so I can solder it?
Ted
You could use this:
(http://img.walgreens.com/dbimagecache/07829116911_450x450_a.jpg)
Technically, silver oxide is still a conductor and probably wouldn't make much of a difference with the sound.
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Has anyone put together a big multichannel amp? I've scrolled through about 1/3 of the thread (huge thread!) and about the most I've seen is a 4 channel. Wonder if an 8 channel (4 boards/2PSUs) has been nicely stuffed in a case.
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Has anyone put together a big multichannel amp? I've scrolled through about 1/3 of the thread (huge thread!) and about the most I've seen is a 4 channel. Wonder if an 8 channel (4 boards/2PSUs) has been nicely stuffed in a case.
I don't think you want to run more than 2 amp boards per PS board. You may also need multiple transformers as well. I'm sure it can be done but I'm not sure if you'll get much of a cost savings over other commercial amps. Although the classdaudio amp would probably be more efficient.
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So, I am about to switch out the gain pots for two vishay naked resistors. Should I desolder the connectors on the board and solder in the resistors (best possible sound from the resistors) or simply hook the resistor into the plastic clips like some of you guys did so I can try different ones in the future? Part of me wants to get the best possible connection with these and move on, and part of me likes the idea of tweaking...
Thoughts?
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Tweak first, then solder when you are happy with what you hear. Please let us know, so we can learn from all of your costly and demoralizing mistakes.
Seriously, you have nothing to lose by testing first until you are satisfied.
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I am building a multi amp monster. I've been waiting to post until I have something to report. I am tri-amping Magnepan 3.3r's. Here's the run down. Three tiers, two power supplies on the bottom, two SDS-4's bridged for the bass panels, two SDS-254's for mid-high's. On a hinged top the Marchand XM-44 embedded crossovers, and a Moscode minuet tube preamp. How's that for overly ambitious?
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I would most definitely be willing to add anything on running it on Battery power...
Could you tell me what the power supply board dimensions are? HxWxD
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I'm going to try to assemble this thing "for real" this weekend, and will take some photos.
Maybe a wiki with some documentation might help.
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I will get you the full PS dimensions in about 30 min, but I know it is 5 1/4" L and 3 1/8" wide for sure. It has a heat sink underneath that is less than the height of the stand-offs, so I will just measure the height above the board...
Also, what do you all think about wiring up a switch? Running the battery supply and the SDS board, both boards have switches. I was planning on doing a switch on the PS so that it does not have any current in it when off. Thoughts?
Part 2, I have a DPDT On-On switch. How do I wire it :duh:
Here is the board. I will take a better pic but it has both a location for a remote signal and a place to solder in wires instead of the switch...
http://classdaudio.com/products/power-supplies/12v-dc-switching-power-supply-500-watt-car-audio.html
Ted
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Also, what do you all think about wiring up a switch? Running the battery supply and the SDS board, both boards have switches. I was planning on doing a switch on the PS so that it does not have any current in it when off. Thoughts?
Part 2, I have a DPDT On-On switch. How do I wire it :duh:
(http://i576.photobucket.com/albums/ss207/corndog642/classdaudio%20amp/b2a2f4e3.jpg)
Here's how I wired my DPDT switch. The easiest way to figure it out is use your meter. The middle terminal is your input and the upper or lower terminals are the output depending on which way you throw the switch. The unconnected terminal breaks the connection cutting off power to the power supply.
In your case you could get a simple SPST switch and mount it next to the Powercon connector. I know from my car audio days it's better to break the negative connection first with a battery. Then you don't have to worry about messing up the circuit boards with unnecessary soldering.
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Awesome, thanks! For whatever reason, Trung wired up both sides of the switch where the other side appears to send power to the remote on switch on the PS board, and the first side is wired like yours to the on/off on the PS board...
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Awesome, thanks! For whatever reason, Trung wired up both sides of the switch where the other side appears to send power to the remote on switch on the PS board, and the first side is wired like yours to the on/off on the PS board...
Ah, I see. That makes sense as this power supply was designed to work in car audio.
I'm not sure if all of that was necessary but I can see why he did it that way. The simplest way is to simply break the connection between the battery and the power supply. To be fair I'm not familiar with the details of your power supply board.
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I hope I'm not confusing things here. :scratch: Are you referring to your battery powered amp or another one? I keep going back to your pics of the battery powered amp. I just saw the cable with the in-line switch and wondered if this is used for the amp. If so then you're already good. Looking at your amp it looks like a pretty straighforward build and what I would do.
Oh, and to clarify, in my picture you're seeing the red and black leads of my transformer.
EDIT Again: I just noticed the little toggle switch at the front of the amp. Now I get what you're saying. :duh: Ok, so now that I'm no longer confused, what I wrote before about breaking the connection between the battery and the power supply is still correct. That is if that remote turn-on connection is optional like it is on the amp board. If you don't need to use it then just use that cable switch to break the negative side of the incoming power wires.
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Tweak first, then solder when you are happy with what you hear. Please let us know, so we can learn from all of your costly and demoralizing mistakes.
Seriously, you have nothing to lose by testing first until you are satisfied.
Agreed. I've learned this the hard way.
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So, I brought it in the house to give it a preliminary test before assembling it for real...
(http://dl.dropbox.com/u/5420586/av/amp/overview.jpg)
Overview. Note the matching Nova case.
(http://dl.dropbox.com/u/5420586/av/amp/closeup1.jpg)
Power supply.
(http://dl.dropbox.com/u/5420586/av/amp/close2.jpg)
Amp board hooked up to the Nova's pre-Amp RCA out.
The sound is quite good from my first test.
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Well, I learned a LOT over the last 2 days.
1. If you plan on removing the various connectors on the boards, see if Tom will ship the boards without them. Removal is not trivial, and then getting everything back exactly right is also non-trivial.
2. Get a larger chassis then you need! If you are going to make leads as short as possible, and hardwire to the board, you need room.
3. Make sure you dry fit EVERYTHING before drilling holes for stand-offs.
4. Figure out what everything does before you wire it up :duh:
Anyway, the amp is moved into it's final chassis. I used solid silver (22 AWG) for the RCAs and solid copper (14 or 16 AWG) electra cable for the speaker wire and power. I replaced the pots with resistors and hardwired everything. Lastly I put the wiring in place for the switch.
Things that I messed up/sucked. The Neutrik Powercon. Had I put the board into place with the powercon before drilling holes for the stand-offs, I would have realized that the place I chose for the board was TOO close to the back. Oh well, a trimming of the powercon worked, but made it impossible to mount the powercon inside like I wanted, and made it VERY hard to solder wires under the board.
Solid wiring is REAL hard to work with when it is connected in multiple places. REAL HARD...
So, I wired up the switch like I thought it was supposed to be (I was copying another person's battery PS wiring) I had wires running to the switch location on the board, so when the switch was thrown they would form a circuit. I also ran a wire from the positive hot wire, to the switch, and then to the remote signal turn on. Again, when the switch turned on, it was supposed to send a signal. FOr whatever reason, if ANY wire was hooked into the remote signal on the boar, the PS was ALWAYS on, no matter what switch you played with :evil: Needless to say, I am now only running the switch wires, and they work :)
Anyway, I have quickly verified that the amp does in fact play, but I still haven't played it to check the resistor and wiring change out as I am working on the faceplate...
Here are some pics of the inside. If you are wondering about the speaker hook-ups, they are Electra Tube connectors. They are pretty cool 8)
Ted
(http://i41.photobucket.com/albums/e257/praedet/DIY%20Audio/b6a49692.jpg)
(http://i41.photobucket.com/albums/e257/praedet/DIY%20Audio/ba340d31.jpg)
(http://i41.photobucket.com/albums/e257/praedet/DIY%20Audio/8f9600ce.jpg)
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Now THAT is a sweet looking amp! Inspiring too as that is pretty much what I want to build later this year. I was also considering putting 3 of those into one box for one hell of a 6-channel amp!
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Thanks, and get a BIG box for 6 channels! :duh:
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Ted
Very nice :thumb:
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Thanks, you are my hero!
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What is the advantage of removing those blue terminal block things? Can you use a thicker wire? I'd like to use 12 gauge if possible...
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If you're going to use thicker wire then you would be better off keeping the terminals. But really, 16awg is plenty large enough to deliver the current.
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Truly, it is a better connection...
But, if I had the board sitting in front of me again with those on, I son't know that I would remove them. I would ask for one without them ;)
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Hey guys,
A quick update-
this is my first electronics project (SDS 254) and i think it's really a good one for the novice. In terms of sound, I'm very happy with the amp. I am working toward a nicer 2 channel system and morphing my HT setup. The current rig is an Onkyo 805, modula MT mains, a Paradigm center and various surrounds. I have an IB sub with 2 15s. My front end is a SB with a MHDT paradesia plus dac. I feel like it opened up after a few hours use but that could be my imagination. I am currently building a pair of Dennis Murphy/Paul Kittinger MTM design using the Seas ER-18. Can't wait to hear what it does with these (ordered some figured madrone today!!)
The ClassD was a significant improvement over the Onkyo internal amps- no big surprise. Much more meat to sound, more headroom, better image, cleaner mids, etc. Can't wait to get the Onkyo POS out of the way altogether. Next project (after the current one :thumb:) is to build the Dodd or Pass buffer. All will be right with the world. Great project and an absolute no-brainer for the $$$. The thought of battery power seems like a PITA but I am sure it sounds great. We'll see-
Thanks for the security blanket of the forum!
Jeff
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The thought of battery power seems like a PITA but I am sure it sounds great. We'll see-
It's really not that bad. With a smart charger like the CTEK US800 you just hook it up and forget about it.
(http://ecx.images-amazon.com/images/I/41D30XSgtLL._SL500_AA300_.jpg)
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I think the potentiometers supplied are this:
Pot; Cnd Pl; Rest 10 Kilohms; Bushing Mount; Linear; Pwr-Rtg 0.5W; Shaft Dia 0.25in
Mfr. Part#: 575SX1A48F103SS
http://www.alliedelec.com/search/productdetail.aspx?SKU=7532264
So, if I want to replace these, I presume I need something that is 1/2 Watt and 10 kOhm. I thought for audio one wants a log rather than linear response?
Also, any verdict on that purple wire? It says it is wired to the transformer grid, so I presume I want to ground it, but I don't want to do anything stupid.
I assembled it within the shell housing now and am listening to it as I design and order face-plates. I am thinking of something along these lines, with 4 potentiometers/gain control (if I bi-amp) in front. What I am posting below corresponds to a bi-amp configuration. I haven't yet decided whether I will do that or not, but it makes a good "worst case scenerio". I just about have enough room in the Nova chassis to do that, with two amp boards positioned at the rear, and the transformer in the front left, and the power supply board on the front right.
If I have two amp boards, that means 4 gain controls. I'm considering putting those on the front, where they would be accessible, and then a window, like the Nova's tube window, to peek in at the LEDs on the amp boards and power supply. I think that would be much cooler than ugly LED lights mounted on the front. I don't know if I'll put their logo on, but I did it in the mock-up.
Please suggest improvements!
(http://www.computeraudiophile.com/files/Screen%20shot%202011-05-01%20at%208.56.27%20PM.png)
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While it's certainly up to you to decide on the location of the gain pots, I hope you aren't confusing them with a normal volume control. All they are meant to do is match your preamp's output to the gain of the amp. You basically set it when you hook it up to your preamp and then you shouldn't need to mess with them anymore. The preamp is used for master volume.
A lot of the guys here measure the resistance of the pot at the gain setting that works for them. Then they remove the pot and replace it with a simple high quality resistor of that same value. The supplied pots are pretty cheap and will degrade the sound slightly. A good resistor will be much more transparent.
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Thanks. You are right. I appreciate the feedback. Having them on the front only invites fiddling.
By the way, how do you determine what the optimal gain is? I just have it turned all the way up. Assuming that is the case, does that mean zero resistance (and do I then just connect the wires), and also since there are 3 wires in this thing, and two in a resistor, what gets connected?
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When I fire up the amp, I can hear a very faint ~60 Hz hum, both directly from the unit and in the speakers. It is preamp-volume independent. Is this normal?
I haven't yet grounded anything. I still don't know what to do with the purple grid wire. Would that help, or am I more likely to create a ground loop?
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I don't think you'll hurt anything by grounding that purple wire. Try it and see what happens.
In my amp The boards are grounded to my box but I have yet to connect the box to the ground connection of my IEC jack. There's just a tiny hint of noise that I have to get my ear right up to the speaker to hear. This could also be from my my preamp. I'll have to disconnect the preamp to see for sure.
I've also experienced a hum and slight vibration from my transformer but it's intermittant and most of the time is silent. Can't explain that except it's not the first time I've experienced that from these kinds of toroidal transformers.
If you go back through the thread you should be able to find guys that swapped the pots for resistors and showing their work.
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OK, I volunteered via a PM with another member to get some info from Tom (the amp designer) on the gain resistors/pot situation. Here is his response:
First, the amps are AC coupled (EDIT BY RAINDANCE - So you can try them with your Little Dot Mk III if you want). The gain is in the first stage of the amp.
I was very careful in selecting the pots that come with the amps. They feature high quality conductive elements and are pretty much dead quiet. Of course, you can use stepped attenuators for possibly a little better performance, but most could never be able to hear the difference. These do not come with the kits because as I’m sure you already know, you can spend allot more money on quality stepped attenuators than the cost of the amp kit. Fixed resistors are another and possibly the best choice as long as you know the correct gain to set the amp at to get the most out of your preamp or other input device. Without taking this into account and just changing to a fixed resistor, it is possible that you won’t achieve the optimum sound quality from your equipment if your preamp is not matched correctly to the amp and adjusted to find the maximum and optimum sweet spot of the preamps volume control. Distortion from the preamp can be a problem on many units if the volume control is turned up too high, and you also might not be getting the best from your preamp if the volume is turned too low… they are all different.
To put it simpler…
The gain controls are used to match the amplifier’s gain to the gain of the other amplifiers in the system as in active or passive preamps, DAC, iPod or mp3 players, etc. The gain controls allow you to match the amplifier to the input device. Not all input devices have the same maximum preamp output voltage. Some preamps are capable of producing 15 volts RMS out while others are only capable of 1.5 Volts RMS out. Most preamps or other input device will reach its maximum output level (clipping) well before the volume control reaches the upper end of its range, usually at a point of 75-90% of its maximum range.
For those who wish to change the pots for fixed resistors, here are resistor values to produce required gain. Gain is listed in dB: To change gain potentiometer to a fixed resistor, you would connect a fixed resistor between the yellow and black wires on the gain controls (of course, remove the gain pots). Leave the red wire disconnected.
Use high quality 1% resistors:
560 Ohm = 31 dB
1K = 30 dB
2.2K = 27 dB
5.2K = 23 dB
6.2K = 18 dB
7.5K = 16 dB
I hope this is of some help. Please feel free to post this on the forums if it will help others. On my personal systems here, I use the same pots that come with the kits.
Well I found this on p. 113 with Google. I'm not really sure how to proceed, as I basically have no idea how to find the optimal gain (turn it down and the preamp volume up to restore the initial volume and see if it sounds better or worse?). There must be a more objective way.
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Hi, First of all, I don't know which model you have. From what I understand the units come with approximately 32DB of gain. Now, that's ok if you have a buffer, or passive Pre-amp which has no gain. if you have the CD units, before you buy, you should ask tom to make it approximately 27DB of gain, which is about standard in the industry for amplifiers. Now if you have a SDS unit, it has a buffer built in, as well as providing a volume pot for each channel. At max the gain is
32DB. Rather than dial it down and guess if you have the gain set correctly, you can just sub these pots out for resistors of specific values. It appears that certain brands of resistors do make a difference in sound. If you are using a pre-amplifier, then you want to have at least the lower 27DB of gain, which means you need a 2.2 K-ohm resistor.
This DB gain factor is from 0 at input to 27DB at output. I'll let the more technically minded give you a further explanation.
So to answer your question, as a summary, if you are using a buffer, then leave the gain at max 32DB. if you are using an active pre-amplifier, SolidState or Tube, then you need to lower the gain to at least the standard 27DB. Hope this helps.
Now, some have lowered the gain anyway even though they had a buffer, and the sound improved.
Ray Bronk
I guess this answers my other question, more or less (still wondering how you find the sweet spot in practice).
A summary thread comprised of some of these posts like the last two could be really useful.
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I'm building a SDS 254 that is 12 volt d/c powered and want to know what size fuse to use? There is a 30 amp fuse in my Dodd built CDA 254, so I would think it would be the same?
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If I decide to (passively) bi-amp, is it best to retain the ability to adjust the gain of bass vs mid/treble (or vice-versa), or is it best to assume identical gains would strike the correct balance?
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Mike
There are a fuse already on your DC power supply, you don't really need one.
But it does not hurt to add more, and 20A on mine.
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Thanks Tung
Mike
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just a update on my cda-224 amp. I have had it up and running for the last couple of monthes and why i didnt pull the trigger long before. It is my main amp now and im thinking about getting a bigger one now. great product!
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Yeah, I am doing some round robin with amps and receivers the past few days and just put the CDA254 I had on woofer duty back to main with my new full range speakers and man it just sounds really frickin' good. Which I knew exactly what causes some to experience 'lean' bass and recessed mids, this is the 3rd or 4th set of speakers I've matched the CDAs and they are just smooooth every time and nice and full (no DCB1 at this time though to add that punch and 3-D effect). Just relaxes me right away to listen to it.
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I'm about to wire up my class D SDS 254= Dodd tube buffer and wasn't sure of all the connection. Here is diagram of what I think are some of the connection, does the negative from the class D go to ground buss? if so were do I connect ground from class D or is it not used? Can I connect the 3uf sonicap direct to class D + inputs?
(http://www.audiocircle.com/image.php?id=46406)
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Has anyone installed an IR-activated remote-control relay for a power switch? I'd really like to do this but haven't a clue how to go about it.
I recently found this thing on the interweb:
http://www.tauntek.com/tinyir2-learning-ir-remote-control-receiver.htm
It seems like the right thing, but maybe a bit advanced for me. Also, I have no idea how to find a suitable relay and to hook the two up.
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With a lot of great help from Gary and Trung got 90% of class D/ tube buffer put together, just waiting on RCAs I ordered to arrive. Here are some pics. If anyone sees anything that not right or could be done better please let me know as I'm still pretty new at this.
Mike
(http://www.audiocircle.com/image.php?id=46460)
(http://www.audiocircle.com/image.php?id=46461)
(http://www.audiocircle.com/image.php?id=46462)
(http://www.audiocircle.com/image.php?id=46463)
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Trung informed me by pass caps were wired wrong in earlier pics I posted, here is correct pic.
(http://www.audiocircle.com/image.php?id=46474)
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I'm having trouble with my SDS-4 amps. I am using them in bridged mode. I get nothing out of one and the other has a very bad hum. I also am using SDS-254's, and they are working fine. I have tried switching inputs to no avail. How do I need to have the jumpers. I believe the gain pot need only be on the bridged side, right?
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Hi Mike,
Looks like you are running direct from buffer to amp?
How are you going to attenuate the signal?
Neil
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Hi Neil
If you mean adjust the volume, then I use my Mac. I have the Spacial system which basically turns your Mac into a pre and eq. I use Itunes to control the analog volume control in my Dac.
Mike
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I need some more help from you guys. I want to use this amp with my home theater receiver. I would like the amp to turn on and off with the receiver, automatically. Can you guys help me out on how to do this and what is needed?
Thanks,
Topp
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^^^^^
To me, the easy way to control the power of your amp is use power console, like Belkin PureAV or Monster console, they can remote turn on your amp by your receiver.
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I was hoping to make it more like a commercial amp and have the remote trigger on the amp.
Thanks,
Topp
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Back in February I asked Tom at Class D Audio if he might consider offering a 12V trigger module. His reply was
"We are working on a sound activated power on, and a 12V trigger is a good idea so I will get one ready in the near future. We do have a 12V in +/- 50V out SMPS power supply with trigger, but that is mostly for auto and marine use."
I stated then that maybe half of his kit buyers might purchase it. Maybe that was a bit optimistic, but 1 out of 3 probably isn't too far off the mark. I guess the near future isn't quite here yet, but I still think it would be a popular and appreciated accessory offering.
Steve
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I still don't know what to do with the purple grid wire.
Tom verified it should be grounded (suggested to the chassis, which implicitly gets the ground from the mains).
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Has anyone installed an IR-activated remote-control relay for a power switch? I'd really like to do this but haven't a clue how to go about it.
I recently found this thing on the interweb:
http://www.tauntek.com/tinyir2-learning-ir-remote-control-receiver.htm
It seems like the right thing, but maybe a bit advanced for me. Also, I have no idea how to find a suitable relay and to hook the two up.
This question was along similar lines to the 12 volt trigger (which I would prefer, if I had something to supply the trigger). Tom suggested this would work with the amp on/off switch, but not for the mains.
I've also found for $50 an external trainable IR-activated 120V 15 amp on/off. My power conditioner also has one, but I can't get it to work (but it might be replaced under warranty).
I guarantee there is a market for remote on/off.
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I did send an email to Tom asking his input. He said the trigger should turn off the power to the transformer and not the switch on the board. But I am not sure why, I was assuming so it completely cuts power and there is no power draw. I originally thought just to have a 12 volt relay that closed the switch on the board. However, I am not sure if the receiver's trigger output has enough current to keep the relay closed. I thought I remember seeing someones amp that they made something to turn on and off the amp, but I can't seem to find it anymore.
Thanks,
Topp
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The face plates I ordered from Front Panel Express arrived today, so I put the panel on my Nova case to get an idea for how it will look when properly assembled (please ignore all the wires, etc).
(http://www.audiocircle.com/image.php?id=46926)
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Ok, that is pretty damn cool!
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Thanks again for your advice and encouragement. (I'll probably need more soon.) Especially ditching the gain controls on the front. I might put them on the bottom, or just replace them with resistors.
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The ability to run two amp boards from the power supply, along with the extra space in the cabinet, compelled me to order a second amp board.
I figure I will start out passively bi-amping ("fool's bi-amping") until I figure out how to add an active crossover.
Are there any good DIY active crossover kits? I had a brief google search that came up with this: http://www.audio-kits.com/page/page/4071180.htm
If I do this, I want to make sure what I get is good enough not to degrade the quality, and if I can cram it into the same cabinet, my wife might not even notice....
Then I guess I need to do a bit of speaker surgery to remove the passive crossovers.
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http://www.minidsp.com/
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avionic has posted probably the best idea for active.
I would recommend you read JohnR's very thorough review.
http://www.hifizine.com/2011/03/refining-a-4-way-open-baffle-speaker-minidsp-2x4/
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Thanks, both of you. Those look incredibly helpful. I'll read soon...
So, to make sure I am clear on the concept, I am taking my signal from my DAC via my pre-amp, then put it through the miniDSP, and then into the amps? So it gets converted from digital to analogue, then back to digital, where it is processed, and then back to analogue a second time? Wouldn't it be better to process the signal first, before sending it to a single DAC?
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Thanks, both of you. Those look incredibly helpful. I'll read soon...
So, to make sure I am clear on the concept, I am taking my signal from my DAC via my pre-amp, then put it through the miniDSP, and then into the amps? So it gets converted from digital to analogue, then back to digital, where it is processed, and then back to analogue a second time? Wouldn't it be better to process the signal first, before sending it to a single DAC?
Source > DAC > PreAmp > DSP > amp(s) > speakers = :singing:
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For the record there is nothing wrong with passive crossovers. The best speakers I've heard had passive crossovers. Going active can actually be more complicated.
I'm not saying you shouldn't do it. Just know it may not be as simple as it seems.
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For the record there is nothing wrong with passive crossovers. The best speakers I've heard had passive crossovers. Going active can actually be more complicated.
I'm not saying you shouldn't do it. Just know it may not be as simple as it seems.
I don't think anyone said that there was something wrong with them...Yes, it is complicated and will take time and lots of effort.
Back to Class D Audio...
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Source > DAC > PreAmp > DSP > amp(s) > speakers = :singing:
Right, but isn't that glossing over what DSP stands for? i.e.,
Source > DAC #1 > PreAmp > ADC #2 > DSP software > DAC #3 > amp(s) > speakers = :nono:
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I don't think anyone said that there was something wrong with them...Yes, it is complicated and will take time and lots of effort.
Back to Class D Audio...
I never left it. I just got a second amp board in the mail today, and, in fact, I am re-soldering the old potentiometers and soldering the two new ones as I type, clearing my nose of carcinogenic fumes.
I suck at soldering. I think the last time I did this I used Pb.
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Right, but isn't that glossing over what DSP stands for? i.e.,
Source > DAC #1 > PreAmp > ADC #2 > DSP software > DAC #3 > amp(s) > speakers = :nono:
Not necessarily a :nono: The ADC and DAC are tightly coupled so you don't get jitter errors between them.
Or, get a digital I/O card for the miniDSP (or whichever crossover you use)
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Well, it will be awhile before my wallet recovers anyway, so I can spend some time reading up on the options.
Meanwhile, I need to tidy up what I have so far, which is now a SDS-254 vertical bi-amp.
The wiring is a bit of a mess, so I think I might need to re-do it from scratch. The case is fairly crammed now.
[revised]I had a bit of a low-volume buzz sound from one amp board, but it turned out the ground wire between it and the power supply came loose.
Would housing the toroid and power supply in a separate (metal) box improve signal/noise at all? I assume tidying the wiring and double-checking all the connections could only help.
Also, I get an audible pop in the speakers when each of the two amps powers up. Is this normal?
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I actually have a multi-amping project using a pair of sds-224 in flight as well. In my case, the xover will be done on the PC with output via a Steinberg MR816. I've stalled a bit as I was waiting for my connexelectronic SMPS to be delivered - my case is too small for 2 amp boards plus the standard xformer/PS setup. The smps took quite a while to be delivered, but it did eventually show up.
Still a few things to be decided, particularly volume control. I have an MSB MVC which is a very slick remote-controlled 8-channel volume control which is the default plan, but the MR816 includes the ability to have the master fader control all output channels. This raises the possibility that I may be able to run direct balanced out from the MR816 into the sds-224 boards, and just use the dsp attenuation. The question is whether I can get the gain of the sds-224's down low enough that I don't need massive dsp attenuation. My gut instinct is that if I can keep it to a working range of no more than 10-15dB, then direct wiring and a balanced signal path should be a noticeable improvement over having the MSB in the loop, but maybe not - the MSB seems like a pretty good piece of kit. It'll be a couple weeks before I'll be able to get the time to finish this up, unfortunately.
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I don't claim to understand what you are doing, but here is a guide to gain from Tom (posted earlier in this thread):
For those who wish to change the pots for fixed resistors, here are resistor values to produce required gain. Gain is listed in dB: To change gain potentiometer to a fixed resistor, you would connect a fixed resistor between the yellow and black wires on the gain controls (of course, remove the gain pots). Leave the red wire disconnected.
Use high quality 1% resistors:
560 Ohm = 31 dB
1K = 30 dB
2.2K = 27 dB
5.2K = 23 dB
6.2K = 18 dB
7.5K = 16 dB
It is a log relationship, so you should be able to extrapolate.
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Thanks for posting that. I just happen to have some 1% 1K resistors laying around which I bet will sound better than those pots.
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Tom actually expressed some dismay about how people regard the pots. He thinks it unlikely that you would get a sonic improvement, and believes, despite their superficial appearance and price-tag, are actually quite good. I'm certainly curious, as I now have 4, which I set using a multimeter to 2.2 KΩ, but the slightest movement, and I am doomed. Plus, I manage to screw up the solder connection on at least one every time I mess with the amp (which is still quite frequently). Finally, all that spaghetti wire is kind of annoying. Right now I have them hanging out the top vents. So replacing them with resistors, even if there is no sonic improvement, I think would be an advantage eventually.
Do you just jam them into molex connectors, or what?
Edit: The answer is on page 108. (photo)
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I soldered my resistors on the underside of the SDS 258 board for a point to point connection.
The pots sound blurry, makes the amp sound ordinary. Soldering increases the clarity of sound and makes the amps seem like a bargain.
I'm sure it's something that can't be measured. Like when I measure my speakers FR with cheap block resistors and then substitute same value Mills the FR stays the same. Same with putting in some teflon caps. Mills and teflon caps no doubt improve the clarity of sound but I couldn't measure any difference. So I went with my ears.
Everything has limits.
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One of the benefits of this new amp is I can now tell when my tube is engaged on my pre-amp in my Nova. However, the solid-state pre-amp sounds better than the circuit with the 6922 ElectoHarmonix $12 tube.
Is there any 6922 tube that would be an ideal complement to the Class D amp? I was thinking Amperex NOS, but worry about spending >$100 on this only to discover it is not an improvement...
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I can recommend a couple of places.
Ram Labs sells cream of the crop tubes at reasonable prices.
http://www.tubeaudiostore.com/tubes.html
Tube Depot carries Genelex Gold Lion 6922 tubes for a bit more but still well under $100.
http://www.tubedepot.com/gl-e88cc.html (http://www.tubedepot.com/gl-e88cc.html)
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Well, I just ordered 4 of the Vichy naked 2.2 K resistors, and they are on their way, so I am hoping I can figure out how to attach them. Is it possible to re-use the Molex connectors? I have no idea how to get them to let go of the wires.
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Well, I just ordered 4 of the Vichy naked 2.2 K resistors, and they are on their way, so I am hoping I can figure out how to attach them. Is it possible to re-use the Molex connectors? I have no idea how to get them to let go of the wires.
I just yanked the wires out. Then using a needle-nose pliers I recrimped the connector to a solid core wire. There might be a better way but it works for me. Another option is to remove the molex connector from the board and just solder the resistors to the board.
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Thanks. I'll probably solder eventually, but I want to hear it first.
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Finally took the time to get the SDS254 I got from Wush hooked up. Thanks Ainsley!
The SDS replaced a Yamaha M80. Speakers are Zwaves from the big thread at AK. Started with a CD in my cheap 5 disc player. When the music first started I wasn't sure I liked what I was hearing. So much more detail that my first reaction was that it would seem harsher, more fatiguing. The Selenium drivers are not smooth to my ringing old ears. The sound I am going for has to be smooth so as not set my ears off. I detest harsh or bright.
Within less than 2 minutes I knew my initial impression was wrong, very wrong. While the sound is definitely more detailed it is also much smoother and much more open. Fills the room better at low volume while still being able to hear all the music. Snare drum hits have more attack and detail yet somehow are smoother?? and easier on my picky ears.
Switched to some Marshall Tucker on the TT. HOLY CRAP!! The difference is amazing. Guitar sounds like my son is in the room with his Taylor.
Bottom line is I shoulda hooked this thing up much sooner. Thanks to everyone that has contributed so much to this thread as it is what got me to this amp. Gotta go. My typing finger is getting tired.
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Fills the room better at low volume
That's exactly how I described it too.
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Finally took the time to get the SDS254 I got from Wush hooked up. Thanks Ainsley!
The SDS replaced a Yamaha M80. Speakers are Zwaves from the big thread at AK. Started with a CD in my cheap 5 disc player. When the music first started I wasn't sure I liked what I was hearing. So much more detail that my first reaction was that it would seem harsher, more fatiguing. The Selenium drivers are not smooth to my ringing old ears. The sound I am going for has to be smooth so as not set my ears off. I detest harsh or bright.
Within less than 2 minutes I knew my initial impression was wrong, very wrong. While the sound is definitely more detailed it is also much smoother and much more open. Fills the room better at low volume while still being able to hear all the music. Snare drum hits have more attack and detail yet somehow are smoother?? and easier on my picky ears.
Switched to some Marshall Tucker on the TT. HOLY CRAP!! The difference is amazing. Guitar sounds like my son is in the room with his Taylor.
Bottom line is I shoulda hooked this thing up much sooner. Thanks to everyone that has contributed so much to this thread as it is what got me to this amp. Gotta go. My typing finger is getting tired.
What power supply configuration did you end up using? I was thinking about getting the SDS254, but haven't decided which supply config to get with it.
Ray Bronk
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What power supply configuration did you end up using? I was thinking about getting the SDS254, but haven't decided which supply config to get with it.
Ray Bronk
I got the amp from Wush on this forum. It uses the SMPS500R power supply that I think came from Connexal?? If you check this therad around Page 110 I think you will find the info.
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I using a Dodd tube buffer with DR6H30 tube with my class d amp can anyone suggest what value resistors to use with this set up.
Mike
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I using a Dodd tube buffer with DR6H30 tube with my class d amp can anyone suggest what value resistors to use with this set up.
Mike
Hi Mike,
I'd suggest if you are using a buffer only, then I'd get the 1K value resistor. I think there was one value smaller which would give you slightly more gain, which you won't hear. The 1K gives you 30DB versus the smaller value which would give you 31DB. plus, I like to think that I am not running the ClassD amps at max.
Or, if you wish to get the amps to the "standard" 27DB, then get the 2.2K value resistor. Probably with a buffer would be better to get the 1K. If you watch movies and play the audio through the ClasssD amp, then that extra 4DB of gain will be handy.
Ray Bronk
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Thanks Ray. I only us the system for music. Will try out 1k and let you know.
Mike
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I just bought 2.2 k Vichay naked resistors but haven't had a chance to stick them in yet.
Also, today's mail brought a learning IR on/off switch, which I can now use to turn the power off and on with the same button on the same remote that turns off/on my Nova.
http://www.simerec.com/zapper.htm
$50. Doesn't seem to degrade the audio quality.
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I get a pair of popping noises (one per amp board) when I power this thing on. Is that normal? Is there a way to suppress this without impairing sound quality?
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^^^^^
If the amp ON before the pre may caused pop.
Specially with tube pre.
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No, it really is just the amp. This happens even when everything else is off.
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Please more detail when it pop.
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I just bought 2.2 k Vichay naked resistors but haven't had a chance to stick them in yet.
So what you waiting for? All ears want to know how it sounds.
Also, I had asked this question I think before, and didn't receive an answer. So I'll try again.
Would I get better sound if I used say two SDS224 each bridged versus one SDS25? Any help would be most appreciated.
Ray Bronk4
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Please more detail when it pop.
If everything is powered down, and I turn on the AC power to the transformer and power supply that feeds the two SDS 254 amp boards, I hear 2 pops in rapid succession. If I have one amp board connected, I hear a single pop. They aren't loud or anything terrible, and it definitely is not a thump, but just slightly annoying. The amp turns off silently.
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I just bought 2.2 k Vichay naked resistors but haven't had a chance to stick them in yet.
So what you waiting for? All ears want to know how it sounds.
Time.
Also, I had asked this question I think before, and didn't receive an answer. So I'll try again.
Would I get better sound if I used say two SDS224 each bridged versus one SDS25? Any help would be most appreciated.
Ray Bronk4
Why not use two SDS 224 (or 254) vertical bi-amped?
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I used Front Panel Express to make my front and back plates. It wasn't cheap, but the quality was outstanding.
I have a promo code for $20 off (min $100 order) before the end of August 2011. PM me if you can use it.
I also have an image for making the Class D Audio color engraved logo, if anyone wants it. It was a PITA to generate, so please feel free. As it is a vector graphic, it scales up or down.
(http://www.audiocircle.com/image.php?id=46926)
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Well, I finally managed to put in my four Vishay VAR-Series "naked" Z201 Z-FOIL RESISTORS (http://www.partsconnexion.com/resistors_vishay_var.html). I don't know the audiophool terminology, but piano (first think I have listened to) somehow sounds more realistic. They certainly in no way made anything worse.
I bought some new molex connectors so I could keep the pots ready to swap back in, but unless I need to experiment more with gain if I active bi-amp, I doubt I will be doing that. My crimping skills are better than my soldering skills, and my heat sink isn't confidence-inspiring.
Anyway, if you don't need the pots, these are a great replacement ($15 ea.).
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It's been a while since I've posted to this thread, or to Audiocircle for that matter. Reading up on some of the comments I was surprised to see a few people dissatisfied with their amplifiers. What I've come to learn over the last year is that these amplifiers sound 'good' in basic kit form. But when the power supply is upgraded along with fixed resistors in place of the gain pots and careful matching of components (impedance) the sound truly does rival higher end amplifiers.
I own a sds-258 with upgraded Jensen 4-pole power supply using Uriah Dailey's Lighter Note LDR based volume control and sometimes the hotrodded Salas DCB1 buffer (depends on the music.) It's a terrific FULL RANGE combo driving my Ohm Walsh 5000 speakers and continually has me shaking my head in disbelief at the level of sound quality achieved with a little DIY. Prior to my sds-258 amplifier I owned an Accuphase E-450 so I'm not kidding when I say these amplifiers have potential. I really have no intention of changing anything in my system because it's the best I've heard it in a long time, although I still am curious to hear how a simple yet excellent tube preamp would jive with everything. I know a lot of you are happy with the Dodd buffer but curious to see if anyone has tried the Decware CSP2 with their ClassDaudio amplifier. Anyone?
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I still recommend the Bottlehead Quickie with PJCCS upgrade. For around $150 including shipping it's a sweet little preamp.
(http://i576.photobucket.com/albums/ss207/corndog642/Bottlehead%20Quickie/7669d368.jpg)
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Sorry to be lazy, but do you have a Bottlehead link?
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I still recommend the Bottlehead Quickie with PJCCS upgrade. For around $150 including shipping it's a sweet little preamp.
If you run it for 4 hours a day, that's 40 9-volt and 20 D-cell batteries to the landfill each and every year. If you use rechargeables, there aren't many chargers that will charge that assortment of batteries simultaneously.
For me, I just can't see it being worth the hassle and/or the waste.
Steve
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Sorry to be lazy, but do you have a Bottlehead link?
http://www.bottlehead.com/
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I haven't posted for ages due to losing interest after I got my SDS-254 amp. Now I'm back. I still maintain that the CDA-254 is the better sounding amp by a long shot (for my ears at least) due to a black background (very very low noise floor). But the reason I'm posting - I just resurrected my CDA-254 amp to try with my Little Dot Mk III headphone amp (as a preamp). It has a 600 ohm output impedance, so it matches the CDA series amp really well.
Well, match made in heaven. The low gain of the CDA amp suits the highish gain I'm running the Little Dot at perfectly (this is another subject, but the higher gain settings use less feedback on the Little Dot). Absolutely wonderful pairing, really blew me away. Anyone else try this?
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http://www.bottlehead.com/
:oops: :duh:
These people do not appear to be as easily distracted as I would have been:
(http://www.tapeproject.com/tableshot.jpg)
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If you run it for 4 hours a day, that's 40 9-volt and 20 D-cell batteries to the landfill each and every year. If you use rechargeables, there aren't many chargers that will charge that assortment of batteries simultaneously.
For me, I just can't see it being worth the hassle and/or the waste.
Steve
Well, that's not even considering its sonic qualities which are pretty damn good for the money. And really, the batteries seem to last longer than you'd think.
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So, are they in parallel somehow, or series? What voltage does it actually need?
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The tubes are 3S4. The D cells heat up the filaments. One for each tube. The 9V are run in series to get 36V for the "high" voltage. The PJCCS helps tighten things up electrically which ends up as improved detail, bass, and just a better over all sound. It's a very simple circuit. I suppose you could save some money buying 3 big AGM batteries and hooking them up in series to get 36V. You would have to take them out of the circuit and switch to parallel in order to charge them. You probably would need to charge them once a year if that. :wink:
Of course if you want a truly superior tube preamp the Foreplay 3 is also available.
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If you run it for 4 hours a day, that's 40 9-volt and 20 D-cell batteries to the landfill each and every year. If you use rechargeables, there aren't many chargers that will charge that assortment of batteries simultaneously.
Well, that's not even considering its sonic qualities which are pretty damn good for the money. And really, the batteries seem to last longer than you'd think.
It's not "what I think", my calculations of the number of batteries you would toss away were based on the manufacturer's estimate of 100-200 hours as well as actual user measurements of 100mA draw from the the two parallel D-cell batteries for the filament circuit and 4mA draw from the four series 9V batteries for the plate circuit.
I used 150 hours for calculations, so not even the worst case scenario. I don't doubt the sonic qualities for the money, just as I don't doubt the sonic qualities of the Sutherland Ph.D. phono preamp with it's 16 D-cells.
Again, for me, these multiple battery power schemes are just too far beyond the somewhat less wasteful or less hassle to remove, charge and replace multiple rechargeable batteries than components that use single LA, AGM or LiFePO4 batteries with permanently connected smart chargers. YMMV.
Steve
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Apparently neither do the posters on this thread, nary a comment. They are a single minded lot, don't you think? Do you suppose she might show up at the Capital Audio Fest next week? I wonder if those legs go all the way up? I'm going to take a cold shower now.
:oops: :duh:
These people do not appear to be as easily distracted as I would have been:
(http://www.tapeproject.com/tableshot.jpg)
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These people do not appear to be as easily distracted as I would have been:
Well, you've seen one reel to reel, you've seen them all.
:wink:
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All the way up to what?
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I just got some Vishay resistors for my sds 254 and wanted to know where to hook them up, connector has three places, resistor has two ends, what goes where?
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I just got some Vishay resistors for my sds 254 and wanted to know where to hook them up, connector has three places, resistor has two ends, what goes where?
The search engine is your friend.
See here (http://www.audiocircle.com/index.php?topic=76400.msg861962#msg861962).
Anand.
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Thanks,
"The search engine is your friend" Except I think computers were created by the spawn of the devil solely for the purpose of tormenting mankind. Or I'm old and not very computer lit. And if I could figure out how to put one of those smily faces at top of page here that would be good.
Mike
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Thanks,
"The search engine is your friend" Except I think computers were created by the spawn of the devil solely for the purpose of tormenting mankind. Or I'm old and not very computer lit. And if I could figure out how to put one of those smily faces at top of page here that would be good.
Mike
:D
I created that smiley face by pressing the shift button, then pressing the colon : button at the same time, followed by pressing the shift button again and the letter D at the same time.
Best,
Anand.
P.S. 64 isn't old :thumb:.
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Mike,
When you reply to (or create or modify) a post, are you not seeing the row of smiley faces (and the more link at the end) below the toolbars?
(http://www.audiocircle.com/image.php?id=48589)
Clicking on one of them inserts it :D at the text cursor.
Also there is no specific search function to search for text within a long topic, but if you have located the topic you want (like this one), you can use your browser's Find function to search. For example, to search for "Vishay" within this post:
1. Click the Print link/tab at the upper right hand corner of the page to return a page with the complete topic spanning all pages (minus photos, smilies, hyperlinks, etc.)
2. Use your browser's Find function to search for text (Internet Explorer and Firefox use Edit > Find from the menu or Ctrl + F from the keyboard). Type Vishay in the Find search field that appears, then click Next to find each occurrence of that word.
Steve
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Google it (http://www.google.com/search?client=safari&rls=en&q=site:audiocircle.com+%22vishay%22+%22class+D%22&ie=UTF-8&oe=UTF-8)
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Thanks Steve, I see the smiley faces, but I was clicking and dragging them into the text box :duh:.Thank you for info very helpful. :thumb:
Mike
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Anyone noticed that complete finished amps are being offered now on the ClassD site? No details of course.
I emailed and asked for some detail. Will report back if/when I get an answer.
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Anyone noticed that complete finished amps are being offered now on the ClassD site?
Just checked the site; They look like prototypes. I tried logging in but strangely my email id appears to have been removed from their database. Wonder why a company removes the details of their customer from their database. Even my review seems to have been deleted.
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What had you posted in your review Rajesh? Just wondering if they deleted it because you posted something negative?
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Anyone noticed that complete finished amps are being offered now on the ClassD site? No details of course.
I emailed and asked for some detail. Will report back if/when I get an answer.
As the first person to make cases for the Class D products, this is no surprise as I sent Tom one of mine...he has been planning this for a long time.
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Class D is in my opinion only good for low frequency amplification.
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What had you posted in your review Rajesh? Just wondering if they deleted it because you posted something negative?
Nothing negative, it was in fact a very positive review; the amp does sound very sweet in mids and has decent highs; it is only in the LF content that it suffers. I was told be some DIYers to wait for the amp to break-in to look for the missing lows which never came on.
My another grouse is that Mr. Tom didn't bother to reply me when I took up the issue. He didn't give me the tracking info even. Things improved only after a tough talk. It may be that you guys from US are lucky to be living where he lives and hence get prompt responses.
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Nothing negative, it was in fact a very positive review; the amp does sound very sweet in mids and has decent highs; it is only in the LF content that it suffers. I was told be some DIYers to wait for the amp to break-in to look for the missing lows which never came on.
From your pics in the gallery, it appears you are using the small power supply caps. I understand that the power supply makes a very noticeable difference in the sonics of these amps.
From a review of the CDA-254...
I’ve always been intrigued that it seems bass is diminished when actually; it becomes "better" than it had been. A great test CD is still, Wasserman's Trios, the bass will awe and fascinate you.
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@Roymail, thank you that was helpful. If fact a couple of DIY friends did tell me about changing to bigger caps but I was wary since the PS was the one recommended by the manufacturer and being a non-technical person that I am. May be I should try out your suggestion.
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I would also recommend a larger transformer. I got the 1000VA tranny for my SDS258 as well as bigger caps/ rectifier and my bass is fantastic!
:thumb:
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Or ditch the PS and get a SMPS from Connex
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Brian Bell chipamp.com LM3886 gainclone or Class D Audio CDA-224...?
Some of you have experience with both amps, so I'd really like your input. I haven't heard the Class D amps but have no doubt they are very good to say the least. The one LM3886 I heard was also amazing, in fact I was stunned how good it sounded with beautiful mids and highs along with solid low end sonics.
I'm very tempted to assemble a Class D amp. My only reservation is the 7K input impedance of the CDA series. Using a SS preamp, should I be concerned? :scratch:
Thoughts anyone? Thanks! :D
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I think Tom will adjust the impedance if you ask him. As I recall he made some changes early on because of people complaining his original input impedance was too low.
steve
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Brian Bell chipamp.com LM3886 gainclone or Class D Audio CDA-224...?
Some of you have experience with both amps, so I'd really like your input.
After building the class D CDA254, since I was not impressed by it rendition of LF content, I went ahead and built a Myref amp which is modded by linuxguru of DIY audio fame which is based on LM 3886. I've posted about the build http://www.hifivision.com/diy/11495-group-buy-mauro-penasa-myref-rev-c-kit-3.html#post176384 (http://www.hifivision.com/diy/11495-group-buy-mauro-penasa-myref-rev-c-kit-3.html#post176384) and http://www.hifivision.com/diy/11495-group-buy-mauro-penasa-myref-rev-c-kit-4.html#post183538 (http://www.hifivision.com/diy/11495-group-buy-mauro-penasa-myref-rev-c-kit-4.html#post183538)
It is a fantastic sounding equipment and cost me about 2k INR (about 45 USD)
I have since sold it to one of the forum members who wanted to do some experiments and wanted to have one badly and no more kits were available.
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Tom finally got back to me with this reply:
The SDS-450 is made to run very tough loads... even below 2 ohms. It puts out 150W RMS per channel into 8 ohms, 300W RMS per channel into 4 ohms, and 600W RMS per channel into 2 ohms. It's a very powerful amp. It looks just like, and is the same size as other SDS amps. It has the same sonic qualities as our other amps meaning it is one of the finest sounding amplifiers available today. You can read some customer reviews here, and the first is in regards to this amp... http://classdaudio.com/index.php/testimonial
We have one other amp called the SDS-470 which does put out 250W RMS into 8 ohms and 500W RMS per channel into 4 ohms. It's also made to run tough loads. The cost is $590.00 plus shipping cost. Shipping here in the USA is about $25.00 to $35.00. we use all top of the line components and my tech is really a perfectionist and does a beautiful job assembling them.
This sounds like an incredible bargain to me...definitely cheap and cheerful. I think I may give it a try.
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That's not bad. I paid around $600 total for my SDS-258.
(http://i576.photobucket.com/albums/ss207/corndog642/classdaudio%20amp/b711d1b1.jpg)
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Tom finally got back to me with this reply:
This sounds like an incredible bargain to me...definitely cheap and cheerful. I think I may give it a try.
I realize I never got back to you, but with the caveat that I am still quite new to this hobby, I have been extremely impressed with the amps. One of my amp boards had a problem, and Tom immediately fixed or replaced it (I am not sure which) and got it right back to me, so I can also endorse the customer service.
I am currently passively vertical bi-amping with two SDS 254s, with an eye toward making it active in the not-too-distant future.
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WGscott-
No problem. You post enough at the various forums that I got the picture.
BTW, I ordered a built amp from Tom yesterday. New model, SDS-470. 250W X 2 @8 ohms, double output @ 4 Ohms. In silver desktop style case. One 2 channel amp board inside. Price, $590, assembled, before shipping. Discount code: "ACircle" knocked another $30 (5%) off the price, so it was $560, net.
Tom gave me the initial quote, and then I asked if I could shorten the process by calling and asking a few questions. He said he's hard to get a hold of and he'd rather call me. Called a few hours later. Answered all my questions. Great customer service. I ordered immediately.
I see this as a pretty low risk proposition. Basically it seems Tom is now offering complete models in a case, built to order (mine is 220V), for about $200 - $250 above the price of his corresponding kits. It would cost me about that to buy the case and additional parts where I live. Tom told me his tech who builds them is a perfectionist and does an outstanding job, so the build will also be better than what an inexperienced guy like me could do, and I will know that the build "works".
The directly competing models on the market (almost all use ICE modules) with similar output cost from $1500 to $3000 - almost 3-6 times as much. Nightshade audio also makes amps based on Toms boards (I think Nightshade uses their own proprietary PS), but even his prices are a few hundred more than Tom's, even with a basic case. ($850 for a basic CDA model with 125W X 2 into 8ohms, 250 X 2 into 4. Nightshade does offer lots of case options/colors though).
All reports/reviews seem to point to the ClassD being competitive in terms of SQ to the class d competition. Obviously personal taste makes a difference in how you perceive the SQ of the result. I doubt I will be disappointed in the sound, as I've heard a few ClassD amps (Nuforce, Bel Canto) and liked them.
I guess I could decide that the unit doesn't look nice enough. But if that really bugs me (which I doubt, the case seems to have a basic "utilitarian", but not ugly look) I can always order a custom faceplate or build a wood enclosure and improve the looks for a modest sum.
Anyway, Tom told me that it would take about a week to be ready. International shipping and customs clearance will take about another week. So in about 2 weeks I should be able to report back with first impressions. Also pictures, if I can get enough light in the room to get some clear ones with my pocket camera.
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Why are people still buying the kits? Doesn't it make more sens to buy a SMPS from Connex or something?
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The SMPS from Connex takes quite a while to get shipped to the US, and costs more than the power supply that Tom offers with the kits. I've tried both, and I'll be darned if I can hear any difference between the two different power supplies with the SDS 254 amp module.
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WGscott-
No problem. You post enough at the various forums ...
Only this and CA. Anything else and it is an impostor.
I can always order a custom faceplate or build a wood enclosure and improve the looks for a modest sum.
That's what I did. My front plate came to about $150. I spent about $300 on the case, total. Although it looks ok, and matches my Nova, my assembly job is definitely amateur hour. Having it done right is definitely cost-effective, and, as you say, you can always swap in a different face plate. I used http://www.frontpanelexpress.com and I can give you the Class D Audio engraving logo image thing that took me forever to make, if you are interested.
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I have two SDS-224 amps I use in a bi-amped active crossover set-up. Tom (of Class D Audio) has told me that some of his customers have reported hearing sonic differences with various PSU configurations and others not. Obviously, these type of anecdotal comments depend on the system and the listener in terms of how discerning both are or not. I currently use a discrete PSU consisting of: Antek xfer > Valab 12ns ultra fast rectifier > 3 15,000 uf Jensen 4 pole caps > SDS-224 audio circuit.
I was wondering if anyone could weigh in on their experience in terms of what/if any sonic improvements they have heard by optimizing their PSU's. Certainly, the SDS amps don't need a regulated PSU, but I've been toying around with trying one of Paul Hynes' series regulators in my PSU. Thanks for any information you can share.
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The SMPS from Connex takes quite a while to get shipped to the US, and costs more than the power supply that Tom offers with the kits. I've tried both, and I'll be darned if I can hear any difference between the two different power supplies with the SDS 254 amp module.
The fact that they sound the same to you is still good news for the Connex! as I'm sure a lot of folk are skittish about the smps sound quality. Other big plusses are ease of use and weight for newbies: fuse is built-in so no need to worry about wiring that, much less wiring needed period than the stock PS, (therefore) decreased high voltage risk, and the fact that the Connex weighs absolutely nothing and takes up a small amount of space - an equivalent toroid is very heavy and along with the capacitor/rectifier board, limits enclosure options.
Ordering from Connex does take some patience though. Ack.
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Hi All,
Just for understand, why my first post is stopped? maybe it is a publicity...I think it is a information for diy.
Regards
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Hi All,
Just for understand, why my first post is stopped? maybe it is a publicity...I think it is a information for diy.
Regards
Welcome aboard MDI. It has nothing to do with you, we had (have) a big problem with spammers on the site, so it's a security measure to verify that you're a real person, not a computer. When you get to three posts you'll be able to post unrestricted. Thanks for your patience.
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Hi,
I'm a long time reader of this tread and I want to share with you what I did with a SDS-254.
I did an integrated amp with a preamp kit from Dantimax. http://electronics.dantimax.dk/Kits/index.html
I now have an amp with 6 inputs a digital volume control with a remote and a nice blue display!!!! The amplifier will be build in a nice wood case. I have some nice wallnut burl that I could use....
But so far so good. The amp sound very good.
I will post the photos when the enclosure will be finish, probably not before mid September...
Thank you all for the inspiration
Zoula
(http://www.audiocircle.com/image.php?id=49489)
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Considering the new SDS-470, and the fully built models, do high quality, hi-tech solutions like this mark the end of the kilodollar amp?
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What is SDS 470?
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New model, SDS-470. 250W X 2 @8 ohms, double output @ 4 Ohms.
:thumb:
http://classdaudio.com/sds-470-and-power-supply.html
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New model, SDS-470. 250W X 2 @8 ohms, double output @ 4 Ohms.
:thumb:
http://classdaudio.com/sds-470-and-power-supply.html (http://classdaudio.com/sds-470-and-power-supply.html)
Where do you find the specs? When I go to the page you linked it only shows the details "SDS-470 amplifier with large power supply ". The complete SDS-470 amplifier page also has no details other than "Custom made SDS-470 in Silver Desktop Case wired for 50 cycles, 220V".
The SDS-480 kit page reveals that it is an "SDS kit including two SDS-224 Amplifiers, transformer, and large power supply".
I also checked the Manuals page, but there are only the original manuals for the original amps before there were CDA or SDS model designations.
It's good that the amplifiers work well and the majority of builders are satisified, but the information available on the website is still to this day as confusing and sketchy as ever and hasn't yet given me the confidence to take the plunge. Maybe there will be details available soon for the new assembled amplifier offerings.
Steve
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Class D Audio website over due for an update. :scratch:
There are few AC members contacted Tom about the SDS-470 and that how I got the info. from.
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Where do you find the specs? When I go to the page you linked it only shows the details "SDS-470 amplifier with large power supply ". The complete SDS-470 amplifier page also has no details other than "Custom made SDS-470 in Silver Desktop Case wired for 50 cycles, 220V".
The SDS-480 kit page reveals that it is an "SDS kit including two SDS-224 Amplifiers, transformer, and large power supply".
I also checked the Manuals page, but there are only the original manuals for the original amps before there were CDA or SDS model designations.
It's good that the amplifiers work well and the majority of builders are satisified, but the information available on the website is still to this day as confusing and sketchy as ever and hasn't yet given me the confidence to take the plunge. Maybe there will be details available soon for the new assembled amplifier offerings.
Steve
I wouldn't hold your breath. Tom seems like a funny guy. He makes these kits available for the DIY crowd. And most of DIY types that have taken the plunge have been satisfied. And that seems good enough for him. This thread seems to be all the free advertising he needs to keep selling kits.
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New model, SDS-470. 250W X 2 @8 ohms, double output @ 4 Ohms.
:thumb:
http://classdaudio.com/sds-470-and-power-supply.html
What is the difference between this amp and the SDS-258? Thanks!
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SDS-258
250W X2 @ 8 Ohm Only.
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SDS-258
250W X2 @ 8 Ohm Only.
Got it... thanks Trung!
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What is the difference between this amp and the SDS-258? Thanks!
SDS kit including two SDS-224 Amplifiers, transformer, and large power supply.
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Now I've done it... FINALLY pulled the trigger on a pair Class D Audio amps after lurking about this board for the past year or so. Got two of the new SDS-450 amps I plan to run either mono or passive biamp on a pair of Magnepan 1.6QR.
I officially now have way too many projects sitting in my closet, hope I can get this one fired up ASAP.
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Before I start drilling away and permanently mounting my amp components I wanted to get your guy's input on the best way to layout the case. Currently I am only planning on running 2 of the CDA-254 boards, but I want to plan to allow me to add a third later if desired. In case your wondering I am going to use the third one for a car amp.
Below are the 2 layout options I have come up with. Can you guys let me know which one you think is better or if there is another option I should consider? For both layouts I was going to have the RCA inputs closest to the back.
Option A
(http://www.audiocircle.com/image.php?id=49753)
Option B
(http://www.audiocircle.com/image.php?id=49754)
Thanks,
Topp
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Option B
I thought you could run only two amp boards off of one power supply?
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I asked Tom how many amps his power supply could run, and he said 3. But I ideally it would have a larger toroidal transformer.
Thanks,
Topp
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Received my Built SDS-470 amp. One amp board with 250W X 2 into 8 and 2 X 500 into 4 ohms. Can bridge to 1 X 500. It's about 12 X 12 inches and 4 or so inches in height. Very heavy for it's size. That transformer is seriously big. Everyone who knows something about electricity and has seen the inside of the amp has commented on it.
The good news: It works, and looks pretty good, too. First impression of the sound is favourable. Will write more on that after it breaks in and I've had more of a chance to listen.
But getting there was a bit of a story.
Received the amp through International express mail. Got it home and opened the box. Disappointed....not packed well. Just placed in a cardboard box and then Styrofoam chips poured in to fill the box. That's it.
Plugged it in as a test and...fuse on my electrical board jumped. Tried a few different electrical chords and outlets- same result.
Opened the case: Wow, damage during shipment. Some of the screws attaching the amp board and PS board loosened from their sockets during shipment and the boards could move around inside the case. Also, two of the 3 cables connecting the transformer to the PS board had torn free. Apparently, rough handling together with the fact that the packing didn't prevent the whole amp from moving inside the box had generated forces that totally loosened several screws and cables.
Downloaded the electrical schematic from Tom's website, and wrote Tom to confirm that the way I thought to reconnect everything was correct. Left my phone number (I have a US VOIP number that forwards to my cell phone). Tom called later that day and confirmed my plan. Was very apologetic about the packaging, and promised to fix that issue. Also suggested I check the fuse and replace it.
Reconnected the loose bits. Turned amp on....the relevant house fuses still jumped. Luckily I have 2 neighbors who are electricians. One agreed to look so I brought him the amp. He came to the conclusion that two of the wires between the electrical (IEC) socket input and the on-off switch at the front were hooked up in reverse – one way on one end, the other way on the other end. He switched them to match the schematic. Turned on amp...no fuses jumped! Let's get this thing home and see what happens.
At home, placed the amp in system. Turned it on. But....no sound. Many expletives deleted.
At the suggestion of the electrician, wrote Tom and found out exactly what the voltage ins and outs at various points in the amp are supposed to be, so we could check for problems.
The second neighbor/electrician dropped by the next day. Asked him to get out his multi-tester and have a look. He did and immediately asked me if the amp had a burnt fuse. It hadn't previously, but now we checked and the fuse was most definitely burnt. Replaced fuse. Checked that amp seemed to be functioning according to values relayed by Tom. Yes... seems okay.
Plugged amp in, everything seemed fine, and all the little LEDs on the boards lighting up as they should.
Put amp back in system. Connected and turned everything on....no music/audio, just hum and noise....more expletives. Then remembered that the amp had a switch on the back for switching between “bridged” and “not bridged” modes. Flicked switch to other position and... music! No hum!
So in the end, the amp is working. But basically due to amateurish packaging, it arrived damaged and my experience with it was somewhat like doing it DIY. Not what should happen with a “finished” product. I'm just lucky I have friends who were willing to help me out.
As far as sound, I won't say too much till it breaks in and I listen some more. The amp is being fed from the pre-out of my MF-X-150 integrated (I will eventually replace the preamp also.)
First impressions: very noticeable increase in bass slam, and just a feeling of less strain, a more easy overall flow in the sound. Drums and bass definitely are improved. Soundstage is different, too. Just not sure how yet. This amp also seems "faster". So some very noticeable improvements, but I don't want to describe them as earthshaking. But this is only in the first few hours, we'll see what I think in a few days. I assume more differences will become apparent. Have to listen to some music that used to strain the system, like a big symphonic work, and see how that sounds.
Anyway, I think audiophiles often exaggerate the differences upgrades make. Every small difference becomes “a veil being lifted”, or “my system sounds totally different”, etc. I don't want to create expectations for others who might be thinking of buying one of these. But it does sound noticeably different, and is doing more or less what I hoped when I decided to by a class D amp with more than double the power of what I was using previously.
As far as cosmetics, it looks pretty good. The case looks more or less like a grey PC case, but the front panel is silver and in a brushed metal - quite nice. Doesn't look very different from the front panel of my MF equipment. How can you tell it's not a high end piece of equipment? The screws on the front panel are standard round Philips head screws. Not flat headed, and not flush with the surface of the front panel. As far as I know, this was the second “complete amp” Tom has sold, and the first silver one (the others are black). So the on-off switch and company logo are black. Don't blend well with the amp faceplate, IMO. I'm guessing Tom doesn't even have silver switches or logos to match the faceplate, at least for now. But hey, that's the kind of stuff you pay big bucks for when you buy from the "audiophile" companies. And this thing definitely didn't come with that kind of price tag.
Finally, I do want to stress that if it wasn't for the shipping problems, I'd have been very happy. The amp does seem to be well made, and with good parts. The binding posts are better than the ones on my MF amp, for instance. (I'll try to include some pictures).
Here's what I wrote Tom to sum up the buying experience:
“Suggestions for the future:
1) You have to pack future amps so they can’t move inside the box. Generally audio products I’ve received are packed with form fitting hard Styrofoam on 2 opposite sides of the device case that extend out to the sides of the box and prevent movement.
The other option would be to wrap it in bubble wrap so that with the wrap the amp totally fills the space in the box. That way it couldn’t move and would also be protected.
There are signs the amp also took a blow from below, so that has to be taken into account. You need some top/bottom protection . If I lived in the States, I simply would have asked you to replace/fix the amp upon receipt. It’s not a kit, so your customers for complete products aren’t going to want to fix them on their own – unlike kits. I was willing because the hassle and expense of shipping the amp back and forth to the States simply wasn't worth it.
2) I think you need to label all the connections and switches on the back. This is something that finished products have. For instance, the switch for the “bridge” isn't marked in any way, so I wouldn't have had any idea why there was a toggle switch on the back of the amp before I asked you.
3) Cosmetics. The brushed front panel looks quite nice. I know you’re just getting started making finished amps, but IMO the silver faceplate would look a lot classier if the on-off switch was silver colored, and the company logo was say, black or colored lettering on a silver background. Both would blend in much better with the silver faceplate that way and look more “high-end”.
Hopefully the amp will work fine for many years from here on out.”
(http://www.audiocircle.com/image.php?id=49827)
(http://www.audiocircle.com/image.php?id=49828)
(http://www.audiocircle.com/image.php?id=49829)
(http://www.audiocircle.com/image.php?id=49830)
(http://www.audiocircle.com/image.php?id=49831)
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my experience with it was somewhat like doing it DIY
:lol:
I was going to say something like that, but I was worried you wouldn't think it was funny.
I hope it settles down/in and that you enjoy it.
I would invest in a new face-plate. I used these guys: http://www.frontpanelexpress.com/index.html
I can give you my logo template; it was sort of an ordeal to make it.
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:lol:
I was going to say something like that, but I was worried you wouldn't think it was funny.
I hope it settles down/in and that you enjoy it.
I would invest in a new face-plate. I used these guys: http://www.frontpanelexpress.com/index.html
I can give you my logo template; it was sort of an ordeal to make it.
Basically, I ended up being the guinea pig for an inexperienced company selling a complete product for the first time. I'm sure Tom will learn from his mistakes and others will get well made amps for a good price, without the damage. He should probably add another $10 bucks per amp to his shipping charge just to pay for better packaging. The amps would still be cheap, and both he and his customers would be happier.
Thanks for the suggestion about the faceplate. I'll think about it. But at this point I'm so tired of the hassle that I think I'll just try and enjoy the music for a while.
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Thanks for the suggestion about the faceplate. I'll think about it. But at this point I'm so tired of the hassle that I think I'll just try and enjoy the music for a while.
I think you will feel better about the not-too-bad-looking front panel with a set of replacement satin stainless steel hex button head screws available most anywhere in the world for a few dollars.
(http://www.audiocircle.com/image.php?id=49837)
I think the rear panel does absolutely need to be silkscreened with legends.
As far as the shorted AC electrical input wiring, I'm totally baffled as to how it is possible the manufacturer didn't at the very least power up the amp to insure that it was in fact operational?
Steve
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When shipping an amplifier, I would strongly suggest a minimum of 2 inches of hard styrofoam on all sides, bottom and top. The amp itself should be wrapped with an appropriate amount of bubble wrap, then placed in the box so as there is NO MOVEMENT at all.
Why would you package it any other way?
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Basically, I ended up being the guinea pig for an inexperienced company selling a complete product for the first time. I'm sure Tom will learn from his mistakes and others will get well made amps for a good price, without the damage. He should probably add another $10 bucks per amp to his shipping charge just to pay for better packaging. The amps would still be cheap, and both he and his customers would be happier.
Thanks for the suggestion about the faceplate. I'll think about it. But at this point I'm so tired of the hassle that I think I'll just try and enjoy the music for a while.
firedog,
I'm happily still using your SB Touch remote control! Thanks again for the sale (and for the great packaging).
I feel bad about your purchase, as this is a really great amplifier for the money (I completely concur, Tom does have to up the ante in packaging completed amplifiers, it is not the same as mailing a circuit board). It was cheaper to build than my dual mono gainclone, yet it outperforms it, in many areas for less money. I diy'ed my own using jtwrace's chassis. Pics are available right here (http://www.audiocircle.com/index.php?action=gallery;area=browse;album=4434). I also used Front Panel Express, if you need some ideas. The rear was made by jtwrace using engraving from his work, but the same can be done easily by Front Panel Express.
Hope you enjoy the amp. I will be using them in my family room to power some Magnepan MMGW's I got for the wife and kids. Should work great.
Best,
Anand.
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Nice work there Anand. :thumb: I can see that you have connected the Balanced input with RCA using two wires out of which one is without any insulation or shielding. IMHO it may be a good idea to provide shielding to prevent any stray EMI/RF being picked up by the system.
BTW, what is the role of IEC power filter? It sounds interesting.
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Firedog and Corndog71...
I notice on the pics of both your amps there are no gain pots... are these set for a fixed gain? It's hard to tell from the pics if you have a resistor in the molex connector where the pots usually attach.
Thanks... just wondering since I've got the SDS-450 on the way and I am planning to gain match it to my DAC/preamp.
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My understanding is that all the SDS boards have the possibility for gain control on the board. But ask Tom about your amp.
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My understanding is that all the SDS boards have the possibility for gain control on the board. But ask Tom about your amp.
firedog, did you request a specific gain setting?
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No, I just told Tom about my preamp and he said the standard setting should work fine.
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Nice work there Anand. :thumb: I can see that you have connected the Balanced input with RCA using two wires out of which one is without any insulation or shielding. IMHO it may be a good idea to provide shielding to prevent any stray EMI/RF being picked up by the system.
BTW, what is the role of IEC power filter? It sounds interesting.
I opted not to do it, due to the incredible CMRR rendered by the input stage of the SDS unit (http://www.jensen-transformers.com/an/ingenaes.pdf), which was designed by Bill Whitlock. Besides, the length of wiring is minimal in comparison to other designs or even interconnects, etc...Regarding the lack of insulation on one of the wires, yah...I got lazy and it was super short!
The unit is dead quiet on 95dB/8 ohm/1 watt @ 1 meter speakers.
Anand.
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BTW, what is the role of IEC power filter? It sounds interesting.
http://www.audiocircle.com/index.php?topic=18443.0
Or use the search function and type in "Felix". There are many threads on them.
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http://www.audiocircle.com/index.php?topic=18443.0
Or use the search function and type in "Felix". There are many threads on them.
Thank you Jason. Appears to be a longish thread. Will read it at leisure. Subscribed to it.
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Thank you Jason. Appears to be a longish thread. Will read it at leisure. Subscribed to it.
Welcome. You can also do this http://www.audiocircle.com/index.php?topic=91208.0
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Firedog and Corndog71...
I notice on the pics of both your amps there are no gain pots... are these set for a fixed gain? It's hard to tell from the pics if you have a resistor in the molex connector where the pots usually attach.
Thanks... just wondering since I've got the SDS-450 on the way and I am planning to gain match it to my DAC/preamp.
I added the pots.
(http://i576.photobucket.com/albums/ss207/corndog642/classdaudio%20amp/a2f5308e.jpg)
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Ooooh... Hover pots, I like them. :thumb: or are they antigravity pots
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Okay, been listening to the SDS-470 pretty intensively today and it has about 75 hours of continuous play on it at this point. First, it seems to be working fine, so we can chalk all the previous problems up to "experience", and learn from it.
As far as sound, these are my impressions compared to using my MF-X150 integrated as the amp (I don't have a way to directly A/B it to anything else, but using the SDS as power amp with the MF as the pre is the only change I made to a system that I'm very used to):
1. Bass - very authoritative, controlled, with "slam" - whatever you want to call it. Also sounds very warm and rounded - in a good way. Thumps when it should. Like the real thing. You can really hear/imagine a hit on a drum head, for instance.
2. Percussion. Very good and improved. Percussion seems very sharp and well defined - no fuzzy edges.
3. Transients, Dynamics - micro and macro - very good. Overall my system sounds "faster" and seems to respond better to changes in the music. In general, there is a sense of "ease" in the sound, a little more like it is flowing from the speakers, and less like the the sound of the system "working". This is especially apparent on big pieces like orchestras or big bands, but noticeable even on rock music and small ensembles.
4. Mids and up- Very Good. Voices, Horns and piano sound very lifelike. Better than what I expected. Listening to Keith Jarrett "The Koln Concert" as I write, and it really sounds like a piano.
5. Highs - Not sure here. At first I thought it was lacking a little in the upper highs. Most noticeable with cymbals. But I'm starting to change my opinion. It seems that on recordings where the cymbals are more prominent (like a jazz trio or quartet) they sound fine; on recordings where they aren't so prominent or hit with brushes, they seem slightly in the background, a little less clear, or less emphasized. This may mean that the amp is doing exactly what it should, and my previous amp was emphasizing the cymbals slightly. Or it may mean the amp doesn't sustain cymbals quite as well or as long as it should. Not sure. I definitely don't hear any harshness, sibilance, or over done highs as some report with class D. (Later edit: more listening. I listened closely to several passages, one at a time, then switched cables to listen to the same passage with just the integrated amp. Seems like nothing is actually missing from cymbal reproduction, but for some reason I sometimes have the impression the cymbals just don't sound quite as loud with this amp. Odd.) Maybe the amp needed "breaking in" to sound its best. So my final conclusion is that the hi-end reproduction is very good, but cymbal reproduction is the only area in which I think the ClassD amp is only the equal to the MF amp and doesn't outshine it. (Another edit: see below, http://www.audiocircle.com/index.php?topic=76400.msg979919#msg979919, for later update about this).
Update: Now that I've had the amp for awhile, I'm very happy with the sound. The difference in the treble was more a difference in presentation and sound stage. My previous amp had a very up front presentation, this one has a deeper soundstage, so sometimes some instruments sound "far away" in comparison. See my other post here.
6. Sound stage- definitely deeper from back to front. More separation between instruments. Can hear each one more clearly. Again, especially apparent with large ensembles. The side to side sound stage is also wider, but this is harder to hear, as my small room is a limiting factor here.
Overall, I'm pretty happy with the purchase so far. Seems like I'm getting pretty much what I paid for. I think this amp produces sound well above its price point. And I still have plans to upgrade preamp and dac (or buy a DAC that doesn't need a pre) at some point, so that may improve the sound even more.
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Thanks for the great review firedog.
Glad to hear that you like it.
I am hoping to get my SDS-470 next week. :)
I will be using it with an EE DAC and Dodd tube buffer.
Neil
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Neil-
Be very interested to hear how you think your amp sounds with and without the buffer. Also where in the chain you think it sounds best.
Thinking of getting either one of the Chinese ones thats also a preamp or the new smaller Dodd Buffer (only one input).
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Just got my SDS254. I'm very impressed by the product quality and the boards and transformer where all very well packed. I can't wait to try it but I'm going to take the build nice and slow.
I'd love some advice on adding suitable volume control. If I am using a single balanced input (from my Behringer ULtracurve DEQ2496) can I add a volume control directly to the SDS254 itself? The Ultracurve has selectable output of 12 or 22 dBu, and the output impedance is 100 ohms at 1kHz. I'd like something remote controllable and my budget is about $150 (no more initially!).
PS This thread has been super helpful, so thanks to all previous contributors.
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There might be a simple reason why you can't just use the potentiometers as a simple volume control, but if there isn't, and that is all you need, seems simple enough. You might want to replace the linear one with a log one so it behaves conventionally, and maybe one that does both with a single knob.
Another option is the passive Dodd buffer everyone is talking about here and the other threads.
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Thanks wgscott. I got a reply back from Tom, as ever not an effusive one, that confirms what you say.
"Yes, you can use the gain controls for volume."
Which makes sense to me.
However, I've noticed in this hobby that everything can seem simple, straightforward and logical, then I'll read a few forum posts and get confused.
For example just control the volume using some gain pots, no preamp needed, really minimal added components and more direct path = purest sound (the audiophile's dream).
But read some forum posts - no, things sound better with additional componentry (preamp or buffer), even though this adds much more (you'd think sound-destroying) circuitry in the audio path, or you need to look at all the impedances etc. It get's sooo confusing.
Think I'm going to try it cheap, pure and simple - gain pots only...Anyone tried it?
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I think the passive buffer, in addition to providing a convienient and potentially remote-controllable volume control, is that it does impedance matching from the input source. Also, perhaps related, some have found particular gain settings on the amp to deliver optimal sound quality (i.e., dialed back to somewhere abound 28 dB of gain rather than 32).
The best thing to do is to try it both ways and see for yourself.
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One of my amp boards had to be repaired or replaced, but I am back up and running now for a few weeks, and all sounds good. I think. But being privy to every stupid thing I did along the way, I can see how there might be substantial room for improvement. I wouldn't mind a bit of general advice and a reality check.
1. My case is fairly tightly crammed, with 2 amp boards, a power supply board, and the transformer. The wiring as a result looks a bit like a spaghetti bowl, and there is no real shielding, given that my case is wood with front and back aluminum panels only. Would I benefit from moving the transformer and power supply board (or just the transformer itself) into a separate, shielded metal box?
2. I chopped up a standard shielded 14-3 gauge power cable to use for wiring the power supply to the amp boards. Should I do this differently? Should I ground the shielding?
3. Are solid-core wires better?
4. I currently have a passive bi-amp configuration while I figure out whether or not to get an active crossover kit. I am vertically bi-amping in the sense that I have a stereo amp board for each speaker. Is this any better than horizontal bi-amping, given it is all coming from one power supply?
5. In the current passive bi-amp configuration, I have one RCA input for left and one for right going into the box, and I split the left signal for one amp board, and I split the right signal for the other amp board. Is this ok, or should I have some circuitry in there until/unless I replace it with an active crossover?
6. Perhaps related to #5, if both amp boards are connected, I get two little pops when I turn on the power supply. This originates within the amp, so if the pre-amp is disconnected, I still have the same issue. If I disconnect either of the amp boards, there is no pop in the remaining one, so I assume it has to do with the two interacting at the level of the power supply. Is this a cause for worry, and if so, what should I do about it?
7. My inhibition to adding an active crossover is due to my inhibition to disconnecting the passive crossovers in my speakers. Can any harm come from leaving both in place?
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As I wrote in a previous post, I'm a new owner of an SDS-470. The only reservation I've had about the amp so far is that of cymbal reproduction - on many recordings it sounds fine, on others it sounds "recessed" or more in the background, compared to what I'm used to.
I wrote Blair at Nightshade audio about the possibility of matching one of his tube preamps with the SDS. I'm interested in a tube pre, and since Blair builds his own amps based on the ClassD boards, I thought he would be a good person to ask. As part of my email, I also described to him the "issue" I sometimes hear with cymbals. He had an interesting response to that part of my query:
"Class D Audio's amps have a panoramic sound stage, not a forward one. Portions of some recordings will sound more recessed as a result. It sounds like you're hearing the parameters of the amp's sound stage to me. "
That comment fits what I'm hearing - a different soundstage than what I'm used to, and that's why it's sometimes very noticeable to me.
Hopefully, I will get more used to the sound of the new amp, and won't notice that aspect anymore. After all, I want to enjoy listening to the music, and not notice the amp.
Update: Now that I've had the amp for awhile, I'm very happy with the sound. The difference in the treble was definitely more a difference in presentation and sound stage. My previous amp had a very up front presentation, this one has a deeper soundstage, so sometimes some instruments sound "far away" in comparison.
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Does this sound right to everyone else? Personally, when there is a cymbal crash that I'm used to hearing with my A/B mosfet amp, I'd expect to hear it regardless whether I'm using a Class D or any other amp. Big cymbal crashes are exciting and ad realism to the orchestra. Soft cymbals vs loud cymbals... I'm not sure about this? :scratch:
This is where the power supply really comes into play. Gotta have that power in reserve. I guess I'm not really getting this panorama sound thing.
I've kept up with this thread since the beginning, but I don't recall this being mentioned before. Maybe I just missed it. Other please jump in here.
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Maybe I'm not explaining what I'm hearing well. I just listened to a Don Cherry (jazz quartet) album and the Neil Young "Live at Fillmore" album.
On both the cymbals sound fine - just like I'd expect. But on SOME albums, it seems like the cymbals are farther down in the mix, not quite as loud, or farther away than I'm used to. That's why I think what Blair said may be right - the presentation of this amp is different to what I'm used to, and therefore on some albums - those with significantly more depth in the soundstage - this amp recreates that and the cymbals sound different to me.
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Maybe I'm not explaining what I'm hearing well. I just listened to a Don Cherry (jazz quartet) album and the Neil Young "Live at Fillmore" album.
On both the cymbals sound fine - just like I'd expect. But on SOME albums, it seems like the cymbals are farther down in the mix, not quite as loud, or farther away than I'm used to. That's why I think what Blair said may be right - the presentation of this amp is different to what I'm used to, and therefore on some albums - those with significantly more depth in the soundstage - this amp recreates that and the cymbals sound different to me.
OK, that's helpful and clears things up a bit. I'm not doubting what you are hearing or what Blair is saying. Others have repeatedly commented that the Class D amps do have a different sound, not the same as SS or tubes. I can't comment further since I've never heard one.
Regardless, most seem to like what they hear with Class D. Appreciate the explanation, firedog.
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I feel with better imaging amps they do not push the sound
of cymbals out towards the speakers location ie:further away,
or behind the speakers.
It might be a more accurate representation of the "actual"
cymbal location in the sound field.
I know with these amps that I am getting great imaging
with better depth.
Also try different power cords, I just bought a PS Audio AC5
and it made a big difference. It did smooth out the upper treble
a bit.
JT
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Built my SDS254 a few weeks ago and have been enjoying it for the most part. It replaced an old Adcom GFA 545II. I use a Melos SHA-1 Tube Headphone/Line stage for the pre-amp. I am hoping some one can tell me what size resistors in place of volume pots to use on amp board. I had gain issues with the Adcom and 1/4 turn was almost full volume? I have seen the chart but not sure what size resistor? My pre-amp specs are Line Gain 19 db, Input Impedance 100k Ohm, Out Impedance 0.5 volt. Thank for any help you can provide.
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Here are the resistor values listed a while back that will adjust the gain downward. I've found the 5K resistor to be a nice starting place (cuts the gain down to 24 db or so)... but with a preamp with the amount of gain you have, you may find yourself liking even less gain in the amp.
"For those who wish to change the pots for fixed resistors, here are resistor values to produce required gain. Gain is listed in dB: To change gain potentiometer to a fixed resistor, you would connect a fixed resistor between the yellow and black wires on the gain controls (of course, remove the gain pots). Leave the red wire disconnected.
Use high quality 1% resistors: 1/2 watt is sufficient.
560 Ohm = 31 dB
1K = 30 dB
2.2K = 27 dB
5.2K = 23 dB
6.2K = 18 dB
7.5K = 16 dB
I hope this is of some help. Please feel free to post this on the forums if it will help others. On my personal systems here, I use the same pots that come with the kits."
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Built my SDS254 a few weeks ago and have been enjoying it for the most part. It replaced an old Adcom GFA 545II. I use a Melos SHA-1 Tube Headphone/Line stage for the pre-amp. I am hoping some one can tell me what size resistors in place of volume pots to use on amp board. I had gain issues with the Adcom and 1/4 turn was almost full volume? I have seen the chart but not sure what size resistor? My pre-amp specs are Line Gain 19 db, Input Impedance 100k Ohm, Out Impedance 0.5 volt. Thank for any help you can provide.
Adjust the gain pots to what you think is best (e.g., turn the volume up half-way before blood comes out your ears) and then measure the resistance with a multimeter. Then go for the closest standard resistor value. I bought 2.2K Vishay naked resistors, about $15 each.
Tom also says the pots are high quality and you shouldn't feel any need to replace them. For me the main motive was to keep them from being accidentally changed.
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Thanks guys for the help. I will measure the resistance and try some out.
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Here are the resistor values listed a while back that will adjust the gain downward. I've found the 5K resistor to be a nice starting place (cuts the gain down to 24 db or so)... but with a preamp with the amount of gain you have, you may find yourself liking even less gain in the amp.
"For those who wish to change the pots for fixed resistors, here are resistor values to produce required gain. Gain is listed in dB: To change gain potentiometer to a fixed resistor, you would connect a fixed resistor between the yellow and black wires on the gain controls (of course, remove the gain pots). Leave the red wire disconnected.
Use high quality 1% resistors: 1/2 watt is sufficient.
560 Ohm = 31 dB
1K = 30 dB
2.2K = 27 dB
5.2K = 23 dB
6.2K = 18 dB
7.5K = 16 dB
I hope this is of some help. Please feel free to post this on the forums if it will help others. On my personal systems here, I use the same pots that come with the kits."
Thank you very much for the information. I found it particularly useful.
After discovering the missing lows, I had relegated my CDA254 to the attic. I've recently purchased a Tube preamp and Class AB SS power amp and a pair of electrostatic tower speakers. The electrostatic panels take over from 1.3Khz.
Your post has given me an idea. Since my preamp has two sets of outputs, I can bi-amp the speakers. I can use the Class AB SS to drive the woofers and drive the electrostatic panels with the CDA254. I can do the level matching of both the power amps by incorporating a resistor of appropriate value. But will this affect the sonics in anyway?
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As far as I remember, most of you guys have used Toroid trafos. Has anyone used an 'R' core? Are there some advantages of using R core which would be more expensive.
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My understanding is that there are more problems than just gain matching when using dissimilar amps for bi-amping. Relative phase is most likely a big problem.
Did you ever manage to figure out why you were getting inferior bass? Most people think Class D amps in general are better at bass than treble (and thus one sometimes hears of people who bi-amp with tube amps for treble and Class D for the bass and/or subs).
Since the transformer and power supply that is recommended with the kit is comparatively inexpensive (I would have to look but I think $100 for both), why not at least try that to see if it helps?
If the bass is problematic with the amp you currently have, do you trust the mid/treble?
The Vishay resistors themselves are claimed to be superior in sound to the pots provided in the kit (Tom suggested to me that you would have to have a golden ear to pick out the difference).
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Your post has given me an idea. Since my preamp has two sets of outputs, I can bi-amp the speakers. I can use the Class AB SS to drive the woofers and drive the electrostatic panels with the CDA254. I can do the level matching of both the power amps by incorporating a resistor of appropriate value. But will this affect the sonics in anyway?
Not positive, but I believe the CDA amps do not have adjustable gain pots... they are preset to a fixed gain. Are you talking about changing a resistor on the board?
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Thank you wgscott for voicing your opinion. My only mistake I didn't order the whole kit and ordered only the amp and the Power supply from Tom as I suspected that there could be issue of safe handling of the heavy trafo and hence assumed that it can be sourced locally. Since toroids are not readily available and need to be custom ordered in Chennai, India, I have gone in for a EI core trafo of the voltage and capacity prescribed by Tom. I have a feeling that if I replace the EI trafo with a toroid or R core, things might improve. I have made inquiries on the costing and discovered that R core is more expensive than toroid. Hence I'm checking if any of those in AC have used a R core and if it would result anyway in better
sound.
My understanding is that there are more problems than just gain matching when using dissimilar amps for bi-amping. Relative phase is most likely a big problem.
Did you ever manage to figure out why you were getting inferior bass? Most people think Class D amps in general are better at bass than treble (and thus one sometimes hears of people who bi-amp with tube amps for treble and Class D for the bass and/or subs).
Since the transformer and power supply that is recommended with the kit is comparatively inexpensive (I would have to look but I think $100 for both), why not at least try that to see if it helps?
If the bass is problematic with the amp you currently have, do you trust the mid/treble?
The Vishay resistors themselves are claimed to be superior in sound to the pots provided in the kit (Tom suggested to me that you would have to have a golden ear to pick out the difference).
Not positive, but I believe the CDA amps do not have adjustable gain pots... they are preset to a fixed gain. Are you talking about changing a resistor on the board?
Yes, precisely; either on the Class D amp or the Class AB SS amp.
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Rajesh: Why not get a SMPS from Connex?
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Rajesh: Why not get a SMPS from Connex?
Hi soundnoob, thanks for the suggestion but unfortunately, buying something from abroad sitting in India is quite cumbersome, complicated and also expensive. I discovered it hard way when I bought the Class D amp. :( So don't want to take the trouble once more.
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Greetings, I've recently just ordered a couple of ClassDAudio amps, was wondering if my wiring plan is correct... The intention is to run each SDS board off a Connex 500R SMPS as monoblocks using the XLR balanced inputs, while retaining "flick of a switch (or two switches in this case)" capability to run as two stereo amps off the RCA inputs
(http://www.audiocircle.com/image.php?id=50524)
At present, the case I'm planning to use is rather small and may not allow space for a 2nd XLR, so may forego the R channel XLR connection option. Would like to check with the more experienced folks here whether this is feasible or advisable?
Cheers all, and hello! <my first post 8-P>
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Guys, I have a couple of questions; one on the potentiometers and the other on set up for XLR.
Potentiometers
The instructions say:
For the potentiometers included, the black wire goes to the center pin on the pot, and if holding the pot with pins facing up, and the pot shaft facing toward you and the pins of the pot facing up, the black wire goes to the right pot pin, the white to the center pin and the red to the left pin.
But how can the black wire go both to the center pin and to the right pot pin? I'm confused.
XLR Set up
The instructions say:
I already set up your amp for single ended input. The important thing to remember is… do not use the – on the input. Connect the + to + and the negative to G(ground). If you connect to -, it will damage the amp. For balanced input, just remove J1 and J2 jumpers completely. J1 and J2 have jumpers on pins 2 and 3… this is for single ended input. If you change the jumpers to pins 1 and 2, it will reverse the polarity…most situations this will probably not sound so good, so no need to mess with that.
Does this mean that for Balanced input I remove the jumpers and do connect + to +, - to -. and G to G?
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^^^Ignore the wiring colors for the pot as he has sent out pots with various colors...
Read this
^^^Thanks! Tom e-mailed me the following, apply it if you have the same color as me, or follow the picture above or the one after Tom's directions
"Thank you for pointing that out to me. I forget we just got in new wires and they’re different color than the last. Now, with the pot shaft facing toward you and the pins of the pot facing up, the black wire goes to the right pot pin, the white to the center pin, and the red to the left pin."
(http://i41.photobucket.com/albums/e257/praedet/DIY%20Audio/f5b2c7de.jpg)
If you have little to no volume with an SDS, the pot is probably the problem...
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Thanks Praedet, that's helpful.
Just need some direction on the balanced set up now. The amps are wonderful but he could do with a copyeditor for the instructions...
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Thanks Praedet, that's helpful.
Just need some direction on the balanced set up now. The amps are wonderful but he could do with a copyeditor for the instructions...
rarem,
Connect Pin 2 to "+" on the board. Connect Pin 3 to "-" on the board. Connect Pin 1 to "G" on the board.
Ideally Pin 1 should be connected to Chassis Ground, in order to maximize the benefits of balanced connections. Whether Tom has done that through the board by way of a solder mask directly to the mounting screw, I don't know. But that is the classical way of connecting Pin 1. I've seen several manufacturers who don't do that, so Pin 1 ends up being 'signal ground' instead :roll:.
Best,
Anand.
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Thanks Anand. I appreciate that, especially the tip on ground. Do I also need to remove the jumper, or not?
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Thanks Anand. I appreciate that, especially the tip on ground. Do I also need to remove the jumper, or not?
For balanced use only,yes you remove the jumper. If not you have to wire a DPDT switch so that pins 2 and 3 are attached together when using RCA inputs and not attached when using balanced. MarkSim has some nice diagrams earlier in this thread.
Anand
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Are there any known issues with connecting a subwoofer at speaker level with a Class D Audio amp?
I've heard, for example, Rel T-series don't play well with (at least some) Class D amps.
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Are there any known issues with connecting a subwoofer at speaker level with a Class D Audio amp?
I've heard, for example, Rel T-series don't play well with (at least some) Class D amps.
Been wondering the same. Got conflicting responses of "Check with your amp manufacturer" and "Check with your speaker manufacturer" from those respective parties.
Particularly concerned about when running the SDS amps in balanced mode where the speaker outputs are floating (no common ground). I would like to use them at speaker level with an ACI Force subwoofer on each mono amp. These connect with a speaker level to line level adapter that has resistance built in.... but will this work with a floating speaker output without damaging the amp?
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Has anyone compared the sound of these amps to Virtue's Tripath based amps? Which did you like better?
Has anyone tried them with GR-Research N3S or N2X speakers? How is the sound?
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My SDS-258 drives my AV123 X-series speakers very well. GR sells kits of them on the cheap.
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Has anyone compared the sound of these amps to Virtue's Tripath based amps? Which did you like better?
Has anyone tried them with GR-Research N3S or N2X speakers? How is the sound?
The SDS-470 sounds great with my GR-Research OB7's, very smooth, detailed and killer bass.
A surprisingly huge improvement over my previous amp.
Neil
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Hi...
First post on my first forum...hope I'm asking appropriate questions. I'm attempting to build a tri-amp active system to drive my Klipshorns (I'm upgrading the mid and tweeter drivers as well). I've have 3 SDS-224 amp kits fed by Marchand XM-1 active crossovers. I plan on driving the woofer section at full gain, then lower the mid and high amp gains using the supplied potentiometers. Has anyone tried to simply solder the yellow and black wires on the gain controls together rather than use a low ohm resisters? Seems that would be an easy (and cheap) way to get full gain on one amp, then use pots on the other amps to adjust the amplitude. Once set, I'd measure the resistance on the adjusted mid and high pots and replace them with fixed resistors.
Thanks, Mike
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Earlier in the thread there were observations from some that the sound improved when the gain was attenuated somewhat. Also, wouldn't you want to be able to balance the gain for all six channels to get the flattest response?
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I did solder the wires...got full gain as expected. Also got same hiss/hum that I got at full throttle with the pots. Sound was best around half way, which measured 5k ohms. I'm going to solder a 4.7k ohm to the wires and see what happens. Yes, I will then adjust the gain on the mids and highs to balance to the bass (using the supplied pots).
Mike
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Hi...
First post on my first forum...hope I'm asking appropriate questions. I'm attempting to build a tri-amp active system to drive my Klipshorns (I'm upgrading the mid and tweeter drivers as well). I've have 3 SDS-224 amp kits fed by Marchand XM-1 active crossovers. I plan on driving the woofer section at full gain, then lower the mid and high amp gains using the supplied potentiometers. Has anyone tried to simply solder the yellow and black wires on the gain controls together rather than use a low ohm resisters? Seems that would be an easy (and cheap) way to get full gain on one amp, then use pots on the other amps to adjust the amplitude. Once set, I'd measure the resistance on the adjusted mid and high pots and replace them with fixed resistors.
Thanks, Mike
Hello Mike and welcome to AC. We welcome your posts! :D
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Right-sizing and Headroom / Dynamics
Hi all,
I've worked my way through about 80% of this thread, so I hope this hasn't come up. Basically, I'm trying to decide how big of an amp to build. I don't know this from personal experience, but the "internet audiophile community" seems to generally say that, with amps, more headroom is better. I.e., it's better to have a much bigger amp than you really need. I believe the rationale for this notion is that it helps with dynamics in music (and movies as well).
Right now my current setup is: FLAC CD rips on a computer, fed via optical to an Emotiva XDA-1 preamp-DAC, to a QSC RMX2450 "pro" amp via balanced XLR, to Salk Songtower speakers (4 ohms at 88 db). The QSC amp has an obscene amount of power; I went with a pro amp because they offer good value (in terms of watts/dollar).
I'm really happy with this setup, and I think it sounds great. But the QSC does require active cooling (although I fan modded it so it's inaudible), and uses a fair amount of power. Our entertainment center is in a corner, so it sits out of sight behind the TV; I wouldn't want to keep it in an enclosed space. So that got me thinking about class D amps in general, as they are known for high efficiency. I started reading about the Wyred 4 Sound series of amps, as they get a lot of good press, and then I ran across this thread... Besides the rational reason for wanting a different amp, I'm a perpetual tweaker (I can't leave things alone; I'm sure many here have the same problem), so a great-sounding, low-cost DIY project is something I simply must do. :)
Having said all that, I want to come back to the "more headroom" idea. First question: is the extra headroom a function of the power supply, the amp, or both?
Second: I hooked a Kill-A-Watt AC power meter up to my QSC while listening at typical levels. It's only pulling about 60 Watts. I believe the QSC is a class AB amp, which have low efficiency, but let's assume that it's 100% efficient. That means I'm sending actually sending considerably less than 100W to my speakers. Realistically, I'm probably sending 30--50 Watts to the speakers.
That in mind, would I be well-served by an SDS-254 (rated at 250W @ 4 ohms)? Perhaps with an upgraded power supply and transformer? I should I hold out for Tom (at Class D Audio) to come out with something bigger? I've got a question about that in to him now---if he does have something bigger, should I get that instead?
Thanks!
Matt
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The SDS-254 will have no problem driving the Songtowers easily. I think its a fine combination.
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Second: I hooked a Kill-A-Watt AC power meter up to my QSC while listening at typical levels. It's only pulling about 60 Watts. I believe the QSC is a class AB amp, which have low efficiency, but let's assume that it's 100% efficient. That means I'm sending actually sending considerably less than 100W to my speakers. Realistically, I'm probably sending 30--50 Watts to the speakers.
The Kill A Watt meter does not have the speed to react to a peak transient on the order of milliseconds, nor does it have a peak hold function. Whatever your average power used is, a 10dB transient requires 10 times the power, even if it's only for 100 miliseconds, and that's where headroom comes into play.
Steve
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Matt, check out the SDS-470 from classD audio / Tom.
250 wpc @ 8 ohms.
I just started using one and what a diff over my SS 200 wpc amp.
Complete amp for 600+.
Neil
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Neil, does the SDS-470 also do 4 ohms since the Songtowers are 4 ohms, I believe. I know some of the Class D Audio amps do 4 ohms and some don't. Just checking... thanks!
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Neil, does the SDS-470 also do 4 ohms since the Songtowers are 4 ohms, I believe. I know some of the Class D Audio amps do 4 ohms and some don't. Just checking... thanks!
I have exchanged a few emails with Tom at Class D Audio regarding the SDS-470. He said, "[the SDS-470] will give you a very solid 500W RMS per channel into 4 ohms and can also put out up to 1000W RMS per channel into 2 ohms." He even sent me a picture of it:
(http://www.audiocircle.com/image.php?id=51851)
I went ahead and ordered one (a kit) today. :)
Matt, check out the SDS-470 from classD audio / Tom. 250 wpc @ 8 ohms.
I just started using one and what a diff over my SS 200 wpc amp.
Could you elaborate a bit more on your setup? What make/model of amp did you replace? What kind of speakers do you have? What about the source and preamp? Is your SDS-470 built from the stock kit, or did you do mods? And of course, we all love pics! :)
I think this will be a fun project!
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Neil, does the SDS-470 also do 4 ohms since the Songtowers are 4 ohms, I believe. I know some of the Class D Audio amps do 4 ohms and some don't. Just checking... thanks!
Hi Roy, looks like Matt answered your question.
Mine is a stock, complete amp from Tom. I believe it has a 500 VA trans.
It has more than enough power to drive my 92db OB7's.
Matt check your PM
Neil
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Maybe this is obvious to people who know way more about audio than I do, but the biggest improvement with a more powerful amp was how it sounded when I had the volume set to a low listening level.
If you put your kilowatt on the Class D amp, you will think you forgot to turn it on. :D That is part of the charm.
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I reply to Matt Garmann'
I am new here,and an audiophile located in south France.
I received three weeks ago one SDS470,which has been installed temporarily to replace my Ayon TritonII tubed amp which i sent to the mfr for a free of charge upgrading + a change of all tubes to "black treasure kt88" ones.
The SDS amp is fed by a Weiss DAC2 and connected to 2X Duntech Crown Prince speakers,impedance:4 ohms.
Its been a very big surprise to immediately face the fact the SDS is of the same league as the Triton for which concerns the global sound quality and transparency.
So surprising that two friends of mine,really golden eared audiophiles (and perfectionnists),when hearing the sound of my system with the SDS (they already heard the Triton),asked me to purchase for them to Tom 2x SDS,which i did last sunday....
The transparency and resolution are at least equal to those of the Triton,we can also hear that there is less harmonic2,which is easily understandable..in the medium-treble zone,the sound seems more "flat" means more natural,without any (small) presence proeminence,eliminating any fatigue when listening for a long time.
There are two other small differences:
-The extreme treble zone (15 to 20khz)although present,is a little "shy",which i had to compensate by reducing the linear capacitance of the interconnects and searching for all other compensations,which has been finally sucessfull.
-The bass and extreme bass area is extremely powerfull,a little bit more than with the Ayon...so I had to slightly reduce the section of the (+) cable feeding the boomers (i use bi-wiring) and slightly increase the number of litz wires feeding the medium- treble drivers.
Nota:changing the mains 220v cable modifies the level of low frequencies,a good compromise is easy to find out.
Testing the amp with the CD:"calle54 9 chico o'farill afro cuban jazz suite" is very impressive ,never heard it like that,you can be scared with the realism of percussions and ultra low frequency strokes.
500W on 4 ohm is well present on transients..but the low level information is neither erased nore even degraded..
Testing on "carreras domingo pavarotti en concert 16-17encore o sole mio,nessun dorma" is the best listening experience with my system,in spite of the fact this CD is very far from perfect,you can recognize the type of condenser microphones..
As a conclusion,the SDS is so resolving that any mod of any element of the system changes the colour of the sound,in particular the position of plugs,the digital cables,filtering the mains line of the CD/DAC,etc....
This is why the comments given about this amp could be controversial since for example it is used with high capacitance interconnects,the sound could be qualified of soft or round,if the speaker cables are not optimised,the sound is only "good" but not breathtaking,if your CD player is having jitter you will believe that the metallic harmonics are coming from the amp however not guilty for this frequent shortcoming....
The reason why,according to my own personal opinion,this SDS amp is a high-end one,is that it never limited me to search for a better sound by any mod of the system,I never heard a distortion which could be surely attributed to it,i never heard a loss of information(the silence of this amp is fully "black"),it is clearly worth being connected to other elements of the highest level .
The cables and interconnects must be chosen with care until obtaining an holographic image with a tremendous depth and wide scene,which needs less mediums and a little bit more extreme treble. Sincerely Mxt
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Maybe this is obvious to people who know way more about audio than I do, but the biggest improvement with a more powerful amp was how it sounded when I had the volume set to a low listening level.
If you put your kilowatt on the Class D amp, you will think you forgot to turn it on. :D That is part of the charm.
Nail on the head wgscott. :thumb:
The dynamics at low levels is amazing.
I have to look to make sure my sub woofer is off.
I rarely feel the need to use it with music anymore.
Neil
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^^^^^
To me, the easy way to control the power of your amp is use power console, like Belkin PureAV or Monster console, they can remote turn on your amp by your receiver.
My current power amp does not have a 12V trigger, so I use a Smart Strip Power Strip (http://www.amazon.com/Smart-Energy-Saving-Autoswitching-Technology/dp/B000P1QJXQ/), and my preamp is the "master". This is basically a poor man's 12V trigger. Works great for my current amp, and I don't see why it wouldn't work for the Class D Audio amps.
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I reply to Matt Garmann'
I am new here,and an audiophile located in south France.
I received three weeks ago one SDS470,which has been installed temporarily to replace my Ayon TritonII tubed amp which i sent to the mfr for a free of charge upgrading + a change of all tubes to "black treasure kt88" ones.
... snip ...
Thank you for that detailed account of your experience with the SDS-470. It has only made me more excited to receive mine!
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I just bought a CDA254 for my son to run with his Maverick DAC/Pre. I want to place it in this metal chassis-
http://www.par-metal.com/product-ttp-20series.php
Is there any thing special that I need to know about before I do this?
Has any one found a good round power button for the unit?
Will any of these work-
http://www.e-switch.com/product/tabid/96/productid/74/sename/pv3-series-illuminated-sealed-long-life-anti-vandal-switches/default.aspx
http://www.e-switch.com/product/tabid/96/productid/73/sename/pv2-series-water-resistant-long-life-anti-vandal-switches/default.aspx
http://www.e-switch.com/product/tabid/96/productid/77/sename/pv6-series-illuminated-sealed-long-life-anti-vandal-switches/default.aspx
Any help would be much appreciated.
Larry
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If you need to drill any holes into the aluminum, take it slow.
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For sheet metal
(http://www.buydrillbits.com/images/hss/CM1.125.gif)
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I just bought a CDA254 for my son to run with his Maverick DAC/Pre. I want to place it in this metal chassis-
http://www.par-metal.com/product-ttp-20series.php
Is there any thing special that I need to know about before I do this?
Has any one found a good round power button for the unit?
Larry
Larry, I like some of those, but isn't that site selling wholesale? Can you order one or two switches?
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Larry, I like some of those, but isn't that site selling wholesale? Can you order one or two switches?
The chassis can be bought from par metal but the power switch can be bought from Digikey or Future Electronics.
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Most of the switches you have been showing are momentary on or off style.
To make them work in your application you need something like this as well.
http://www.amb.org/audio/epsilon24/ (http://www.amb.org/audio/epsilon24/)
I used one of those style switches in a UCD amp I put together once.
JP
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I am pretty sure they make a version that is on-off.
But I am not sure if they will work, thats why I was posting here to get some opnions and help.
http://www.e-switch.com/product/tabid/96/productid/73/sename/pv2-series-water-resistant-long-life-anti-vandal-switches/default.aspx#
http://www.e-switch.com/product/tabid/96/productid/77/sename/pv6-series-illuminated-sealed-long-life-anti-vandal-switches/default.aspx#
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Hey guys, I'm sure glad I found this thread. I recently bought Tom's SDS-224 kit and have a couple questions. For some reason he seems to be hesitant to answer my emails regarding much needed product information. Hopefully you guys can shed some light on the situation.
Question 1. Looking at his transformer wiring diagram all the leads from the transformer are accounted for except for one lead which is purple. I can't find anywhere on his website that addresses this wire. I've heard from another person that it may be a chassis ground. Problem 1, I have an all wooden chassis. What do I do with this lead in this case?
Question 2. I have a very nice preamp, so is it possible to just not hook up the gain pots? Or are they required to complete a circuit of some sorts? In my opinion it'd be best to do all the volume attenuation with my preamp instead, but if I'm wrong and it's a necessity that these are connected, then it is what it is. I also have no idea how to wire these, as my kit came with zero paperwork besides for the transformer wiring diagram.
Question 3. Is there a certain type of LED's to use? It looks like it uses 4 molex connectors for external LED's. I don't mind using these, but could use an idea of exactly what I need these to be. Also, are these required to be used? Ideally I'd like to not have crazy bright LED's, and if again, I could just not hook them up I think it'd be the best solution.
I look forward to you guys' input.
Thanks,
StevenZ
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Steven welcome, that purple wire is a secondary and just gets taped off.
The pots have to be connected, you will find diagrams a few pages back.
Led's need not be connected.
Enjoy
Hey guys, I'm sure glad I found this thread. I recently bought Tom's SDS-224 kit and have a couple questions. For some reason he seems to be hesitant to answer my emails regarding much needed product information. Hopefully you guys can shed some light on the situation.
Question 1. Looking at his transformer wiring diagram all the leads from the transformer are accounted for except for one lead which is purple. I can't find anywhere on his website that addresses this wire. I've heard from another person that it may be a chassis ground. Problem 1, I have an all wooden chassis. What do I do with this lead in this case?
Question 2. I have a very nice preamp, so is it possible to just not hook up the gain pots? Or are they required to complete a circuit of some sorts? In my opinion it'd be best to do all the volume attenuation with my preamp instead, but if I'm wrong and it's a necessity that these are connected, then it is what it is. I also have no idea how to wire these, as my kit came with zero paperwork besides for the transformer wiring diagram.
Question 3. Is there a certain type of LED's to use? It looks like it uses 4 molex connectors for external LED's. I don't mind using these, but could use an idea of exactly what I need these to be. Also, are these required to be used? Ideally I'd like to not have crazy bright LED's, and if again, I could just not hook them up I think it'd be the best solution.
I look forward to you guys' input.
Thanks,
StevenZ
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Hey guys, I'm sure glad I found this thread...
Question 2. I have a very nice preamp, so is it possible to just not hook up the gain pots? Or are they required to complete a circuit of some sorts? In my opinion it'd be best to do all the volume attenuation with my preamp instead, but if I'm wrong and it's a necessity that these are connected, then it is what it is. I also have no idea how to wire these, as my kit came with zero paperwork besides for the transformer wiring diagram.
I look forward to you guys' input.
Thanks,
StevenZ
Steve,
Study this picture, and forget about the color of the wires, just STUDY the orientation of what goes where with the respect to the pot orientation and the Molex connector:
(http://i41.photobucket.com/albums/e257/praedet/DIY%20Audio/f5b2c7de.jpg)
You *can* replace the pot(s) with resistors, instructions on that is available here (http://www.audiocircle.com/index.php?topic=76400.msg980568#msg980568).
Anand.
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Thanks for the help guys. I got everything soldered up and ready to throw in the chassis. Regarding the purple wire, I just noticed that there is a standoff on the amplifier board that has an arrow pointing to it with the print "Chassis Ground" written near it. If the purple wire is indeed a chassis ground and this has chassis ground written on it, does it not make sense to connect the purple wire to this standoff?
I'm very excited to get this amp up and running. You guys are great, and I can tell this forum is a great place to learn and meet new people with the same passion.
Thanks!
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Thanks for the help guys. I got everything soldered up and ready to throw in the chassis. Regarding the purple wire, I just noticed that there is a standoff on the amplifier board that has an arrow pointing to it with the print "Chassis Ground" written near it. If the purple wire is indeed a chassis ground and this has chassis ground written on it, does it not make sense to connect the purple wire to this standoff?
I'm very excited to get this amp up and running. You guys are great, and I can tell this forum is a great place to learn and meet new people with the same passion.
Thanks!
No it is not a ground wire, Tom has said before that a ground isnt essential on these units. My unit is in a wood case without a ground. DO NOT connect the purple wire to chassis!!!
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StevenZ, welcome to AC.
Both Anand and Keith (Nick77) are trustworthy sources and have been down this road before. Just make certain to use the correct transformer green and blue secondaries for the power supply input or CT marked GND. Tom may have marked them for you. They are the two middle wires of the four.
All the best, and please post your impressions of the amp when you get it going. :D
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I am thinking about getting the SDS-470 for a pair of Dayton RS265HF sealed subs but need to know if they come with pots or are they fixed? I was looking at the picture on the previous page and it looked like they would use the pots. I need the pots to match the levels with my SDS-254 and tubed preamp and active cross over. I tried one 254 on the subs but they dont seem to have enough power and got pretty warm to the touch very quickly. Im running them with two Dayton SA240s and they go deeper and a lot louder but dont sound nearly as good as the SDS254 did. I think these subs are just very power hungry and need alot of head room. I also think the SDS-470 would probably be just right. Any one else using these subs?
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I am thinking about getting the SDS-470 for a pair of Dayton RS265HF sealed subs but need to know if they come with pots or are they fixed? I was looking at the picture on the previous page and it looked like they would use the pots. I need the pots to match the levels with my SDS-254 and tubed preamp and active cross over. I tried one 254 on the subs but they dont seem to have enough power and got pretty warm to the touch very quickly. Im running them with two Dayton SA240s and they go deeper and a lot louder but dont sound nearly as good as the SDS254 did. I think these subs are just very power hungry and need alot of head room. I also think the SDS-470 would probably be just right. Any one else using these subs?
I have the SDS-470. I haven't built it yet, but I can say for sure that it has the pots. If I'm not mistaken, all of the SDS series have the pots; I believe it's part of the upgraded feature list that commands the price increase over the CDA series.
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Thanks Matt, glad to here this and will be ordering one soon.
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Does the SDS-470 come with the transformer in kit form, I didnt see it mentioned on web site only heavy duty P/S? What size is it or should I order if it isnt part of the kit? Thanks
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I just received my used CDA-254 today and I want to add an external power switch. Does any one know if I have to hook up the LED lights or can I leave the holes in the circuit board empty?
Also, what external power switches are people using?
I have been looking at these listed below in the link but I do not know if they have the right specs. What amp rating do I need?Can I get some opinions?
http://www.e-switch.com/product/tabid/96/productid/77/sename/pv6-series-illuminated-sealed-long-life-anti-vandal-switches/default.aspx
http://www.e-switch.com/product/tabid/96/productid/73/sename/pv2-series-water-resistant-long-life-anti-vandal-switches/default.aspx#
Thanks for the help,
Larry
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Justinm - I think you can order the SDS-470 with or without transformer, but I would check out the completed build, it has a great value.
Lary - Are you got your used CDA-254 board only or what else?
Sorry, it's not clear on your question.
e-switch only rating for 2A 48V DC and need 2.8V DC for the LED.
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Trung, I bought a fully built CDA-254S in a wooden chassi. I am going to put it in this chassi-
http://www.par-metal.com/product-ttp-20series.php
One of the boards on the CDA-254 has connections to hook up an out board power switch- Scroll down to power switch connections in the link to the manual-
http://classdaudio.com/documents/35V_Manual.pdf
Will this power switch work-
http://www.e-switch.com/product/tabid/96/productid/150/sename/rra-series-round-illuminated-power-rocker-switches/default.aspx#
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Lary
If you use the remote switch on the main board, the E-Switch should be fine, but the LED won't work
See your PM
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Does the SDS-470 come with the transformer in kit form, I didnt see it mentioned on web site only heavy duty P/S? What size is it or should I order if it isnt part of the kit? Thanks
The website isn't updated, so it doesn't show the full SDS-470 kit (board + PSU + xformer). Just contact Tom directly via email and he'll give you instructions on how to order it. That's what I did.
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Steven welcome, that purple wire is a secondary and just gets taped off.
It is a ground wire, so you can ground it too. (Doesn't seem to make any difference.) It says this on the transformer, and I confirmed with Tom.
The pots have to be connected, you will find diagrams a few pages back.
or replaced with resistors (see previous posts).
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wgscott, so you're saying it's okay to connect the purple wire to the top lug on my IEC connector? If so, that's what I'll do.
So just a quick update, I pulled through last night and feverishly hooked everything up. Got it fired up by early morning and will leave it on for about 150 hours of burn-in. I have a serious concern. My amp is running pretty warm. I wouldn't say hot. I can hold my hand on the heat sink indefinitely BUT for being class D I was expecting it to run cool, or even ice cold. Am I wrong in thinking this way? Is everyone's amps running this warm? My amp isn't even playing music and it's this warm. Plus the top is off.
If you guys would like to see photos of my build as well as other speakers I've built please see my image hosting website. Szaiontz.imgur.com
As for me, I'll solder up that purple wire here in a few.
Thanks!
Steven
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My amp is running pretty warm. I wouldn't say hot. I can hold my hand on the heat sink indefinitely BUT for being class D I was expecting it to run cool, or even ice cold.
That would be normal. :wink:
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Steven
Like Nick said, it's warm.
Nice wood working skill. :thumb:
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mine isn't even warm.
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wgscott, so you're saying it's okay to connect the purple wire to the top lug on my IEC connector? If so, that's what I'll do.
So just a quick update, I pulled through last night and feverishly hooked everything up. Got it fired up by early morning and will leave it on for about 150 hours of burn-in. I have a serious concern. My amp is running pretty warm. I wouldn't say hot. I can hold my hand on the heat sink indefinitely BUT for being class D I was expecting it to run cool, or even ice cold. Am I wrong in thinking this way? Is everyone's amps running this warm? My amp isn't even playing music and it's this warm. Plus the top is off.
If you guys would like to see photos of my build as well as other speakers I've built please see my image hosting website. Szaiontz.imgur.com
As for me, I'll solder up that purple wire here in a few.
Thanks!
Steven
My SDS-254 runs a little warm after playing loudly for a while and got pretty hot when pushed with 10" 4ohm subs (Dayton RS265hf). This is why Im getting the SDS-470 for subs and using 254 on mains. However its always cold with out a signal through it after it cools down for a few minutes. Its not in a box yet either just an mdf board with spikes.
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Does any one know the power specs for the SDS 258, 450 and 480 at 4 ohms?
I am thinking about getting one of these amps to replace my Parasound A21 which is 400wpc at 4 ohms. I am wanting to stay in the same power range. My Magnepans really like the power and headroom of the A21. I am not sure if it will be a step up or not. I will pair it with my Van Alstine hybride preamp and hybrid DAC. I would like to buy one of the new AVA FET Valve 400R and 600R amps but at $3K and $3.5k they are out of my price range right now with paying for college tuition for 2 kids.
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Does any one know the power specs for the SDS 258, 450 and 480 at 4 ohms?
I am thinking about getting one of these amps to replace my Parasound A21 which is 400wpc at 4 ohms. I am wanting to stay in the same power range. My Magnepans really like the power and headroom of the A21. I am not sure if it will be a step up or not. I will pair it with my Van Alstine hybride preamp and hybrid DAC. I would like to buy one of the new AVA FET Valve 400R and 600R amps but at $3K and $3.5k they are out of my price range right now with paying for college tuition for 2 kids.
I think what you may want is the SDS-470. I just emailed Tom recently for specs on all these and the 470 seems to fit the high power low impedance requirements with 300 in 8ohms, 600 in 4, and 800 in 2. Ask Tom about how to order since the kit isnt listed right on the website yet. Hope this helps.
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I think what you may want is the SDS-470. I just emailed Tom recently for specs on all these and the 470 seems to fit the high power low impedance requirements with 300 in 8ohms, 600 in 4, and 800 in 2. Ask Tom about how to order since the kit isnt listed right on the website yet. Hope this helps.
Thanks! It's just what I am looking for. I wish Tom would update his site. It looks like the 470 would be the one. Plenty of power and judging by the specs you listed it looks like it would have plenty in reserve for dymanics. I bet it sounds great at low volume levels too.
I got to do an in home audition and review of the new AVA 600r amp and that was the best sounding amp I have heard at low volumes. It was very detailed. Turning it up just made it better.
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Thanks! It's just what I am looking for. I wish Tom would update his site. It looks like the 470 would be the one. Plenty of power and judging by the specs you listed it looks like it would have plenty in reserve for dymanics. I bet it sounds great at low volume levels too.
At the risk of confounding matters for you, I recently contacted Tom about the same thing and ended up settling on a pair of the SDS-450 amps. I think we are using the same speakers... Magnepan 1.6QR. Initially I though I'd start with a single SDS-470 even though it seemed like overkill (though that's never really the case with Maggies). But I wanted to keep the option open to go to a pair of amps for passive biamping or even mono blocks for more power.
Here's the response I got from Tom: If you're going to run the amps in bridge mode, I would recommend the SDS-450 kits. They also run cooler and can put about 1000W RMS into your Magnepans.
The different models got so confusing with regards to power and price I put together a chart clarifying this for myself, based on what info I could dig up from Tom's site and this thread. Here's what I came up with:
| Model | SDS-224 | SDS-254 | SDS-258 | SDS-450 | SDS-470 |
|
|
| Stereo watts | | | | | |
| 8 ohm | 60 | 125 | 250 | 150 | 300 |
| 4 ohm | 120 | 250 | -- | 300 | 600 |
| 2 ohm | -- | -- | -- | 600 | 800 |
|
|
| Mono watts | | | | | |
| 8 ohms | 240 | 500 | -- | 600* | 800* |
| 4 ohms | -- | -- | -- | 600* | 800* |
|
|
| Board $ | 235 | 245 | 265 | 245** | 265** |
|
|
| Kit $ w/xfmr | 285 | 320 | 370 | 350 | 370 |
* Note from Tom: As far as power output in bridge mode the protection circuitry will prevent the amps from putting out more power than they actually could. The SDS-450 will put out about 600W into 8 ohm bridged and about the same into 4 ohm… protection circuit. The SDS-470 is just more power at about 800W bridged.
** Not currently listed on website, temporary price as of today 10/17/2011 possibly until this weekend. Will go up about $40 when listed on website. If anyone wants one before they are listed on the website, purchase the SDS-254 or SDS-258 and email Tom with instructions to upgrade to the SDS-450 (for SDS-254 price) or SDS-470 (for SDS-258 price).
The SDS-480 kit ($468) and SDS-1000 kit ($498) are simply the 224 and 254 kits with two amp boards and a single HD power supply, respectively.
I will send a copy of this to Tom to see if he can verify these numbers and fill in the holes. I know it would make amp selection much easier if this was all available. Verified with notes added from Tom at Class D Audio
Oh, and I STILL have to assemble my amps and give them a try... maybe this weekend. :whip:
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Great chart kirkor! Thanks for that!
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That is a real helpful chart, thanks. Whish Toms website had something like this. I have been bugging him a lot lately about specs and just ordered a SDS-470 for 2 subs. Now I wonder what 2 470's bridged would put out for $40.00 more than the 450's and when bridged how stable they would be at 2-4 ohms?
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Got a quick response back from Tom and updated my previous post with the missing info for the SDS-450 and SDS-470.
If you are looking to buy just the 450 or 470 amp boards with a power supply, it looks like now would be good time to jump on them...
For right now (possibly until the weekend), I’m selling the SDS-450 for the same price as the SDS-254 and the SDS-470 for the same price as the SDS-258. When I have the time to get them listed on the website, the price of each will go up about $40.00. If anyone wants one before I list them on the website, they can purchase the SDS-254 or SDS-258 and email me to upgrade it to the SDS-450 (for SDS-254 price) or SDS-470 (for SDS-258 price).
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I just tried the CDA-254S in my reference system with my Magnepan 1.6's and Van Alstine hybrid preamp and DAC. Compared to my Parasound A21 amp the 254S lacked the deep bass, dynamics and treble resolution that the A21 has. Bass was tighter and better controlled. There 254 has a darker background, no grain and more air, transparency and wider sound stage. But the midrange was thinner and it needed more slam and power. I think that it may have better dynamics and bass with the 400va power transformer that the 254L has.
So now the question is, do I take a chance on an SDS-470? How do the SDS amps compare to the CDA amps in sound, bass, treble ?
Thanks,
Larry
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^^^^^
I think NeilT had try the CDA-254 and he has the SDS-470 now.
You may drop him a note. :wink:
To me big Transformer and PWR supply caps are important, more headroom and powerful bass.
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Snip...
So now the question is, do I take a chance on an SDS-470? How do the SDS amps compare to the CDA amps in sound, bass, treble ?
Thanks,
Larry
From my readings of this thread, for months now ;), the consensus seems to be that the SDS series is an improvement over the CDA series of boards.
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^^^^^
I think NeilT had try the CDA-254 and he has the SDS-470 now.
You may drop him a note. :wink:
To me big Transformer and PWR supply caps are important, more headroom and powerful bass.
I tried the cds 254, thanks again Trung, and then bought the 470. It seems, from memory, that the 470 does everything a little better than the 254. I really liked the 254, but for the obvious reasons went with the 470, headroom, power, prebuilt, and only around 600 shipped.
The bass is amazing, especially at low level listening. I barely use my servo sub anymore.
I hope this helps.
Neil
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Thanks Neil!
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I've got another dumb question. Is it okay for the power supply section of my amp to stay on all the time? For the last week all I've been doing is shutting down the amplifier board with my external switch (making the LED's yellow) while leaving the power supply board still powered up.
Is this the way it was intended to operate or should I shut both of them down every time I am not using the amp?
Thanks,
StevenZ
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Hi Guys...
My attempt to tri-amp my Klipschorns turned out to be very disappointing. The midrange sound was hollow/muddy. It has occurred to me that the BMS 4592ND-MID 16 ohm driver I'm using may be the problem. Is it true that the SDS-224 amp can have problems driving speakers over 8 ohms? If so, I may wire a 10 ohm resistor in parallel with the driver to bring the impedence down to around 6 ohms. Any comments?
Thanks, Mike
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I've got another dumb question. Is it okay for the power supply section of my amp to stay on all the time? For the last week all I've been doing is shutting down the amplifier board with my external switch (making the LED's yellow) while leaving the power supply board still powered up.
Is this the way it was intended to operate or should I shut both of them down every time I am not using the amp?
Thanks,
StevenZ
I leave my power supply on all the time, and only power up the active (output) section with the 'on/off' switch when I'm gonna listen, and I don't have any issues. The amp stays a bit warm though, so make sure you've got proper ventilation. Mine is an SDS amp.
Neil
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Thanks for the reply. Good to know. I keep the lid cracked on mine until I get a proper vent in there.
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StevenZ, did you get your amp going? What pre are you running in front of it? And, what speakers?
I've read plenty good things about the SDS amps series when properly implemented. Curious to hear your impressions.
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Is it true that the SDS-224 amp can have problems driving speakers over 8 ohms? If so, I may wire a 10 ohm resistor in parallel with the driver to bring the impedence down to around 6 ohms. Any comments?
Don't know if the SDS-224 has any problems driving 16 ohm loads, but if you put a resistor in parallel with the driver, the resistor would have to be a very large one with a power rating sufficient to dissipate the wattage. You would be dissipating more power in the resistor than the speaker driver, and in the resistor's case it would be 100% as heat.
Steve
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Don't know if the SDS-224 has any problems driving 16 ohm loads, but if you put a resistor in parallel with the driver, the resistor would have to be a very large one with a power rating sufficient to dissipate the wattage. You would be dissipating more power in the resistor than the speaker driver, and in the resistor's case it would be 100% as heat.
Steve
Thanks, Steve
The crossover currently installed (ALK Engineering) sounds really good with the amp, considering that it has to balance three drivers of varying impedance and sensitivity. The midrange is attenuated with an autotransformer, which also multiplies the 16 ohm driver impedance. A 10 watt/10 ohm "swamp resistor" in parallel brings down the impedance to approx 8 ohms. I just wondered if this was the issue.
Again, thanks for the reply.
Mike
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Hey guys I'm currently running an Audio-GD NFB12 DAC/Preamp with my SDS-224. They're powering a set of Mark Audio Alpair 7 Gen 3 drivers. My other set is a pair of 15" Hawthorne Audio Silver Iris coaxial drivers mounted open baffle. The amp/speaker/pre sounds fantastic. I honestly couldn't be more happy with the combination. Powerful preamp, powerful amp, and truly wonderful driver.
The Mark Audio full range drivers are amongst the finest I've ever heard. If anyone is considering building a set of full range speakers. Put these at the top of your list. They won't disappoint.
Cheers,
Steven
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Hey guys I'm currently running an Audio-GD NFB12 DAC/Preamp with my SDS-224...The Mark Audio full range drivers are amongst the finest I've ever heard. If anyone is considering building a set of full range speakers. Put these at the top of your list. They won't disappoint.
Hmmm.
I have a CDA-224 amp kit, and two EL70 (made by Mark Audio customized for CSS) 4" full range drivers just finishing break-in. I wonder what I should do with them :green:.
Seriously, thanks for the vote of confidence on the MA drivers sounding good with classD amps. I was waiting on a tube kit, but the vendor did not deliver. After that experience, more research and this thread led me to ordering the classD.
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Hey guys I'm currently running an Audio-GD NFB12 DAC/Preamp with my SDS-224. They're powering a set of Mark Audio Alpair 7 Gen 3 drivers. My other set is a pair of 15" Hawthorne Audio Silver Iris coaxial drivers mounted open baffle. The amp/speaker/pre sounds fantastic. I honestly couldn't be more happy with the combination. Powerful preamp, powerful amp, and truly wonderful driver.
Thanks for posting your impressions of the Class D amp along with your other gear. Glad you heard things are sounding good at your house. :D
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Absolutely. I couldn't be more thrilled at the way this amplifier sounds and how well it works with the Audio-GD NFB12 DAC/Pre. I fully believe that the Class D Audio amps need an active line stage to achieve their highest potential.
I'm now a huge supporter of Tom's amplifiers and will spread the word with whomever may be interested in building one. My only complaint is Tom's lack of customer service and the much needed updates on his website. A nicely put together manual would have been appreciated with the kit as well. With those things aside, I feel that his amps offer a great solution for those who crave a DIY build and demand a high performing, tonally accurate 2 channel listening experience.
Cheers to you guys who pick up where Tom leaves off.
-StevenZ
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Hmmm.
I have a CDA-224 amp kit, and two EL70 (made by Mark Audio customized for CSS) 4" full range drivers just finishing break-in. I wonder what I should do with them :green:.
Seriously, thanks for the vote of confidence on the MA drivers sounding good with classD amps. I was waiting on a tube kit, but the vendor did not deliver. After that experience, more research and this thread led me to ordering the classD.
I'm glad you're supporting Mark Audio drivers. I've got a couple builds under my belt using his drivers and each one of them has been a complete success. The provided "Pensil" cabinet plans are easy enough for anyone with minimal build experience to complete and will offer the best possible results.
Though they get docked a couple points for their lower sensitivity (when compared to other FR drivers), they gain them all back by actually having usable suspension travel for a lush bass response.
If you need any pointers or advice for speaker building feel free to PM me and I'll help where I can.
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What do you guys think would be an appropriate switch mode power supply (SMPS) for the SDS-470 in bridged mode? Perhaps something like this A1000SMPS from Connexelectronic (http://connexelectronic.com/product_info.php/cPath/25_46/products_id/110)? I'm thinking about building a pair of 800 Watt (at 4 Ohms) monoblocks with the SDS-470 board. I'd like to use a SMPS to reduce size and weight. Plus, I seem to recall at least one person reported success using Connexelectronic switch mode power supplies earlier in this thread.
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Hey Matt, send a PM to Wushuliu (Ainsley) or poseidonsvoice (Anand.) I'm certain that either of them can answer your questions about the SMPS. Or, maybe they will answer in a post. Just two of many here on AC that have the experience and knowledge to help you.
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I'm pretty sure you could ask Christi of Connex too.
That sounds like a bad a__ project. Be sure to post pictures.
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I am using a Connex 500 SMPS with one of the smaller SDS amps, and it works beautifully. it is light weight, a no-brainer to hook up, and sounds no different to me than the linear supply that I originally had with my amp (and sold to a work colleague). It is quiet (no hum, buzz, etc) and doesn't seem to radiate any untoward noise even though it is placed immediately next to the amp board in the chassis. The only down side to using the Connex supplies is the wait to get one (mine took about 30 days from order to delivery here in the USA). Seems to me that the A1000 would be a perfect match for the SDS 470.
Neil
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I am curious and want to know, how many people have have had amps that cost over $2200 and have replaced them with these SDS-amps? And what amps did they replace?
What do they like about the SDS-amps better than the amp that they replaced.
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I am using a Connex 500 SMPS with one of the smaller SDS amps, and it works beautifully. it is light weight, a no-brainer to hook up, and sounds no different to me than the linear supply that I originally had with my amp (and sold to a work colleague). It is quiet (no hum, buzz, etc) and doesn't seem to radiate any untoward noise even though it is placed immediately next to the amp board in the chassis. The only down side to using the Connex supplies is the wait to get one (mine took about 30 days from order to delivery here in the USA). Seems to me that the A1000 would be a perfect match for the SDS 470.
Awesome! Did you happen to measure power consumption with the SMPS?
Switch-mode power supplies are supposed to be more efficient, right? That is one of my big goals with giving these amps a try: getting speaker power on par with my QSC, but with lower AC power.
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What do you guys think would be an appropriate switch mode power supply (SMPS) for the SDS-470 in bridged mode? Perhaps something like this A1000SMPS from Connexelectronic (http://connexelectronic.com/product_info.php/cPath/25_46/products_id/110)? I'm thinking about building a pair of 800 Watt (at 4 Ohms) monoblocks with the SDS-470 board. I'd like to use a SMPS to reduce size and weight. Plus, I seem to recall at least one person reported success using Connexelectronic switch mode power supplies earlier in this thread.
To be honest out of 143 pages only several people have imployed the smps.
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Hi,
I'd like to get your feedback about classdaudio power amps.
Did someone has compared to Wyred power amps (B&O modules) ?
I'm looking for the MC model here http://classdaudio.com/products/complete-amplifiers-1/complete-6-channel-amp.html
I've sent an email to Tom and waiting for him to answer my questions.
Are SDS-258 best modules from the brand ? I need it to manage both 4 Ohm and 8 Ohm speakers.
Not sure this module can deal with 4 Ohm impedance.
Do you know if we can adjust the gain with a dial (for each chanel outptut) ?
Regards.
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Are SDS-258...I need it to manage both 4 Ohm and 8 Ohm speakers.
Not sure this module can deal with 4 Ohm impedance.
Do you know if we can adjust the gain with a dial (for each chanel outptut) ?
http://classdaudio.com/sds-258.html
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Awesome! Did you happen to measure power consumption with the SMPS?
Switch-mode power supplies are supposed to be more efficient, right? That is one of my big goals with giving these amps a try: getting speaker power on par with my QSC, but with lower AC power.
I did not measure the power consumption of the SMPS. I checked the output voltage and adjusted it down just a wee bit, but never checked to see how much power it draws. Part of why I switched to an SMPS was to take advantage of the efficiency of both it and the Class D amp module... and I am just assuming Christi has been accurate and truthful about the efficiency of the SMPS.
Neil
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I finally completed my SDS-470 kit build this past weekend. I thought I'd post my initial impressions.
First: on the first test, I powered it on, but got no sound. I noticed the on-board LEDs indicated "Left Off" and "Right Off". The power supply lights were on. I used my DMM, and verified that I had DC going to the amp board. Nothing changed on the preamp side, and the music was playing. I was about to come here to ask for help when I noticed the little built-in "on/off" switch on the side/bottom of the amp board! I switched it on, and I got music! Classic ID-10-T error on my part. :)
Anyway: config is as follows: FLAC files (from CD rips) on computer, optically connected to Emotiva XDA-1 preamp/DAC, to power amp via XLR, to Salk Songtower speakers. Original power amp was a QSC RMX2450 "pro" amp; new amp is obviously the SDS-470 kit.
This are my initial impressions only, since I've only been able to listen to music for 20--30 minutes at a time over the last few days. So far, it seems to me about the same as the QSC. And that's not a bad thing! I was completely happy with the sound quality of the QSC. My goals for the SDS470 were (1) lower power consumption; (2) same (or improved) sound quality; and (3) have fun. Going by those three criteria, this was a complete success.
On the power consumption front, I'm using an AC Watt meter (Kill-A-Watt). The SDS470 seems to pull about 22 Watts, both at idle (no music) and typical listening levels. I haven't really cranked it up yet. Compared to the QSC, which pulled 40--60 Watts between idle and music. A definite improvement in power usage. As I suggested above, I'd like to get a switch-mode power supply (SMPS) to see if I can further reduce idle power consumption.
Regarding the "have fun" thing: I definitely enjoyed the electronics aspect of this. But I didn't particularly enjoy working on the case. I bought an aluminum Par-Metal case on Ebay. If I go forward with the dual bridged sds470 monoblock project, I think I'll just bite the bullet and pay for professionally machined and finished enclosures. I even went bare-minimum on my design: combined fuse+IEC, no power switch, two XLR inputs and four speaker binding posts. For a future build, I'd like to have two switches (mains power and amp board power), separate IEC and fuse holder, plus all kinds of LEDs. I just don't have the patience for all that drilling and cleanup.
Anyway, as for the sound quality discussion (what everyone is probably most interested in). On the very first listen, as I mentioned briefly above, I really couldn't tell much difference between the SDS470 and the RMX2450. On a few rare occasions, I thought I've heard a little bit of sibilance... but lately, I haven't heard that. Not sure if I imagined it or not. Also: depending on the input gain setting of the pots, I can hear a very faint hiss coming from the speakers when my ears are a few inches away or less (and there is no music playing). Adjusting the gain fixes this though.
I don't know if my ears are getting used to the unit, or it's being "broken in" (a concept I'm not sure I really believe in anyway), but last night I felt like the amp had a little different "character" from the QSC. Is it better? Maybe. It does sound great, there is no doubt about that. I'm just not sure if the difference is all in my head or not. It's too annoying to keep switching between the two amps, so I try to just go from memory (I'll be the first to admit I have an awful memory :) ). But last night, I thought I was experiencing a bit of what I've read so much about on this thread, particularly increased instrument separation and a bigger soundstage.
Ultimately, I just need to spend more time with it. But so far so good. Next step I believe is to give a SMPS a try. If that proves successful, then I might move forward with the monoblock idea. At a minimum, I would spring for a professionally machined and finished enclosure.
I'll try to find some time to post pics.
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I even went bare-minimum on my design: combined fuse+IEC, no power switch, two XLR inputs and four speaker binding posts.
Hey Matt, are you running a fully balance system? There is no mention of SE rca inputs. If the SDS-470 sounds no different than a QSC pro amp, I doubt this thread would be almost 150 pages. Not sure what's holding it back. :scratch:
Glad you're having fun.
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I even went bare-minimum on my design: combined fuse+IEC, no power switch, two XLR inputs and four speaker binding posts.
Hey Matt, are you running a fully balance system? There is no mention of SE rca inputs. If the SDS-470 sounds no different than a QSC pro amp, I doubt this thread would be almost 150 pages. Not sure what's holding it back. :scratch:
Yes, the Emotiva XDA-1 has both fully balanced XLR outputs and single-ended RCA outputs. I'm using the former.
Regarding the suggestion that the SDS-470 sound quality is similar to the QSC: I didn't mean this as a slight in any way. In fact, I meant quite the opposite. I know there is a debate as to whether or not pro amps can compete with "audiophile" amps. I personally think they can. (And there is no debate that, strictly in terms of watts per dollar, pro amps always win. This is the cheap and cheerful forum, after all. :)) That's a long-winded way of saying I do believe that the QSC sounds excellent. So to say the SDS-470 is on equal footing is---coming from me---a major compliment.
Having said all that, keep in mind, those were my initial impressions only. Time spent with the amp thus far is minimal (relative to the QSC). And as of last night, I think I'm starting to pick up on the nuances between the two amps.
To elaborate on the "cheap and cheerful" point: on this consideration, I think a pro amp is a perfect comparison to the Class D Audio amps. That is, both are trying to "cheat the system", so to speak; both try to get audiophile quality at a lower price point. To get an "audiophile" amp that is comparable in terms of wattage to the QSC or CDA, you'd have to spend at least $1.5k, probably more like $2k.
Anyway, I've always lingered in the "super cheap" category; only this year have I really started to make inroads into what would probably be called the "mid-fi" category. The only dramatic improvement I've ever seen with a component switch is when I replaced Energy RC-30 speakers with the Salk Songtowers.
Glad you're having fun.
Absolutely! Just to reiterate: I don't want to give anyone the wrong impression, I think the SDS-470 is great.
It's entirely possible that I just have unrefined hearing. :)
p.s. I can't help but argue the pro amp thing a little bit: using thread length as an indication of how good an amp is, then pro amps in general are good according to this 160 page AVSForum thread (http://www.avsforum.com/avs-vb/showthread.php?t=418666&page=160).
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Matt, appreciate your additional remarks and impressions. Everyone needs to keep in mind that audio is a very subjective hobby. If you're pleased with the sound, that's all that matters. :D
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I should also add that my room and overall setup/positioning leaves a lot to be desired. I don't have a dedicated listening room---it's just our living room. And it's a massive "great" room, all hardwood floors. We have one rug, and minimal window dressings, but no other sound-specific treatments. Here's a link to a schematic of our floor plan (http://raw-sewage.net/images/floor_plan.png). Look at the lower-left where the "media console" is; the speakers flank either sides of this. As you can see, it's a corner placement, generally considered a no-no for good 2-channel sound. Also, the speakers are fairly close together, especially when the distance to any possible listening position is taken into account. Given all these constraints, I think there is a definite ceiling to how good any component can sound. What that limit is, I can't say, but I'm sure it exists.
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Matt I do not feel you need to make excuses for your comments about ClassD Audio products. I got blasted for not jumping on the band wagon. My ClassD amp has been junked and I am using the PS for something else.
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Matt I do not feel you need to make excuses for your comments about ClassD Audio products. I got blasted for not jumping on the band wagon. My ClassD amp has been junked and I am using the PS for something else.
because out of 144 pages there are only a handful of people who did not like their amps and a few also needed some component matching to get the best from theirs, so maybe 'blasted' should read 'non-stop suggestions', for which this thread is indeed guilty.
Wow. Junked. I assume it's broken. If not, what a shame. I'm sure someone else could have a use for it.
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No offense Pelliot, but why is it necessary to beat a dead horse?
You have notoriously difficult speakers to drive and you bought the wrong amp to drive those speakers. This has been said to you repeatedly. You clearly have a mismatch of components and at the very least you should listen to the amplifier with a buffer in place before making silly remarks about jumping on the bandwagon. There are some very generous members on Audiocircle that I'm sure would be willing to lend you a buffer to try out. I would lend you mine if it wasn't integrated with my LDR. If it's too much work then just sell the kit and move on.
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No offense Pelliot, but why is it necessary to beat a dead horse?
You have notoriously difficult speakers to drive and you bought the wrong amp to drive those speakers.
Irrespective of the reason for amp not sounding up to the expectation, I agree to what has been highlighted.
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Hey guys, I've got a quick question for y'all. Last night I took my SDS-224 over to a friends house to listen on his Usher TOTL speak.ers (not the diamond or BE dome, the older model silk dome). So we popped in some Nat King Cole and cranked it up. Keep in mind his speaker's nominal impedance is 8 ohms, which according to my amp's power chart cranks out 60 watts per channel. Now, another thing about his speakers, they're 90db efficient. So back on track, we're listening to it, and things are sounding fantastic, then all of a sudden I notice the right channel cutting in and out. Just the right channel, so I walk up, crack the top off the amp and notice that the right channel is dropping out and the yellow LED's are lighting up, then switching back to blue. I touch the heat sink to see if maybe it's overheating, dead cold. What was happening? Was I just driving the amp too hard? I didn't hear any noticeable distortion at all. In fact it was the best I've ever heard the amp sound. Can someone tell me what was going on with my amp?
Just a little bit more information, he was providing a signal to the amp with a Naim preamp, and a Sony XA5400es. Great equipment, though with the gains set exactly alike, how could it be that one channel was dropping out constantly? I rechecked all connections and everything is solid. What am I missing?
-Steven
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Either call or email Tom at Class D Audio about the problem. I'm not sure what's going on. I don't recall reading about that particular issue. Let us know the outcome. Thanks.
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Steven
Yellow light on one channel - Check out the DC voltage from the PWR supply board to main board, +/- voltage.
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Either call or email Tom at Class D Audio about the problem. I'm not sure what's going on. I don't recall reading about that particular issue. Let us know the outcome. Thanks.
I was thinking the same thing but also wonder what power supply you have.
What gauge wire are you using??
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I have the power supply that came with the kit. I just sent Tom an email regarding this problem. I have the same AWG wiring as the transformer uses going to the amp board. Should I use a larger more robust wire? Also, I haven't checked any values as I don't have a DMM. I feel I must mention this, now since you guys suspect a power supply problem. When I power down the power supply, one set of LED's goes off long before the other set. Would it be safe to assume that the set that goes off quicker is the right channel, the channel that's giving me grief?
I hope Tom replies. My last request for help sent to him went unanswered. I hope he doesn't disregard this one and actually answers me back. I left him my phone number as well just in case that's his preferred method of contact. I really love the amp, but perhaps I got a dud power supply and/or amp board. We'll see how this pans.
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I use a high quality 16awg solid core wire twisted into a double run for wireing each post. Dont want any bottlenecks. :wink:
Yours comes with the larger ps, thats a good thing. My SDS254 has 60k capacitance and sounds really good, never had any issues.
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I had same problem with my battery powered Dodd class d. Tom said low voltage cut off was set to high. I sent amp to Tom who readjusted to lower voltage and it worked fine after that.
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Hi Steven...
I had the same issue when I moved my temporary setup to a more permanent one. I ended up using spade connectors to and from the power supply, started it back up, and haven't had the issue since. I too thought all the "tinned" bare wire connections were solid, but I wonder if the spade connectors are the key (?).
Mike
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all of a sudden I notice the right channel cutting in and out. Just the right channel, so I walk up, crack the top off the amp and notice that the right channel is dropping out and the yellow LED's are lighting up, then switching back to blue. I touch the heat sink to see if maybe it's overheating, dead cold.
What a coincidence!! When I paired the amp with an old NAD1020A Pre-amp, the same thing happened to me all the three times I tried playing it. The pre-amp was not at fault as it played fine with another power amp I played it with. The heatsink doesn't appear to have been overheated. It remains just warm.
That's when I decided to put it on the attic.
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Rajesh, I won't jump to conclusions. Anything could be the problem. What I'll do is run double wiring from the PS to the Amp board to eliminate the possibility that there's any bottle-necking going on regarding current supply. I talked with Tom earlier today and he said that he won't know without looking at the actual unit. He wants me to send it back to him next week so he can evaluate it in person. He guaranteed me that everything will get worked out.
His reply was very quick and I feel confident he will take care of the situation one way or another. I'll also take more precautions and solder up some larger AWG wiring to the speaker terminals as well.
I'll keep you guys posted.
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I wish Tom focused more on the customer service, even if it meant fewer amp choices (I think there are too many and too little info provided about each at this point).
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Rajesh, I won't jump to conclusions. Anything could be the problem.
Actually StevenZ, my post was a supplementary to my earlier posts which, I've linked below:-
1. http://www.audiocircle.com/index.php?topic=76400.msg931340#msg931340
2. http://www.audiocircle.com/index.php?topic=76400.msg936492#msg936492
3. http://www.audiocircle.com/index.php?topic=76400.msg936546#msg936546
4. http://www.audiocircle.com/index.php?topic=76400.msg936676#msg936676
5. http://www.audiocircle.com/index.php?topic=76400.msg936868#msg936868
What I'll do is run double wiring from the PS to the Amp board to eliminate the possibility that there's any bottle-necking going on regarding current supply.
OK, fair suggestion. I'll take it out from the attic and test it again. First through a potentiometer and later through a tube pre-amp. Will post the results here.
I talked with Tom earlier today and he said that he won't know without looking at the actual unit. He wants me to send it back to him next week so he can evaluate it in person. He guaranteed me that everything will get worked out.
His reply was very quick and I feel confident he will take care of the situation one way or another.
You are lucky is all that I can say. Probably my bad luck that I'm located so far away. He didn't bother to reply to my mail regarding the heating problem (of which I had reported in one of my earlier posts linked above) So I decided not to bother him ever again. :(
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I finally completed my SDS-470 kit build this past weekend. I thought I'd post my initial impressions.
First: on the first test, I powered it on, but got no sound. I noticed the on-board LEDs indicated "Left Off" and "Right Off". The power supply lights were on. I used my DMM, and verified that I had DC going to the amp board. Nothing changed on the preamp side, and the music was playing. I was about to come here to ask for help when I noticed the little built-in "on/off" switch on the side/bottom of the amp board! I switched it on, and I got music! Classic ID-10-T error on my part. :)
Anyway, as for the sound quality discussion (what everyone is probably most interested in). On the very first listen, as I mentioned briefly above, I really couldn't tell much difference between the SDS470 and the RMX2450. On a few rare occasions, I thought I've heard a little bit of sibilance... but lately, I haven't heard that. Not sure if I imagined it or not. Also: depending on the input gain setting of the pots, I can hear a very faint hiss coming from the speakers when my ears are a few inches away or less (and there is no music playing). Adjusting the gain fixes this though.
I don't know if my ears are getting used to the unit, or it's being "broken in" (a concept I'm not sure I really believe in anyway), but last night I felt like the amp had a little different "character" from the QSC. Is it better? Maybe. It does sound great, there is no doubt about that. I'm just not sure if the difference is all in my head or not. It's too annoying to keep switching between the two amps, so I try to just go from memory (I'll be the first to admit I have an awful memory :) ). But last night, I thought I was experiencing a bit of what I've read so much about on this thread, particularly increased instrument separation and a bigger soundstage.
Ultimately, I just need to spend more time with it. But so far so good. Next step I believe is to give a SMPS a try. If that proves successful, then I might move forward with the monoblock idea. At a minimum, I would spring for a professionally machined and finished enclosure.
I'll try to find some time to post pics.
Actually, your next little project should be the elimination of the two pots, in favor of two 1% resistors. You might see what your QSC is. If the standard for the QSC is 27DB, then if memory serves me right a 1.2? resistor for each channel should make a difference. Several pages back there is a chart with the correct resistor ratings to use. The pots Tom uses are cheap, and replacing them fixed with resistors will have a dusk and night result, that you might be able to hear. Just a suggestion or two.
If you put/mounted those pots in your case, a search on the net you can find caps to cover the holes they made.
Ray Bronk
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Actually, your next little project should be the elimination of the two pots, in favor of two 1% resistors. You might see what your QSC is. If the standard for the QSC is 27DB, then if memory serves me right a 1.2? resistor for each channel should make a difference. Several pages back there is a chart with the correct resistor ratings to use. The pots Tom uses are cheap, and replacing them fixed with resistors will have a dusk and night result, that you might be able to hear. Just a suggestion or two.
If you put/mounted those pots in your case, a search on the net you can find caps to cover the holes they made.
Yup, I've been planning to use fixed resistors in place of the pots all along. I just wanted to use the pots initially to experiment/dial in the right amount of gain. (Before I bought the kit, I read through this entire thread, taking notes. One of the things I noted was the gain versus resistance table you mentioned. :))
Also, for anyone who's interested, I asked Tom for a switch mode power supply (SMPS) suggestion for the SDS-470. He replied with this link: ConnexElectronic SMPS800R (http://connexelectronic.com/product_info.php/products_id/124?osCsid=rfn0ot5lrfqk32glq8tngvlib0). He said, "Make sure the voltage is +/- 65 to 68 volts."
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Also: is Front Panel Express (FPE) the only option for obtaining a professionally-machined custom enclosure? I don't have the skill (or the patience) to make a nice custom case. What I'd like is a powder-coated matte black steel case, complete with vent holes. On the front, I'd like to have to big rocker switches (mains power and amp on/off) and LED cutouts. On the back, IEC, fuse holder, XLR and binding posts. Just wondering if FPE is the only game in town.
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I built another SDS-258 a couple of months ago and utilized a Par Metal desktop case I had on hand. I had it powder coated in satin black. For the front panel I used 1/4" black laser cut acrylic with very subtle rounded corners. Total cost including the enclosure was $110. It looks the business and I'm very satisfied with how it turned out. That said, it was a pain in the butt to drill and cut the openings in the rear panel. If I had to do it again I would order one of the cases from mudushop or vt4c. Much less muss and fuss.
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I have a few questions for some of the experts out there. I just got my SDS470 a couple weeks a go and want to use it with my SDS254. I plan on putting them both in the same case. I also would like like to separate the transformers and maybe power supplies in a separate case below all hooked up with 2 neutrik powercon connectors. My questions are about cable length. 1st witch wire run should be shorter for best sound, power supply to amp board or transformer to power supply? 2nd would it be better to keep the transformers in there own case away from the other boards? 3rd which wire run should be shorter speaker binding posts or rca's? 4th does transformer and power supply need any type of ventilation like vent holes. Thanks for any suggestions you can make.
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Also: is Front Panel Express (FPE) the only option for obtaining a professionally-machined custom enclosure? I don't have the skill (or the patience) to make a nice custom case. What I'd like is a powder-coated matte black steel case, complete with vent holes. On the front, I'd like to have to big rocker switches (mains power and amp on/off) and LED cutouts. On the back, IEC, fuse holder, XLR and binding posts. Just wondering if FPE is the only game in town.
Matt, Par Metal will punch all the cut outs for you. I'm not sure about the cost but the cases will be cheaper and come already vented. I am going to order one this week. 12x12x5
http://www.par-metal.com/product-ttp-20series.php
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Here are a couple pics I promised:
(http://www.audiocircle.com/image.php?id=53491)
(http://www.audiocircle.com/image.php?id=53492)
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Here are a couple pics I promised:
(http://www.audiocircle.com/image.php?id=53491)
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That looks great; congrats.
So is that the SDS-470? Pardon but I'm a bit out of touch on this thread, (now so long!), but I'm confused about what a 470 actually consists of. From the picture, it strongly resembles an SDS-258, (like I have), with a larger heat sink. Is that appendage under the module also more heat sink or something else? Looks like a standard High Duty power supply; does it ushigherer voltage and/or higher powetransformerer?
(With due respect to Tom, the website does leave something to be desired in terms of technical info -- I'd suggest that he would spare him spare himself quite a few repetitive questions if he put a little more info on the site.)
This is a pic of my SDS-258 in home-made, MDF case -- with benefit of hindsight I wish I'd gone for a Par-Metal. Note that I've made use of the Status LEDs and the Stand-by switch.
(http://gallery.audioreview.com/data/audio//500/DSCN0799-X1.jpg)
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That looks great; congrats.
Thanks!
So is that the SDS-470? Pardon but I'm a bit out of touch on this thread, (now so long!), but I'm confused about what a 470 actually consists of. From the picture, it strongly resembles an SDS-258, (like I have), with a larger heat sink. Is that appendage under the module also more heat sink or something else? Looks like a standard High Duty power supply; does it ushigherer voltage and/or higher powetransformerer?
Yes, that is the SDS-470. Currently it's set up to run in stereo mode, which is advertised at 600 Watts/Channel at 4 Ohms. (I'm toying with the idea of building a second, and running both bridged---i.e., monoblocks. Supposed to do 800 Watts at 4 Ohms bridged.)
It's the only Class D Audio board I've worked with, but I'm pretty sure it's virtually the same as the SDS-258, except with the added heatsink (and electrical differences of course). Yes, the appendage on the underside is additional heatsink. There are actually two additional, one on each side. (If you go back to page 140, I posted a stock photo of the 470 that Tom sent me (http://www.audiocircle.com/index.php?topic=76400.msg996742#msg996742). There you can see the added heatsinks a little more clearly.)
I forget exactly what model xformer I got (at work now, can't check).
(With due respect to Tom, the website does leave something to be desired in terms of technical info -- I'd suggest that he would spare him spare himself quite a few repetitive questions if he put a little more info on the site.)
Hate to say it, but I agree. This comment seems to be a fairly common theme throughout this thread.
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Yes, that is the SDS-470. Currently it's set up to run in stereo mode, which is advertised at 600 Watts/Channel at 4 Ohms. (I'm toying with the idea of building a second, and running both bridged---i.e., monoblocks. Supposed to do 800 Watts at 4 Ohms bridged.)
It's the only Class D Audio board I've worked with, but I'm pretty sure it's virtually the same as the SDS-258, except with the added heatsink (and electrical differences of course). Yes, the appendage on the underside is additional heatsink. There are actually two additional, one on each side. (If you go back to page 140, I posted a stock photo of the 470 that Tom sent me (http://www.audiocircle.com/index.php?topic=76400.msg996742#msg996742). There you can see the added heatsinks a little more clearly.)
I forget exactly what model xformer I got (at work now, can't check).
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Thanks for the info. The SDS-470 shows six transistors rather than the four on the 258, plus the much larger heat sink.
If you get around to it, I'd like to know if transformer is the same as for the 258 or if it's higher output (which would make sense). As I recall, my 258 gets +/- 64 VDC from the power supply which implies a 45 volt transformer (as I understand).
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As I recall, my 258 gets +/- 64 VDC from the power supply which implies a 45 volt transformer (as I understand).
I'm following this thread with interest, and I may be off with regards to my understanding about this class of amps. But if you were using a linear supply and trying to get +/- 64 VDC, it seems to me that you would need slightly more than 45 volts. I'm thinking something more like a 90V center tapped secondary. 2 x 45V. And maybe even just a bit more than that if you figure in losses and voltage drops.
(http://www.audiocircle.com/image.php?id=53527)
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But if you were using a linear supply and trying to get +/- 64 VDC, it seems to me that you would need slightly more than 45 volts. I'm thinking something more like a 90V center tapped secondary. 2 x 45V. And maybe even just a bit more than that if you figure in losses and voltage drops.
The linear power supplies for these amps use a toroidal transformer with dual secondaries (not center tapped), and when someone like Antek calls it a "45V transformer", dual secondaries are usually implied.
The voltage range for the SDS-258 is +/- 60VDC to +/- 70VDC. I like to have a little safety margin, so 64VDC is right in the middle of the range (with a 45VAC X2 transformer)
Using Antek as an example, the next higher voltage transformer is 48V which would give an ~ 68VDC rectified output, but is only available in 800VA and 1000VA. The next available voltage, 50V, would give an ~ 71VDC rectified output.
As far as voltage drops and losses, I don't know if they would be more than a volt or so. Anyone measured their final DC output with a multimeter?
Steve
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The linear power supplies for these amps use a toroidal transformer with dual secondaries (not center tapped), and when someone like Antek calls it a "45V transformer", dual secondaries are usually implied.
The voltage range for the SDS-258 is +/- 60VDC to +/- 70VDC. I like to have a little safety margin, so 64VDC is right in the middle of the range (with a 45VAC X2 transformer)
Using Antek as an example, the next higher voltage transformer is 48V which would give an ~ 68VDC rectified output, but is only available in 800VA and 1000VA. The next available voltage, 50V, would give an ~ 71VDC rectified output.
As far as voltage drops and losses, I don't know if they would be more than a volt or so. Anyone measured their final DC output with a multimeter?
Steve
Thanks for explaining it to me.
You do get a small voltage drop from the rectifier(s). High speed rectifiers have less of a forward voltage drop, which is a good reason to use them. Your final filtered voltage will also drop depending upon the load.
If the transformer has dual identical secondaries and you tie them together in series, you can use the tie point as a center tap. The transformers in the pic I took (above) have four wires (dual) secondaries, which became a center tap when tied together.
(http://www.audiocircle.com/image.php?id=53532)
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My first classd amp kit should be here this week. I got the CDA-1000 kit with an extra CDA-254 board and larger transformer to power all 3 boards for my active 3-way speakers.
I have a couple questions:
1) This is a budget build so I will be using leftover MDF to mount them on. I tried to search for "Ground" but the search doesn't work to well here. What is the proper grounding procedure?
2) I will be plugging this into a smart strip. The power to the power strip comes on with the receiver. I am assuming I don't need to put in a switch since the strip will be turning it on and off. No power goes to the strip when the receiver is off.
Is that OK?
Sorry for the nube questions, this is my first amp build.
Also thanks to everyone here, without this thread I really wouldn't know much about classDaudio.
Thanks
Moto
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2) I will be plugging this into a smart strip. The power to the power strip comes on with the receiver. I am assuming I don't need to put in a switch since the strip will be turning it on and off. No power goes to the strip when the receiver is off.
Is that OK?
I asked Tom (of Class D Audio) about this, and he gave it the OK. I'm doing exactly this: I leave the switch on the SDS board to the "on" position, and didn't install any kind of mains switch. I've only been using my build for a couple weeks, but it gets turned on and off at least once/day, and no problems so far!
I love the smart strip as a poor man's trigger. Before the Class D Audio amp, I was using a QSC "pro" power amp with no trigger. I used it for many months with the smart strip and had zero issues.
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Thanks Matt.
I may ground mine as was done on page 90. But apparently it isn't necessary as best as I can figure.
Moto
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Shot of the SDS-450 amp board.
(http://www.audiocircle.com/image.php?id=53584)
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Guys, a friend of mine said it was a horrible idea for me to build the amplifier in a wooden box and that it's most likely spraying RF frequencies into all of my other equipment. Can anyone confirm this? I'd hate to rebuild the enclosure. In all honesty I haven't noticed any shortcomings so perhaps he is incorrect.
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In all honesty I haven't noticed any shortcomings so perhaps he is incorrect.
That makes two of us........
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The OP, Steve K, built his into a wood enclosure which you can see on the first page of this thread and elsewhere. Very nice job I might add. Many others have done the same with no issues I'm aware of. :D
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Guys, a friend of mine said it was a horrible idea for me to build the amplifier in a wooden box and that it's most likely spraying RF frequencies into all of my other equipment. Can anyone confirm this? I'd hate to rebuild the enclosure. In all honesty I haven't noticed any shortcomings so perhaps he is incorrect.
I recently bought a CDA-254 in a wooden box and I cannot use my tuner with it due to the RFI. I am placing it in a Par Metal chassi which should take care of the problem. If not, then I will need to buy some 3M copper shielding tape and line the chassi.
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After several weeks of using the SDS-470, I'm all but convinced it's a keeper. I have an SMPS800R on order from Connex; I'm excited to see what this does for power consumption/efficiency.
My only concern now is that I sometimes hear a "pop" or maybe short burst of static when I turn the unit on. I think it only comes out of one speaker, and it seems like it doesn't always happen. It's not very loud, but loud enough to be heard. I've temporarily moved back to my old amp, because I don't want to harm my speakers. Any thoughts on what might cause this?
Also: I mentioned before there is a very faint amount of hiss coming out of the tweeters. Originally I thought changing the input pots fixed this, but I was wrong: the hiss exists regardless of how the pots are set. It's very faint, and really can only be heard when I have my ear a couple inches away from the tweeter. Playing music at any level completely buries it. Not a deal-breaker, but mildly annoying. My old amp is completely silent.
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Here are a couple pics I promised:
(http://www.audiocircle.com/image.php?id=53491)
(http://www.audiocircle.com/image.php?id=53492)
Which size Par-Metal case are you using? Is that the 5" or 4" tall version... 12"x16"? I'm thinking of ordering a couple.
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Matt my amp is dead quiet and havent heard any feedback about hiss before. Maybe those rca input wires need shielding from the ps.
On another note these amps respond VERY well to after market power cords. :)
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Nice case there matt_garman. I just pulled the trigger on the CDA-254L kit. Got $11.25 off on it by using the ACircle promo code. So shipping is free. Ordered the connectors from Parts Express and am waiting to hear back from Par-Metal on their black anodized version of the 20 series desktop case. Will see how it goes when all is delivered. Have been waffling on building this amp so finally got off my gleuteus maximus and am going to do it. :thumb: It will be going up against an Adcom GFA-545ii amp so I expect it to lay down some smack on it. Will see.
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Matt...
I have the same hiss/pop issue. A couple of things I noticed. The hiss was the same even when the rca cables were disconnected from the amp. Also, the hiss would "almost" disappear when the pot was half way, but would reappear when the pot was turned all the way down. I'm driving very sensitive Klipschorns. When I hook up my Klipsch RF-83's (about 5dB less sensitive), the hiss is much less. How sensitive are your speakers? I wonder if the issue is only with very efficient speakers.
Mike
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ptempel...
I also replaced my Adcom GFA-545ii amp with a CDA-224. Even my wife noticed the difference...much more detail. Now I'm considering replacing my Adcom preamp with ????? Good luck!
Mike
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I here the hiss in my tweeters also, older pair of B&Ws, not real efficient. Also heard the hiss with my Adcom 545ii when I was using it, about the same level. I am pleased with the SDS254 and SDS470 Im using now for the mains and subs. The only problem I have is the bass is so well controlled now that I lost quite a bit of extension at the bottom end. I plan on using passive radiators with the subs instead of their sealed box loading to get some lower bass. The bass went deeper with a pair of Dayton SA240 plate amps but was a lot slower with much less control of the cone I think. When I used the Adcom with the subs it was the first time I ever saw the distortion warning led's come on and it wasnt very loud.
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I also replaced my Adcom GFA-545ii amp with a CDA-224. Even my wife noticed the difference...much more detail. Now I'm considering replacing my Adcom preamp with ????? Good luck!
Good going Mike. I'm also going to use the Adcom GFP-555ii with it for a while. From what I've read so far, I'd like to replace it with the Mezmerize DCB1 buffer. Saw the boards available here:
http://www.diyaudio.com/store/usa/boards/p-mezb1-1v10.html
wushuliu has an AC thread on it here:
http://www.audiocircle.com/index.php?topic=85001.0
and the diyaudio build thread is here:
http://www.diyaudio.com/forums/pass-labs/176723-mezmerize-dcb1-building-thread.html
Hope that helps,
Philippe
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Which size Par-Metal case are you using? Is that the 5" or 4" tall version... 12"x16"? I'm thinking of ordering a couple.
It's the 4" tall version. 12x16x4. Par-Metal part number 20-16124.
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Matt my amp is dead quiet and havent heard any feedback about hiss before. Maybe those rca input wires need shielding from the ps.
I'm actually using XLR inputs. At least the wire from the XLRs to the board is shielded. I bought "25' 22 AWG Shielded Silver Kapton Teflon Wire 3 Twisted" from John's Wire Shop on ebay.
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I have the same hiss/pop issue. A couple of things I noticed. The hiss was the same even when the rca cables were disconnected from the amp. Also, the hiss would "almost" disappear when the pot was half way, but would reappear when the pot was turned all the way down. I'm driving very sensitive Klipschorns. When I hook up my Klipsch RF-83's (about 5dB less sensitive), the hiss is much less. How sensitive are your speakers? I wonder if the issue is only with very efficient speakers.
I'm using Salk Songtowers, which according to the specs aren't particularly efficient: 88 dB at 4 ohms. Definitely less efficient than Klipschorns.
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I'm using Salk Songtowers, which according to the specs aren't particularly efficient: 88 dB at 4 ohms. Definitely less efficient than Klipschorns.
Matt, you have some Klipschorns?
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It's the 4" tall version. 12x16x4. Par-Metal part number 20-16124.
Thanks... Got a pair on the way for my monos.
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Matt, you have some Klipschorns?
Nope. But my understanding is that Klipschorns are famous for their high efficiency.
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I'm using Salk Songtowers, which according to the specs aren't particularly efficient: 88 dB at 4 ohms. Definitely less efficient than Klipschorns.
Matt...
I noticed that Salk Songtowers can be ordered with Bi-wire capable binding posts. Are you bi-wiring? The reason I ask, is that the pop is "much" louder when I bi-wire (or in my case, passively bi-amp). Running a single wire creates no pop at all.
Mike
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the pop is "much" louder when I bi-wire (or in my case, passively bi-amp). Running a single wire creates no pop at all.
I find that very interesting. Apparently the amp doesn't like the complex load of additional cabling, bi-wiring. I wonder if the amp would benefit from the addition of a Boucherot Cell.
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My only concern now is that I sometimes hear a "pop" or maybe short burst of static when I turn the unit on.
In circumstances such as this, you might consider using some sort of active loudspeaker protection.
Circuitry that switches in the loudspeakers a few seconds after the amp comes on, allowing the amp to stabilize before sending power to the loudspeakers.
An inexpensive Velleman kit comes to my mind, there are others too.
http://www.vellemanusa.com/products/view/?id=350552
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I received the CDA-254 and and large PS modules last Friday. They came pretty quick. Still waiting for the Antec torroid transformer and a call from Par-Metal on the black anodized case.
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I noticed that Salk Songtowers can be ordered with Bi-wire capable binding posts. Are you bi-wiring? The reason I ask, is that the pop is "much" louder when I bi-wire (or in my case, passively bi-amp). Running a single wire creates no pop at all.
Nope, my are not bi-wire capable. So, running single wire only.
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In circumstances such as this, you might consider using some sort of active loudspeaker protection.
Circuitry that switches in the loudspeakers a few seconds after the amp comes on, allowing the amp to stabilize before sending power to the loudspeakers.
An inexpensive Velleman kit comes to my mind, there are others too.
http://www.vellemanusa.com/products/view/?id=350552
Is this kind of circuit typical in non-DIY amps? I ask, because I've never had this popping issue before. If it's a standard kind of thing, then I might consider it (e.g., any off-the-shelf amp I might buy---such as my QSC---likely has something similar). But if it's not typical for an amp to have something like this, then it feels like a band-aid to me; I'd rather solve the real problem than throw more circuitry at the issue.
I also noticed that when I turn my SDS-470 off, one of the speakers makes a "farting" noise for about a second. It's like a "rippling static" sound. Fairly quiet, but similarly unsettling to the power-on pop/static.
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Is this kind of circuit typical in non-DIY amps? I ask, because I've never had this popping issue before. If it's a standard kind of thing, then I might consider it (e.g., any off-the-shelf amp I might buy---such as my QSC---likely has something similar). But if it's not typical for an amp to have something like this, then it feels like a band-aid to me; I'd rather solve the real problem than throw more circuitry at the issue.
I also noticed that when I turn my SDS-470 off, one of the speakers makes a "farting" noise for about a second. It's like a "rippling static" sound. Fairly quiet, but similarly unsettling to the power-on pop/static.
Well of course always better to pin down the source of the problem than band-aid it.
Farting noise? In electronics it is called "motorboating."
http://en.wikipedia.org/wiki/Motorboating_(electronics)
I'd say that switch on delay/muting circuits are fairly common. I guess it depends on the manufacturer. You'll see relays (you can hear them click on too) in a lot of higher powered receivers, Japanese named brands. Active protection circuitry, in case you try and use low impedance loudspeakers or have a short at the output.
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I have almost eliminated my popping issue, and I wanted to share my theory, just in case it's both correct and relevant. First the boring history. I've been trying to tri-amp, then bi-amp my modified Klipshorns. The modification involved better (and much more efficient) midrange and tweeters, making the bass horn sound "smaller". I came up with the idea of passively bi-amping my 'horns, which means running two amps (SDS-224's) into the bi-wire connections of my crossovers. This would allow me to increase the gain on the bass horn to match the "too efficient" top-end. The bass amp now runs thru a 2.3 mH inductor that connects to the 6 ohm woofer (1st order Butterworth 415Hz low-pass filter). The second amp connects to a 48 uF capacitor (1st order Butterworth 415Hz hi-pass filter), then to the remaining crossover components and 8 ohm drivers. With this configuration, I would hear a loud pop when the amps were turned on. I just installed an active crossover, which eliminates these filters. Now the pop has been reduced to a small click! I'm no expert, but could the 48 uF capacitor have held enough of a charge to create a large discharge once the hi-pass amp was turned back on (causing the loud pop)? The hiss is still there, but as before, only when I put my ear a few inches from the top-end. Don't know why, but my popping issue is history. :scratch:
Mike
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I have almost eliminated my popping issue, and I wanted to share my theory, just in case it's both correct and relevant. First the boring history. I've been trying to tri-amp, then bi-amp my modified Klipshorns. The modification involved better (and much more efficient) midrange and tweeters, making the bass horn sound "smaller". I came up with the idea of passively bi-amping my 'horns, which means running two amps (SDS-224's) into the bi-wire connections of my crossovers. This would allow me to increase the gain on the bass horn to match the "too efficient" top-end. The bass amp now runs thru a 2.3 mH inductor that connects to the 6 ohm woofer (1st order Butterworth 415Hz low-pass filter). The second amp connects to a 48 uF capacitor (1st order Butterworth 415Hz hi-pass filter), then to the remaining crossover components and 8 ohm drivers. With this configuration, I would hear a loud pop when the amps were turned on. I just installed an active crossover, which eliminates these filters. Now the pop has been reduced to a small click! I'm no expert, but could the 48 uF capacitor have held enough of a charge to create a large discharge once the hi-pass amp was turned back on (causing the loud pop)? The hiss is still there, but as before, only when I put my ear a few inches from the top-end. Don't know why, but my popping issue is history. :scratch:
Mike
Did you check your amplifier output to see if there was any DC there?
Holding a charge? A crossover capacitor doesn't work that way, it's not for smoothing DC, it is frequency selective, blocks some frequencies, while passing others. We're talking about AC.
Wonder if the capacitor is problematic, leaky. Is the 48uF cap an electrolytic?
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Did you check your amplifier output to see if there was any DC there?
Holding a charge? A crossover capacitor doesn't work that way, it's not for smoothing DC, it is frequency selective, blocks some frequencies, while passing others. We're talking about AC.
Wonder if the capacitor is problematic, leaky. Is the 48uF cap an electrolytic?
No, didn't check for DC. The caps are Solen FastCaps (Metallized Polypropylene???). Holding a charge was probably a poor choice of words (I'm new at this stuff). I can tell you this, I later went back to a single amp, single wire setup so I could "clean up my mess", and the first time I powered on the amp, I got the loud pop again! Every time after that, no pops. It's as if the inductor has to be in the mix when I power off, or I get the pop when I power on. Since I won't be passively bi-amping, this will not be an issue. I just wondered if this had anything to do with others having "popping" issues.
Thanks for taking interest in this. I probably should have done more research before posting this idea.
Mike
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No, didn't check for DC.
Mike
You really need to check out the amp first. DC at the output is easy to check for, if you have a semi decent digital multimeter.
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Have you tried that amp with any other speakers?
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Is this kind of circuit typical in non-DIY amps? I ask, because I've never had this popping issue before. If it's a standard kind of thing, then I might consider it (e.g., any off-the-shelf amp I might buy---such as my QSC---likely has something similar). But if it's not typical for an amp to have something like this, then it feels like a band-aid to me; I'd rather solve the real problem than throw more circuitry at the issue.
I also noticed that when I turn my SDS-470 off, one of the speakers makes a "farting" noise for about a second. It's like a "rippling static" sound. Fairly quiet, but similarly unsettling to the power-on pop/static.
Matt my 470 seems to be making the same sound when I shut it off thru the left chanel sub woofer. It sounds strange like some kind of static discharging in the left sub voice coil? I never noticed this with the SDS254 or my Daton 240 plate amps. Im not getting the turn on pop though, hope this amp lasts because I love the control it has over the drivers.
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New to DIY. I need advice!
Im probably going to end up picking up the CDA-254L. Do you guys have recommendation to which chassis? Tom has advised 12x12x4, but having never purchased a chassis before, can you guys give me some info?
* Do the Chassis comes with punched holes?
- for binding posts?
- for IEC Jack
- Power Switch
- LEDs?
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The 12x12x4 Par-Metal chassis will work, but I went with the 16x12 to give myself a little more room in laying out the components and keep the power supply farther from the amp board. Also allows for other possible upgrades in the future (power supply, volume control, etc.). Chassis doesn't come punched for anything unless you special order it as such (costs extra).
I've found them pretty easy to drill though I haven't gotten to the back panel yet. Just finished laying out the base plate for my mono SDS-450 amps. Did them mirrored since they'll be positioned side-by-side or behind the speakers. This actually made it easier to lay out and drill the second amp... just clamped them bottom to bottom and drilled through the first (only two of the power supply screws had to be relocated since that board is not symmetrical).
(http://www.audiocircle.com/image.php?id=54307)
(http://www.audiocircle.com/image.php?id=54308)
I also drilled out the footer holes a little larger to accommodate some 1/4" shaft spikes I had on hand... I was only going to use three but found the amp too tippy with the big xfmr off to one side, so there's an extra hole at the front middle.
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The second amp connects to a 48 uF capacitor (1st order Butterworth 415Hz hi-pass filter), then to the remaining crossover components and 8 ohm drivers. With this configuration, I would hear a loud pop when the amps were turned on. I just installed an active crossover, which eliminates these filters. Now the pop has been reduced to a small click!
Same experience here, I bypassed my compression driver protection caps and the turn on pop is almost gone.
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Matt my 470 seems to be making the same sound (farts) when I shut it off thru the left chanel sub woofer. It sounds strange like some kind of static discharging in the left sub voice coil?
Same problem here with a bridged sds-470.
Listen here: http://dl.dropbox.com/u/45539942/AmpShutDownNoise.mp3 (http://dl.dropbox.com/u/45539942/AmpShutDownNoise.mp3)
You first hear the power switch snap off and then my subwoofer.
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The 12x12x4 Par-Metal chassis will work, but I went with the 16x12 to give myself a little more room in laying out the components and keep the power supply farther from the amp board. Also allows for other possible upgrades in the future (power supply, volume control, etc.). Chassis doesn't come punched for anything unless you special order it as such (costs extra).
I've found them pretty easy to drill though I haven't gotten to the back panel yet. Just finished laying out the base plate for my mono SDS-450 amps. Did them mirrored since they'll be positioned side-by-side or behind the speakers. This actually made it easier to lay out and drill the second amp... just clamped them bottom to bottom and drilled through the first (only two of the power supply screws had to be relocated since that board is not symmetrical).
(http://www.audiocircle.com/image.php?id=54307)
(http://www.audiocircle.com/image.php?id=54308)
I also drilled out the footer holes a little larger to accommodate some 1/4" shaft spikes I had on hand... I was only going to use three but found the amp too tippy with the big xfmr off to one side, so there's an extra hole at the front middle.
Thanks! I went ahead and ordered one a few days ago.
I am confused about the transformer. So you have your Red and Black wires, but then there's also a purple wire. Going to the power supply, you have the blue and green wires. But what about the second set that is orange and brown? According to other people's setup, they just tape over it.
Do I need to loop any of the orange / brown wires in closing them?
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Thanks! I went ahead and ordered one a few days ago.
I am confused about the transformer. So you have your Red and Black wires, but then there's also a purple wire. Going to the power supply, you have the blue and green wires. But what about the second set that is orange and brown? According to other people's setup, they just tape over it.
Do I need to loop any of the orange / brown wires in closing them?
This is an e-mail I received from Tom a while back...
You might have received one of the transformers an extra shield, and this is the purple wire. If you're using a 3 prong power cord or IEC, connect the purple wire to the green (ground) wire. Your transformer might also have some brown and orange wires... just tape those off so each wire cannot touch anything and put them aside. They are not used in this kit.
Hope this helps.
Mike
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The 12x12x4 Par-Metal chassis will work, but I went with the 16x12 to give myself a little more room in laying out the components and keep the power supply farther from the amp board. Also allows for other possible upgrades in the future (power supply, volume control, etc.). Chassis doesn't come punched for anything unless you special order it as such (costs extra).
I've found them pretty easy to drill though I haven't gotten to the back panel yet. Just finished laying out the base plate for my mono SDS-450 amps. Did them mirrored since they'll be positioned side-by-side or behind the speakers. This actually made it easier to lay out and drill the second amp... just clamped them bottom to bottom and drilled through the first (only two of the power supply screws had to be relocated since that board is not symmetrical).
I second this and also went with the 12x16x4 Par-Metal black anodized case. Just got almost all the wiring done last night. Only thing left is the IEC ground wire to the chassis. If you're careful with placement, you should be able to get up to two amp boards in this chassis. You can place the torroid and power supply board near the front panel. Then place each amp board close to the sides with the power and speaker connectors facing inward and the inputs close to the side of the case. Then going from the edge to the middle of the back panel you can wire the RCA inputs, speaker binding posts and then the IEC connector in the middle. The other side will mirror this setup (but in reverse). I only have one amp board, but left plenty of space for a second one for possible future expansion (dual mono or 4-channel bi-amping, anyone? :icon_twisted: ). The PS board already has all the connections I need for the second board.
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Almost ready. While ohming out the speaker and RCA connections, I found that the RCA positive posts have a connection to ground. :( The Dayton RCA jacks have plastic washers but the one with the sleeve doesn't have much of a sleeve. Its more like a bump. I might have some teflon plumber's tape to wrap around the threads so they don't touch the case. Will try that.
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I don't know that I would rely on a few wraps of teflon tape. If you have a good sized Ace Hardware with hardware bins, you might be able to find some nylon shoulder washers with sufficient barrel length.
Steve
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I don't know that I would rely on a few wraps of teflon tape. If you have a good sized Ace Hardware with hardware bins, you might be able to find some nylon shoulder washers with sufficient barrel length.
Sounds like a better idea. Thanks Steve. I also don't like the way the DVM is behaving. So will hit up Rat Shack to replace the fuses (20A 250V and 500mA 250V fast acting) while I'm at it.
Philippe
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Its working! :thumb: The torroid is not heating up so looks like I have the center tap done correctly. Initial impression is that it sounds a bit more detailed than the Adcom GFA-545ii. Will put some more hours on it before I sub the Adcom back in. Only minor complaint is a barely perceptible hiss from the tweeters when nothing is playing like others have mentioned. One thing I did notice after replacing the DVM fuses and re-checking the connectors. The black speaker binding posts have a path to the chassis. It appears to be via the amp board and through the mounting posts. Is this normal for the amp board? The RCA connectors are ok after rechecking them as well.
(http://www.audiocircle.com/image.php?id=54506)
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Matt my 470 seems to be making the same sound when I shut it off thru the left chanel sub woofer. It sounds strange like some kind of static discharging in the left sub voice coil? I never noticed this with the SDS254 or my Daton 240 plate amps. Im not getting the turn on pop though, hope this amp lasts because I love the control it has over the drivers.
You guys ever resolve the SDS-470 turn-off noise problem?
My amp at shutdown: http://dl.dropbox.com/u/45539942/AmpShutDownNoise.mp3 (http://dl.dropbox.com/u/45539942/AmpShutDownNoise.mp3)
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You guys ever resolve the SDS-470 turn-off noise problem?
Mine is still making the sound on shut off and a small pop when turned on. I hope it doesnt cause any damage to the amp, but the level of the sound is so low I just ignore it now.
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Mine is still making the sound on shut off and a small pop when turned on. I hope it doesnt cause any damage to the amp, but the level of the sound is so low I just ignore it now.
You should try a small, maybe .1uF snubber capacitor across the On/Off switch, it should kill your turn on pop.
It wont hurt to experiment. Increase the uF if you are noticing it working at least to some extent and you'd like to have it working even some more. If there are no audible results, then simply remove the cap.
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I finally put this bad boy together (CDA-254L). I notice most of you put your transformer with the wires on the bottom side, but it seems that the wires would be bearing all the weight. Is it 'supposed' to be at the bottom?
(http://www.audiocircle.com/image.php?id=54551)
Preamp: IRD Purist
Source: Squeezebox
I played it for about 4 hours tonight. Right off the bat it was grainy, but it quickly smoothed out. After about an hour, the graininess went away, now it is all very smooth.. By the end of the session, the it sounded great! I cant wait to break this in some more.
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Nice work! :thumb: :thumb:
Put a nice power cord on that and you will smile. :wink:
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I finally put this bad boy together (CDA-254L). I notice most of you put your transformer with the wires on the bottom side, but it seems that the wires would be bearing all the weight. Is it 'supposed' to be at the bottom?
I wondered the same thing, so I e-mailed tech support at Antek. The answer was, it doesn't matter. If you go to their website (antekinc.com), you'll notice that they have their power supply transformers "upside down". The tech said that was done because it fit the case better. I have mine "upside down" 'cause it "sits" better with me.
Mike
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I finally put this bad boy together (CDA-254L). I notice most of you put your transformer with the wires on the bottom side, but it seems that the wires would be bearing all the weight. Is it 'supposed' to be at the bottom?
Preamp: IRD Purist
Source: Squeezebox
I played it for about 4 hours tonight. Right off the bat it was grainy, but it quickly smoothed out. After about an hour, the graininess went away, now it is all very smooth.. By the end of the session, the it sounded great! I cant wait to break this in some more.
Well done. I agree with the others and don't think it matters which way the torroid goes. Two rubber pads usually come with it so they help to seat it and reduce vibration. I moticed the same "smoothing out" and am listening to it right now. Am amazed at the detail and control the amp has over the speakers. Only drawback with the Adcom GFP-555ii preamp is that it has too much gain. But that's ok for now since I'd like to try a passive buffer like the Dodd or Pass B1 at some point.
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Thought I'd post my project. I'm bi-amping a pair of Klipshorns, and wanted to see if I could include everything in one case. This is a temporary setup, but so far so good. Includes an SDS-480 kit, and Marchand electronic crossovers (24db slope). Initially, had issues with Marchand's, in that they needed to be powered up BEFORE the amps, or I got a very loud transient POP. Solution was to use my old Monster Power Center. The amp power supply is plugged into a delayed switch outlet, and the Marchand PS into an immediate switch outlet. Now, the amps power on a few seconds after the Marchand PS, and power off a few seconds after the Marchand PS is powered off. I will not need power switches on the enclosure.
Mike
(http://www.audiocircle.com/image.php?id=54560)
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Thought I'd post my project. I'm bi-amping a pair of Klipshorns, and wanted to see if I could include everything in one case. This is a temporary setup, but so far so good. Includes an SDS-480 kit, and Marchand electronic crossovers (24db slope). Initially, had issues with Marchand's, in that they needed to be powered up BEFORE the amps, or I got a very loud transient POP. Solution was to use my old Monster Power Center. The amp power supply is plugged into a delayed switch outlet, and the Marchand PS into an immediate switch outlet. Now, the amps power on a few seconds after the Marchand PS, and power off a few seconds after the Marchand PS is powered off. I will not need power switches on the enclosure.
Nice crossovers. How much did they charge for each crossover? Any reason for not choosing a separate 1U or 2U case for them? I can see myself heading down this path. But would need another amp and different speakers before then. Also, are you using some sort of mic to measure the frequency response of your speakers?
Philippe
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Nice crossovers. How much did they charge for each crossover? Any reason for not choosing a separate 1U or 2U case for them? I can see myself heading down this path. But would need another amp and different speakers before then. Also, are you using some sort of mic to measure the frequency response of your speakers?
Philippe
Thanks. The Ps is $50. Each crossover (mono) is $40. You can see more info at Marchandelec.com. Two XM1's cross at 400Hz, the other two at 40Hz. 400Hz and above to passive crossover, 40Hz to 400Hz to bass driver, 40Hz and below may someday go to subwoofer. Mounting everything in one case really simplified the wireing (no rca's to buy/solder/mount, no cables to connect). Just ran 16 AWG wires from crossovers to crossovers/amps (took less than an hour). I'm having a new passive mid-to-high crossovers built to custom match my drivers. Once they arrive, I'll work with the engineer to determine the best way to measure/adjust the bass gain to match the new passive crossovers, which he'll tune flat from 400Hz and above.
Mike
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Hi,
Here below some pics of my SDS-470 amp that Tom made for me.
(http://nsa28.casimages.com/img/2011/11/16/111116093928600327.jpg)
(http://nsa28.casimages.com/img/2011/11/16/111116094159663703.jpg)
This amp has successfully replaced my old Nuforce MCH 300 SE (6k € pricing).
speed, tube sound, soundstage, lot of material in the voices ...
It's an amazing piece of gear !!
I'd like to compare it to Edge power amp but this US brand is not distributed here in France.
I know Edge uses hybrid model of Ice power modules. it seems perfectly sound (from what I can read).
Did you listen to Edge amp already (Edge G AV 5x250W for exemple) ? .... and compared it to classDaudio amps ?
I know the Edge GAV 5 is sold 11k € in Europe... :o
From my point of view, I find this is very expensive for a Ice Power unit ...
Thx for your feedback.
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Hi,
Here below some pics of my SDS-470 amp that Tom made for me.
Thx for your feedback.
That's a lot of powerful amplifiers for one power supply. What are you driving with it?
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I finally put this bad boy together (CDA-254L). I notice most of you put your transformer with the wires on the bottom side, but it seems that the wires would be bearing all the weight. Is it 'supposed' to be at the bottom?
(http://www.audiocircle.com/image.php?id=54551)
Preamp: IRD Purist
Source: Squeezebox
I played it for about 4 hours tonight. Right off the bat it was grainy, but it quickly smoothed out. After about an hour, the graininess went away, now it is all very smooth.. By the end of the session, the it sounded great! I cant wait to break this in some more.
Well, if you use metal chassis (not in your case), you should put those ac voltages as close to the chassis as you can and also you should twist those wires as much as you can to avoid any hamming from ac voltages. metal chassis are used to ground deathly voltages and also to shield RF and anwanted noises.
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That's a lot of powerful amplifiers for one power supply. What are you driving with it?
Hi,
I made the same remark to Tom.
I successfuly drove with it Elac and Wislon Benesh speakers.
Here below what he answered to me.
your amp has more than enough power for music or home theater. This controversy over transformers and power supplies has been going on for years. This would be true if you were running a constant sine wave through all 6 channels, but music and movies is not a constant sine wave. The amps will actually only bee using about 1/8 power for this. If this amp had a 3KW power supply, it would be huge and just allot of wasted space and power. The only time the amp would need such a large power supply is for bench power testing… something only a manufacture would do. Also, our amplifiers are about 92% efficient and draw much less power form the wall than other types of amplifiers. I think when you listen to your amp, you’ll find you have more than enough power.
I trust him. He will never build and sell undersized power amps...
Since I receive this amp I had the opportunity to test it on Wilson Benesh Vertex speakers (outstanding product, by the way!!).
My ClassDaudio amp worked better than Sugden MPA-4 on Vertex and no lack of power (even at high volume).
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I trust him. He will never build and sell undersized power amps...
Like he said....it will be good for typical home use. You must tell Tom what you are doing with the amp.
If you told him you needed power for large subwoofers, each SDS-470 would get it's own transformer and power supply.
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Like he said....it will be good for typical home use. You must tell Tom what you are doing with the amp.
If you told him you needed power for large subwoofers, each SDS-470 would get it's own transformer and power supply.
This amp is perfect to drive:
- 2.0 full range speakers (35 Hz - 20 kHz (100 Db at 16 ft)).
- 5.1 system (80 Hz - 20 kHz (100 Db at 16 ft)) – Sub Xover is set to 80 Hz.
My sub (Velodyne DD12) have its own power supply
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On the power consumption front, I'm using an AC Watt meter (Kill-A-Watt). The SDS470 seems to pull about 22 Watts, both at idle (no music) and typical listening levels using the standard kit linear power supply. I haven't really cranked it up yet. Compared to the QSC, which pulled 40--60 Watts between idle and music. A definite improvement in power usage. As I suggested above, I'd like to get a switch-mode power supply (SMPS) to see if I can further reduce idle power consumption.
FWIW... I got my SMPS800R from Connexelectronic (http://connexelectronic.com/product_info.php/products_id/124?osCsid=sdupd9oplukte1g5teoe0189m7) last week. Only last night did I finally have a bit of time to try it out.
The main thing I was going for was reduced power consumption through higher efficiency. I was a bit disappointed to see that the SMPS is actually a bit worse, at least at idle/low volume levels. Idle and low listening level AC power consumption was around 25 Watts.
The SMPS is definitely smaller than the linear PS's capacitor bank + transformer. I estimate that the SDS-470 and SMPS800R could fit together comfortably in a 6x12 enclosure, maybe even 6x10.
As for sound quality... too soon to tell. I only had time to set it up, then do basic testing. Definitely no obvious problems. If there are any SQ differences, they will be nuanced.
In my infinite wisdom and grace, I may have damaged one or more components: before connecting the SMPS800R to the SDS-470, I wanted to make sure the output DC voltage was correct (since it was a custom voltage request). And before that, I wanted to check the linear PS's voltage as a baseline reference. When using my DMM to check DC voltage on the linear power supply, I accidentally got the probes too close together and generated a nice arc! I was actually probing on the SDS-470, so the board got a nice burn mark right under the DC input receptacle, as did my DMM probes. In my brief listening period, the amp sounded fine, so I don't think I actually harmed it. Not sure about the linear power supply though, as I didn't have time to test it after the fact. But I didn't blow a fuse, and it was brief enough that I'm hoping no actual damage was done.
Be careful out there! :)
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When using my DMM to check DC voltage on the linear power supply, I accidentally got the probes too close together and generated a nice arc!
Who hasn't? I did similarly once and took out several expensive power transistors. Oh well, live and learn.
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Hi,
I made the same remark to Tom.
I successfuly drove with it Elac and Wislon Benesh speakers.
Here below what he answered to me.
I trust him. He will never build and sell undersized power amps...
Since I receive this amp I had the opportunity to test it on Wilson Benesh Vertex speakers (outstanding product, by the way!!).
My ClassDaudio amp worked better than Sugden MPA-4 on Vertex and no lack of power (even at high volume).
Very nice to see that the Class D amp has made it across the pond, and is being compared with very high priced competition! I remember Wilson Benesch from the 90's, I liked their Act 1 speaker.
Thanks for the review,
Anand.
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Indeed! We rarely see a great product at a great price in this hobby! :thumb:
steve k
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FINALLY... got my SDS-450 monos up and running (balanced input only). However, after getting them connected and making wonderful music, one of the amps kept cutting out (yellow LEDs on) for a few seconds and then coming back on (blue LEDs back on). This started after about 10-15 minutes of play time on my Magnepan 1.6 speakers.
Cable swaps, channel swaps, etc. to verify it is due to something inside the amp... yep. Disconnect, open up, look for mis-wire... all looks proper. Check continuity of connectors... all OK. Check power supply output... +48.9, -48.7 (both amps measure the same).
Now I'm beginning to think its an overheating issue. Working longer now with the top off, thought I was in the clear, but then cutout again just now. Heat sinks on both amps are very warm to the touch, can't hold finger there longer than about 10 seconds... seems strange for an amp that is supposed to be OK down to 2 ohms in stereo and recommended by Tom for my Maggies. And just now the other amp cutout while checking the heatsink temp! Time to contact Tom... wonder if I got the wrong power supply or perhaps the wrong amp as I can't see anything on the board identifying it as a 450, 470, 258, etc.
Or could it be I need to keep right-channel jumper J2 in place when running it as a mono balanced amp? Doesn't seem likely.
Mono SDS-450 amps, balanced XLR input only, 4-pole SpeakOn connector for single-connector biwiring, PowerCon AC connector. Temporary mounting of gain pots until I settle on a fixed resistor value.
(http://www.audiocircle.com/image.php?id=54913)
(http://www.audiocircle.com/image.php?id=54914)
(http://www.audiocircle.com/image.php?id=54915)
Internal bi-wire jumper to 4-pole SpeakOn connector... I don't think I'll ever use binding posts again on anything I build.
(http://www.audiocircle.com/image.php?id=54916)
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I am about to order a Par Metal Case and I have a couple of questions about it.
Will the 16x12x4" case have enough height to fit the 400VA power transformer or will I need to go with a 5" tall case?
Also, did you guys go with Anodine or Anodized cases? Anodine is supposed to offer better EMI/RFI sheilding than Anodized according to the guy that I spoke to at Par Metal. The trade off is that Anodine scratches easier than Anodized. My CDA 254 (currently in a wooden box) gives off a lot of RFI, so much so that I can't use my tuner.
One last question, did you guy's go with the thicker front panel or just the .125" thick front panel which is standard? I am leaning to the thicker front panel.
Thanks,
Larry
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I am about to order a Par Metal Case and I have a couple of questions about it.
Will the 16x12x4" case have enough height to fit the 400VA power transformer or will I need to go with a 5" tall case?
I have exactly that case (16x12x4), and my SDS-470 kit fits perfectly with room to spare. In fact, on mine, the height from case bottom to top of the transformer nut is 3"; so you might be able to get away with a 3" tall case.
Also, according to my measurements, you might be able to get away with a 12x12 case... it looks doable with the SDS-470 (which is slightly bigger than other amp boards due to additional heatsink), so probably even easier with an CDA-254.
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Added a Grant (Chinese) tube buffer between my SS pre and my SDS-470. Thought it would be an interesting experiment. Uses standard Shuguang 6SN7 J tubes.
In general, I like the results. The soundstage is definitely larger - especially wider. Most recordings have a more up front "live" feel.
On rock music from the 60's and 70's it sounds especially good. I was grinning last night listening to the Beatles remasters, both in mono and 24 bit stereo. I think the tubes make the music sound a bit more like LP's, and I think my brain has neurons that think this is how music like this is "supposed to sound". Mp3's definitely sound better run through the buffer. I assume that if I shelled out the cash for some really good 6SN7's it would sound even better.
On quality modern recordings I don't think it adds much. Even on a remastered old recording like the the hi-res Band on the Run (a very good sounding release) it didn't seem to make any great difference. I think it softens the sound slightly, which is a plus on many recordings - especially older ones with mediocre transfer to digital - but not a real plus if the recording is already a very good one.
Anyway, this is my first venture into tubes since I was a kid. It has me seriously thinking about a tube pre, a tube hybrid, or something like the new Peachtree Grand Pre, which has a tube buffer that can be engaged or disengaged as needed.
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There is only ONE tube based item you should think about adding, and that is a Dodd Battery powered buffer, either DIY or Assembled.
Nothing touches it for less then $5-10K...
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Yeah, I've thought about the Dodd Buffer. But I'm not sure it fits my needs for a few reasons. One of them is that I'd like to reduce the number of boxes in my system. Presently I have built up through piecemeal experiments and upgrading:
1. Music Server
2. Empirical Audio Pace Car
3 SB Touch (clocks slaved to Pace Car)
4 DAC
5 Preamp (actually SS integrated being used as a pre)
6 Tube Buffer
7 Power Amp-SDS
8 Speakers
This is unwieldy and uses a forest of cabling and power cords. I also listen in a small room and it takes up a good chunk of space.
So I guess the Dodd could combine the functions of my present pre and buffer. I'm a little hesitant about having a system with only an attenuator and not a gain/volume control. Maybe that makes no sense, but I've just never had such a setup before. I'm sure if I asked, Gary would build me a hybrid Class D amp, possibly even battery powered. Blair at Nightshade has already told me he'd be happy to build such a hybrid integrated (but on grid, of course). I assume a hybrid amp built by one of them would sound at least as good - and probably better -than what I'm using now, and then I wouldn't need a tube buffer at all.
The new Peachtree pre sounds appealing to me, as it supposedly has a good quality asynch USB solution and could theoretically replace numbers 2-6 in the list above. Its tube buffer also has an engaged/not engaged setting. That appeals to me. The Peachtree Grand Integrated could replace the Power Amp too. So I'm going to wait and see how those units sound and then decide on what I want to spend the not inconsiderable amount of cash involved. Obviously one of the considerations will be the quality of the tube buffer in the Peachtree. There are also other options, like a tubed DAC with attenuator.
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1. I have the 250 watt version SDS 258. About 8 months.
I've used 2 different power supplies and there is still an erratic noise, maybe every 1-3 seconds, low level around 200-500hz. It's been doing this since I got it.
Anybody else have this?
2. Setting gain with Vishay resistors makes this a great bargain amp. Ordinary resistors=ordinary sound.
3. I remounted the output inductors on the bottom of the board, same holes. Cleaner, clearer sound, not quite as large improvement as the Vishays. I think less interference for the magnetic/electric field they radiate axially. No metal caps nearby.
See confusing pic below:
(http://www.audiocircle.com/image.php?id=54968)
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Argh, look like I'm going to have to postpone moving my 250w kit into a chassis. I received it today and the color of the chassis is Champagne!!! I was almost going to use it, but after looking at it long enough, the color made me feel like a drug dealer living the "bling" life.
Contacting the seller now.. :(
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Anyone knows what the powerconsumption is a complete CDA-254L amp?
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Anybody here tried jumpering the gain pins and forgoing either the stock gain pot or fixed resistors? I had been using Vishay fixed resistors on my SDS's and just for kicks decided to remove them and just jumper the black and yellow wired pins. There was a meaningful further improvement in transparency in my system. I have 95db efficient speakers though. YMMV.
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1. I have the 250 watt version SDS 258. About 8 months.
I've used 2 different power supplies and there is still an erratic noise, maybe every 1-3 seconds, low level around 200-500hz. It's been doing this since I got it.
Anybody else have this?
No, have never experienced this noise. But am still using the CDA-254L kit with supplied Antek torroid. No mods were done to it. Maybe you can have your amp checked by classdaudio?
2. Setting gain with Vishay resistors makes this a great bargain amp. Ordinary resistors=ordinary sound.
Interesting. I wonder if they use the same resistors on the non-balanced versions. Which model Vishay resistors did you use?
3. I remounted the output inductors on the bottom of the board, same holes. Cleaner, clearer sound, not quite as large improvement as the Vishays. I think less interference for the magnetic/electric field they radiate axially. No metal caps nearby.
Based on the pic I'm guessing that you mounted the amp board on its edge? Another cool idea on the inductors. If I did that mod, then I'd probably keep the same mounting scheme but use longer standoffs to raise it up.
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No, have never experienced this noise. But am still using the CDA-254L kit with supplied Antek torroid. No mods were done to it. Maybe you can have your amp checked by classdaudio?
Interesting. I wonder if they use the same resistors on the non-balanced versions. Which model Vishay resistors did you use?
Based on the pic I'm guessing that you mounted the amp board on its edge? Another cool idea on the inductors. If I did that mod, then I'd probably keep the same mounting scheme but use longer standoffs to raise it up.
Finally tracked down the noise problem, it is coming from my cable box, not the amp. And I've had 4 cable boxes in the past year, changed for other reasons, and all had the same noise.
Vishay SK102? earflappin a few posts above eliminated the resistor with a wire and had further audio clarity. Resistor or not depends on the gain structure of your system.
My amp is mounted on the back of some speakers I built http://www.diyaudio.com/forums/multi-way/167960-inexpensive-gedlee-bouska-waveguide-tweeter-midbass-idea-5.html (http://www.diyaudio.com/forums/multi-way/167960-inexpensive-gedlee-bouska-waveguide-tweeter-midbass-idea-5.html)
Now the amp is not mounted on stand offs any more, but hangs suspended by plastic ties stapled to the MDF box sides. The amp is "floating". Less vibration from the speaker. Cleaner sound.
Adding Vishays and reducing vibrations helps reveal the sound of this well engineered amp.
Anybody replaced the big electrolytic caps on the output side of the amp yet?
OT:
In the photo below you can see the speaker xover inductors, caps and resistors are all "floating" off the back of the speaker box. Result: Cleaner, clearer sound.
Most are suspended by plastic tie wraps stapled to the box. String or coated wire would work, too. "Floating" improves sound even in xovers mounted away from speakers. I had them glued down like Geddes does, but I wanted cleaner sound.
It's free and reversable if you don't like the sound.
Floating the inductors only made the most difference. Caps, a little added clarity.
These type inductors, no plastic core, sound better than a plastic core. Cut off of a plastic core and hear the diff.
(http://www.audiocircle.com/image.php?id=55243)
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I have been researching these amps from Class D Audio and stumbled into this great thread. I have done searches and scoured the ClassD site and still have a couple questions. Many of which I am sure have been answered before and I humbly request your assistance.
This little obsession of mine began with a little Class T amp. The Lepai 20w to be exact. I bought this a couple weeks ago for my little computer system and began modding it as directed by a thread on Parts Express' forums. The modifications took this little amp to unbelievable performance and I realized it's the sound that I have been looking for. I became especially aware of this after I messed up the latest round of mods to the Lepai and essentially bricked it. It no longer works due to a mistake made somewhere in soldering so I ordered another. In the meantime, I swapped it out for a Crown D-75 and then a D-150A.
Even though the Crowns have more power and can get much louder, they both sounded like garbage compared to the $21 modded CLASS T Lepai. Huh? How could this be? This cheap little amp has a warmness and roundness to the tone that can be listened to for hours. I had an epiphany that the sound I have been seeking all this time is actually being hampered by class AB amplification! More power added over the years just increased the harshness and sterility that I tried to overcome with better equipment, speakers, interconnects, etc. Even added tube buffers in my home theater system to try to combat this inherent harshness.
Anyway, decided to try different amplification in my main home theater/music system and searched the internet for more powerful Class T amps. This led me here and to ClassD Audio's website. Would like to start by upgrading the front 3 channels of my main system.
Now the questions:
1. Do these Class D offerings compare to Class T amps in sound quality? I could not really find any "T" amps that were rated for higher power but the reviews here of "D" amps lead me to believe they have the same warmth and clarity.
2. Regarding the offerings on ClassDaudio.com: Should I go with the SDS line? What are the main difference between the SDS and the lower priced offerings? I see that they use balanced connections but could you use RCA's with them? I have an Emotiva UMC-1 processor that is not balanced. Also they have attenuators for each channel. Would the channel pots be essential in obtaining the proper gain through the system?
3. Is it possible to build a 4 channel amp from the kits and just utilize 3 channels for the time being? Will this hurt the amp?
4. What is the consensus on using wood/MDF cases? Is this safe and acceptable? I read about the RFI concerns so could I say, add copper shielding to the inside of the case to combat this?
5. I am seriously considering the CDA-1000 kit and building my own case or buying one of the Antek cases on Ebay. Would this kit work with my processor's gain?
6. I have a Adcom GFA-5500 amp (125w into 8ohms) and my front three speakers are DIY and 4 ohm. It seems that some of the amp modules are not 4 ohm compatable. ( Maybe they are and the website is vague.) I would like to add more power for headroom purposes hence the CDA-1000 choice. If I would be better served by SDS modules in my system, what module and components would work best?
Thank you if you suffered through and read all this. Any help in answering these questions would be greatly appreciated.
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I built the SDS-258 and can say it runs on the slightly warm side and is very pleasant to listen to for extended periods. This one isn't rated for 4 ohms but I believe all of the others are. They're all made for unbalanced inputs and the SDS versions are designed for both balanced and unbalanced. Supposedly the SDS boards sound better but I don't know all of the details.
You can certainly use multiple boards but you may want to confirm with Tom the power supply requirements. Using only 3 channels shouldn't be a problem. The pots are for matching the gain to your preamp. Others have used wood boxes with no problems so you should be fine there too.
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I have 2 CDA-1000 kits. One with an extra board and both with upgraded 500VA transformers (in case I want to add an extra board later).
I am completely happy with them and Tom is great to work with.
Here is a link to the output of the SDS boards, the CDA's have the same output.
http://www.audiocircle.com/index.php?topic=76400.2820
Post #2827
This is a pic of my 9 channel DSP/Amp case. the DSP's are the unbalanced MiniDSP with advanced plugin. I housed the transfomer and power supply in a seperate enclosure.
(http://www.audiocircle.com/image.php?id=55535)
I am using the T-amp to power my compression drivers. I am planning to upgrade it as soon as I can find a high quality budget solution.
I have never heard the SDS's but those that have them seem to love them. If the money difference isn't an issue I would go with the SDS line.
Hope this helps,
Moto
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Thanks guys for the great information. Money is an issue and the main reason I was considering the CDA-1000 kit. Probably be better served by going with the SDS units. I can sell the Adcom when I get this up and running.
Will continue reading and researching this monster thread. Thanks again!
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Oh, MX48. Forgot to mention... That is one amazing build. Are you using this as a 3way front stage for a home theater? I just read up on the MiniDSP stuff and it looks like a perfect fit for these amps.
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Thanks, it looks better in the pic than in real life :).
Yes, 3-way front stage with Danley Synergy Clone HT speakers.
I love my MDSP's for the price especially, 3-in 12-out for just over $300 with plugin (you only need 1 plugin for multiple MDSP's if it is for the same use such as 3-way crossover and PEQ). The plugins are only $10 so it is easy and cheap to change cofiguration later if you change your system in some way.
Moto
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I am building a new system from the ground up with some brand new Magnepan 1.7s. I've always been a headphone guy, so this is my first "real" system. My listening room is pretty small (11'x16' or so), so I don't need tons of power for loudness, but I do know the maggies love power so I want as much as possible even though I'll be listening at low to medium levels. Currently using an old Pioneer receiver (yuck) to drive them until I get everything else figured out. Probably getting the Dodd preamp and not sure about the DAC yet (though the Tranquility sounds like something I would like. Need to find a way to hear one.) 100% of my current listening is directly from J River on my HTPC.
I have read through this whole thread and I see there are a few other maggie owners. Any recommendations for a particular version? My first option is the SDS-470. I was also thinking of the SDS-1000 kit. Is that overkill? And the fallback, basic choice is the SDS0254. This will be my first ever electronics project of any kind, so I'm obviously a bit nervous about that, but these kits seem pretty friendly to newbies. My January at work is shaping up to be nutty, so if I want to hear this thing before February I might just buy a prebuilt unit.
Thanks for any input! I'll be sending this to Tom through the Class D website also to get his recommendation.
P.S. - if it matters, I listen to all kinds of metal, lots of prog-rock/post-rock, classical, opera, and a bit of jazz and other stuff.
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I am building a new system from the ground up with some brand new Magnepan 1.7s. I've always been a headphone guy, so this is my first "real" system. My listening room is pretty small (11'x16' or so), so I don't need tons of power for loudness, but I do know the maggies love power so I want as much as possible even though I'll be listening at low to medium levels.
...
I have read through this whole thread and I see there are a few other maggie owners. Any recommendations for a particular version? My first option is the SDS-470. I was also thinking of the SDS-1000 kit. Is that overkill? And the fallback, basic choice is the SDS0254.
I've got a pair of MG1.6 speakers and contacted Tom regarding which amp would work well with these operating as balanced XLR monoblocks. He recommended the SDS-450 over the 470 saying they would run cooler in bridged mode. Finally got them built and hooked up, and though they sound fantastic from what I can tell during the all too brief listening sessions, they are running very hot with the protection circuitry shutting them down after about 30 minutes of listening. I can't even hold my hand on the heatsinks more than several seconds... and this is occurring at any volume level!
Tom thinks I simply need larger heat sinks and is sending me out a pair to install, but that was a few weeks ago and haven't heard anything back (though I'm giving him the benefit of a doubt since it is the holidays and he may be closed up through New Year's Day). It troubles me a bit that an amp supposedly well suited for my Maggies can so readily overheat. Perhaps mine were built with the incorrect heat sinks (small ones compared to the large ones on the 470).
I'm not the first to have had such problems with Maggies. Another member here got the SDS-254 for use with MMGs and had the same overheating problem, albeit only above a certain volume level, using either a single stereo amp or a pair as monoblocks.
As for ease of building, I found them very simple to put together, provided you are don't mind getting all the hardware and are comfortable with doing (or learning to do) chassis work and basic wiring/jack hookups. The built versions seem like a fair price if you don't want to go through the fun or hassle yourself (depending upon how you look at it).
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I bought a pair of used Magnepan SMGa's off of craiglist for a song awhile back. Brought them home and hooked them up to a Yamaha receiver I had at the time. (cant remember the model number) and they sounded glorious, albeit somewhat shy on bass. The soundstage and clarity was great and the best I had ever heard in my home. However, the amp ran real hot and would go into protect mode easily. I suspected that the impedence curve on the Maggies must be pretty brutal, (2ohm dips) so I hooked up a pro amp I have here.
A QSC RMX-1850HD
http://www.qsc.com/products/amps/rmx/rmx.htm
Built like a tank and designed for 2 ohm loads. The sound quality of the Maggies went up exponentially, bass was far more improved and the soundstage was tremendous. These little panels filled the house with sound and it seemed the instruments were right in the room with you. Unfortunately, one of the panels went dead after a couple days. I pulled off the sock and the wires were completely corroded from age. Something all too common with older used Magnepans I found out. Plan to send these back to Magnepan after the Winter to get them repaired.
What I am getting at is apparently Magnepans are very tough to drive by normal home amplification. The toughest load I have ever come across and perhaps a bit too much for the ClassD Audio amps. The QSC's fan would even engage at times and get quite loud. ( I planned on adding a silent 24v fan as I did with the QSC RMX-850 in my bass guitar rig) However, I had never really heard the fan with PA duty running at a 2.66 ohm load
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I run my Maggies on a Virtue Two and the combo is beyond superb. It drives the hell out of em.
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I have a question. My chassis arrived and I'm mounting the RCA jacks. I notice that most installations photos of the RCA contains a rubber piece that keeps it from touching the chassis. The one I bought from Radio Shack is bare. Would this cause an issue if the negative terminal was touching the chassis?
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I have a question. My chassis arrived and I'm mounting the RCA jacks. I notice that most installations photos of the RCA contains a rubber piece that keeps it from touching the chassis. The one I bought from Radio Shack is bare. Would this cause an issue if the negative terminal was touching the chassis?
Yes, most better quality RCA jacks come with plastic or teflon washers. I found some fiber washers at HD that i used to insulate some RCA's before.
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I have a question. My chassis arrived and I'm mounting the RCA jacks. I notice that most installations photos of the RCA contains a rubber piece that keeps it from touching the chassis. The one I bought from Radio Shack is bare. Would this cause an issue if the negative terminal was touching the chassis?
I did a quick search over at RadioShack, and all the binding posts seem to be insulated from the mounting surface...
http://www.radioshack.com/search/index.jsp?kwCatId=&kw=binding%20post&origkw=binding+post&sr=1
Which set did you get?
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Anyone been in touch with Tom at ClassDaudio over the past couple weeks... trying to get some answers but so far no response. Hoping they're just out for the holidays.
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I have 2 CDA-1000 kits. One with an extra board and both with upgraded 500VA transformers (in case I want to add an extra board later).
I am completely happy with them and Tom is great to work with.
Here is a link to the output of the SDS boards, the CDA's have the same output.
http://www.audiocircle.com/index.php?topic=76400.2820 (http://www.audiocircle.com/index.php?topic=76400.2820)
Post #2827
This is a pic of my 9 channel DSP/Amp case. the DSP's are the unbalanced MiniDSP with advanced plugin. I housed the transfomer and power supply in a seperate enclosure.
(http://www.audiocircle.com/image.php?id=55535)
I am using the T-amp to power my compression drivers. I am planning to upgrade it as soon as I can find a high quality budget solution.
I have never heard the SDS's but those that have them seem to love them. If the money difference isn't an issue I would go with the SDS line.
Hope this helps,
Moto
Moto, I'm looking at the CDA-1000 KIT as well to power my Emerald Physics CS2. They require 4 channels of amplification. Also because they are actively EQ'd they burn some power to boost the bass so I'm intersted in the idea of a more powerful amplifier. Currently I'm using Dayton Audio dta-100a's.
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Anyone been in touch with Tom at ClassDaudio over the past couple weeks... trying to get some answers but so far no response. Hoping they're just out for the holidays.
Had a couple of questions for him on Saturday (bridging a CDA-224 into 4 ohm's), got back to me within a couple of hours.
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intelonetwo:
If I understand correctly you are using 2 Daytons to power your 2 CS2's? I would think the Daytons would be enough for the high's but you would probably (definitely) notice a difference putting the ClassD 254's on your low end and remove 1 Dayton.
Of course this is not considering sound quality which many say is better on the 254 than the Dayton. I don't have the expertise to make that statement, but I do want to replace my T-amp with something else.
Krikor:
Sometimes I think it makes a difference which email address is used. I have had an email go unanswered and resend it with the other address and have him answer in a couple hours.
Moto
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I have 2 CDA-1000 kits. One with an extra board and both with upgraded 500VA transformers (in case I want to add an extra board later).
I am completely happy with them and Tom is great to work with.
Here is a link to the output of the SDS boards, the CDA's have the same output.
http://www.audiocircle.com/index.php?topic=76400.2820
Post #2827
This is a pic of my 9 channel DSP/Amp case. the DSP's are the unbalanced MiniDSP with advanced plugin. I housed the transfomer and power supply in a separate enclosure.
I am using the T-amp to power my compression drivers. I am planning to upgrade it as soon as I can find a high quality budget solution.
I have never heard the SDS's but those that have them seem to love them. If the money difference isn't an issue I would go with the SDS line.
Hope this helps,
Moto
I notice that you have a lot of extra internal cabling inside there, all bundled up. Have you considered cleaning it up a bit? Maybe some point to point wiring soldered directly to the circuit boards instead of connectors and interconnects?
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I notice that you have a lot of extra internal cabling inside there, all bundled up. Have you considered cleaning it up a bit? Maybe some point to point wiring soldered directly to the circuit boards instead of connectors and interconnects?
Yes there is. The bundle between the amp boards are the USB cables to control the MDSP boards. I need custom length cables for those but don't have the expertise to make them. As far as the others I may get to it but right now it has the top on and is in my rack so I can't see them :D.
Moto
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Yes there is. The bundle between the amp boards are the USB cables to control the MDSP boards. I need custom length cables for those but don't have the expertise to make them. As far as the others I may get to it but right now it has the top on and is in my rack so I can't see them :D.
Moto
I was thinking maybe you abscond with all the internal cables and wire them up properly with pieces of wire and soldered connections. Then there would be no need for "custom made" cables.
I can see with all your pre-made or crimped on connections, it looks like you are a bit intimidated when it comes to soldering.
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I was thinking maybe you abscond with all the internal cables and wire them up properly with pieces of wire and soldered connections. Then there would be no need for "custom made" cables.
I can see with all your pre-made or crimped on connections, it looks like you are a bit intimidated when it comes to soldering.
Yep, and get rid of all of those internal RCA plugs/jacks too. It's all just unnecessary and definitely mucking up the sound.
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it looks like you are a bit intimidated when it comes to soldering
Oh yes.
Yep, and get rid of all of those internal RCA plugs/jacks too
OK! I'll get on it. Quit bustin' my B@@ls :D.
Then there would be no need for "custom made" cables
The ones I am referencing are the USB, I wouldn't know where to start with those.
Moto
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The ones I am referencing are the USB, I wouldn't know where to start with those.
Moto
Cut open and strip back an unused USB cable and take a look at what is inside. Should be no problem using a USB cable without the connectors. Desolder the USB connectors from your circuit boards and then solder in the USB cable directly to the connector pads.
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is there a discount code for AC members.
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is there a discount code for AC members.
Tom was giving us 5% discount, shoot him an email.
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is there a discount code for AC members.
Look back near the beginning of the thread, there's a discount code - ACircle - that still works (5%), I think.
BTW, now that I've had my SDS-470 for several months, I'm very happy with it. It cost me under $600 built, and I think I would have to spend at least $2500 to beat it. It's better than the amps I've heard that cost less than that. Haven't directly compared it to something truly hi-end, I hope it isn't as good as some of those, b/c if it is people are wasting their money. But some people don't like the sound of any Class D amp, it seems.
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Hello all,
I've just finish this:
(http://www.audiocircle.com/image.php?id=56027)
This is a sds-224 kit.
I made this preamp for it :
(http://www.audiocircle.com/image.php?id=56028)
This is an hybrid line stage from Diy hifi supplies from China.
The both work very well together : very clear and "précise" sound (i don't know if it is the right word in english), better than my (very) old and beloved Naim Nait1.
This is the first pre-amp I ever made and, hehe, i'm very proud of the result...
Just for the look, the two enclosures are the same:
(http://www.audiocircle.com/image.php?id=56029)
JL
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Hello all,
I've just finish this:
(http://www.audiocircle.com/image.php?id=56027)
This is a sds-224 kit.
I made this preamp for it :
(http://www.audiocircle.com/image.php?id=56028)
This is an hybrid line stage from Diy hifi supplies from China.
The both work very well together : very clear and "précise" sound (i don't know if it is the right word in english), better than my (very) old and beloved Naim Nait1.
This is the first pre-amp I ever made and, hehe, i'm very proud of the result...
Just for the look, the two enclosures are the same:
(http://www.audiocircle.com/image.php?id=56029)
JL
Nice! What are the dimensions of the finished amp?
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Look back near the beginning of the thread, there's a discount code - ACircle - that still works (5%), I think.
BTW, now that I've had my SDS-470 for several months, I'm very happy with it. It cost me under $600 built, and I think I would have to spend at least $2500 to beat it. It's better than the amps I've heard that cost less than that. Haven't directly compared it to something truly hi-end, I hope it isn't as good as some of those, b/c if it is people are wasting their money. But some people don't like the sound of any Class D amp, it seems.
Cool. I've been considering taking the plunge with a finished SDS-470 ($590) for quite some time. If you don't mind my asking; what is the rest of your system and have you had any issues with the unit?
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This is an hybrid line stage from Diy hifi supplies from China.
The both work very well together : very clear and "précise" sound (i don't know if it is the right word in english), better than my (very) old and beloved Naim Nait1.
This is the first pre-amp I ever made and, hehe, i'm very proud of the result...
Just for the look, the two enclosures are the same:
(http://www.audiocircle.com/image.php?id=56029)
JL
Nice builds!
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Beautiful work, uillean! Very clean and simple.
steve k
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Thanks...
For Ajani, the size of the box is :295x330x70mm (without feet)
Just an idea of the size :
(http://www.audiocircle.com/image.php?id=56123)
The original transformer was too hight to fit the box and Tom from ClassD audio was very helpful and found a special low profile one. Great service and easy contact...
JL
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Oh yes.
OK! I'll get on it. Quit bustin' my B@@ls :D.
The ones I am referencing are the USB, I wouldn't know where to start with those.
Moto
(http://www.homebrewusb.com/DIY/Images/pinoutUSB.jpg)
*EDIT: This is the correct version*
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corndog71, the color coding on the data portions of the images you posted contradict each other...
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corndog71, the color coding on the data portions of the images you posted contradict each other...
Huh...
How 'bout that.
What's going on here?
Here's the wiki
http://en.wikipedia.org/wiki/USB (http://en.wikipedia.org/wiki/USB)
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Cool, thanks for the quick clarification!
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Here's a CDA-224 that I built in a Parmetal case for my girlfriend paired up with a Nohr ACA2B preamp. Nice sounding, economical combo. They're driving a pair of Insignias with GR Research mods.
(http://www.audiocircle.com/image.php?id=56140)
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My SDS-450 mono amps are up and running again - and thus far no overheating, no shutdowns after listening for a few hours last night. Tom sent me a couple sets of heatsink "outriggers" (as I call them) or "pontoons" (as he calls them) to increase the thermal mass and keep the amps running cool. Installation involved removing the three screws holding the existing heatsink, sliding the mounting plate underneath the heatsink and pushing the spacers out, then reinstalling the three screws and mounting the pontoons. Not sure if other the other models have the heatsinks mounted on spacers to separate them from the circuit board which is necessary for this mod to work.
The pontoons were a bit taller than the circuit board standoffs, so I used some extra nuts to raise the height of the board yet keep the pontoons in contact with the chassis bottom for additional heat dissipation. If heat still seems high, I may make some heatsink fin extensions with 1/8" thick by 2" aluminum bar stock.
More testing to come this weekend over longer period of time... man, these amps sound good!
(http://www.audiocircle.com/image.php?id=56257)
(http://www.audiocircle.com/image.php?id=56258)
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I have a question about using a metal case. I am going to put my CDA-254 in a Par Metal case. Do I need to place a ground to the case?
Thanks,
Larry
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If I do need to ground it, where do I pick it up from?
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If I remember correctly one of the mounting screw holes is ground. I know when mine were mounted they magically connected to chassis ground. :wink:
Make sure you're RCA inputs are isolated from the chassis.
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Which of the amp kits would be the best match with the Anthony Gallo 3.1s?
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looking forward for your impression krikor
cheers
henry
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Thank you Krikor for posting your success of getting a solution for the thermal problem that you had with your SDS-450 amps. My SDS-254 amps are physically identical to yours and the spacing is the same. From you photos it is easy to see the simple modification to the amps. I'm sure this will work for me as well.
Thanks again Stigs.
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What size fuse are you guys using on your battery amps? The 12v adapter has 2 20amp mini fuses in it, so im guessin about a 50amp fuse?
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Inputs on SDS 470:
Is there any reason for me not to connect 2 preamps to my amp, one to the XLR input and one to the RCA? Obviously not planning on having both preamps on at the same time.
Thanks
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What size fuse are you guys using on your battery amps? The 12v adapter has 2 20amp mini fuses in it, so im guessin about a 50amp fuse?
I have the SDS254, Tom mentioned 6 amp fuse would be good.
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Which of the amp kits would be the best match with the Anthony Gallo 3.1s?
I've found the 3.1s to love power, so I'd recomend the most powerful amp that can handle the 4-Ohm load they present.
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Inputs on SDS 470:
Is there any reason for me not to connect 2 preamps to my amp, one to the XLR input and one to the RCA? Obviously not planning on having both preamps on at the same time.
Thanks
I wouldn't recommend it. Unless you add switches at the amp to keep them separate.
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6amp? that seems small. I also have my dodd buffer and dac on the same supply and they both use 2a fuses.
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6amp? that seems small. I also have my dodd buffer and dac on the same supply and they both use 2a fuses.
Send Tom an email, i dont know your setup. 6 amp is what im using happily. :)
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I am using a 15 amp fuse on my battery powered SDS-254...
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I use a 6 amp fuse for my SDS-258.
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I'd like to get any SDS amp owners opinions regarding how this amp does the treble or upper end, especially cymbals, bells, and similar sounds. I've read some who said the bass and mids are very good but seem to have some reservations regarding the high end.
And, what about separation of instruments? Honestly, I have not spent much time around this thread lately, so I apologize if these questions have been covered in the past.
Thanks to Steve K and everyone else who have been so helpful and forthcoming with info about these wonderful amps.
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I've been very happy with the sound of my SDS-258. It actually runs slightly on the warmer side of neutral and is very easy to listen to for extended periods. There's no harshness to the upper end and it still reveals plenty of detail. Imaging is also very good. For the $600 I spent on mine it is a fantastic bargain! I've heard better amps but they cost several times as much. I don't think you can do much better for under a grand.
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I agree with Corndog71 in regards to the sound of the Class D Audio SDS amps. I have a SDS-470 and am impressed with the full tonal range. It is neutral to slightly warm. I paid $600 for an assembled unit (switchable RCA & XLR) and I think you will be over $1k and probably closer to $2K to reach this level of performance.
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I agree with Corndog71 in regards to the sound of the Class D Audio SDS amps. I have a SDS-470 and am impressed with the full tonal range. It is neutral to slightly warm. I paid $600 for an assembled unit (switchable RCA & XLR) and I think you will be over $1k and probably closer to $2K to reach this level of performance.
That's sure good for $600. I was just up on the ClassD site. I didn't see any info on this SDS450 and SDS470 amp. Just saw them as assembled pieces.
Also, what's this Johnson Upgrade? There is no details at all. on this except that it is $120.
one more thing, there was a in several pages back someone had mentioned putting together a simple buffer for the CDA series of amps which made a definite difference. Could you PM me and Pelliott321 with the details and circuit design/schematic?
Ray Bronk
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On the home page, click on "Complete Amplifiers" or go to http://classdaudio.com/complete-amplifiers.html . There are 3 user comments regarding the SDS-470.
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I rebuilt my SDS-470 with a switch-mode power supply. The smaller power supply allowed me to use a much smaller case; I found one on ebay that had most of the holes I needed already drilled, saving me time.
Here's some pics:
(http://www.audiocircle.com/image.php?id=57521)
(http://www.audiocircle.com/image.php?id=57522)
(http://www.audiocircle.com/image.php?id=57523)
That was my biggest goal, to get a lot of power in a small form factor and have better efficiency than a non-class D amp (note I posted earlier that the SMPS actually seems to have lower efficiency than the stock linear PS, but I went with SMPS because of the size).
First off, it sounds fantastic---for a while. I fired it up last night, listened to some tunes, and was very pleased. It's either "broken in" or I've convinced myself that it does sound better than my QSC power amp (semi joking). It does really seem to "open up" the music more, i.e. greater instrument separation, more 3D soundstage, etc.
But about my "for a while" comment: after I listened to music for a little while, my wife wanted to watch a movie. Towards the end of the movie, we started hearing this "pss hss pss psss" kind of intermittent soft-static sound. We paused the movie, and it persisted. There was only a couple minutes left of the movie, so we lived with it. When the movie ended, we noticed that not only was there the pulsing hiss-sound, but there was an overall static-sounding white noise. This is all from one speaker.
It was late, so we shut everything down and went to bed. Today I fired it up again, and initially, again, it sounded great. I suspected that since the problem showed up after about two hours last night, it must be a heat problem. So I put a blanket over the amp, and sure enough, after a song, it started making the sound. I took the blanked it off, and it went away, but then came back again with a few seconds. I could blow on the top of the amp (it's not shown in the picture, but the top plate fore the chassis has some vent holes) and make the hissing stop momentarily.
Based on what I've read in these threads, I was under the impression that the Class D Audio SDS amps shut down if they overheat. So maybe it's the power supply?
Even when I first turn the unit on, there's a faint "burning" smell that comes out the top. So something is definitely cooking, and when it gets to a point, it starts affecting on of the channels.
Anyone have any thoughts?
Thanks,
Matt
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Way over my head, but can you run it with no cover to test if it is just themal build up? Longer term a mesh top cover might be all it takes.
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I rebuilt my SDS-470 with a switch-mode power supply. The smaller power supply allowed me to use a much smaller case; I found one on ebay that had most of the holes I needed already drilled, saving me time.
Hey Matt, love the small form factor build... very nice! Thanks for the pics, impressive.
I rebuilt my SDS-470 with a switch-mode power supply. The smaller power supply allowed me
Even when I first turn the unit on, there's a faint "burning" smell that comes out the top. So something is definitely cooking, and when it gets to a point, it starts affecting on of the channels.
Definitely not good, must find out what's going on. Let us know what Tom has to say about it.
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Hello All! I stumbled across this thread a few months ago and read through it (a few times). After going back and forth on which of Tom's kits to get, I settled on the SDS-254 kit. I also ordered a par metal case (12x12x4), black anodized aluminum with the silver thicker-gauge face plate. I put it together over the last week and wanted to share a few pics with the group. I have this running in my home office with some 4 ohm DIY speakers. I am using the Grant Fidelity tubeDAC-11 preamp and sending music digitally through the mini-toslink on my MacBook Pro. So far I am loving what I hear. I'm hoping that the sound gets even better once the preamp has 50 or so hours break in on the tube... sorry for the relatively low quality pics; they were taken on my iPhone as I was running out the door to a Superbowl party...
(http://www.audiocircle.com/image.php?id=57566)
(http://www.audiocircle.com/image.php?id=57567)
(http://www.audiocircle.com/image.php?id=57568)
As you can see, I still need to hook up the external LEDs and a "standby/power" switch to the faceplate. I need to use my neighbor's drill press for that ...
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To Roymail:
I am in france..i use a sds470 amp, and have been continuously improving the sound thanks to mods to the speaker cables and interconnects.
Two days ago,i tried a new cable for the treble section of my Duntech Prince speakers.
The (-) is made in flat siltech wire, but i worked only on the (+) wire.
I tested for the (+) wire going to the treble section in bi -cabling, a wire made as follows:
-one thread in pure silver, diameter 0,6 mm, teflon coated
-one thread in litz copper wire, 8X 0,28mm vernish coated
-one thread in litz copper wire, 25X 0,05mm vernish coated
The result is absolutely incredible: the cymbals sound like if in the room, the percussions are very fast, very present,the high treble has got a lot of "air", the dynamic power is improved.
This is confirming that the sds 470 tends to be a little bit "shy" in the extreme treble area, but if the interconnect to the amp is chosen correctly, and if the speaker cable favourizes the extension of extreme treble ,the "shy" character disappears completely and this amp sound incredibly fast and clear, i donot see any amp at any price which could perform undisputedly better.imho.
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To Roymail:
I am in france..i use a sds470 amp, and have been continuously improving the sound thanks to mods to the speaker cables and interconnects.
Two days ago,i tried a new cable for the treble section of my Duntech Prince speakers.
The (-) is made in flat siltech wire, but i worked only on the (+) wire.
I tested for the (+) wire going to the treble section in bi -cabling, a wire made as follows:
-one thread in pure silver, diameter 0,6 mm, teflon coated
-one thread in litz copper wire, 8X 0,28mm vernish coated
-one thread in litz copper wire, 25X 0,05mm vernish coated
The result is absolutely incredible: the cymbals sound like if in the room, the percussions are very fast, very present,the high treble has got a lot of "air", the dynamic power is improved.
This is confirming that the sds 470 tends to be a little bit "shy" in the extreme treble area, but if the interconnect to the amp is chosen correctly, and if the speaker cable favourizes the extension of extreme treble ,the "shy" character disappears completely and this amp sound incredibly fast and clear, i donot see any amp at any price which could perform undisputedly better.imho.
Max, thanks for that helpful information. I will definitely keep this for future reference to try later. I bet you system sounds awesome!
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But about my "for a while" comment: after I listened to music for a little while, my wife wanted to watch a movie. Towards the end of the movie, we started hearing this "pss hss pss psss" kind of intermittent soft-static sound. We paused the movie, and it persisted. There was only a couple minutes left of the movie, so we lived with it. When the movie ended, we noticed that not only was there the pulsing hiss-sound, but there was an overall static-sounding white noise. This is all from one speaker.
It was late, so we shut everything down and went to bed. Today I fired it up again, and initially, again, it sounded great. I suspected that since the problem showed up after about two hours last night, it must be a heat problem. So I put a blanket over the amp, and sure enough, after a song, it started making the sound. I took the blanked it off, and it went away, but then came back again with a few seconds. I could blow on the top of the amp (it's not shown in the picture, but the top plate fore the chassis has some vent holes) and make the hissing stop momentarily.
Matt... when I was having my overheating problems I noticed that sometimes, when the amp was right on the verge of going into shutdown, the orange LEDs on the board would briefly glow and then go out as it approached shutdown temp. Perhaps the amp is heating up just to the point of shutdown but not hot enough to push it over the edge and you're getting that noise as it rides that edge. I don't recall hearing any noise through the speakers with mine, but then I was more concerned about it going into total shutdown at the time.
Try running it again and watching the LEDs when the noise starts up.
On the other hand, maybe your power supply can't handle the extra heat inside that chassis :scratch:
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To Roymail:
I am in france..i use a sds470 amp, and have been continuously improving the sound thanks to mods to the speaker cables and interconnects.
This is confirming that the sds 470 tends to be a little bit "shy" in the extreme treble area, but if the interconnect to the amp is chosen correctly, and if the speaker cable favourizes the extension of extreme treble ,the "shy" character disappears completely and this amp sound incredibly fast and clear, i donot see any amp at any price which could perform undisputedly better.imho.
What interconnects do you think aid the treble?
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To Firedog:
my balanced interconnects are made of copper single wire silver plated awg28 for the earth , and for (+)and(-) a mixing of 6X0,1and 25X0,05mm copper litz wire,varnish coated.
such interconnects are NOT shielded, any shield must absolutely be avoided to refrain from increasing the cable capacitance, lenght is limited to about 60centimeters.
The disposition of wires can be of two different shapes:
-either sticked in parallel on an adhesive band ,the earth being in the middle,distance between wires and earth about 3mm, then when sticked ,a second band of adhesive recovers the wires, thus forming a flat cable
-either tressed like the hair of your daughter, similar to kimber cable, but in such a case ,the two litz wires must be first located inside a protective plastic retractable coating
What is important is to reduce the capacitance of the interconnects by all means,in order to favourize the extreme treble.
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Well, the IR2092 amp has gotten so popular that sure enough there is now a, er, Sure board. Just the amp module, not a kit...
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=320-313 (http://www.parts-express.com/pe/showdetl.cfm?Partnumber=320-313)
(http://www.parts-express.com/images/item_large/320-313_l.jpg)
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Ainsley, I know you will give it a try out. So please report back your findings. The heatsink looks like the real deal. Great price.
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Ainsley, I know you will give it a try out. So please report back your findings. The heatsink looks like the real deal. Great price.
Ha, nope! I am semi-'retired' from the audio nirvana chase and happily using a receiver. Someone else will have to give it a go...
FYI, here's a great technical distortion/listening comparison between IRS2092 and other class-d chips. Confirms some of why the classdaudio amps sound so great.
http://www.diyaudio.com/forums/class-d/194617-distortion-tests-hifimediy-t2-ljm-l20d-sure-tda7498.html (http://www.diyaudio.com/forums/class-d/194617-distortion-tests-hifimediy-t2-ljm-l20d-sure-tda7498.html)
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This thread has motivated me to build an amp with a Sure 100wx2 with battery power supply. I will put a connector on it to run on a wall wart or separate power supply for when I am on the trainer or just need background music. For critical listening I will use the batteries. I am very excited to have a battery pre (Warpspeed) and amp. Super inexpensive system too. I have read that battery operated stereo has a unique and very enjoyable sound.
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I picked up a CDA-254L kit from Tom ad cassdaudio.com . I had many questions before purchasing and after and he responded to all, so wanted to give him kudos for it. Several posts discuss extra cables coming from transfomer and I wanted to pass on my experience. I received the Antek AS-4434 with
brown/orange leads as well as a purple lead. Those brown/orange leads need to be capped off individually and the purple wire goes to ground
at the IEC chassis mount. Also as a precaution when wiring up first time, Tom suggested I wire up only the power pcb to the transformer to
prevent the audio pcb from damage in event I had incorrectedly wired up the power leads from transformer. Once you know its working
and no smoke or plastic melting around transfromer, disconnect and then continue wiring up the audio pcb.
I have had many amps from Conrad Johnson, Rogue Audio, Odyssey Audio, Emotiva and this diy amp bests them all with top to bottom soundstage, clarity. The only minor quibble I have is that the music is pushed a little forward. But I can live with it. I am now thinking of getting another CDA-25L so i can have two of these drive my Maggies 1.6. I am also waiting on the arrival of my Bottlehead Quickie.
Thanks to all who have contributed to this superb diy amp.
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Well, the IR2092 amp has gotten so popular that sure enough there is now a, er, Sure board. Just the amp module, not a kit...[/img]
What kind of PS would one need to make a 6-channel amp (to biamp LCR mains with active crossovers) out of three of those modules?
More generally, with these things does one need anything besides a PS with power cord, box, and SpeakOn jacks for speaker output (because they're both markedly superior to binding posts in terms of safety and usability, and cheaper)?
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More generally, with these things does one need anything besides a PS with power cord, box, and SpeakOn jacks for speaker output (because they're both markedly superior to binding posts in terms of safety and usability, and cheaper)?
My ClassDAudio amps are the first I've used SpeakOns (as well as PowerCons) and I couldn't agree more. I don't think I'll ever go back to posts, spades, bananas, etc. I also like that the actual conductive parts are relatively small and low mass. Plus they are easy to use for biwiring and biamping using the 4-pole models. And the capper, the cost next to nothing compared to some of the binding schemes out ther... an absolute bargain in my book.
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Hi,
i had build a SDS-254 Kit and it sounds fantastic.
I would like to express my sincerest thanks to Tom and community to provide and support such great device.
Attached some pcitures of my DIY Stuff and Amp.
Regards
Marcus
(http://www.audiocircle.com/image.php?id=57948)
(http://www.audiocircle.com/image.php?id=57949)
(http://www.audiocircle.com/image.php?id=57954)
(http://www.audiocircle.com/image.php?id=57951)
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Hi,
i had build a SDS-254 Kit and it sounds fantastic.
I would like to express my sincerest thanks to Tom and community to provide and support such great device.
Attached some pcitures of my DIY Stuff and Amp.
Regards
Marcus
While your cabinets aren't the prettiest, your component lay-out and wire routing are excellent :thumb:
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(http://www.audiocircle.com/image.php?id=57948)
Very nice job, Marcus. Can you tell us specifics about the the power supply?d Thanks!
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To Marcus:
Is this power supply bringing an improvement if compared to the standard one ?
To Roymail:
Here in Marseille, France,we are 3 audiophiles really seduced by the sound of our sds470 's amps,even if compared to high end amps.
- I am responsible for searching which are the best interconnects ,speaker bi-cables, and power cables ,to allow the sds to sound at the highest level
- My friend Emil is working on internal improvements aiming at refining the sound further.(if possible)
He already said to me that the wire lighting up the led located in the power switch can be favourably removed...he is also shortening all the signal wires and modifying the speaker
wires.
About the pots, he's been removing them for vishay resistors,but i dont agree with him since the adjustment allows first to balance the sound image between the speakers,..and overall second since the position of such posts changes significantly the sound...i connect directly a weiss dac2 and the dynamic effect is modified if the output level of the weiss is set to low with pots more open or if it is set to high with pots rotated counterclockwise.
I think the pots have to be conserved (may be replaced by higher quality ones) connected with very short litz wire.
I will let you informed about the results of improvements, ..however the original sds is soo good that i am not sure about the possible level of eventual improvements, except for cabling.
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To Barry :
Thanks. I'm consistently planing to leave the breadboard phase, but it is never come true :D
To Roymail :
The boards are PS Boards from Peter Daniel (Audiosector). Populate with Soft Recovery HFA Diods. The Caps are 4x FTCap GHB Types 63V / 15000µF / 105°C reated.
To Maxitonus :
Sorry i never compare it. :(
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Marcus those look great. I wish i could go without tops, but till I have a pet free home I need the tops. I was thinking abiut building mine into my wood entertainment cabinet (to be build) then I could close off the front and back of that section for the amp wit just some access holes.
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Just talked to Tom and he wanted to share this brand new photo of the new ClassD cases coming out in the next few days. Looking good!!
(http://i59.photobucket.com/albums/g295/mrnick_2006/NewImage.jpg)
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Fully built CDA-254 for $430, SDS for $100 more. That's a heck of a deal.
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Couple more shots, looking good!!
(http://i59.photobucket.com/albums/g295/mrnick_2006/NewImageD.jpg)
(http://i59.photobucket.com/albums/g295/mrnick_2006/ClassD-2.jpg)
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Well, im joining the ranks of the Class D Audio users: I am placing and order for the SDS-470 with the new case this week! Will be using the amp to drive the Gallo 3.1s. As of now, I dont have a premap and Toms suggestion was just to use the amp with my Squeezebox volumes control, he said it sounds great so im gonna place my trust in him! Wish me luck.
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Good luck! Let us know what you think after it's burned in.
steve
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Love those external gain pots.
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just got my kits few days ago.
i will be using 2 SDS-470 with 1 EXODUS Hypex PSU with 1 600VA trafo.
excited 8)
(http://www.audiocircle.com/image.php?id=58422)
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Well, im joining the ranks of the Class D Audio users: I am placing and order for the SDS-470 with the new case this week! Will be using the amp to drive the Gallo 3.1s. As of now, I dont have a premap and Toms suggestion was just to use the amp with my Squeezebox volumes control, he said it sounds great so im gonna place my trust in him! Wish me luck.
That will work, just remember to turn the volume down when you stop listening. If you power up your system and the SB is at moderate to high output, you could damage your speakers. It's sort of non-intuitive to turn down the volume on a device like an SB every time you stop using it, unlike the volume control on an amp.
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That will work, just remember to turn the volume down when you stop listening. If you power up your system and the SB is at moderate to high output, you could damage your speakers. It's sort of non-intuitive to turn down the volume on a device like an SB every time you stop using it, unlike the volume control on an amp.
Thanks Firedog,
I was shocked that this works. For some reason I thought the volume control on the SB Touch degraded sound quality below 80%? Maybe thats just a myth?
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I was shocked that this works. For some reason I thought the volume control on the SB Touch degraded sound quality below 80%? Maybe thats just a myth?
It is a digital volume control, so there is a possibility of lost resolution even though the SB3 has a 24-bit architecture. Not sure I've got this totally correct in my meager understanding, but basically you "throw away" 1 bit of resolution for every 6db of attenuation. If you are playing 16-bit source materials, you've got 8 extra bits of what I'll call padding in there, so you can reduce the volume by 48db before encountering any resolution loss (8 bits x 6db). If you are playing 24-bit material there's no pad in there (but not sure if mild resolution reduction is noticeable at 24-bits?).
I've been reading up on this since I've just started using a DAC with volume control direct into my SDS-450 amps. My Wyred4Sound DAC-2 has a 32-bit architecture so I've got a whopping 96db of volume reduction before resolution loss on 16-bit material, and still 48db on 24-bit material.
Make sure to set your gain pots at a point at or just above the maximum volume you would listen at if the SB was turn up to 100%. This way you can minimize how much you have to turn the SB down and potentially reduce resolution during normal listening. That's one reason I love having the gain pots... you can better match the SDS to your sources. :thumb:
Here's a thread I started with a couple of papers on digital volume controls that I found informative:
http://www.audiocircle.com/index.php?topic=103312.0 (http://www.audiocircle.com/index.php?topic=103312.0)
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Thanks Firedog,
I was shocked that this works. For some reason I thought the volume control on the SB Touch degraded sound quality below 80%? Maybe thats just a myth?
It's not a myth. It chops off bits. The simple solution for you would be to get a volume attenuator. You can get a good one on Amazon for about $60.
http://www.amazon.com/SM-Pro-Audio-Passive-Attenuator/dp/B000T9K8ZO/ref=sr_1_1?ie=UTF8&qid=1330064659&sr=8-1
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Does this mean I should run my SB volume at 100%?
steve k
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Does this mean I should run my SB volume at 100%?
steve k
If you use a pre to control volume then yes. Digital volume control does degrade the quality.
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Make sure to set your gain pots at a point at or just above the maximum volume you would listen at if the SB was turn up to 100%.
You lost me here man, can you explain?
BTW: Has anyone used the Dodd buffer with these amps? Does it work well and do the amps get loud without the buffer introducing gain?
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You lost me here man, can you explain?
Because you lose more bits of resolution the lower you go in volume on the SB3, you want to minimize the amount you have to turn it down to get to a normal listening level. With the SDS amps you can do this by adjusting the gain pots downward, in other words lowering the gain (volume) of the amps rather than the volume output of your SB3.
You just need to set the amp's gain pots at a level that the volume gets loud enough for your tastes when the SB3 is at 100%.
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You lost me here man, can you explain?
BTW: Has anyone used the Dodd buffer with these amps? Does it work well and do the amps get loud without the buffer introducing gain?
I use the Buffer with a fixed gain (vishay) SDS-254. Works great and can get well beyond comfortable listening volume...
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Has anyone used the Dodd buffer with these amps? Does it work well and do the amps get loud without the buffer introducing gain?
Vedder323, just plug your cd player straight into your amp and put on some soft music (nothing loud), and this will show you how loud your system can play with no gain.
The Dodd buffer works great with my Goldpoint attenuator, and much better than the Goldpoint by itself. It adds dynamics, wide soundstage, not in your face but beautiful clarity at all volume levels.
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Praedet what is the value of the vishay you use?
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1 kOhm
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1 kOhm
praedet
Did you ever try to run a bare wire between posts 2 and 3 instead of a resister? I've never been convinced that a resister can be quieter than a wire jumper, but could be wrong!
Just courious.
Mike
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Mike,
Not sure if it would work without a resister, but the resister is also what is determining the gain of the amp. Very worthwhile for a number of reasons (noise floor and greater finetuning of the volume control being the biggies for me).
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I did not in fact try that as the gain would be very high...
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Mike,
Not sure if it would work without a resister, but the resister is also what is determining the gain of the amp. Very worthwhile for a number of reasons (noise floor and greater finetuning of the volume control being the biggies for me).
Works great with my Dodd Buffer (no gain, no gain). I agree...love the flexiblility to match any other pre-amp!
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So you have completely bypassed the pots with no resister at all? Good to know that can work in appropriate set ups. Duly noted.
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So you have completely bypassed the pots with no resister at all? Good to know that can work in appropriate set ups. Duly noted.
Actually, I took two of the power on/off connectors (two wire) that I didn't need, used a file to flatten the side, cut and soldered the two wires together, and popped in on pins 2 and 3. This can be used for a resistor as well! Easily backed out, if you want to go back to the pots.
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Getting Excited, Tom is testing my amp before shipment...
Think the 470 will have any trouble man handling my Gallos? Tom thinks the amp will smack em around and have them begging for more...
Cant wait!
Now, to preamp or not to preamp, that is the question!
(http://www.audiocircle.com/image.php?id=58510)
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To Vedder:
I suggest you not to preamp.
You'd loose some transparency ...but my suggestion is under condition your dac includes a digital volume control.
About extreme treble, i suggest you tu use low capacitance interconnects between the dac and the amp and litz wire for the treble section of your speakers.
I also tested an additional definition in treble when using a mains cable of better design than the standard one.
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If you use a pre to control volume then yes. Digital volume control does degrade the quality.
This sub-thread is very interesting to me. It was my intent to try the SDS-254 in balanced mode with something like a Matrix Mini-i driving it directly, relying on the digital volume control. Would prefer not to use the Nano patch, or any attenuator that does not offer a balanced output.
Can anyone running a digital volume control directly into the SDS amps comment on your perceptions? Can you in fact discern differences at different volume levels?
thanks!
dr_s
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Getting Excited, Tom is testing my amp before shipment...
Think the 470 will have any trouble man handling my Gallos? Tom thinks the amp will smack em around and have them begging for more...
Cant wait!
Now, to preamp or not to preamp, that is the question!
(http://www.audiocircle.com/image.php?id=58510)
I'm very interested in your impressions of this amp driving your Gallo Reference 3. x speakers.
I've been debating one of these amps for some time now for my 3.5s.
What are you using now?
I'm using an Audio Alchemy DLC w/ PS3 > Audio Alchemy OM-150 w/ PSU150 &PSU150M.
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Vedder, I hope you can try with and without a pre. An acitve pre has many advantages in terms of dynamics and impact. Try both and see how each matches your tastes and system
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Thanks all. Ill be forced to try analogue out right to the amp from my touch until i decide on a pre. As of now im leaning towards the dodd preamp, not the buffer.
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Not sure if it was talked about yet, but I found out that the input impedance of the CDA-254 amp is 7K ohms. I asked this question to Tom since I'm currently building a Lighter Note attenuator from Uriah Dailey. So for others planning to use this or another preamp/linestage/buffer with the great amp, there it is.
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7K ohms seems really low. Are you sure you heard him right? It should be a lot higher than that.
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On the impedance issue, you can find this much earlier in this incredibly long thread :):
"I’m sure there is some confusion on the impedance of the CDA series amps. They have gone through changes since out first design. Our first amps worked well with most preamps and input devices, but they did have very low input impedance, and some with tube preamps had problems. Since that time, we have made several changes to try to make them more compatible and able to match up well to all available input devices. We have used up to 45K, but now we have settled on 7.5K input impedance for the CDA series. This seems to match up very well with all available audio equipment so far, and keeps the input noise down to a minimum. The SDS amps have an input impedance of 45K in balanced mode, and about 42K in single ended mode. This seems to work great with these amps and the balanced input stage. For some time now, we haven’t heard of any problems matching our amps to other input devices."
Sorry I didn't note the original poster!
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The CDA series have (list) a 7K Ohm input impedance and the SDS series amplifiers have (list) a 47K Ohm input impedance.
Steve
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Did you ever try to run a bare wire between posts 2 and 3 instead of a resister? I've never been convinced that a resister can be quieter than a wire jumper, but could be wrong!
Hi, i use a simple jumper on pin 2&3, for me it works.
Regards
Marcus
(http://www.audiocircle.com/image.php?id=58641)
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I'm very interested in your impressions of this amp driving your Gallo Reference 3. x speakers.
I've been debating one of these amps for some time now for my 3.5s.
What are you using now?
I'm using an Audio Alchemy DLC w/ PS3 > Audio Alchemy OM-150 w/ PSU150 &PSU150M.
I just bought the rest of the goods for my system...
Ill be using Squeezebox Touch Analogue out > McCormack ALD-1 > Gallo SA amp + SDS470
Looking forward to the combo!
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Amp just arrived! Ill be posting a full review shortly.
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Amp just arrived! Ill be posting a full review shortly.
Excellent, really looking forward to this! Please try and pay attention to the sound of Cymbals, as this is where I find most class D amps seem to fall short.
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I am going to take more time on this review than normal so give me a few days to come up with something substantial. I will say right off the bat that this new enclosure Toms team at class d is putting out really is top notch. Built like a tank and oozes quality.
The back panel is laid out with purpose and makes connections simple. So many companies skimp and cut corners where Tom has paid careful attention and this should be commended
As a preview to the sound:
Anyone jumping from tubes to the class d audio amps will feel like they have just came home from a long vacation. The overall sound leans a tad to the warm side but brings bass, speed and detail that my tube amp just couldnt pull off.
Bass is scary good and drives the Gallos like gods of thunder. I have never heard these speakers hit so low with such ease and authority. I am actually thinking about selling my sa amp, I doubt ill need it with this bad boy.
Mids are clean and accurate, nothing honky or smeared. Acoustic guitars pop and image really well in the deepest of mixes.
Treble and cymbals are crisp and natural. No squinting in agony from big symbol crashes even at triple digit decibels.
As you can see, this is gonna be a very positive review.
Good job Tom, thank god we have affordable audio that sounds like a million bucks.
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Hi
i am Marc , i live in france and i speak a little english
So i have one system with preampli Nelson Pass UGS and Magnepan 3.6
I have amplifier MC 402 and i would like to change with Classe D because i listen yesterday SDS470 and good good and good
So I hesite between classedaudio, wyred 4 sound sx 500 now 1000 and Hypex UcD700HG+HxR
It is complicated for me to make the difference between N-core, lists(classifies) T and other. Seen my English is just it is difficult for me to read quite your comments. Can help me PLEASE
best regards
Marc
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An update on the overheating/static/hissing issues I've mentioned a couple times in the last few pages of this thread...
I drilled bigger holes for the standoffs, and also used a grinding bit to somewhat "countersink" the standoffs. I also noticed that the screws that come with the standoffs are a bit too long, and (at least with my case) actually touch inside the standoff, leaving a little bit of play when you mount the board. So I used some washers as a shim, ensuring that I could fully tighten the standoff screws. Net result was that the amp's heatslugs now mate perfectly to the chassis. I also put some thermal grease (made for CPU heatsinks) between the slugs and the chassis.
Now I can only duplicate the problem if I wrap the whole chassis in a couple fleece blankets. Without the blankets, the whole chassis gets warm (but not hot) to the touch, but I don't have any audio problems. I've only had it all worked out like this for less than a week, so time will tell to be sure. But so far things look encouraging.
I got one of those infared laser thermometers and took some readings after forcing the hissing/overheat issue. What I found was that the PCB itself was hottest, moreso on the right side than the left. The PCB on the right side, near the output area was 150 degrees Celsius, but the left side was only 50 degrees Celsius. I asked Tom about this, but all he said was "If you're using a laser type thermometer you will get this kind of reading." I didn't want to bug him and ask for an elaboration... maybe someone on this thread can do that? I know these laser infared heat guns aren't the most accurate, but shouldn't a 3x difference from one side to the other be indicative of something?
The only other quirk is the SMPS800R makes a slight humming/buzzing sound. Generally it's quiet enough that it can only be heard when my ears are within about a foot of the unit. But sometimes it's a bit louder and sometimes quieter. I just asked Cristi about this over on the diyaudio forums.
I'm still immensely happy with the sound though. I'm actually thinking about buying a second one! :)
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I think you'd have a rather long list of amps that overheat if you wrapped them in a couple of fleece blankets! Not to mention potential fires and a host of other issues.
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I think you'd have a rather long list of amps that overheat if you wrapped them in a couple of fleece blankets! Not to mention potential fires and a host of other issues.
Agreed, I think that goes for a lot/most electronics in general. :)
The fleece blankets came about because when I first noticed this problem, it took watching an entire movie to trigger the issue. I didn't want to sit through the movie again while trying to debug this, so I used the blankets to speed up the heating.
Before the better mounting I just described, even after removing the blankets, the issue would persist.
But now, after the better mounting, once I remove the blankets, the issue goes away.
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What gauge wire runs between the power supply board and amp board?
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Hey Matt, I'm curious about those who initially mounted their amps on boards or in wooden boxes. I don't recall any heat related complaints. Any thoughts?
Glad yours is working well. :D
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What gauge wire runs between the power supply board and amp board?
14 gauge. In particular, Carol 14 AWG 3C SJOOW Power Cable (http://www.parts-express.com/pe/showdetl.cfm?Partnumber=100-574&FTR=100-574).
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Hey Matt, I'm curious about those who initially mounted their amps on boards or in wooden boxes. I don't recall any heat related complaints. Any thoughts?
Glad yours is working well. :D
No thoughts of any significance. :) Only wild guesses, such as:- Perhaps all the wood enclosure guys had overall bigger enclosures (more breathing room and/or more ventilation)
- I don't recall anyone building an SDS-470 in a wood enclosure, seems those were all lower-power amp models
- Maybe the wood enclosure guys all happened to have easier to drive speakers (e.g. lower impedance and/or higher efficiency)
- Maybe those folks have an overall lower volume level (although I believe my listening levels are quite modest, but my room is huge)
- I am definitely in the minority for using a switch-mode power supply, and my crude measurements suggest my SMPS is less efficient than the linear PS (i.e. mine puts out more heat)
Again, that's just speculation.
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Matt, me thinks you speculate correctly. Good points that make sense to me.
Vedder323, what Class D Audio SDS model did you build? Glad it's sounding so good.
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What gauge wire runs between the power supply board and amp board?
I use a solid core 16AWG wire. I used the same kind of wire for the outputs.
(http://i576.photobucket.com/albums/ss207/corndog642/classdaudio%20amp/b711d1b1-1.jpg)
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What gauge wire runs between the power supply board and amp board?
I thought I'd share some info I received from Tom over the past year.
You should use about 16 gauge wire power and speaker outputs but can use smaller such as 20 gauge for inputs.
The blue LED’s are 3.4 volt and the yellow are 2 volt… don’t use LED’s with different voltages.
One other note (this may have been already been mentioned). Tom's website has been updated to include bare cases, bare cases with all connectors, as well as custom amplifiers. I may purchase a bare case with connectors just to see how complete the parts are. Can't seem to get away from the wooden base I started with!
Mike
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is anyone here running their amp on batteries using class d's 12 car audio PS? I just hooked it up and its not working.
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Hmmm, yeah, I have an SDS-254 running on the car audio PS and a SLA battery no problems. Did you hook up the gain pots correctly? Which amp?
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I have one of the cda amps so no pots. The fuses on the PS have 12v but the led on the amp dont light up and i checked all the switches.
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Looks like only the CDA-254 will work with the battery power supply. Is that the one you bought? The battery supply should be putting out +/- 50 volts, and the 254 series is the only amp that falls into that range. Any other amp will get too much/not enough voltage.
Mike
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Thats the one i got. I put my meter on the outputs and nothing. I should see -50vdc and +50vdc right?
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Sorry...I don't have that power supply, but yes, the specs say 50 volts. Sorry for all the obvious questions, but here they come! Does that power supply have any lights that show it is on? Do you have the small switch on the side of the CDA in the on position? Any way to get a picture? I've made just about every mistake (including frying a CDA-224), so I've been there!
Mike
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One more thing. Did you check the voltage on the input side (where the battery connects)?
Mke
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14.4 at the terminal and fuses on the board and no leds on the PS. Ive moved all the switches around and still nothing.
http://classdaudio.com/power-sppplies/12v-dc-switching-power-supply-500-watt-car-audio.html
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Sorry I wasn't any help. I'd e-mail Tom...he's always been very helpful. Maybe you got a bad PS.
Good Luck!
Mike
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Yeh i sent them a email yesterday but i was hopeing we could get it running. Thanks guys.
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Ok so I got the PS to turn on by touching 12v to the remote and some blue smd leds came on on the PS and only the yellows on the amp. So i cycled the switch on the amp and still nothing. Also the PS wont turn off untill i disconnect the power and theres a 1.1 volt difference between rails(-43.3/+42.2). I assume its a bad PS.
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hi guys,
i need some help to check and instruction for wiring the SDS-470. this is my first amp module build, so please bear with me :)
i got some questions :
1. Wiring Power Switch --- whats the best way to do this? Wired the trafo to switch -- then to AC outlet? if this is the case, which one should i wire (please see the pic attach)
2. Trafo 0 V = CENTER TAP? (the BLUE & GREEN taped together) -- on ANTEK TRAFO
3. GAIN POT wiring to the ALPS 50kohm Stereo Pot -- is that the right orientation?
4. Do i need to connect ground from Trafo to the AC outlet, or just connect together (blue and green) and leave it?
i appreciate very much for any help.
cheers
henry
(http://www.audiocircle.com/image.php?id=59110)
(http://www.audiocircle.com/image.php?id=59111)
(http://www.audiocircle.com/image.php?id=59112)
(http://www.audiocircle.com/image.php?id=59113)
(http://www.audiocircle.com/image.php?id=59114)
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if anyone would like to see exodus hypex psu
they are well built.
http://www.diycable.com/main/pdf/mch.pdf
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Hi Henry...
I meant to get you as many answers as I could last night, but spaced it out (sorry). Does your tranny have a purple wire? That's the ground wire that I connect to the AC outlet. I see no mention of a fuse??? What kind of power switch is that?
Anyway, I'll look at my setup tonight and answer as best as I can, unless someone else beats me the the punch!
Take care,
Mike
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hi mike,
thanks. looking forward for ur directions.
cheers
henry
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Hi Henry
Pot connections look good to me (as long as the pin on the left side of the picture is ground). I'll be curious how well a 50k Ohm pot reacts, as 10k is dead quiet. Don't forget to put some heat shrink on the wires before soldering...I always forget!
As far as the tranny connection, did the diagram from ClassDAudio not help? Here is the link...let me know what's confusing and I'll try to clarify. Again, I'm no expert!
http://classdaudio.com/documents/transformer_115VAC_instructions.pdf (http://classdaudio.com/documents/transformer_115VAC_instructions.pdf)
Good luck. Hope this helps.
Mike
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I got one of those infared laser thermometers and took some readings... What I found was that the PCB itself was hottest, moreso on the right side than the left. The PCB on the right side, near the output area was 150 degrees Celsius, but the left side was only 50 degrees Celsius. I asked Tom about this, but all he said was "If you're using a laser type thermometer you will get this kind of reading." I didn't want to bug him and ask for an elaboration... maybe someone on this thread can do that? I know these laser infared heat guns aren't the most accurate, but shouldn't a 3x difference from one side to the other be indicative of something?
Does anyone know what Tom means by his statement, If you're using a laser type thermometer you will get this kind of reading? I've since pushed for an elaboration, but haven't received any response.
As long as I don't wrap the unit in blankets, I don't have any audio issues. But the unit still runs quite hot, according to my thermometer. The other day, everything sounded fine, but I pulled the cover and took some readings. One of the big capacitors on the right output side read 160 degrees Celsius. But the left side was only 60 degrees.
The only other quirk is the SMPS800R makes a slight humming/buzzing sound. Generally it's quiet enough that it can only be heard when my ears are within about a foot of the unit. But sometimes it's a bit louder and sometimes quieter. I just asked Cristi about this over on the diyaudio forums.
His reply: The buzzing noise comes when the smps works in burst mode or discontinuous mode. this is a pulse-skipping operation mode implemented to reduce power consumption at no load or very low load. it starts to operate normal as soon as the load reaches 50-70mA on each rail or ~3-5W power. that's below most of the amplifier quiescent current, but some amps could draw less than that if they are muted.
So, all my issues are solved except for this heat issue. Note that if I switch inputs and/or outputs, it's still the right-channel side that consistently reads two to three times hotter than the left-channel. Assuming my thermometer is at least in the right ballpark, then I worry that the life of my SDS-470 could be dramatically shortened from running at these temperatures.
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So, all my issues are solved except for this heat issue. Note that if I switch inputs and/or outputs, it's still the right-channel side that consistently reads two to three times hotter than the left-channel. Assuming my thermometer is at least in the right ballpark, then I worry that the life of my SDS-470 could be dramatically shortened from running at these temperatures.
If I were you I'd send the board back to Tom to be checked, it is possible you got a bad one...
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Does anyone know what Tom means by his statement, If you're using a laser type thermometer you will get this kind of reading? I've since pushed for an elaboration, but haven't received any response.
As long as I don't wrap the unit in blankets, I don't have any audio issues. But the unit still runs quite hot, according to my thermometer. The other day, everything sounded fine, but I pulled the cover and took some readings. One of the big capacitors on the right output side read 160 degrees Celsius. But the left side was only 60 degrees.
His reply: The buzzing noise comes when the smps works in burst mode or discontinuous mode. this is a pulse-skipping operation mode implemented to reduce power consumption at no load or very low load. it starts to operate normal as soon as the load reaches 50-70mA on each rail or ~3-5W power. that's below most of the amplifier quiescent current, but some amps could draw less than that if they are muted.
So, all my issues are solved except for this heat issue. Note that if I switch inputs and/or outputs, it's still the right-channel side that consistently reads two to three times hotter than the left-channel. Assuming my thermometer is at least in the right ballpark, then I worry that the life of my SDS-470 could be dramatically shortened from running at these temperatures.
Matt,
I had similar issues using 2 SDS470 units with 2 SMPS800R in a 1U enclosure. The right channels kept hissing after about an hour of play. This was definitely an issue with the chassis and not enough ventilation. I noticed your unit was confined in a small chassis as well but slightly taller than 1U. I tried a larger heat sink (larger outriggers) but this was not the problem.
I added a 12 volt fan inside my case and the anps run cool now.
I sent 1 amp back to Tom due the overheating and the one he replaced it with did the same things.
I think if you created more air flow in your chassis the problems will go away.
Joel
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Sorry it took so long but I wrote a full review for the SDS-470. I have had the amp for 2 weeks and love it more and more each time I listen to it.
http://www.audiocircle.com/index.php?topic=104385.new#new
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I had similar issues using 2 SDS470 units with 2 SMPS800R in a 1U enclosure. The right channels kept hissing after about an hour of play. This was definitely an issue with the chassis and not enough ventilation. I noticed your unit was confined in a small chassis as well but slightly taller than 1U. I tried a larger heat sink (larger outriggers) but this was not the problem.
I added a 12 volt fan inside my case and the anps run cool now.
I sent 1 amp back to Tom due the overheating and the one he replaced it with did the same things.
I think if you created more air flow in your chassis the problems will go away.
Right after I posted about the issue, Tom replied. He said, The temp difference is because there are different power supplies on the amp and in different places. After I told him that my case has no vents except on the top, he said, I think that's the problem. You need some more ventilation. Can you drill holes in the bottom possibly under the amp and power supply?.
I won't have a chance to do that until at least next weekend. But I'll give it a try. There's not a huge rush for me to do this, since I'm not having any actual audio problems (but the temps do scare me a bit).
I agree, I bet a fan (even a low-RPM one) would make a huge difference in temperature. The only problem is, my case is so small, I don't know where I'd put one. My project turned out to be a bit more ambitious than I expected. :)
At any rate, I concur with what everyone else has been saying: these amps sound wonderful. Originally I said I didn't hear much of a difference between it an my QSC RMX2450. But now that I've gone back and forth between the two amps, there is definitely a difference, which clearly favors the SDS-470. The most notable difference to me is instrument separation and definition; this is most pronounced on classical music. The second most notable difference is bass, which just seems better, especially on bass-centric music like trance.
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Getting Excited, Tom is testing my amp before shipment...
Think the 470 will have any trouble man handling my Gallos? Tom thinks the amp will smack em around and have them begging for more...
Cant wait!
Now, to preamp or not to preamp, that is the question!
(http://www.audiocircle.com/image.php?id=58510)
Hi Vedder323
I received my case kit with all connectors for my SDS-224. As usual...no instructions. I was wondering if you had the above picture in a much higher resolution that you could e-mail me? I'm assuming the case power switch is connected to the amp, and I'm really confused how to hook up the balanced and unbalanced connectors thru the switch to the amp. I'm hoping a better picture will answer a lot of questions.
maboxler at msn dot com
I'll contact Tom if you can't help.
Thanks in advance.
Mike
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I know it is in this huge thread somewhere but I cannot find it again - does anyone know the Molex connector part number used to replace the pot with a fixed resistor? I know some just use the connectors with the kits but I want to save those. Thanks.
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Planning to put my pair of bridged sds-224 in a better enclosure. Any thoughts on the merits of a dual chassis (amp/PS) vs mono block design?
lovin the info in this thread, thanks guys
big
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Planning to put my pair of bridged sds-224 in a better enclosure. Any thoughts on the merits of a dual chassis (amp/PS) vs mono block design?
lovin the info in this thread, thanks guys
big
Hey big
Do you already have two trannys/power supplies? Two monoblocks would be NICE! Anyway, I just received my SDS enclosure with components direct from ClassDAudio (already had the SDS-224, too lazy to build a nice case).
http://classdaudio.com/amplifier-kits-1/parts-components-1.html (http://classdaudio.com/amplifier-kits-1/parts-components-1.html)
These are really nice, but only for one amp. I'm not sure if Tom is planning on expanding his enclosure line to include multiple amps, but it sure looks like he's busy with new products. Anyway, if you have the parts already, the bare cases may work for you. Comes with Neutrik connectors and single speaker connects (holes about an inch apart, not .75).
Mike
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Hey big
Do you already have two trannys/power supplies? Two monoblocks would be NICE! Anyway, I just received my SDS enclosure with components direct from ClassDAudio (already had the SDS-224, too lazy to build a nice case).
Yes, running a dual mono in a hammond case atm. not satisfied with the hammond, looking into the par-metal 20 series.
Im leaning towards the mono block build. just looking for some thoughts on the pro's/con's of each.
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The Molex connectors I used were not a perfect fit and had to be filed a bit (the locking system on them was different than Tom uses), but are snug and won't fall out. Mouser part number for them is: 538-10-11-2033, and you'd also need crimp terminals for them that will attach to the legs of the resistors (that must be soldered IMHO) - Mouser part number 538-08-50-0114. There is a photo of how the resistors look in the connectors on page 108 of this thread
I know it is in this huge thread somewhere but I cannot find it again - does anyone know the Molex connector part number used to replace the pot with a fixed resistor? I know some just use the connectors with the kits but I want to save those. Thanks.
[/quote
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Walkern - Thanks for that.
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Least I could do... this thread is really LONG!
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I'm expecting my SDS-470 kit and the SDS enclosure with parts tomorrow. Anybody have any idea on how to wire the balanced/unbalanced connectors and switch?
thanks in advance
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I'm expecting my SDS-470 kit and the SDS enclosure with parts tomorrow. Anybody have any idea on how to wire the balanced/unbalanced connectors and switch?
thanks in advance
I just "finished" my enclosure. Like most of my projects, I got to a good stopping point, and plan on finishing the rest later (ya...right!). Tom sent me 8 or 9 pictures of the inside of the enclosure. This one may help you. I will be interested in your take on the wiring. If you need all the pictures, PM me with your e-mail, and I'll forward you the whole folder.
Mike
(http://www.audiocircle.com/image.php?id=60230)
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Thx Mrboxler, pics always help :) Did yours come pre-wired at all? From what I can see red is live, orange is ground, both wires for balanced and unbalanced are connected to same screw-in connections but how is the toggle switch wired?
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From looking at the pic, the unbalanced wires go to the balanced connector, than from the balanced connector to the board. I believe that the toggle is actually wired to the board as there is some circuitry on the board to compensate for the balanced vs. unbalanced signal.
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Thx Mrboxler, pics always help :) Did yours come pre-wired at all? From what I can see red is live, orange is ground, both wires for balanced and unbalanced are connected to same screw-in connections but how is the toggle switch wired?
No wires at all! Since I only use the unbalanced, I did not install the switch or the unbalanced connectors (although I have them screwed onto the case so I won't loose them, and I plan on dealing with this later).
Having said that...
Tom's tech wired the balanced connectors to the amp (+ - G), then daisy chained the + and G from the balanced connectors to the unbalanced connectors. That's why you see only three wires per channel screwed to the amp. (I've attached another picture that may be clearer). You could just as well wire each connector to the amp, but 5 wires may get a little tight.
The switch replaces the jumpers on J1 and J2. I found it odd that only two of the three pins were used (2 and 3, I believe). I can't remember if no jumper indicates balanced mode...I lost the original instructions. When you get the kit, you will notice a bare side on the threads of the switch. I e-mailed Tom if the bare side should go up...he didn't say yes or no. Judging by the picture, you only need to deal with the top two pairs on the switch, and pins 2 and 3 on the amp. Sorry, I'm at work and am going off memory as far as pin numbers. This is where I got tired and confused. Using a multi-meter, it seemed as though this combination would not match the lettering on the back of the case. I'll be interested in your take.
This may not help. If you are still confused, I'll e-mail Tom for clarification.
(http://www.audiocircle.com/image.php?id=60232)
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Sorry...can anyone verify the amp setting for balanced input. I'm assuming it is no jumper on J1 and J2.
Vinylb...I'll open my case tonight and double check a couple of things. I'll also try to post some things I ran into, so you don't have to go through some of the brain damage I did!
Mike
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Got an email from Tom, he says for balanced input remove jumpers J1 & J2 completely (this is for the SDS-470 board).
Pins 2 & 3 on jumpers J1 & J2 are to be shorted and used only for unbalanced. Moving to pins 1 & 2 for J1 & J2 will reverse polarity.
I also received instructions about the wiring of the balanced and unbalanced which is confusing, to me at least.
Barry_NJ i think you right, unbalanced is wired to balanced and balanced to connectors....at least thats what its starting to look like.
But I still dont get how the toggle works unless the live goes to it first ? but then you would need 2 lugs on it or two toggles?
Any input you have to prevent me from making mistakes would be very beneficial and truly appreciated.
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Got an email from Tom, he says for balanced input remove jumpers J1 & J2 completely (this is for the SDS-470 board).
I also received instructions about the wiring of the balanced and unbalanced which is confusing, to me at least.
Barry_NJ i think you right, unbalanced is wired to balanced and balanced to connectors....at least thats what its starting to look like.
But I still dont get how the toggle works unless the live goes to it first ? but then you would need 2 lugs on it or two toggles?
Any input you have to prevent me from making mistakes would be very beneficial and truly appreciated.
I just e-mailed Tom too...he's probably wandering why the same questions.
The toggle is wired directly to J1 and J2, pins 2 and 3. When the toggle is in the RCA position, the top pair of connectors on the toggle are "ON", simulating the jumper. In the XLR position, the connectors are "OFF", simulating no jumper.
Hope this helps. I'll try to clarify as you go. Like I told Tom...I can see things from a novice's point of view. Yes, wire from amp to balanced connector, then daisy from balanced connector to unbalanced connector. The toggle switch is not a part of this wiring.
Mike
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Ah ok so the toggle acts as a jumper - that makes sense. Are jumpers/molex connectors, included in the kit?
As for the IEC and fuse, is that all internally wired so we just connect transformer to hot, live and ground connector on IEC?
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Ah ok so the toggle acts as a jumper - that makes sense. Are jumpers/molex connectors, included in the kit?
As for the IEC and fuse, is that all internally wired so we just connect transformer to hot, live and ground connector on IEC?
No...the molex connectors are not included (I haven't found out what the part number would be). Now you know why I'm considering avoiding the toggle switch altogether. If I need to switch from/to balanced, I'll remove the cover and jump/unjump (is that a word) pins 2 and 3 by hand.
The fuse is part of the IEC; however, the fuse is not supplied. I got my 6.3 250V 20mm slow blow fuse at RadioShack. Not sure what amp fuse you require. While you are there, you will need the female flag disconnects for the IEC to transformer connection (the caps on the power supply force you to make a quick turn out of the IEC). Model: 64-3088 | Catalog #: 64-3088. I used the blue ones...the red ones were too small. First problem I ran into. The disconnects were still too big, and pressed up against one of the PS caps. Took me a while to figure out a solution. I used a dremmel tool to grind down the excess plastic (about 1/8") off the part that connects to the IEC. I also loosened the nuts holding the PS and moved it as far from the IEC as possible, then secured it. This combination gave me a 1/16" gap between the disconnects and the Cap (WHEW!). I did not have a proper cripping tool for flag disconnects, so I soldered the wire to the disconnect. If you have the right tool, you are probably okay. If not, I'll take a picture of a "modified" "soldered" disconnect and post it.
Breath!
I went from a wood board to this "nice" case. Grounding becomes very important. 1) Run a short wire from the ground tab on the IEC to a dedicated nut on the back of the chassis. Tom connected to a nut holding the IEC to the chassis. I believe in never using a nut that is shared with another component. Besides...that was a really sharp bend. I ended up drilling a new hole above the IEC, grinding off the powder coating to bare metal, and running the ground wire to that dedicated nut. Bad news...the top of the chassis hit that nut (F&*$). I had to cut a peice off the chassis cover (not noticable, again, I can take a picture of this, of course you can simply connect to the IEC nut and avoid this altogether. I happen to feel better with my solution).
The ground wire from the tranny can connect to one of the screws that holds one of the feet to the chassis. Grounding done! Connect the neutral and hot wires from the tranny to the IEC, wire the tranny to the PS, and power it up.
You will need a break at this time.
I'll let you ponder this. When you get the kit, a lot of this will make more sense, and a lot more questions will pop up.
Again, I'll help as best as I can, or Tom, if you prefer.
Mike
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Holy mackeral...sounds like you been thru some challenges Mike. Appreciate you sharing your experience with me. With my CDA-254l kit and parmetal 20x case I had to "jimmy" a slot for the IEC and seperate fuse holder and had to go back to Radioshack or HDepot...dont recall to get those slide on clips to attach to those flat prongs/tabs found on the IEC and fuse holder. As for the grounding, I took Tom's advice and attached the purple wire from transformer to ground connection on IEC.
I'll have to wait for tomorrow, hopefully when it arrives to see what I have ahead of me.
Neville
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Cool. Here's another shot of the back panel. As you can see, the IEC ground attaches to the nut holding the IEC to the panel. It's hard to tell where Tom's tech attached the "purple" wire, but it was not to this IEC nut.
Dry fit things together...I'll be glad to answer any more questions.
Mike
(http://www.audiocircle.com/image.php?id=60240)
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Should probably make this a sticky.
Greetings, I've recently just ordered a couple of ClassDAudio amps, was wondering if my wiring plan is correct... The intention is to run each SDS board off a Connex 500R SMPS as monoblocks using the XLR balanced inputs, while retaining "flick of a switch (or two switches in this case)" capability to run as two stereo amps off the RCA inputs
(http://www.audiocircle.com/image.php?id=50524)
At present, the case I'm planning to use is rather small and may not allow space for a 2nd XLR, so may forego the R channel XLR connection option. Would like to check with the more experienced folks here whether this is feasible or advisable?
Cheers all, and hello! <my first post 8-P>
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Thanks krikor...
I KNEW I saw that diagram somewhere in the vast thread.
I know I'm a novice, but the diagram seems to prove my point. The supplied toggle switch is a DPDT, when a DPST would have been fine. The problem, as I see it, is that the top two connections are wired to the amp. If you look at the picture of the back of the chassis, the up position is labeled BAL, the bottom RCA. Seems to me that with the switch in the top position, the connection to pins 2 and 3 would be closed (ON), and the amp would be in unbalanced (RCA) mode.
What am I missing???
Mike
(http://www.audiocircle.com/image.php?id=60255)
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I think the position of the switch is inverse to the top/bottom of the connections. When you flip the switch up it moves the slider inside the switch down, being on the other side of the fulcrum from the lever/toggle. Flip up to engage the bottom contacts, flip down for the top contacts.
If you are unsure, just hook up a meter and check continuity between contacts with the two switch settings.
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My kit arrived in USPS large priority box, which got me curious. Well it turns out the case was "flattened" and arrived in parts which is a really good way to prevent shipping costs and damages to it. Parts for the enclosure and the amp and power supply were inside the "flattened" case. Everything was very well packed, including the enclosure parts. Here are pics showing the enclosure.
(http://www.audiocircle.com/image.php?id=60260)
Bottom enclosure - note holes ready for installation of kit
(http://www.audiocircle.com/image.php?id=60261)
Top enclosure
(http://www.audiocircle.com/image.php?id=60262)
rear "connector ready" plate. Eric Clapton cd used to size the plate...thx Mr Slowhand
(http://www.audiocircle.com/image.php?id=60263)
front plate with 2 led holes at bottom right
I really like my Par-Metal 20x case but this is on a much higher level....better be for the price :)
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Here are the other parts:
(http://www.audiocircle.com/image.php?id=60264)
(http://www.audiocircle.com/image.php?id=60265)
Bottom left 2 packets are screws. Bottom right is the led's and housing for led's. Top right packet is enclosure feet.
(http://www.audiocircle.com/image.php?id=60266)
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I think the position of the switch is inverse to the top/bottom of the connections. When you flip the switch up it moves the slider inside the switch down, being on the other side of the fulcrum from the lever/toggle. Flip up to engage the bottom contacts, flip down for the top contacts.
If you are unsure, just hook up a meter and check continuity between contacts with the two switch settings.
I'm pretty sure I tried that, but I plan on taking the cover off and trying it again. Could very easily have had the switch upside down when I hooked up the meter.
Thanks, Mike
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Mike, did you use thermal paste on the underside of the "pontoons"? I am referring to the heatsinks that almost touch the bottom of the enclosure.
I could have it touch if I add a washer or two but not sure if there will be any benefit to it.
thx
Neville
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My SDS-224 doesn't have the same heatsink. I doubt that the case would become part of the heatsink, but an e-mail to Tom may be in order. Let us know!
Mike
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I found some old computer fans that had 2 and 3pin female connectors so I can re-use those for the led and gain pots. Just put the rear plate on and was trying to attach the transformer and hit a wall - I am going to have to get right angle female spade plugs. It's pretty tight between the rear plate and the power supply board. Plenty of room between rear plate and amp board.
While I am out I am going to have to get something similar to led to solder on the external switch.
for J1 & J2 I am going to use the same connections found on computer fans.
My Antek AN4442 has 4 leads for 12v and thinking of using that to power a fan I am going to attach near the heatsink. Any idea on how I get that wired to a fan? Thinking 2 orange leads joined together and the same for the 2 brown leads, how do I know which is neutral and live ?
Neville
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First off...I'm an idiot. With the toggle switch INSTALLED in the case, and the toggle switch in the down position (RCA), the top two connectors measure zero ohms (you were right krikor, I must have measured it backwards when it was out of the case). This makes sense...the switch cannot be mounted upside down as long as you wire the top two connectors to the amp. When does one graduate from novice in this hobby anyway?
Neville, you must be referring to the flag disconnects I mentioned earlier. Pretty tight! As mentioned earlier, you may need to grind them down a little more to clear the caps. I know I did.
My transformer doesn't have 12V outputs, so can't help you there. Are you sure you need a fan?
Mike
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Mike now I understand it, terminology threw me off.
I need to pickup 16ga cable and if they don't have right angles
I'll grind them down.
Did you have any clearance issues with speaker posts?
I probably don't need a fan but figured why not since
My maggies are going to put this amp to work.
I googled the transformer and found I only need to use
The Orange leads for 12v.
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Sorry for the late response. Retirement party for a friend at work last night. Good food, open bar...you get the picture.
I had no issues with the speaker posts. The ones near the PS had to make a quick turn...I used cable ties to bind the four wires together.
I hope we are talking about the same thing on the IEC connection. Here is a picture of what I bought.
(http://www.audiocircle.com/image.php?id=60343)
You'll notice the metal connection is recessed. I grinded the excess plastic down to the metal, gave me a little more clearance. You could even grind down the metal female connect a little to get more clearance. I didn't grind the male connectors in the IEC. I used 14 AWG wire into these. Probably overkill, and why the ground connection was hard to bend onto the IEC nut, but...
I also found a good way to solder the wire into the flag connector. If you don't want to crimp (I tried, ruined a flag connector, and had to buy a whole new package, since it came with only 3). I'll post a picture of my solution if you are interested.
Mike
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How is the hang over? :)
yes that is exactly what I am looking to get. If you got time, you can PM me your pic.
thx
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Feeling good! My wife has the camera at her shop...I'll get you the picture ASAP. It also occured to me that, if you have a little room between the PS and the tranny, you could drill out the standoff holes used for the PS (1/8" bit?) . That would allow you to push it away from that back plate a little more. As you can tell, it's a little tight back there.
Mike
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Mike,
Please post the pic here for the benefit of all ;)
Thanks, Barry
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Here it is...
(http://www.audiocircle.com/image.php?id=60345)
As you can see, the plastic was ground down enough so I could push it further into the IEC, and now it clears the cap. Before this mod, the disconnect was pushing into the cap.
The flag disconnect I bought has plastic that stops the wire from going out the other side. I grinded that small piece of plastic off, and allowed 1/4" of bare wire to stick out thru this opening. This allowed me to heat the end of the wire, apply solder to the bare wire, and the solder sucked into the crimping hole enough to bond the disconnect with the wire. I cut off the excess wire, and had a great connection. Hopefully you can see the shiny solder (the flash blurred it a little). This picture also shows my modified ground connection.
Hope this helps. Some else will probably have a better solution, but this was the best I could come up with.
Mike
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Radioshack and HDepot dont carry any right angle connectors. What has become of RShack? Going to try to hit up Frys and if I still come up empty I am going to drill new holes for the ps board.
thx for the pic Mike.
Now looking at wiring up the 6 lug toggle switch to J1 and J2...got me perplexed.
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Here's a thought, and forgive me because I don't have a board or chassis to check with. But can the PS Board be rotated 90 or 180 degrees to give more clearance to the IEC connections?
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Here's a thought, and forgive me because I don't have a board or chassis to check with. But can the PS Board be rotated 90 or 180 degrees to give more clearance to the IEC connections?
Good thought, but case is too small for 90 degree and 180 degree would make the other wiring almost impossible. However...a 5 or 10 degree pivot might move the offending cap enough from the IEC to eliminate the grinding I did to shorten the disconnect. I didn't want to drill any more holes...but.
Neville, bummer on the flag disconnects. Even with a minor PS adjustment, a regular disconnect will be tight. When this is over, I think I'll recommend to Tom to supply the disconnects with the kit.
Regarding the toggle switch...is your issue which pins/connectors to use, or how to make those connections?
Mike
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Here's a thought, and forgive me because I don't have a board or chassis to check with. But can the PS Board be rotated 90 or 180 degrees to give more clearance to the IEC connections?
Barry thats exactly what I am doing now....finding a better location for it. So far it appears best location in terms of wiring is to have the ps board
adjacent to transformer and then the amp board between ps board and rear plate. I could move the ps board (in its current location) about 2 inches further away from rear plate but the caps still prevent easy access to it. Rotating so caps to the left are better but you have a lot of wiring going across. So its one or the other :)
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Good thought, but case is too small for 90 degree and 180 degree would make the other wiring almost impossible. However...a 5 or 10 degree pivot might move the offending cap enough from the IEC to eliminate the grinding I did to shorten the disconnect. I didn't want to drill any more holes...but.
Neville, bummer on the flag disconnects. Even with a minor PS adjustment, a regular disconnect will be tight. When this is over, I think I'll recommend to Tom to supply the disconnects with the kit.
Regarding the toggle switch...is your issue which pins/connectors to use, or how to make those connections?
Mike
How about soldering wires directly to IEC at an angle?
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Justin I thought about that but went for the new layout.
(http://www.audiocircle.com/image.php?id=60378)
Those rear "screws" are really a pain. I only have the size a notch or two up from it.
I am confused about how to wire the the toggle, 3 rows of 2 lugs or 2 rows of 3 lugs......one side has 1,2 & 3 on it. Toggle is either on or off so I don't understand the middle lugs unless I should be looking at it from 2 rows and 3 lugs.
Was hoping to get this done tonight because of travel over next few days....oh well it will have to wait until I return.
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Think of it as two rows of two lugs (the top two pairs of lugs). Wire the top lug on one side of the switch to pin 2 of J1, wire the middle lug on that same side of the switch to pin 3 of J1. Wire the top and middle lugs of the other side the same way to pins 2 and 3 of J2. When the toggle is down (RCA), the top and middle lugs on both sides of the switch are closed (ON). Connect a mult-meter to them...you should get 0 ohms. This connects pins 2 and 3 on the amp's J1 and J2, putting it into RCA mode. When the toggle is up (BAL), the middle and bottom lugs are closed (ON). However, the top and middle lugs (where you have connected the wires) are open (OFF). The multi-meter will show no connection...pins 2 and 3 are not connected...the amp is in BAL mode. The bottom two lugs on the switch are not used (see pictures).
Tom could have just used a 4 pin switch, causing both sides to be open or closed, and reversed the inputs on the back. Then when the switch were flipped up, a normal ON position, the amp would be in RCA mode. I assume the thinking was that the switch could be mounted upside down, causing damage to the amp.
Mike
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Radioshack and HDepot dont carry any right angle connectors. What has become of RShack?
I bought some at my local ACE Hardware store.
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bummer on the flag disconnects.
I bought some at my local ACE Hardware store.
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Justin I thought about that but went for the new layout.
The only thing that makes me nervous about that layout is the lack of venting under and over the PS Board as there would be with the stock layout(?)
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I bought some at my local ACE Hardware store.
Yea...they are everywhere (almost). The point I want to make to Tom is that he probably gets them for pennies each (I saw 1000 for $149 on EBay). Most people don't have them in their stash at home, and the cost and inconvenience of tracking some down can be frustrating. With the flag disconnects, the original layout works very well (I agree on the cooling issue), as long as you don't solder yourself into a corner.
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Thx for heads up on Ace, will check when I get back. As for heat
I am planning on adding a 12v fan later on. Will test it before going with fan.
As much as I like case I too have found it very frustrating and plan to send tom my recommendations from a noob point of view.
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Hello,
i want to share some possible recaping for everbody who have fun to experience with tweaking the SDS board. The caps are all placed in the input stage of the board.
On the right side there are two smd caps which are using as PS caps for the input stage circuit, in the middle there are two smd caps which are using as bootstraping / filter of the input stage.
I changed the caps to panasonic FC caps. The recap is no game changer but for me it sounds more "powerful" / "muscial".
Note : Please double check the polarity, there is a small dot on the assembly printed of the pcb, they marks the postive side of the caps.
(http://www.audiocircle.com/image.php?id=60454)
Regards
Marcus
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Mike, did you use thermal paste on the underside of the "pontoons"? I am referring to the heatsinks that almost touch the bottom of the enclosure.
I could have it touch if I add a washer or two but not sure if there will be any benefit to it.
Take a look at my build back on page 152 (http://www.audiocircle.com/index.php?topic=76400.msg1048398#msg1048398). I've been having some overheating problems with my amp. However, I'm using a significantly smaller enclosure, plus a switch-mode power supply that is less efficient than the default linear PS (i.e. puts out more heat).
The first time I put my system together, I didn't have a good mating between the chassis and the "pontoons" of the SDS-470. The system would overheat quite readily.
I then rebuilt the system, after using a grinding bit on the standoff holes (to effectively "countersink" them), and also put some washers on the standoff screws. This ensured that my pontoons were fully mated to the chassis and I could apply a lot of pressure to them. I also put some CPU thermal paste between the chassis and heatslugs.
I thought I was in the clear, as I could only get the unit to overheat if I wrapped it in a fleece blanket... but we've had a string of unseasonably warm weather here in Chicago. And my wife said that during the day, it got to be around 80 deg F in the house, and the amp started overheating.
Now Tom wants me to drill some ventilation holes in the bottom of my chassis. I haven't had a chance to do that.
Despite these problems, I have a fully-built SDS-470 on order. I don't expect to have any heat problems, since it will be a much bigger chassis with a more efficient (i.e. less internal heat) power supply.
Anyway, based on the issues I've had, I would definitely use thermal paste between the chassis and pontoon heatslugs. I don't know if Tom does on his prebuilt ones or not. But I can't imagine doing so would negatively affect anything.
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Matt, have you tried leaving the top off or using a heavy screen type top or adding a small fan to the mix?
Your layout is nice, just needs adequate venting. Thanks!
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Matt, have you tried leaving the top off or using a heavy screen type top or adding a small fan to the mix?
I have not tried either of those, but I'm quite confident that they would solve the problem. For a while there, whenever the overheating issues started, I would pull the top off so I could use my temperature gun. But within seconds of pulling off the top, the issues went away. Based on that alone, I'm sure having no cover or a mesh/screen cover would definitely help. But I'd really like to keep the case as-is, if possible. My next plan is to try Tom's suggestion of adding vent-holes to the bottom.
I've thought about using a fan, and really don't want to go there. From my experience with computers, small fans need to spin rapidly to actually move any air. And given the size of my case, I'd have to use a small fan. If I had room for a decent-sized fan (92mm or bigger), I could get one that is slow enough to be silent, yet still move a reasonable amount of air.
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Take a look at my build back on page 152 (http://www.audiocircle.com/index.php?topic=76400.msg1048398#msg1048398). I've been having some overheating problems with my amp. However, I'm using a significantly smaller enclosure, plus a switch-mode power supply that is less efficient than the default linear PS (i.e. puts out more heat).
The first time I put my system together, I didn't have a good mating between the chassis and the "pontoons" of the SDS-470. The system would overheat quite readily.
I then rebuilt the system, after using a grinding bit on the standoff holes (to effectively "countersink" them), and also put some washers on the standoff screws. This ensured that my pontoons were fully mated to the chassis and I could apply a lot of pressure to them. I also put some CPU thermal paste between the chassis and heatslugs.
I thought I was in the clear, as I could only get the unit to overheat if I wrapped it in a fleece blanket... but we've had a string of unseasonably warm weather here in Chicago. And my wife said that during the day, it got to be around 80 deg F in the house, and the amp started overheating.
Now Tom wants me to drill some ventilation holes in the bottom of my chassis. I haven't had a chance to do that.
Despite these problems, I have a fully-built SDS-470 on order. I don't expect to have any heat problems, since it will be a much bigger chassis with a more efficient (i.e. less internal heat) power supply.
Anyway, based on the issues I've had, I would definitely use thermal paste between the chassis and pontoon heatslugs. I don't know if Tom does on his prebuilt ones or not. But I can't imagine doing so would negatively affect anything.
Matt, sorry to hear you still having problems. I recall reading your posts earlier but thought you had it all sorted out. Are you able to get a reading of the temps below the ps board? If so, what are they?
Nice to hear somebody also implemented thermal paste below the pontoons. Do you have any temp or data to indicate how beneficial thermal paste and mating the pontoons with the chassis was? Looking at the screws attaching the pontoons to the amp board's heatsink does not look like there is enough "bonding" to allow sufficient distribution of heat from board heatsink to pontoons. But I could be wrong. Any advice you have will be appreciated.
If Tom, wants you to drill holes/air vents in the chassis, how would you do it? I guess I am a ludite when it comes to this unless you have the tools create rows where heat escapes. I own bare minimal tools although I sure wish I had a hardware store in my store room, thats not going to happen.
Mike, I see on ebay, a seller selling that lot of flag disconnects, but I really dont want 1000' of them :) I emailed another seller selling lot of 20 for $6 if they would fit IEC. Waiting to hear back from them. After driving nearly 650 miles, one way, I don't have the energy to drive to ACE, at least not today or tomorrow.
.Marcus, nice layout with double decker amp boards :) Reminds me of the bus I use to take when I was a young lad, but that was in a different country and era. What values and make are the caps you replaced with ? From what you said, you found it powerful and musical, can you elaborate a little on that ?
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Matt, sorry to hear you still having problems. I recall reading your posts earlier but thought you had it all sorted out. Are you able to get a reading of the temps below the ps board? If so, what are they?
No, things are packed in there too tightly to get any temperature reading under either the PS or amp board. IOW, I'd have to completely dis-assemble everything to take that kind of reading.
Nice to hear somebody also implemented thermal paste below the pontoons. Do you have any temp or data to indicate how beneficial thermal paste and mating the pontoons with the chassis was? Looking at the screws attaching the pontoons to the amp board's heatsink does not look like there is enough "bonding" to allow sufficient distribution of heat from board heatsink to pontoons. But I could be wrong. Any advice you have will be appreciated.
Unfortunately, I do not have any hard data on this. My temperature gun was a gift that I received after I had already re-mounted the board with better mating and the thermal compound.
All I can say, in a very informal sense, is that with the poor mounting and no thermal paste, the amp would readily overheat on its own. And with the improved mounting and thermal paste, it would not overheat unless wrapped in a fleece blanket or the ambient temperature in the house was over 80 deg F.
But, as you can see, I changed two variables (better mating, thermal paste), so it's impossible to say how much each contributed to the better cooling.
If Tom, wants you to drill holes/air vents in the chassis, how would you do it? I guess I am a ludite when it comes to this unless you have the tools create rows where heat escapes. I own bare minimal tools although I sure wish I had a hardware store in my store room, thats not going to happen.
I never posted pictures of the top of the case, but that already has vent holes. I did take pics of the top cover (with the vent holes) and sent them to Tom. He said they are adequate, but I should add holes to the bottom of the chassis. Since it's the bottom, where I don't care about looks, I'm just going to take the whole thing apart, and go to work with my drill. I don't really have any plan; I'm just going to do it by feel (unless someone suggests a better method!).
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This all makes me glad I went with the bigger case.
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This all makes me glad I went with the bigger case.
I'm sure the details are buried in this thread somewhere, but what size and brand of case did you use?
Thanks, Mike
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I'm sure the details are buried in this thread somewhere, but what size and brand of case did you use?
The one I used I found on ebay, and it continues to re-appear (presumably the seller has a lot or is making them himself): "#### HiFi Audio DIY Aluminum Chassis Aluminum Case B", seller ericyam (http://www.ebay.com/itm/HiFi-Audio-DIY-Aluminum-Chassis-Aluminum-Case-B-/190661768020).
Dimensions:
External: W 200 mm x H 85 mm x D 330 mm = 7.9" x 3.3" x 13"
Internal: W 175 mm x H 63 mm x D 320 mm = 6.9" x 2.5" x 12.6"
See pictures of my build back on page 152 (http://www.audiocircle.com/index.php?topic=76400.msg1048398#msg1048398).
By the way, the ebay listing has a picture where you can see what the top vent holes of my case look like.
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.Marcus, nice layout with double decker amp boards :) Reminds me of the bus I use to take when I was a young lad, but that was in a different country and era. What values and make are the caps you replaced with ? From what you said, you found it powerful and musical, can you elaborate a little on that ?
Hi Vinylb,
you are a funny guy by thinking about double decker bus :) If the double decker amp play they take me away also :D
Original PS Caps are 10µF / 16V, i had replace them with 470µF / 25V :green:
Original Bootstrap / Filter Cap is 220µF / 4V, i had replace them with 220µF / 10 V.
I recommended to keep the capacity value of the Bootstrap / Filter Cap.
Please find some additional information about the input stage here :
http://www.thatcorp.com/datashts/Galo_THAT_Line_Dr_%20Rx.pdf (http://www.thatcorp.com/datashts/Galo_THAT_Line_Dr_%20Rx.pdf)
Especialy Page E13 / E14 describe which componets are used for the test circuit.
btw.. i will change the 100 Ohm resistors of the signal input path with some higher grade (e.g. TX Foli) stuff.
For me the bass has more bunch and the sound are more accurate. The music plays more free.
Regards
Marcus
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I'm sure the details are buried in this thread somewhere, but what size and brand of case did you use?
Thanks, Mike
http://www.ebay.com/itm/3U-Black-Audio-Rackmount-Enclosure-DIY-Chassis-Case-10-19115B-/251031818592?_trksid=p4340.m185&_trkparms=algo%3DSIC.NPJS%26its%3DI%252BC%26itu%3DUA%26otn%3D5%26pmod%3D370238951697%26ps%3D63%26clkid%3D7464984291040949996
(http://i.ebayimg.com/t/3U-Black-Audio-Rackmount-Enclosure-DIY-Chassis-Case-10-19115B-/05/!B(nmnpg!mk~$(KGrHgoH-EEEjlLlyOEvBKdQ1Ngz!w~~_12.JPG)
I have to warn you though that the bottom panel is steel and was not easy to drill holes into. The rear panel is aluminum and was much easier. I like how it all comes apart. All assembled it's a freakin beast!
(http://i576.photobucket.com/albums/ss207/corndog642/classdaudio%20amp/461d0ccd.jpg)
Here's a shot I took before mounting the gain pots to the back panel.
(http://i576.photobucket.com/albums/ss207/corndog642/classdaudio%20amp/b711d1b1.jpg)
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I have to warn you though that the bottom panel is steel and was not easy to drill holes into. The rear panel is aluminum and was much easier. I like how it all comes apart. All assembled it's a freakin beast!
Nice case, but darn, how come so much for the shipping? It doesn't weight that much!
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Hi Vinylb,
you are a funny guy by thinking about double decker bus :) If the double decker amp play they take me away also :D
Original PS Caps are 10µF / 16V, i had replace them with 470µF / 25V :green:
Original Bootstrap / Filter Cap is 220µF / 4V, i had replace them with 220µF / 10 V.
I recommended to keep the capacity value of the Bootstrap / Filter Cap.
Please find some additional information about the input stage here :
http://www.thatcorp.com/datashts/Galo_THAT_Line_Dr_%20Rx.pdf (http://www.thatcorp.com/datashts/Galo_THAT_Line_Dr_%20Rx.pdf)
Especialy Page E13 / E14 describe which componets are used for the test circuit.
btw.. i will change the 100 Ohm resistors of the signal input path with some higher grade (e.g. TX Foli) stuff.
For me the bass has more bunch and the sound are more accurate. The music plays more free.
Regards
Marcus
Marcus.
If you trace the PCB tracks carefully I think you will find that there is no bootstrap / filter caps as you suggest. Tom has omitted these, probably with good reason. The 220uF caps you changed are PSU decoupling caps. Still might be worthwhile change.
The 10uF caps are in the signal path but you need to take great care with replacing these. Standard electrolytic caps are very unlikely to improve on what is there and the longer leads are likely to cause issue with EMI pickup. The sound will change, but for the better? Tom has stated he was very careful on what caps he used here. A 470uf is way bigger than is needed. I tried using a 4.7uF BlackGate in this spot but wasn't convinced it made things better.
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The datasheet here has better detail of the input stage:- http://www.thatcorp.com/datashts/THAT_1200-Series_Datasheet.pdf
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Nice case, but darn, how come so much for the shipping? It doesn't weight that much!
That does seem high for ground shipping. He must be tacking some on. Not sure how that works.
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Marcus.
If you trace the PCB tracks carefully I think you will find that there is no bootstrap / filter caps as you suggest. Tom has omitted these, probably with good reason. The 220uF caps you changed are PSU decoupling caps. Still might be worthwhile change.
The 10uF caps are in the signal path but you need to take great care with replacing these. Standard electrolytic caps are very unlikely to improve on what is there and the longer leads are likely to cause issue with EMI pickup. The sound will change, but for the better? Tom has stated he was very careful on what caps he used here. A 470uf is way bigger than is needed. I tried using a 4.7uF BlackGate in this spot but wasn't convinced it made things better.
Hi RichG,
thank you for answer and share your finding, could you please elobarate your conclusion a little bit, because i guess you or i'm on the wrong track ?
Did you trace the PCB, how the capaitors are connected to the IC ? Some analogy to the Datasheet ?
Thanks,
regards
Marcus
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I must confess that i never trace the pcb circuit, but i will explain how are my findings :
The Tantal Chip near the That1200 i guess is connected to Pin 5 & 8 because the position is ideal, if you take a look in the datasheet you would find suggested Capacitor called "Cb", it is used as Bootstrap / Filter Cap.
This tantal chip is labled with Numbers 220 and 4 as suggested in the datasheet to use a 220µV / 3V cap here.
220µV / 4V make not sens in case of PS Cap, because 4V only ?
The area on the right side of the PCB i guess is to create the PS for the input stage by normal Z Diode Regulated topology. I had measure the voltage across the caps and find 14 V, they are used as decoupling this voltage.
I guess if you check the connection you would find that both That1200 Chip supply Pins 4 & 7 connected to this Tantal Capacitors.
The tantal chips are labeld with 10 / 16 what mean 10µF / 16V and make sense at this place.
If you change this tantals caps to smaller values (4.7µF) you maybe degrade the PS of the input stage !
I'm not expect any EMI Problem at this place, because is there a EMI Problem it would also impact the circuit path of the board, the pins are only increase the circuit path by some Millimeters.
Btw.. may be if you use a external wired gain pot they would more prone to EMI.
Thanks
Regards
Marcus
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Hi Marcus,
Sorry, I think I was a little confused with your post last night and we may well be talking about different caps after all.
It's a while since I did any work on this board, but I did take a picture of the BG caps in place:-
(http://www.audiocircle.com/image.php?id=60559)
Prior to doing this I spent a couple of hours tracing the circuit and comparing to the data sheets. For the input stage I believe Tom has used the circuit shown if fig 14 of the datasheet I linked to. This is then followed by the IRAUDAMP7D reference design circuit with the addition of the pot across the input.
The caps I changed are the DC de-coupling caps between these stages - Tants have a certain signature when used as decoupling and I felt an improvement could be gained here. As I said the improvement was minimal - perhaps a little smoother. As I said, Tom was very picky about the cap used here.
I didn't consider changing the bootstrap caps or the PSU caps at the time as I felt the impact would be minimal at best. It's interesting that you felt this was indeed positive. It would be great if you could post a picture showing the caps you changed - I may well do some more investigation when I have the time.
Regarding the EMI - I can't help feeling that the main reason that people hear an improvement when swapping out the pots for fixed resistors is the reduction in noise pickup. Perhaps if screened cable were used this would bring things closer. Using through hole electrolytic caps for PSU coupling you may have issues relating to noise pickup and also the extra inductance from the leads. SMD caps have a big advatage here.
I'm glad to see somebody else exploring the possibilities with mods of these boards. Keep up the good work.
Cheers, Richard
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Hi Marcus,
Sorry, I think I was a little confused with your post last night and we may well be talking about different caps after all.
It's a while since I did any work on this board, but I did take a picture of the BG caps in place:-
Prior to doing this I spent a couple of hours tracing the circuit and comparing to the data sheets. For the input stage I believe Tom has used the circuit shown if fig 14 of the datasheet I linked to. This is then followed by the IRAUDAMP7D reference design circuit with the addition of the pot across the input.
The caps I changed are the DC de-coupling caps between these stages - Tants have a certain signature when used as decoupling and I felt an improvement could be gained here. As I said the improvement was minimal - perhaps a little smoother. As I said, Tom was very picky about the cap used here.
I didn't consider changing the bootstrap caps or the PSU caps at the time as I felt the impact would be minimal at best. It's interesting that you felt this was indeed positive. It would be great if you could post a picture showing the caps you changed - I may well do some more investigation when I have the time.
Regarding the EMI - I can't help feeling that the main reason that people hear an improvement when swapping out the pots for fixed resistors is the reduction in noise pickup. Perhaps if screened cable were used this would bring things closer. Using through hole electrolytic caps for PSU coupling you may have issues relating to noise pickup and also the extra inductance from the leads. SMD caps have a big advatage here.
I'm glad to see somebody else exploring the possibilities with mods of these boards. Keep up the good work.
Cheers, Richard
Hi Richard,
now things come to be clear, we talk about different mods :wink:
Many thanks for came up with some imteresting details and point to additional possible mod. These capacitors are used to DC de-coupeling between THAT1200 out and IRS2092 in ?
Please find a picture on page 159, there you could see the replaced caps.
I will provide a more detail picture later on.
Do you expect that it would be possible to identify change in the EMI behavior by comparing the "background noise" ?
regards
Marcus
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Thanks for the pics, corndog71. I'm looking into a case that will hold 2 SDS-224's, a tranny, and a PS. Looks like the size you bought will be a little tight for an extra amp.
I think I'll need something a few inches deeper. I noticed one can buy a 12 series that is all aluminum...might make the drilling easier. Decisions, decisions.
Mike
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Thanks for the pics, corndog71. I'm looking into a case that will hold 2 SDS-224's, a tranny, and a PS. Looks like the size you bought will be a little tight for an extra amp.
I think I'll need something a few inches deeper. I noticed one can buy a 12 series that is all aluminum...might make the drilling easier. Decisions, decisions.
Mike
If you haven't already purchased your stuff, you might consider a Connexelectronics SMPS instead of the stock Class-D tranny/PS board. I have a setup using a pair of SDS-224s and a Connex supply which works well, and has a much smaller footprint than the stock setup. It is a bit more money, and you have to be a bit patient when ordering the SMPS, but I'm quite happy with the results.
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If you haven't already purchased your stuff, you might consider a Connexelectronics SMPS instead of the stock Class-D tranny/PS board. I have a setup using a pair of SDS-224s and a Connex supply which works well, and has a much smaller footprint than the stock setup. It is a bit more money, and you have to be a bit patient when ordering the SMPS, but I'm quite happy with the results.
Thanks...I'll look into it! Which model did you purchase?
Mike
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Thanks for the pics, corndog71. I'm looking into a case that will hold 2 SDS-224's, a tranny, and a PS. Looks like the size you bought will be a little tight for an extra amp.
I think I'll need something a few inches deeper. I noticed one can buy a 12 series that is all aluminum...might make the drilling easier. Decisions, decisions.
Mike
Mike, for the money I don't think you can beat the Par-Metal all aluminum enclosures. Got mine from them via Ebay which saved a few more bucks. Plenty of room, easy to drill and disassembles easily for working on the panels.
Here's a shot of my SDS-470 monoblocks. Plenty of room for a second amp board in each enclosure.
(http://www.audiocircle.com/image.php?id=54914)
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Mike, for the money I don't think you can beat the Par-Metal all aluminum enclosures. Got mine from them via Ebay which saved a few more bucks. Plenty of room, easy to drill and disassembles easily for working on the panels.
Thanks...
Which model/size are they? I agree, looks good for two amps!
Mike
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Which model/size are they? I agree, looks good for two amps!
I went with the 16x12x4. Not sure what part number that is and just the standard finish. See below from when I first mounted up the boards and xfmr.
The 12x12x4 Par-Metal chassis will work, but I went with the 16x12 to give myself a little more room in laying out the components and keep the power supply farther from the amp board. Also allows for other possible upgrades in the future (power supply, volume control, etc.). Chassis doesn't come punched for anything unless you special order it as such (costs extra).
I've found them pretty easy to drill though I haven't gotten to the back panel yet. Just finished laying out the base plate for my mono SDS-450 amps. Did them mirrored since they'll be positioned side-by-side or behind the speakers. This actually made it easier to lay out and drill the second amp... just clamped them bottom to bottom and drilled through the first (only two of the power supply screws had to be relocated since that board is not symmetrical).
(http://www.audiocircle.com/image.php?id=54307)
(http://www.audiocircle.com/image.php?id=54308)
I also drilled out the footer holes a little larger to accommodate some 1/4" shaft spikes I had on hand... I was only going to use three but found the amp too tippy with the big xfmr off to one side, so there's an extra hole at the front middle.
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I will provide a more detail picture later on.
(http://www.audiocircle.com/image.php?id=60564)
Regards
Marcus
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Krikor, I agree, par-metal cases are very good value for money and I too purchased mine on ebay, had a change of heart on color and called them up and they added a few bucks for black. I dont have all the tools, drill bits available, in fact very limited tools so It was a bit of a pain to drill the correct sized holes. It did provide a sense of accomplishment and pride when I was done, albeit rather "mCgyver style" with some of the holes :)
So its about $85-100 for par-metal and drill own holes or $225 with everything done for you but you have to hunt for extras and kinda locked into Tom's non household standard screws and limitations of the rear plate and close proximity to the ps board.
Oh btw I did pick up flag disconnects and the allen key for those small little screws at ACE hardware. Allen key is not very helpful because of the small size its already stripped a little so it was a mission to get those screws in. I also moved the ps board back to its original location - all this talk of heat got me nervous. Maybe water cooling is the next mod ? I dont think so, at least not for me....ok to put that in a PC but not my hi-fii stuff.
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Hi Richard,
now things come to be clear, we talk about different mods :wink:
Many thanks for came up with some imteresting details and point to additional possible mod. These capacitors are used to DC de-coupeling between THAT1200 out and IRS2092 in ?
Please find a picture on page 159, there you could see the replaced caps.
I will provide a more detail picture later on.
Do you expect that it would be possible to identify change in the EMI behavior by comparing the "background noise" ?
regards
Marcus
Thanks Marcus.
Are these the caps you've changed? Looks like quite a fiddly job :)
(http://www.audiocircle.com/image.php?id=60567)
Getting some higher quality caps on the PSU rails close to the chips is probably a good idea. I think I'm going to have to open mine up again and have a play. While doing the changes did you do any direct listening comparisons between modded and normal boards?
Checking for EMI is not trivial, it may have a direct influence on audible noise but is likely to be more subtle and manifest in other ways. A very fast and sensitive scope or analyser is probably needed, which I don't have.
The caps I changed for BGs were indeed the DC blocking between 1200 and 2092.
BTW the data sheets for the 2092 and iraudamp7d make for interesting reading:
http://www.irf.com/technical-info/refdesigns/iraudamp7d.pdf
http://www.irf.com/product-info/datasheets/data/irs2092.pdf
cheers
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K well I am all done, plugged her in and she sounds really good. BUT I do have some issues i need to address:
1. changing from unbalanced to balanced produces a buzz and music comes through from unbalanced
2. increasing gain pots decreases the volume - what the .... maybe I have them backwards?
Going to check connections. Any other suggestions?
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K well I am all done, plugged her in and she sounds really good. BUT I do have some issues i need to address:
1. changing from unbalanced to balanced produces a buzz and music comes through from unbalanced
2. increasing gain pots decreases the volume - what the .... maybe I have them backwards?
Going to check connections. Any other suggestions?
Good job!
1) Can you easily disconnect the toggle switch from the amp? This should be the same as balanced. Still get the buzz?
2) This is hard to describe. Can you take a picture of the pot...I should be able tell you if it's wired correctly.
Mike
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Mike i got it fixed !!!!!! I had the gain pots connected to the amp board reversed. This fixed both issues. I get a little music from unbalanced when switched to balanced but its very faint. No buzzing now. I recall you mentioned checking the ohms, I will do that. So just to confirm with the toggle lugs facing me
and the lugs are 3 rows of 2, 1st row, lug 1 goes to pin 2 on jumper, lug 2 goes to pin 2 on other jumper. Middle row of lugs, left lug goes to pin 3 to same jumper as lug 1 and middle, right lug goes to pin 3 on other jumper.
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Mike i got it fixed !!!!!! I had the gain pots connected to the amp board reversed. This fixed both issues. I get a little music from unbalanced when switched to balanced but its very faint. No buzzing now. I recall you mentioned checking the ohms, I will do that. So just to confirm with the toggle lugs facing me
and the lugs are 3 rows of 2, 1st row, lug 1 goes to pin 2 on jumper, lug 2 goes to pin 2 on other jumper. Middle row of lugs, left lug goes to pin 3 to same jumper as lug 1 and middle, right lug goes to pin 3 on other jumper.
"Sounds" right to me (pardon the pun). Those gain pots are tricky...you have a 50/50 chance to mess it up, even if you think you have them right.
So you have two preamps active at the same time playing different tunes?
With the switch up (BAL), you should show an open connection from pins 2 and 3 on both J1 and J2. With the switch down, you should get 0 ohms.
Good Luck!
Mike
UPDATE!!! I just removed my jumper from pins 2 and 3, and got a 50K Ohm reading between the two! I assumed it would be open. Perhaps that is why you can get a faint signal though the unbalanced inputs...
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"Sounds" right to me (pardon the pun). Those gain pots are tricky...you have a 50/50 chance to mess it up, even if you think you have them right.
So you have two preamps active at the same time playing different tunes?
With the switch up (BAL), you should show an open connection from pins 2 and 3 on both J1 and J2. With the switch down, you should get 0 ohms.
Good Luck!
Mike
UPDATE!!! I just removed my jumper from pins 2 and 3, and got a 50K Ohm reading between the two! I assumed it would be open. Perhaps that is why you can get a faint signal though the unbalanced inputs...
I only have one input active and found it odd that i could hear music when I switched. I tested it open and closed and get 0Ohms on both. I must be doing it wrong or testing the wrong points ? I changed multimeter to lowest Ohm in my case its 200, took multimeter red and black nodes and attached it to the 2 leads coming from toggle and flipped switch.
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I only have one input active and found it odd that i could hear music when I switched. I tested it open and closed and get 0Ohms on both. I must be doing it wrong or testing the wrong points ? I changed multimeter to lowest Ohm in my case its 200, took multimeter red and black nodes and attached it to the 2 leads coming from toggle and flipped switch.
Sorry...I misunderstood (I think). You have a preamp hooked up to the RCA inputs only, and when the toggle is down (RCA), all is good. When the switch is up (BAL), you can still hear faint tunes through the RCA inputs(?).
If my statement is correct, then my theory is that, even with no "jumper" between pins 2 and 3 on my amp, I'm showing a 30k to 50k resistance between the pins (not open as I had originally thought). That may allow just enough voltage to be amplified and heard. Probably BS, but a theory none the less.
As far as your multi-meter...with the toggle up (BAL), and measuring the resistance between the top "left" lug and the middle "left" lug, you should get no reading. With the toggle down (RCA), you should get 0 ohms. Are you saying that you get 0 ohms both ways? That would mean a bad switch!
Wife's calling me...chat tomorrow.
Mike
Sun is up, coffee is kicking in. Can you easily remove the connectors to pins 2 and 3 of J1 and J2 and measure the resistance between these bare pins? Is there a possiblility that the two connectors are touching each other (that would also give you 0 ohms). I know...I'm really fishing here!
Mike
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Thanks Marcus.
Are these the caps you've changed? Looks like quite a fiddly job :)
(http://www.audiocircle.com/image.php?id=60567)
Getting some higher quality caps on the PSU rails close to the chips is probably a good idea. I think I'm going to have to open mine up again and have a play. While doing the changes did you do any direct listening comparisons between modded and normal boards?
Checking for EMI is not trivial, it may have a direct influence on audible noise but is likely to be more subtle and manifest in other ways. A very fast and sensitive scope or analyser is probably needed, which I don't have.
The caps I changed for BGs were indeed the DC blocking between 1200 and 2092.
BTW the data sheets for the 2092 and iraudamp7d make for interesting reading:
http://www.irf.com/technical-info/refdesigns/iraudamp7d.pdf
http://www.irf.com/product-info/datasheets/data/irs2092.pdf
cheers
Hi Richard,
thanks for point to the useful datasheets.
Yes these are the caps and you are right it is a little bit fiddly :) But good prepearing of the cap pins and SMD Pads are the key :wink:
I recap the boards and listen to it, first impression was that it wors, because the sound was a little bit harsh but after some time the caps settled.
What are the values of the tantals you replaced ?
I'm to be tempted to bypass them :green:
But i guess this is a bad idea in face of possible DC offset.
I will give a Elna Silmic a try or addition small high grade bypass cap.
Thanks,
Regards
Marcus
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Btw.. the caps named CP4A and CP2A of Figure 33 in Reference Design Sheet are used as PS Caps for the input stage of the 2092 and could be also replaced as mod ?
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Hi Richard,
thanks for point to the useful datasheets.
Yes these are the caps and you are right it is a little bit fiddly :) But good prepearing of the cap pins and SMD Pads are the key :wink:
I recap the boards and listen to it, first impression was that it wors, because the sound was a little bit harsh but after some time the caps settled.
What are the values of the tantals you replaced ?
I'm to be tempted to bypass them :green:
But i guess this is a bad idea in face of possible DC offset.
I will give a Elna Silmic a try or addition small high grade bypass cap.
Thanks,
Regards
Marcus
The tatals were 10uF which I've replaced with 4.7uF. Given that the following stage has an input Z of about 3K this gives a low cutoff of around 11Hz which I feel is adequate. I wouldn't bypass them completely as the 2092 might show some DC at it's input which could cause problems, especially as their are no blocking caps on the 1200 stage.
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Btw.. the caps named CP4A and CP2A of Figure 33 in Reference Design Sheet are used as PS Caps for the input stage of the 2092 and could be also replaced as mod ?
Definitely candidates - just need to find them :?
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The tatals were 10uF which I've replaced with 4.7uF. Given that the following stage has an input Z of about 3K this gives a low cutoff of around 11Hz which I feel is adequate. I wouldn't bypass them completely as the 2092 might show some DC at it's input which could cause problems, especially as their are no blocking caps on the 1200 stage.
Thanks for input.
Did you know how that additional 100K / 47K as used in reference and datasheet circuits between input and VS could impact the input impedance if used in SDS Design ?
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Definitely candidates - just need to find them :?
If i find some time and mod the couple C's i will try to find them also :)
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Thanks for input.
Did you know how that additional 100K / 47K as used in reference and datasheet circuits between input and VS could impact the input impedance if used in SDS Design ?
The 100k just allows a DC route to earth to stop pops when starting up. Will have little impact on SQ if at all.
The 47k is the feedback resistor. This is critical! A higher quality resistor here 'may' have an impact, but you need to be really careful here as the whole stability of the amp will be effected by any changes here. Personally I'd leave this well alone. It's popular to change feedback resistors on conventional DIY amps but being Class D there well might be some serious side effects to changing this which are unpredictable. The datasheet might give some pointers....
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The 100k just allows a DC route to earth to stop pops when starting up. Will have little impact on SQ if at all.
The 47k is the feedback resistor. This is critical! A higher quality resistor here 'may' have an impact, but you need to be really careful here as the whole stability of the amp will be effected by any changes here. Personally I'd leave this well alone. It's popular to change feedback resistors on conventional DIY amps but being Class D there well might be some serious side effects to changing this which are unpredictable. The datasheet might give some pointers....
Many thanks for explanation.
You are right, it should be leave well alone.
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Sorry...I misunderstood (I think). You have a preamp hooked up to the RCA inputs only, and when the toggle is down (RCA), all is good. When the switch is up (BAL), you can still hear faint tunes through the RCA inputs(?).
If my statement is correct, then my theory is that, even with no "jumper" between pins 2 and 3 on my amp, I'm showing a 30k to 50k resistance between the pins (not open as I had originally thought). That may allow just enough voltage to be amplified and heard. Probably BS, but a theory none the less.
As far as your multi-meter...with the toggle up (BAL), and measuring the resistance between the top "left" lug and the middle "left" lug, you should get no reading. With the toggle down (RCA), you should get 0 ohms. Are you saying that you get 0 ohms both ways? That would mean a bad switch!
Wife's calling me...chat tomorrow.
Mike
Sun is up, coffee is kicking in. Can you easily remove the connectors to pins 2 and 3 of J1 and J2 and measure the resistance between these bare pins? Is there a possiblility that the two connectors are touching each other (that would also give you 0 ohms). I know...I'm really fishing here!
Mike
With toggle in rca mode I get 0.02 ohms (mmeter set to 200ohms) on left and right, If I switch to Balanced I get 0ohms.
I'm going to take the toggle out of chassis to do check if on my wiring. I suspect too something with it.
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I know one member briefly mentioned adding a Yaqin tube buffer, but I wanted to see what the general consensus would be on adding this to an SDS-254. This is the one I bought here on AC with Dodd power http://www.audiocircle.com/index.php?topic=100532.0
Obviously I'd love to add a Dodd buffer, but it's not in the cards from a financial perspective, so I was thinking the Yaqin CD3 in the hopes of adding a little warmth to my system.
Here is what I am running, I would be grateful for any input. Also, my system has to do double duty as an ht setup.
Source: 2012 Mac Mini Server hdmi
Pre: Harman Kardon AVR-254
Amp: SDS-254 for fronts, Emotiva UPA-2 for rears, strange combo but I am not to critical of rear channels as serious listening is in stereo.
Interconnects: Standard RCA, and 12 ga Monoprice
Speakers: Front Selah Verita Ported - Rear Selah Aura Jr. - Sub Selah TC12
Last two nights I had speaker dreams, I am a sick man, and I appreciate any help/therapy for my affliction :thumb:
Paul
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Does anyone have a supplier and part number for the three-pin receptacle that connects the gain pots to the PCB?
On the build I did myself, I just pulled them off the pots included with the kit; I read someone else earlier in this thread stole them off old computer fans.
I now have a complete amp from Tom; I'd like to replace the pots with fixed resistors, but I don't want to ruin these pots; I'd like any mod I do to the complete amp to be trivially-easy to reverse.
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Does anyone have a supplier and part number for the three-pin receptacle that connects the gain pots to the PCB?
On the build I did myself, I just pulled them off the pots included with the kit; I read someone else earlier in this thread stole them off old computer fans.
I now have a complete amp from Tom; I'd like to replace the pots with fixed resistors, but I don't want to ruin these pots; I'd like any mod I do to the complete amp to be trivially-easy to reverse.
Sorry if I asked you this before. Do you have any unwanted two-pin receptacles used for ON/OFF, LED's? If so, I filed off the "tabs" on the back, and they will slid onto the two pins needed on the PCB. Attach the resistor the same way you would have done with the 3 pin receptacle. I've tried to find the same thing you are looking for...no luck.
Mike
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Does anyone have a supplier and part number for the three-pin receptacle that connects the gain pots to the PCB?
On the build I did myself, I just pulled them off the pots included with the kit; I read someone else earlier in this thread stole them off old computer fans.
I now have a complete amp from Tom; I'd like to replace the pots with fixed resistors, but I don't want to ruin these pots; I'd like any mod I do to the complete amp to be trivially-easy to reverse.
Hi Matt, yes I used my old connectors from computer fans. I have several types of molex connectors from the actual molex headers found on pcb to the 2 & 3 pin molex header connectors. Frys or Microcenter should have these. Another place that stocks them online is newegg.
http://www.newegg.com/Product/Product.aspx?Item=N82E16812189119 (http://www.newegg.com/Product/Product.aspx?Item=N82E16812189119)
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With toggle in rca mode I get 0.02 ohms (mmeter set to 200ohms) on left and right, If I switch to Balanced I get 0ohms.
I'm going to take the toggle out of chassis to do check if on my wiring. I suspect too something with it.
I re-soldered the wires and i do not have any music bleeding through now but when I connect to Balanced I hear a slight buzz. I am ok with that for now since I only use RCA. But any suggustions would be helpful too :)
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I re-soldered the wires and i do not have any music bleeding through now but when I connect to Balanced I hear a slight buzz. I am ok with that for now since I only use RCA. But any suggustions would be helpful too :)
Not that I will know the answer, but when you say "connect to balanced", do you mean you are connecting a balanced preamp to the amp, or do you mean you you have an unbalanced preamp hooked up, but the toggle is in the BAL position? Sorry for all the questions about your questions.
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Not that I will know the answer, but when you say "connect to balanced", do you mean you are connecting a balanced preamp to the amp, or do you mean you you have an unbalanced preamp hooked up, but the toggle is in the BAL position? Sorry for all the questions about your questions.
Sorry, my bad for not putting enough detail. I only have rca connections from my Bottlehead Quickie preamp connected to the rca connection/inputs. When in that position, it sounds good. When I move the toggle to Balanced I get a slight buzz.
I also ran some polarity tests and found that I had my left and right inputs switched. I had this same problem on my CDA-254 kit. I guess my left and right is different to way Tom looks at it. I noticed the SDS chassis left and right inputs do not align to the left and right inputs on the amp board. From what I can tel Tom designed as if you were looking at the chassis from above and not from the rear...maybe I am just old, dazed and confused :)
I looked at Tom's pictures and he had it wired straight from amp board left to rear input right. I thought it was odd at time i assembled. I also noticed in his pictures he has his transformer wired so that blue goes to AC-L which should be going to AC-N and Green going to AC-n which should be going to AC-L. Also saw that he has the power switch on side of chassis wired but could not see any molex headers or wires connecting to the right of amp board where its designated ext. power switch. Anybody else encounter this or anything else?
See pic below
(http://www.audiocircle.com/image.php?id=60614)
(http://www.audiocircle.com/image.php?id=60616)
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Good Catch! I only used the photos to get an idea of the wiring techniques...not the wiring itself! I wired mine according to the PCB...Left means Left... Also, I'm surprised the PS even powers up. Have you notified Tom of the Tranny to PS wiring "error". Or can if be wired either way???
I ignored the on/off switch on the PCB, and wired the case switch between the AC live on the IEC and the red wire on the tranny.
A dumb thought on the buzzing. I've spent enough time researching balanced vs unbalanced wiring in the last few days to make my head spin. As I understand it, in balanced mode, the input stage of the amp is going to calculate the difference between the two inverted signals from the + and - inputs to recreate the original signal from the preamp (which in turn eliminates noise picked up by the cable). Since you have no signal on the - input, and you have a full signal on the + wire, I wonder if this difference creates a buzzing sound. Would be interesting to borrow a balanced preamp just to test it out. I may remove my jumpers from pins 2 and 3, turn on my preamp, and see if I get a buzzing as well.
Best, Mike
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I'm having a problem with my SDS 254, when I turn it on the left channel blue light only stays on for about 10-20 seconds then goes out. I tried disconnecting left side in to make sure problem wasn't with tube buffer no change, also disconnected resisters on gain, no change. Here are pics, only other thing I can think of is maybe jumpers for bridge, stereo are not connected right?
(http://www.audiocircle.com/image.php?id=60641)
(http://www.audiocircle.com/image.php?id=60642)
(http://www.audiocircle.com/image.php?id=60643)
Anyone have any idea what problem is or any suggestion on figuring it out?
Thanks, Mike
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Hey Mike...
Jumpers look good for non-bridged amp, unbalanced inputs. Interesting configuration of caps/resistors on your inputs!
Did you check the input voltage from the PS?
Mike
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Good Catch! I only used the photos to get an idea of the wiring techniques...not the wiring itself! I wired mine according to the PCB...Left means Left... Also, I'm surprised the PS even powers up. Have you notified Tom of the Tranny to PS wiring "error". Or can if be wired either way???
I ignored the on/off switch on the PCB, and wired the case switch between the AC live on the IEC and the red wire on the tranny.
A dumb thought on the buzzing. I've spent enough time researching balanced vs unbalanced wiring in the last few days to make my head spin. As I understand it, in balanced mode, the input stage of the amp is going to calculate the difference between the two inverted signals from the + and - inputs to recreate the original signal from the preamp (which in turn eliminates noise picked up by the cable). Since you have no signal on the - input, and you have a full signal on the + wire, I wonder if this difference creates a buzzing sound. Would be interesting to borrow a balanced preamp just to test it out. I may remove my jumpers from pins 2 and 3, turn on my preamp, and see if I get a buzzing as well.
Best, Mike
Have not notified Tom yet, wanted to get others take on it, maybe I was just not looking at it properly. I also noticed in one picture he has the neutral/black wire going to live/red at the IEC connections.
I'll see what happens if I disconnect the rca cables and change the rca/balanced toggle.
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Vinylb...
Unplug the RCA connections so there is no input signal and then see if you get any buzzing. The toggle is not there to switch between the RCA and XLR inputs, but rather to select which type you have connected (in other words, you shouldn't be using both at once). The RCA is always connected to the amp input, so when you switch to XLR your amp is in essence only seeing one leg of a balanced signal which is probably what's causing the buzzing (at least in my neophyte guessing... you obviously don't have the other inverted leg since your are not running a balanced system).
As for the green and blue wires, I don't think it makes any difference which way they are connected to the PS since power is coming from a centertapped AC xfmer. You'll have like 40VAC on the L, 0VAC on the center tap (combined blue/green wires - these you want to make sure you get correct) and another 40VAC on N. The same is probably true for the IEC wiring... as long as the fuse and switch are on the live side, I don't think it matters which way the xfmer is connected.
Same holds true for the left/right amp inputs to back of panel. Doesn't really matter if you wire left to right and right to left as long as you make the same connections for the speaker jacks so that the correct orientation appears at the back of the amp (though that doesn't really matter either since you can always connect the left speaker to the right jack and vice versa). However, if you are talking about the polarity for each left/right connection (+ and GND) that is another matter and you'll want to get them correct.
On/Off switch on the amp board is optional and for putting the amp in standby mode, but leaves the power supply on. You need the switch between the IEC and transformer to completely turn off the amp.
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I'm having a problem with my SDS 254, when I turn it on the left channel blue light only stays on for about 10-20 seconds then goes out. I tried disconnecting left side in to make sure problem wasn't with tube buffer no change, also disconnected resisters on gain, no change. Here are pics, only other thing I can think of is maybe jumpers for bridge, stereo are not connected right?
Does the orange light come on after the blue light goes out? Sounds like it is going into some sort of protection mode. Could the speaker wires be shorted on the left channel?
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The orange light comes on when amp powers up but not after blue light goes out. Voltage from power supply 93.5 volts. the caps and resisters are part of Dodd tube buffer out put. I disconnected left speaker outs no change.
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^^^^^
SDS-254 - Required Power Supply: +/- 40 Volts DC to +/- 50 Volts DC Accepts Balanced or Single Ended inputs at up to 18 volts
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So it sound like the problem is with power supply putting out to high of voltage. I have 14.6 volts going into power supply. Anything in pic of power supply that doesn't look right?
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While I'm really enjoying this thread, I'm appalled at the number of Do It Yourselfers here that haven't a clue as to what they are doing. Who seem to lack the basics, especially when understanding circuitry and diagnosing problems that they might encounter.
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Well, ya gotta start somewhere.
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Wow...that took the Cheerful right out of the thread! Sorry you find me appalling (at least my wife has company!). I have learned a lot working with these kits, and realize I have a lot more to learn. I appreciate everyone's help, and hope to someday to be able to return the favor.
Mike...sorry, but I don't have that PS. Wish I could help!
Mike
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Well, ya gotta start somewhere.
No problem if you are an experienced builder or have an electronics background, technical education.
Anyone not knowing what they are doing could end up with something useless, a total loss. Hopefully that doesn't happen.
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No problem if you are an experienced builder or have an electronics background, technical education.
Anyone not knowing what they are doing could end up with something useless, a total loss. Hopefully that doesn't happen.
Well I mildly disagree on this. While I agree basic soldering skills, an idea of what a circuit looks like, and experience building a couple of project kits would be recommended, I don't think you need a technical education in electronics to tackle this project.
A big part of this thread is people with more experience and education, such as yourself, helping those with less skills. Helping. That would sorta be the word I would hope we focus on here. Denigrating. That would be the term we would want to avoid.
Just me helping people with less skills in those areas.
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Sorry I am not at the level of most folks around here. I was under impression forums like this were setup to ahare information and also educate by sharing experiences
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Sorry I am not at the level of most folks around here. I was under impression forums like this were setup to ahare information and also educate by sharing experiences
+1
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+2, especially since these Class D amps are so well suited to DIY beginners.
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Just finished building my first DIY amp, courtesy of Class D (CDA 254L Kit). I do not have background in electronics and zero experience in soldering wire, but the project was a success! Thanks to the help of Tom's assistant, Roger.
I must say, the sound of CDA 254 is more detailed and has more punch on the bass than my Primaluna Prologue. I am very happy with the final result and it is now my main rig for 2-channel listening.
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Congratulations :thumb:
Did you use the Class D Audio case, or something else?
Mike
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Thanks. I built my own case, using MDF (17"x12"x4"). I am planning to add two more amp module for 6-channel. Each module will have separate toggle switch for flexibility. Once I completed the 6-channel, I can either use it for home theater or monoblock, or have separate speakers for each module.
(http://www.audiocircle.com/image.php?id=60725)
(http://www.audiocircle.com/image.php?id=60726)
(http://www.audiocircle.com/image.php?id=60727)
(http://www.audiocircle.com/image.php?id=60729)
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Just finished building my first DIY amp, courtesy of Class D (CDA 254L Kit). I do not have background in electronics and zero experience in soldering wire, but the project was a success! Thanks to the help of Tom's assistant, Roger.
I must say, the sound of CDA 254 is more detailed and has more punch on the bass than my Primaluna Prologue. I am very happy with the final result and it is now my main rig for 2-channel listening.
Congrats to you !!! Dig the custom enclosure and ample room for expansion :)
What speakers are you driving with 254L kit?
My
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Vinylb...
Unplug the RCA connections so there is no input signal and then see if you get any buzzing. The toggle is not there to switch between the RCA and XLR inputs, but rather to select which type you have connected (in other words, you shouldn't be using both at once). The RCA is always connected to the amp input, so when you switch to XLR your amp is in essence only seeing one leg of a balanced signal which is probably what's causing the buzzing (at least in my neophyte guessing... you obviously don't have the other inverted leg since your are not running a balanced system).
As for the green and blue wires, I don't think it makes any difference which way they are connected to the PS since power is coming from a centertapped AC xfmer. You'll have like 40VAC on the L, 0VAC on the center tap (combined blue/green wires - these you want to make sure you get correct) and another 40VAC on N. The same is probably true for the IEC wiring... as long as the fuse and switch are on the live side, I don't think it matters which way the xfmer is connected.
Same holds true for the left/right amp inputs to back of panel. Doesn't really matter if you wire left to right and right to left as long as you make the same connections for the speaker jacks so that the correct orientation appears at the back of the amp (though that doesn't really matter either since you can always connect the left speaker to the right jack and vice versa). However, if you are talking about the polarity for each left/right connection (+ and GND) that is another matter and you'll want to get them correct.
On/Off switch on the amp board is optional and for putting the amp in standby mode, but leaves the power supply on. You need the switch between the IEC and transformer to completely turn off the amp.
Krickor, thanks for your replies. I figured the L & N cables were ok to swap but center taps being critical. Switch supplied with the kit, I dont believe is rated for the use between IEC and transformer. In my 254L kit I did use a 120v rated switch. But I believe the switch Tom supplies can only be used for one purpose and that is to power on/off the amp board...but I could be wrong.
Also...thanks for correcting and enlightening me on the purpose of the toggle switch.
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Krickor, thanks for your replies. I figured the L & N cables were ok to swap but center taps being critical. Switch supplied with the kit, I dont believe is rated for the use between IEC and transformer. In my 254L kit I did use a 120v rated switch. But I believe the switch Tom supplies can only be used for one purpose and that is to power on/off the amp board...but I could be wrong.
Also...thanks for correcting and enlightening me on the purpose of the toggle switch.
FYI...I had the same question for Tom when I received the case. His reply...
"As for the switch on the case… this is for the transformer AC so when you turn the amp on. The power supply and amp turn on. Just leave the switch on the amp turned on."
I can only assume it's rated appropriately.
Mike
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FYI...I had the same question for Tom when I received the case. His reply...
"As for the switch on the case… this is for the transformer AC so when you turn the amp on. The power supply and amp turn on. Just leave the switch on the amp turned on."
I can only assume it's rated appropriately.
Mike
I stand corrected. Thx for info Mike
I have put my cover on and now enjoying my amp.
Sda-470 is perfect match for my maggies 1.6.
As much as I enjoyed my cda-254, 470 has a wider and deeper soundstage.
I also hear better seperation of instruments and continue to be amazed but how much more I am hearing.
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I just found this thread and haven't read every post yet. I've been looking for information on the SDA-470 amp kit. Is it a Class D Audio (brand) product? Maybe I'm not looking in the right place, or is this model a custom order? This model sure sounds interesting from the description, because if it will image well on Magneplanar speakers it should image well with other less demanding speakers, also. Thanks so much!
Pix4work
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I just found this thread and haven't read every post yet. I've been looking for information on the SDA-470 amp kit. Is it a Class D Audio (brand) product? Maybe I'm not looking in the right place, or is this model a custom order? This model sure sounds interesting from the description, because if it will image well on Magneplanar speakers it should image well with other less demanding speakers, also. Thanks so much!
Pix4work
I assume the references are to the SDS 470; yes it is available, but only appears on the site as one of the options on the "build an SDS" page and as a complete build. It doesn't appear on the "kits" page or the "boards" page.
I actually wrote Tom yesterday about buying an SDS-470 board; he said he is finishing testing a new improved version of the board, and that it will be on the site soon. In any case, even if Tom doesn't update the site, write and ask about the board if you're interested. And yes, it sounds like a good match for Magneplanars, as it doubles power at 4 ohms, and almost doubles again at 2.
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sorry, double post
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Congrats to you !!! Dig the custom enclosure and ample room for expansion :)
What speakers are you driving with 254L kit?
My
I am currently using a modded AV123 X-LS mini-monitor, but it will be upgraded pretty soon, probably another GR-Research speaker. The amp is a perfect match for this modded X-LS speaker. The warm sound that I am used to (using Primaluna) is about 90% using CDA-254, but better bass and more detailed. I can never be happier. :D
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No problem if you are an experienced builder or have an electronics background, technical education.
Anyone not knowing what they are doing could end up with something useless, a total loss. Hopefully that doesn't happen.
This was the first and only DIY electronics project I have ever built. It has been working fine for a year now. There actually isn't a whole lot to it. You connect three boards together with a few wires. It was a fun project.
I worry that in this country we have created such a fear of things like this, and school science labs, etc., that we have beaten the scientific and technical creativity out of the populace.
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This was the first and only DIY electronics project I have ever built. It has been working fine for a year now. There actually isn't a whole lot to it. You connect three boards together with a few wires. It was a fun project.
I worry that in this country we have created such a fear of things like this, and school science labs, etc., that we have beaten the scientific and technical creativity out of the populace.
I'm glad you got it right the first time, apparently not so for some of the others. Maybe what I should have said, is that it doesn't appear to be a kit for beginners. If you mess it up, then you end up with an expensive $175 loss.
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In the old days, companies that sold kits sent detailed instructions with diagrams. Today they could easily send printed instructions with pictures and put a "how to" video on the web. Hard for me to believe that this wouldn't reduce the number of support emails Tom answered and be very worth it for him.
Without that, first timers like me are afraid to build a kit.
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Yes. by far the biggest failing of the ClassD stuff is the lack of documentation! I'm absolutely amazed Tom doesn't get this sorted, he must spend hours on email with questions.
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I agree, Tom could stand to beef up his documentation and info on the website.
But at the same time... if you take the time to read through this whole thread, you should clearly understand what needs to connect to what. I did exactly that: read every page of this thread (over the course of many days), taking notes along the way.
And even if you don't want to take the time to read through the whole thread, you could "soft" hook-up everything (i.e. no solder), and before plugging it in, take pictures and post here. If the pictures are good enough, I'd be really surprised if at least one person didn't come along and say yea or nay. And if no one responds here, I'd be shocked if Tom himself wouldn't review your work.
If you don't have the patience to read through this thread and/or wait on responses to questions and pictures, then the DIY route probably isn't for you. There's another side to the read-and-understand-before-building argument, and that is safety. Those big capacitors on the power supply board store a lot of potential---life-threatening levels.
The power supply side of the build is where you face the biggest risk to your health; likewise, it is probably the side where the equipment risk is highest. But it's probably also the simplest. I distinctly remember many people, early in these threads, clarifying how the transformer leads connect to the power supply board. I believe Tom now ships all transformers with the unused leads taped off. So even if you're completely impatient and foolish, you have a 50/50 chance of hooking things up correctly. Connecting the power supply board to the amp board is really trivial: + goes to +, - goes to -, and GND goes to GND.
Furthermore, you can easily check every stage of the power supply with a cheap (<$10) digital multi-meter (DMM). I would argue that basic familiarity with a DMM is a hard prerequisite for building these kits. At least understand how to check voltage and resistance. Hook just the transformer up, plug it in, check the potential across the transformer leads. Transformer output is documented. Now connect the power supply. Check voltage across the power supply outputs; this is also documented, but check with Tom to be absolutely certain.
(Just don't be sloppy with your DMM leads like me; that power supply is good for an electrical arc that will have you seeing white for a few minutes! Now I use alligator clips. :) )
Also note that if you power up the power supply board before you're done working on the kit, you need to wait a while before working with it again. Those capacitors store electricity even after the amp is unplugged. I'm not sure how long you need to wait... probably 30 minutes (but again, this is something you can verify with your DMM).
The input/output side is more about common sense: turn your preamp all the way down on your first run; turn the gain all the way down (i.e. maximum resistance); don't use your nicest speakers initially; double- and triple-check all connections before plugging in; slowly increase volume/gain.
At any rate, Tom is now offering fully-built amps that are "plug and play". Personally---and this is pure speculation on my part---I think the price will rise on at least the complete amps, if Tom manages to polish up his website and get his amps in the hands of some widely-read "pro" reviewers.
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Very well said! :thumb:
steve k
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If i find some time and mod the couple C's i will try to find them also :)
Recently i had some time to change the couple C's and PS Caps of 2092 Input stage, please see picture bellow :
First i try the Nichicon KZ as couple C's (Elnas was on transit) :
(http://www.audiocircle.com/image.php?id=61104)
Later on i receive the Elnas and replace the Nichicon KZ :
(http://www.audiocircle.com/image.php?id=61101)
I like the sound of the Elna Silmic II more than KS (from first minute without burn in :) ) , KZ are more mellow, i decide to change the 220µF near the THAT1200 to Elna also :
(http://www.audiocircle.com/image.php?id=61103)
Regards
Marcus
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I'm glad you got it right the first time, apparently not so for some of the others. Maybe what I should have said, is that it doesn't appear to be a kit for beginners. If you mess it up, then you end up with an expensive $175 loss.
It is far more simple than a beginners kit I purchased at the same time I ordered a soldering iron (wound up using my old one which I then found after 20 years rotting in a drawer). I did wire the pots backward, had a ground wire come loose, etc. Pretty much anything worth doing involves some degree of risk, but in this case the risk is small. It is also quite possible for some to shock themselves severely, which if you want to wring your hands, seems more worthy of concern.
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ooops
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Recently i had some time to change the couple C's and PS Caps of 2092 Input stage, please see picture bellow :
First i try the Nichicon KZ as couple C's (Elnas was on transit) :
(http://www.audiocircle.com/image.php?id=61104)
Later on i receive the Elnas and replace the Nichicon KZ :
(http://www.audiocircle.com/image.php?id=61101)
I like the sound of the Elna Silmic II more than KS (from first minute without burn in :) ) , KZ are more mellow, i decide to change the 220µF near the THAT1200 to Elna also :
(http://www.audiocircle.com/image.php?id=61103)
Regards
Marcus
Looking good Marcus 8) And how's the sound - much improvement?
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Recently i had some time to change the couple C's and PS Caps of 2092 Input stage, please see picture bellow :
First i try the Nichicon KZ as couple C's (Elnas was on transit) :
Later on i receive the Elnas and replace the Nichicon KZ :
I like the sound of the Elna Silmic II more than KS (from first minute without burn in :) ) , KZ are more mellow, i decide to change the 220µF near the THAT1200 to Elna also :
(http://www.audiocircle.com/image.php?id=61103)
Regards
Marcus
Hm, unless you are a solder pro (and maybe you are) I would not mess with those boards. The chips are sensitive and adding those caps may be doing more harm than good. Especially on the bottom of the board.
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Looking good Marcus 8) And how's the sound - much improvement?
Thanks :)
The system run around 2h and i really love it, normaly i'm to be reserved, but form me it is a clear improvement, don't expect such nice sound by change some components. The Elnas really match in my system. But i would say i have well improved and sensitiv system which surface every change.
Regards
Marcus
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Hm, unless you are a solder pro (and maybe you are) I would not mess with those boards. The chips are sensitive and adding those caps may be doing more harm than good. Especially on the bottom of the board.
I had / have similar concerns. These type of mods should only be done by those who have the skills to do it right - as you say it could make matters worse. A wrong move could be very tricky to correct.
But it looks like Marcus has done a good job and whose to argue if he hears an improvement.
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Thanks :)
The system run around 2h and i really love it, normaly i'm to be reserved, but form me it is a clear improvement, don't expect such nice sound by change some components. The Elnas really match in my system. But i would say i have well improved and sensitiv system which surface every change.
Regards
Marcus
I've a bunch of Silmics in my draw - looks like they might have found a use. Just need to clear my bench of other projects first.
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Yeah, Marcus did a very clean and tidy job. Way better than I could have done! :thumb:
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Thank you :)
I had work some years in the electronic development of a company. That was very helpful to gain soldering skill. :wink:
Please try the Elena in Both position and let me know your findings. If possible also update the PS Caps of THAT1200 and IRS2092 with higher cap value, low esr types ( I use Panasonic FC).
Regrads
Marcus
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I guess it could be done by everybody who have had some little solder experience. But you need the right tools (solder pin (not to small, around 3mm) , desolder wick, "good old" solder (before RoHS ) :wink: ).
Prepare is the key.
Pins of the Capacitors :
(http://www.audiocircle.com/image.php?id=61126)
My issue is, i have only two hands :)
But for me it helps to do it in following steps:
Make one pad of the target position free (desolder wick) and put some solder to the other pad.
Now fix the capacitor to that pad by heat up the solder on the pad (solder iron in one hand) and positioning the capacitor (in other hand) .. after that it is easy to put some solder to other "free" pad, because capacitor is already in place.
Regards
Marcus
PS : Sorry my english is not the best :( Hopfully some one could understand and imagine.
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I guess it could be done by everybody who have had some little solder experience. But you need the right tools (solder pin (not to small, around 3mm) , desolder wick, "good old" solder (before RoHS ) :wink: ).
Prepare is the key.
Pins of the Capacitors :
(http://www.audiocircle.com/image.php?id=61126)
My issue is, i have only two hands :)
But for me it helps to do it in following steps:
Make one pad of the target position free (desolder wick) and put some solder to the other pad.
Now fix the capacitor to that pad by heat up the solder on the pad (solder iron in one hand) and positioning the capacitor (in other hand) .. after that it is easy to put some solder to other "free" pad, because capacitor is already in place.
Regards
Marcus
PS : Sorry my english is not the best :( Hopfully some one could understand and imagine.
Marcus - good advice and your English is more than adequate.
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Couple of pages back I posted how I was trying to get around the limited space between power supply board and rear chassis plate and drilled holes and moved it close to the front - after somebody posted (forgive me for not finding the posters name) a caution of the heat, I took advice and moved it back.
Well I can tell you that was good advice - I was cleaning and moving my equipment around my rack and decided to put the amp on my carpet. Well after moving stuff around I decided to listen to some music and that turned into an hour or two of listening. Then suddenly my SDS-470 started clipping and the front led's blinked several times. Felt underneath where the amp board and power supply board are they were hot. Putting them back in rack on taller feet eradicated the heat issue below.
I still have some concerns about the heat on top of chassis even when put back in rack - it gets hot. It has never clipped in the rack, just got hot. For now I have Mcgyvor rigged a small fan to turn on when my other components turn on, but plan to run a 12 volt computer fan at 7 volts and have it run off battery with a switch and case I have lying around.
Kudos to all in this forum who have contributed especially AE, Mboxler, Matt_garman. I could not have felt confident without your support and previous posts. Now what do I do about my CDA-254L kit in Par-metal case, that is gathering dust? :) forcing it to do duty as a center channel amp for my lcd tv just does not do justification to these wonderful amps.
I also wonder if Tom will ever get around to creating a preamp or integrated amp? Currently running mine off Bottlehead Quickie with upgrade and sounds good, real good - just dont like how microphonic it is.
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I guess it could be done by everybody who have had some little solder experience. But you need the right tools (solder pin (not to small, around 3mm) , desolder wick, "good old" solder (before RoHS ) :wink: ).
Prepare is the key.
Pins of the Capacitors :
(http://www.audiocircle.com/image.php?id=61126)
My issue is, i have only two hands :)
But for me it helps to do it in following steps:
Make one pad of the target position free (desolder wick) and put some solder to the other pad.
Now fix the capacitor to that pad by heat up the solder on the pad (solder iron in one hand) and positioning the capacitor (in other hand) .. after that it is easy to put some solder to other "free" pad, because capacitor is already in place.
Regards
Marcus
PS : Sorry my english is not the best :( Hopfully some one could understand and imagine.
.Marcus, your English is just fine. The only regret I personally have is not picking up another language apart from the 3 I know. Does English/British and English/American count? :) Oh and I wish I chose low current electrical engineering instead of working in the family butcher. But thats another story.
Anyways thanks for your detailed posts.
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If possible also update the PS Caps of THAT1200 and IRS2092 with higher cap value, low esr types ( I use Panasonic FC).
Regrads
Marcus
Update:
Change to Panasonic FR in all PS Positions (both, reported tweak position and default populate "Big" FC 680µF / 63V) give also (clear !) improvment vs. Panasonic FC.
Summary of tweak :
THAT1200 Bootstrap Filter
SMD Tantal 220µF -> Elna Silmic II 220µF/ 6.3V
THAT1200 - IRS2092 Couple C
SMD Tantal 10µF -> Elna Silmic II 10µF / 16V
THAT1200 PS Part:
SMD Tantal 10µF -> Panasonic FR 680µF / 25V
IRS2092 PS Input Stage
SMD 22µF -> Panasonic FR 330µF / 25V
IRS2092 PS Output Stage
Panasonic FC 680µF / 63V -> Panasonic FR 1000µF / 50V
!! Note : This tweak limited Main Supply Voltage to 50V max !!
Main PS Stage
Panasonic FC 680µF / 63V -> Panasonic FR 1000µF / 50V
!! Note : This tweak limited Main Supply Voltage to 50V max !!
Regards
Marcus
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Flying home from California after a brief visit with Tom at Class D Audio. Picked up a new pair of SDS-450 amp boards with improved heat handling capabilities (as well as some other tweaks to the circuit I believe). Great guy, nice tour of the skunk works and a good sneak peek at some upcoming new products.
A treat was getting to hear a pair of Polk SDA-SRS speakers (the 2.3TL if I've got the models right) driven by one of his little 254 stereo amps. The bass was incredible and full, rich sound all the way up. Source was simply a lowly Squeezebox Touch through an older looking preamp I cannot recall the make of.
Future products? How about a relatively inexpensive 2"x2" amp board with volume control putting out about 15 watts. You can even move a jumper to bridge it for 30 watts. Just hook up a DC power supply anywhere from like 10-24 volts (or something like that, I may have the exact range wrong) or a battery and you're good to go. I'm thinking about a portable cigar box amp. Tom's sample sounded great with an iPod Nano source and a pair of NHT bookshelf speakers.
Looking forward to getting my SDS amp boards home and hooked up. Will post pictures once I've got them unpacked.
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PS : Listen to SDS254 with updated PS Caps to Panasonic FR for 1h, amazing :o
If you have the knowledge and solder skill highly recommended reported tweak, it is a really and clear improvement.
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Flying home from California after a brief visit with Tom at Class D Audio. Picked up a new pair of SDS-450 amp boards with improved heat handling capabilities (as well as some other tweaks to the circuit I believe). Great guy, nice tour of the skunk works and a good sneak peek at some upcoming new products.
A treat was getting to hear a pair of Polk SDA-SRS speakers (the 2.3TL if I've got the models right) driven by one of his little 254 stereo amps. The bass was incredible and full, rich sound all the way up. Source was simply a lowly Squeezebox Touch through an older looking preamp I cannot recall the make of.
Future products? How about a relatively inexpensive 2"x2" amp board with volume control putting out about 15 watts. You can even move a jumper to bridge it for 30 watts. Just hook up a DC power supply anywhere from like 10-24 volts (or something like that, I may have the exact range wrong) or a battery and you're good to go. I'm thinking about a portable cigar box amp. Tom's sample sounded great with an iPod Nano source and a pair of NHT bookshelf speakers.
Looking forward to getting my SDS amp boards home and hooked up. Will post pictures once I've got them unpacked.
I didn't know there was a 450. What's the power rating for the SDS 450?
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Ajani... 450 was on the website briefly, but has not been there recently. Here's some info I posted way back when...
At the risk of confounding matters for you, I recently contacted Tom about the same thing and ended up settling on a pair of the SDS-450 amps. I think we are using the same speakers... Magnepan 1.6QR. Initially I though I'd start with a single SDS-470 even though it seemed like overkill (though that's never really the case with Maggies). But I wanted to keep the option open to go to a pair of amps for passive biamping or even mono blocks for more power.
Here's the response I got from Tom: If you're going to run the amps in bridge mode, I would recommend the SDS-450 kits. They also run cooler and can put about 1000W RMS into your Magnepans.
The different models got so confusing with regards to power and price I put together a chart clarifying this for myself, based on what info I could dig up from Tom's site and this thread. Here's what I came up with:
| Model | SDS-224 | SDS-254 | SDS-258 | SDS-450 | SDS-470 |
|
|
| Stereo watts | | | | | |
| 8 ohm | 60 | 125 | 250 | 150 | 300 |
| 4 ohm | 120 | 250 | -- | 300 | 600 |
| 2 ohm | -- | -- | -- | 600 | 800 |
|
|
| Mono watts | | | | | |
| 8 ohms | 240 | 500 | -- | 600* | 800* |
| 4 ohms | -- | -- | -- | 600* | 800* |
|
|
| Board $ | 235 | 245 | 265 | 245** | 265** |
|
|
| Kit $ w/xfmr | 285 | 320 | 370 | 350 | 370 |
* Note from Tom: As far as power output in bridge mode the protection circuitry will prevent the amps from putting out more power than they actually could. The SDS-450 will put out about 600W into 8 ohm bridged and about the same into 4 ohm… protection circuit. The SDS-470 is just more power at about 800W bridged.
** Not currently listed on website, temporary price as of today 10/17/2011 possibly until this weekend. Will go up about $40 when listed on website. If anyone wants one before they are listed on the website, purchase the SDS-254 or SDS-258 and email Tom with instructions to upgrade to the SDS-450 (for SDS-254 price) or SDS-470 (for SDS-258 price).
The SDS-480 kit ($468) and SDS-1000 kit ($498) are simply the 224 and 254 kits with two amp boards and a single HD power supply, respectively.
I will send a copy of this to Tom to see if he can verify these numbers and fill in the holes. I know it would make amp selection much easier if this was all available. Verified with notes added from Tom at Class D Audio
Oh, and I STILL have to assemble my amps and give them a try... maybe this weekend. :whip:
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Hi,
I read about 10 to 15 posts of this thread and also the website of ClassDAudio there is no mention of the chipset used in Model 254 and 258. Can anyone confirm these 2 models use this chipset IRS2092.
Sound wise which one sounds better is 254 or 258?
Thanks.
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Ajani... 450 was on the website briefly, but has not been there recently. Here's some info I posted way back when...
Thanks.
I know this has been said a billion times before, but Tom really needs to update his site!
Also, what I really don't get is why he doesn't just stop making some of the older model SDS boards. If he creates a new version more stable into lower loads, then just be rid of the old one. Simplify his operations and the list of products. So if the 470 is supposed to be an improved version of the 258, then stop making the 258 and just keep the 470 - better yet call it 258 MKii or something.
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I have two SDS 224 in a single case; post #2368 of this thread. I had planned to use them for Bi-amping an OB system that I built, but plans change and now I am considering running them bridged. Any thoughts?
These amps sound wonderful and have been very reliable. No heat issues.
Thanks,
Bill
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I have two SDS 224 in a single case; post #2368 of this thread. I had planned to use them for Bi-amping an OB system that I built, but plans change and now I am considering running them bridged. Any thoughts?
These amps sound wonderful and have been very reliable. No heat issues.
Thanks,
Bill
Hi Bill
I just finished doing exactly that yesterday! Just hooked the amp up to my Klipsch RF-83's...sounding good. One detail that's not well documented...hook speaker outs to + and + on each amp, use the left speaker out for + and the right speaker out for -.
Good luck!
Mike
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Photos of revised SDS-450 amp module with improved heat handling capabilities to prevent premature tripping of the protection circuit. Also applies to SDS-470.
- Larger heatsink pontoons
- Resistors mounted off the board to help with cooling
- Thermistor moved towards the rear of the heatsink (small circle in middle of the heatsink at the power input/speaker output end of the PCB), originally at other side of the heatsink between the FETs where it was the hottest
- Heatsink added spanning underneath PCB
Tom also mentioned that there was a change to the FET buffers which lie underneath the raised heatsink just behind the FETs.
(http://www.audiocircle.com/image.php?id=61566)
(http://www.audiocircle.com/image.php?id=61567)
(http://www.audiocircle.com/image.php?id=61568)
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What would happen if you presented the SDS-470 with a 16 ohm load?
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Photos of revised SDS-450 amp module with improved heat handling capabilities to prevent premature tripping of the protection circuit. Also applies to SDS-470.
- Larger heatsink pontoons
- Resistors mounted off the board to help with cooling
- Thermistor moved towards the rear of the heatsink (small circle in middle of the heatsink at the power input/speaker output end of the PCB), originally at other side of the heatsink between the FETs where it was the hottest
- Heatsink added spanning underneath PCB
Tom also mentioned that there was a change to the FET buffers which lie underneath the raised heatsink just behind the FETs.
(http://www.audiocircle.com/image.php?id=61566)
(http://www.audiocircle.com/image.php?id=61567)
(http://www.audiocircle.com/image.php?id=61568)
Nice pics! Thanks for the info.
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What would happen if you presented the SDS-470 with a 16 ohm load?
In general, a higher ohm rating is easier for an amplifier to deal with than a low one, so I imagine it would be fine.
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Forgive if this is not the right place to put it, but I decided to sell my CDA-254L kit and black par-metal chassis with connectors. Was thinking $200 plus fedex ground to your location. Any takers?
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Forgive if this is not the right place to put it, but I decided to sell my CDA-254L kit and black par-metal chassis with connectors. Was thinking $200 plus fedex ground to your location. Any takers?
You should put that here ---> http://www.audiocircle.com/index.php?board=103.0
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You should put that here ---> http://www.audiocircle.com/index.php?board=103.0
Thanks Barry ! I posted it there.
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SDS-450 amps up and running again with the revised boards. Sounding good and no heat issues thus far (left them running all night).
(http://www.audiocircle.com/image.php?id=61842)
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SDS-450 amps up and running again with the revised boards. Sounding good and no heat issues thus far (left them running all night).
(http://www.audiocircle.com/image.php?id=61842)
Look great ! It look like you use a mirror to take the picture :wink: I like that idea you make left / right positioning.
Regards
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In general, a higher ohm rating is easier for an amplifier to deal with than a low one, so I imagine it would be fine.
First off, how about if you term it more correctly. Higher impedance.
Sure, higher impedances are generally easier on an amplifier, but not necessairly better as far as frequency response and damping factor are concerned.
You'll find that some amps work 'best' into some specific load, probably depending on the output devices themselves.
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First off, how about if you term it more correctly. Higher impedance.
Sure, higher impedances are generally easier on an amplifier, but not necessairly better as far as frequency response and damping factor are concerned.
You'll find that some amps work 'best' into some specific load, probably depending on the output devices themselves.
I responded with, "In general" and "I imagine"... How did you respond to the original question? I figure rajacat should really ask the designer...
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Hi all,
This is my first post on this board, so perhaps I should introduce myself. My name is Craig Young, and I have been searching for a new power amp for my system, which consisted of an Audible Illusions Modulus 2D preamp, a Counterpoint SA-220 power amp (now deceased ...) driving a pair of Apogee Centaurus ribbon hybrids. I am currently using a friends set of Bel Canto REF 1000M monoblocks to drive these speakers and am A/Bing them with my brothers Odyssey Stratos Plus Class A/B amp. Source is an OPPO 981 DVD / CD player as well as my home theater system which is driven by a Lenovo T61 laptop in a docking station. My listening environment is very sub-optimal, although it is potentially a very good room. It is not a dedicated listening room, however, and has too many hard surfaces (bare walls, no draperies, hardwood oak floor, etc.). It does have an 18 foot vaulted ceiling, and with some acoustic treatment would likely make a very good listening room.
My background is in music, and I was formerly a professional classical musician. I am currently working in electrical engineering, doing building power and lighting design.
I have done a bunch of reading on this board and others. I originally considered buying another used amp such as a set of Bel Cantos, but cannot currently justify the price. I am also not totally sold on B&O ICEpower modules. So, I began exploring a DIY project, as I have some DIY experience, and my twin brother has extensive DIY and design experience, and is willing to help out, or even to just build the whole thing.
I originally toyed with Hypex NC400, but the realization that the finished product would run ~2K caused me to turn in this direction. I have read this entire thread as well as everything I could find on diyaudio about ClassDAudio.
I spent some time corresponding with Tom yesterday to verify what amp he felt could drive my Apogees (84dB sensitivity and 5/3 Ohm nominal / minimum impedance). I also wanted to verify that my tube preamp, which has about an 1800 ohm output impedance, would work properly.
Based on my discussion with Tom, I placed an order this morning for an SDS-254 kit, minus power caps, which I am replacing with (6) 10,000 uF Panasonic caps. I will be using a Par-Metal 16 x 12 x 4 enclosure, and will use single ended RCA outputs from my preamp to drive balanced XLR inputs on the power amp. I will be building my own interconnect cables using (probably) Belden microphone cable.
Thank you all for your comments in this rather lengthy thread, and I look forward to posting listening impressions.
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Welcome to AC, Craig. I recently bought the same case to house two bridged SDS-224's, and really like the results. I went with the RCA inputs on the amp. Will you be wiring the 3 XLR pins staight to the amp, or will you follow something similar to the NC400 datasheet (wire pin 1 to case, wire case to amp)? Either way, did Tom think the RCA to XLR connection would reduce noise???
Looking forward to your build. Enjoy!
Mike
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Yes, I will build the RCA to XLR cables per either the RANE note (posted a number of pages back in this thread) or the Hypex NC400 doc. The pinout is the same. Shield is connected to pin 1 at XLR. XLR pin 2 is the signal at the RCA end and pin 3 at XLR connects to the RCA housing.
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Hi all,
This is my first post on this board, so perhaps I should introduce myself. My name is Craig Young, and I have been searching for a new power amp for my system, which consisted of an Audible Illusions Modulus 2D preamp, a Counterpoint SA-220 power amp (now deceased ...) driving a pair of Apogee Centaurus ribbon hybrids. I am currently using a friends set of Bel Canto REF 1000M monoblocks to drive these speakers and am A/Bing them with my brothers Odyssey Stratos Plus Class A/B amp. Source is an OPPO 981 DVD / CD player as well as my home theater system which is driven by a Lenovo T61 laptop in a docking station. My listening environment is very sub-optimal, although it is potentially a very good room. It is not a dedicated listening room, however, and has too many hard surfaces (bare walls, no draperies, hardwood oak floor, etc.). It does have an 18 foot vaulted ceiling, and with some acoustic treatment would likely make a very good listening room.
My background is in music, and I was formerly a professional classical musician. I am currently working in electrical engineering, doing building power and lighting design.
I have done a bunch of reading on this board and others. I originally considered buying another used amp such as a set of Bel Cantos, but cannot currently justify the price. I am also not totally sold on B&O ICEpower modules. So, I began exploring a DIY project, as I have some DIY experience, and my twin brother has extensive DIY and design experience, and is willing to help out, or even to just build the whole thing.
I originally toyed with Hypex NC400, but the realization that the finished product would run ~2K caused me to turn in this direction. I have read this entire thread as well as everything I could find on diyaudio about ClassDAudio.
I spent some time corresponding with Tom yesterday to verify what amp he felt could drive my Apogees (84dB sensitivity and 5/3 Ohm nominal / minimum impedance). I also wanted to verify that my tube preamp, which has about an 1800 ohm output impedance, would work properly.
Based on my discussion with Tom, I placed an order this morning for an SDS-254 kit, minus power caps, which I am replacing with (6) 10,000 uF Panasonic caps. I will be using a Par-Metal 16 x 12 x 4 enclosure, and will use single ended RCA outputs from my preamp to drive balanced XLR inputs on the power amp. I will be building my own interconnect cables using (probably) Belden microphone cable.
Thank you all for your comments in this rather lengthy thread, and I look forward to posting listening impressions.
Some suggestions:
If your sources have volume controls, sell the Audible pre. Or buy a resistor stepped attenuator (It can have a switch between different sources) with one vishay in series for good sound and sell the Audible pre. (I used to have the Audible Illusions Modulus 2B preamp then a CAT pre. They are both blurr machines.)
The SDS may have enough gain to make up for the lack of a pre. But with those insensitive speakers I'm not sure. Have Tom do the calculation.
Why not spend $20 more (you should get more than that for the pre) and get the SDS 258 and get twice the power and +3dB, sounds about twice as loud.
I've had 2 different pair of Ice amps, 200w and 1000W, both modded. My unmodded SDS 258 beats them easily.
Why run the inputs as a psuedo/quasi balanced line? Better sound? Or preparing for when you have real balanced input from a source?
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Some suggestions:
If your sources have volume controls, sell the Audible pre. Or buy a resistor stepped attenuator (It can have a switch between different sources) with one vishay in series for good sound and sell the Audible pre. (I used to have the Audible Illusions Modulus 2B preamp then a CAT pre. They are both blurr machines.)
The SDS may have enough gain to make up for the lack of a pre. But with those insensitive speakers I'm not sure. Have Tom do the calculation.
Why not spend $20 more (you should get more than that for the pre) and get the SDS 258 and get twice the power and +3dB, sounds about twice as loud.
I've had 2 different pair of Ice amps, 200w and 1000W, both modded. My unmodded SDS 258 beats them easily.
Why run the inputs as a psuedo/quasi balanced line? Better sound? Or preparing for when you have real balanced input from a source?
Thanks for the suggestions. If you look closely at Audible Illusions, the Modulus 2D is significantly different from the 2B or 2C. I would have to respectfully disagree with you as to it being a "blur machine". I have used this preamp for the past almost 20 years and love it. I like the idea of a tube preamp with a class d power amp, but I will evaluate that over some longer time period before making a change.
As far as the SDS258, I talked to Tom about it, and he did not recommend it for my speaker (yes, I gave him the specs for them). He said this:
"Yes, the SDS-254 should drive your speakers just fine. I think with the ratings of these Apogee speakers, you should get about 200W MS up to 250W RMS from this amp.
I don't recommend the SDS-258 for these speakers as its not made to drive the loads these speakers are capable of. If you want more power, we do have the SDS-470 (not on our website) that is 300W RMS per channel."
In terms of running balance versus unbalanced, according to Hypex, for example, this arrangement benefits unbalanced sources almost equally to balanced sources. A number of posts on this board indicate that use of the balanced option improves soundstage and air in user systems here. Plus, the reality is that with the SDS-254 I can do either by simply removing a jumper or replacing it. Finally, it provides future proofing as well.
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Just to emphasize the importance of matching these amps to speakers I have put my spare CDA254 back into service with new speakers. The speakers are minimum 6ohm and >8ohm for most of it. Now I hear the 'glassy' treble some people complain about time to time. I never had this issue with my previous 2way speakers which were solid 4ohm. However this is in line with the IR2092 spec sheet that shows 8ohm speakers will have rising treble way past 20khz (up to 40 I think) with the default output filter. So make sure to get the amp that matches your speakers!
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Thanks for the suggestions. If you look closely at Audible Illusions, the Modulus 2D is significantly different from the 2B or 2C. I would have to respectfully disagree with you as to it being a "blur machine". I have used this preamp for the past almost 20 years and love it. I like the idea of a tube preamp with a class d power amp, but I will evaluate that over some longer time period before making a change.
As far as the SDS258, I talked to Tom about it, and he did not recommend it for my speaker (yes, I gave him the specs for them). He said this:
"Yes, the SDS-254 should drive your speakers just fine. I think with the ratings of these Apogee speakers, you should get about 200W MS up to 250W RMS from this amp.
I don't recommend the SDS-258 for these speakers as its not made to drive the loads these speakers are capable of. If you want more power, we do have the SDS-470 (not on our website) that is 300W RMS per channel."
In terms of running balance versus unbalanced, according to Hypex, for example, this arrangement benefits unbalanced sources almost equally to balanced sources. A number of posts on this board indicate that use of the balanced option improves soundstage and air in user systems here. Plus, the reality is that with the SDS-254 I can do either by simply removing a jumper or replacing it. Finally, it provides future proofing as well.
I missed those posts about the balanced option with a jumper. I'll try it soon, thanks!
My speaker is and easy load 6-8ohms so a SDS254 makes more sense.
If you don't think your pre is a blurr machine try running your source straight in to an amp and play a quiet piece of music that won't harm your speakers. Then insert the pre and play the same piece at the same level. If there is no impedance mismatch the non-pre version should be cleaner and clearer sounding. Of course I could be wrong!
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Hi all,
Here are a couple of in progress pics of my SDS-254, in a Par-Metal 16x12x4 case. Also, I do have a couple of questions.
1.) My kit came with the Honeywell gain controls, but no mounting hardware or knobs. Is this normal? I have an email into Tom, but he has not responded yet.
2.) Any comments on this amp as to long term listening? Any fatigue or glare in the high frequencies noted with this? The information in this thread suggests that it is a very good sounding amplifier, but I thought I might be able to get some longer term comments.
Finally, This is a drawing of my layout.
(http://www.audiocircle.com/image.php?id=62428)
(http://www.audiocircle.com/image.php?id=62431)
(http://www.audiocircle.com/image.php?id=62429)
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Yep...no hex pot nuts or knobs. I got my knobs from Radio Shack. I bought a bunch of the nuts from Ebay. If you have trouble finding them, you are welcome to PM me with your name and address and I'll mail you a couple.
Mike
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No issues with long term listening, ive had my SDS254 for well over a year now.
What caps are you installing?
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No issues with long term listening, ive had my SDS254 for well over a year now.
What caps are you installing?
Thanks for the listening report - it is helpful, as the Bel Cantos I am using right now can be a bit fatiguing, and they have some mid-range suckout. Some of it is the listening room as I do not have enough dampening surface in it.
As far as caps, I am putting Panasonic (6) 10,000 uF TS-HA 63V caps in.
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Hi all,
Here are a couple of in progress pics of my SDS-254, in a Par-Metal 16x12x4 case. Also, I do have a couple of questions.
1.) My kit came with the Honeywell gain controls, but no mounting hardware or knobs. Is this normal? I have an email into Tom, but he has not responded yet.
2.) Any comments on this amp as to long term listening? Any fatigue or glare in the high frequencies noted with this? The information in this thread suggests that it is a very good sounding amplifier, but I thought I might be able to get some longer term comments.
Finally, This is a drawing of my layout.
(http://www.audiocircle.com/image.php?id=62428)
(http://www.audiocircle.com/image.php?id=62431)
(http://www.audiocircle.com/image.php?id=62429)
Hi, Sorry because I can't see your pics because of being blind, so I have one suggestion for you. Don't mount those pots in your case. I suggest you maybe use them just as a guide to figure out the level of where your amp to be, and then get some good quality 1% resistors if you can. The amp will sound better, so I read in these pages. For Example, a 1.2KOhm resistor will set the amp's level to the standard 27DB gain. If I do remember they are about 32DB gain at stock. So just something for you to think about. Those pots so I read aren't that good. So something to keep in mind.I hope this gets to you before you drill any holes in your case to mount those pots.
Ray Bronk
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Oops - too late - the case is already drilled for the pots. I guess from reading the thread that my take on it was that they did not affect the sound. Tom states they are high quality pots, and they seem to turn smoothly, etc. So, we will see. Thanks for the reply, though.
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Oops - too late - the case is already drilled for the pots. I guess from reading the thread that my take on it was that they did not affect the sound. Tom states they are high quality pots, and they seem to turn smoothly, etc. So, we will see. Thanks for the reply, though.
Hi, Well, hopefully the pot holes are in the back of the case. In that case, you can go online and search out for caps that will cover those holes. If you go back several pages you'll see what people have had to say about the pots and resistors.
Ray
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Thanks for the input. I went back and looked through the thread, but could not find much suggesting that the pots were a problem. I will stick with them, and I will report back on my experience with them.
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If you go back to the posts beginning on page 104 and read through you will find any number of posts suggesting that replacing the pots with fixed high quality resistors can offer a rather dramatic improvement in the sound of the SDS amps. In my experience the naked Vishays worked some real magic. It IS useful to use the pots initially to ascertain the 'ideal' amount of gain you want (depends on the type of preamp and speakers you will be using). You can always leave the pots mounted in the chassis to fill the holes, and just leave them disconnected.
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Thanks. I have read the entire thread through, before buying the amp, but I did not go back that far looking for info on the pots. I will take a look at it. Thanks for the advice. You are correct, once I get things dialed in, I can always put a fixed resistor in and leave the pots mounted.
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Since there is no "Thread Search" function in this forum, here's a tip for anyone trying to find a specific bit of information, in a specific thread, especially one as large as this...
If you use the "PRINT" function in the menu at the top-right or bottom-right of the thread posts, it will open the full thread in one page as a text document. You can then use your browsers search function to find the key word you're looking for ie. "vishay".
Hope this helps.
using the method outlined above I quickly found this post, and many others following it...
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Title: Re: $175 Class D amp--120 wpc
Post by: walkern on 22 Oct 2010, 03:09 PM
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I had some left over 3 pin Molex connectors and decided to try substituting a single resistor for each input level control on my SDS 254 amp. I tried 10 ohm Vishay metal film resistors first, and then switched to 4.7K ohm carbon film resistors so I would better match the volume control output characteristics of my Pass DCB1. The resistors both offered (a) a more 3D or holographic sound stage (2) more layering and extension both in front and to the rear of my speakers, and (c) a quieter background from which sound emerged (sounded much like adding good AC power conditioning). The Vishay metal film resistors clearly tipped up the treble balance, and initially sounded a bit gritty or spitty or splashy, and they also tightened up the bottom end a bit. The carbon film (generic... had 'em laying around from Radio Shack) resistors were smoother sounding with no emphasis in any particular region, but they did warm up the midbass a bit (fuller, but not bloated or tubby). All in all I would say the improvement is as great as the difference between the CDA amps and the SDS amps, and all for less than $10. The Molex connectors I used were not a perfect fit and had to be filed a bit (the locking system on them was different than Tom uses), but are snug and won't fall out. Mouser part number for them is: 538-10-11-2033, and you'd also need crimp terminals for them that will attach to the legs of the resistors (that must be soldered IMHO) - Mouser part number 538-08-50-0114.
Highly recommended cheap and cheerful tweak that won't void your warranty. I'm sure higher quality resistors would be worth trying. The 10 ohm value leaves the input impedance similar to having the control pots fully turned up. The 4.7K ohm value was equivalent to turning the control pots down by about 6 db.
Neil
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Barry_NJ, thanks very much! The lack of a thread search function was making for a lot of extra reading.
On another similar note, did people ever arrive at a consensus as to what resistors work the best? From what I have read, the Vishay "naked" TX2375 or TX2575 series seemed to be the one many were getting, but Walkern talked about Riken and Holco as well. Oh, and finally, where is everyone sourcing these from? Partsconexxion? Elsewhere?
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Ditto thanks to Barry_NJ. Great work around for searching. :thumb:
Regarding the pots. Tom does believe that contrary to their appearance, the Honeywell pots are very good quality and sound great (without directly negating the use of resistors, I get the impression he doesn't think they provide a significant improvement). That said, I think its an easy enough tweak that it makes sense to implement once you've settled on a specific gain level and don't need to adjust it frequently.
I also wonder if the benefits derived perhaps come more from the elimination of those long leads carrying the signal to the pot and back again, going through all that "noise" inside the chassis?
I have not tried fixed resistors just yet, but plan to eventually.
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Ditto thanks to Barry_NJ. Great work around for searching. :thumb:
Regarding the pots. Tom does believe that contrary to their appearance, the Honeywell pots are very good quality and sound great (without directly negating the use of resistors, I get the impression he doesn't think they provide a significant improvement). That said, I think its an easy enough tweak that it makes sense to implement once you've settled on a specific gain level and don't need to adjust it frequently.
I also wonder if the benefits derived perhaps come more from the elimination of those long leads carrying the signal to the pot and back again, going through all that "noise" inside the chassis?
I have not tried fixed resistors just yet, but plan to eventually.
Hi, Well, don't know since I don't have one of these amps. Somewheres in this thread is a chart that has been repeated several times here. The 1.2 KOhm resistor will set the level to about the 27DB level which is supposedly standard for amps. I'd suggest you look for 1% resistors. Quarter to half watt should be ok. Yeah, maybe all that wiring coming from the pots to the connector may play a role here. When I someday order my amps, I will order them without the connectors, with the fixed resistors in place. one less mechanical thing that can possibly take away from the sound of the amp.
if the holes are already in the case, I'll look around for caps, or if it's the faceplate, i'll order one without the holes drilled.
Ray Bronk
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Barry_NJ, thanks very much! The lack of a thread search function was making for a lot of extra reading.
On another similar note, did people ever arrive at a consensus as to what resistors work the best? From what I have read, the Vishay "naked" TX2375 or TX2575 series seemed to be the one many were getting, but Walkern talked about Riken and Holco as well. Oh, and finally, where is everyone sourcing these from? Partsconexxion? Elsewhere?
The Riken and Holco resisters were both nice, but once I got the naked Vishays I never looked back. If memory serves I got them from Michael Percy... www.percyaudio.com (http://www.percyaudio.com).
Neil
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The Riken and Holco resisters were both nice, but once I got the naked Vishays I never looked back. If memory serves I got them from Michael Percy... www.percyaudio.com (http://www.percyaudio.com).
Neil
Hi Neil,
What size of resistors and what values and how many did you get? What was the cost and shipping ETC.
Ray
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The naked Vishays I got (TX 2352) were .6 watt rated... cost $12 each, and you need 2 for each stereo amp. I don't remember what shipping was? I chose a 4.75K value as that dropped the gain of the amp to where it worked best for my system (I have high sensitivity speakers, and don't listen LOUD anymore). A 10 ohm resistor gives you max gain according to Tom. Here is a chart with some other options for values to adjust the gain to your liking and some general instructions:
"For those who wish to change the pots for fixed resistors, here are resistor values to produce required gain. Gain is listed in dB: To change gain potentiometer to a fixed resistor, you would connect a fixed resistor between the yellow and black wires on the gain controls (of course, remove the gain pots). Leave the red wire disconnected.
Use high quality 1% resistors:
560 Ohm = 31 dB
1K = 30 dB
2.2K = 27 dB
5.2K = 23 dB
6.2K = 18 dB
7.5K = 16 dB"
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The naked Vishays I got (TX 2352) were .6 watt rated... cost $12 each, and you need 2 for each stereo amp. I don't remember what shipping was? I chose a 4.75K value as that dropped the gain of the amp to where it worked best for my system (I have high sensitivity speakers, and don't listen LOUD anymore). A 10 ohm resistor gives you max gain according to Tom. Here is a chart with some other options for values to adjust the gain to your liking and some general instructions:
"For those who wish to change the pots for fixed resistors, here are resistor values to produce required gain. Gain is listed in dB: To change gain potentiometer to a fixed resistor, you would connect a fixed resistor between the yellow and black wires on the gain controls (of course, remove the gain pots). Leave the red wire disconnected.
Use high quality 1% resistors:
560 Ohm = 31 dB
1K = 30 dB
2.2K = 27 dB
5.2K = 23 dB
6.2K = 18 dB
7.5K = 16 dB"
Hi, Ah yes, the chart. Thanks for the correction. Somehow, I thought it was a 1.2 Kohm resistor. Oh well, guess I'm getting old. lol.
Now since I haven't seen the board or the whole setup, is the classD three boards, one PS, and two separate board for each amp, or one board containing both channels. In order to operate this in bridged mode, you have to have two boards? is this correct? Sorry forgot how this all works.
Ray Bronk
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I don't know which SDS amp kit you are putting together. The 224, 254 and 258 are all single amp boards, (with one power supply board and 1 transformer). The SDS 1000 is two amp boards (2 X 254), with one power supply board and 1 transformer. You can check out photos of the single amp board models at Tom's website www.classdaudio.com (http://www.classdaudio.com)
Neil
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I don't know which SDS amp kit you [Ray Bronk] are putting together. ..... You can check out photos of the single amp board models at Tom's website www.classdaudio.com (http://www.classdaudio.com)
No, he can't which is the reason he's asking.
Hi, Sorry because I can't see your [CYoung234] pics because of being blind .....
Steve
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I don't know which SDS amp kit you are putting together. The 224, 254 and 258 are all single amp boards, (with one power supply board and 1 transformer). The SDS 1000 is two amp boards (2 X 254), with one power supply board and 1 transformer. You can check out photos of the single amp board models at Tom's website www.classdaudio.com (http://www.classdaudio.com)
Neil
Hi Neil,
Thanks for the info. So $24 for two resistors? hmmm, gosh, just stick 'em in an envelope (softpack) and send them for almost nothing, well a few bucks anyway.
Ray
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Hello gentlemen,
sorry fr my english but i'm a frenchie, very satisfied with my SDS470 feeding Duntech Prince speakers.
Now i want to try passive bi-amping, in order to avoid that the distorsion of the low frequencies may reach the medium-treble drivers, and assess whether the improvement is relevant or not really.
Therefore i need to keep the pots in order to allow to adjust separately the level for -low and -high frequencies.
This is why i have some questions, destined to those having tested passive bi-amping with four channels of amplifying.
1 Has somebody acquired some return of experience with passive bi-amping?compared results vis a vis the single amp?
2 Bi-amping is imposing to keep the pots (to allow for adjusting separately the level for lows and highs),.. therefore connect he 2 XLR symetrical (balanced) inputs in parallel..do yu know whether the position of each pot is modifying the input impedance or not? did anybody measure exactly which is the value of one channel's input impedance in balanced mode?(which will be divided by 2 when paralleled)
3 Is somedody having some return of experience with replacing the original pots by very good ones (ALPS for example)while shortening at minimum the wires connecting such pots to the board??results?
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Okay, I finished my amp last night and took some measurements of the DC and AC out on the binding posts - they were all very good. The amp fired up perfectly. However, when I put it into my system - no sound. The gain pots are turned up 1/2 way. I have it set up for balanced operation but I am converting from RCA at my preamp out using some homebuilt cables. I tested the cables on my Bel Cantos, and they would not work at first - I had the pinouts as follows:
XLR Pin 1 - Shield, Pin 2, HOT (Blue), Pin 3 COLD (White) 0 the cable is Mogami W2549
RCA - Blue to the center pin, White and Shield to the body.
To get this to work with the Bel Cantos, I had to disconnect the shield from the RCA end.
At any rate, this has to be simple, as the amp powers up correctly. Oh, I had the J1 and J2 jumpers removed (actually I just had them on pin 3 so I would not lose them. Here are a few pictures showing the wiring. The gain controls were wired Black, White, Red from left to right with the control facing you and the pins facing DOWN.
(http://www.audiocircle.com/image.php?id=62531)
And, the gain control wiring:
(http://www.audiocircle.com/image.php?id=62532)
Later today, I will set it up for unbalanced RCA operation and try that. I rterminated the RCAs but did not terminate them at the amp - they are just taped off right now. Let me know if you have any other ideas or see something mis-wired.
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I think you mis-wired the pots. Looking from the back as you have it photographed the red wire should be on the right.
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I think you mis-wired the pots. Looking from the back as you have it photographed the red wire should be on the right.
Nick77, thanks. I wired them per an email I received from Tom yesterday, but he may have been in a hurry or something. Here is what he said:
==============================================================
No... black on left, white in the middle, and red on the right.
-----Original Message-----
From: Craig Young [mailto:craig_young234@sbcglobal.net]
Sent: Friday, May 11, 2012 5:11 AM
To: sales@classdaudio.com
Subject: RE: Contact Form
Tom, thanks. Hey, one more question. The gain control leads are now Red, White and Black. If I am holding the gain control facing me with the terminals pointing DOWN, are the colors RED, BLACK, WHITE from left to right? Thanks,
========================================================
I recall someone had a picture showing this with the RED, WHITE and BLACK cabling, so I will track it down and double check it. Okay, I checked it (Post #2509 on page 126), and my wiring matches that.
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Did you turn the amp on? Not trying to insult you---this was the mistake I made! There is a little rocker switch on one side of the amp; it kind of hangs under the board, so at least I missed it initially.
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Did you turn the amp on? Not trying to insult you---this was the mistake I made! There is a little rocker switch on one side of the amp; it kind of hangs under the board, so at least I missed it initially.
LOL - no offense taken! It is good to always check the simple stuff first. Yes, it is turned on, and when the amp turns on, the yellow LEDs come on for a split second and then settle on BLUE solid. The YELLOW LEDs turn off completely. So, it appears that the amp powers up fine. We tested the PS before I hooked up the amp board, and the PS was supplying a solid +50V and -50V at the PS output to the board. The BLUE LEDs on the PS board are on solid as well. Later today of tomorrow I can take some photos with my meter to show what I see with the amp on. But before I do that, I will wire up the RCAs and test it as unbalanced, because I really think it is something simple with the input.
As a curiousity, has anybody else run an unbalanced preamp into this amp using the balanced XLRs, and, if so, what was your cable pinout?
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One other potential culprit for no sound... the pots/attenuators work backwards from what I expected. If you turn them clockwise to maximum, I would have expected that to turn the amp's gain all the way up... but it doesn't... it turns it all the way down. If you turn them counterclockwise to the max, THAT turns the gain all the way up. Just a thought.
Given that some balanced connectors us different pin configurations for what is hot, neutral and ground, I suspect you are correct that your XLR connections may be the stop gap. Glad you got the amp up and running, and that all the LEDs are indicating proper functioning. Fingers crossed that the single ended RCA connections work!
And SORRY RAY! I did not realize you were blind. My bad!
Neil
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Okay, all is well. I set it up for RCA's and it is working fine. The gain pots needed to be adjusted slightly to center it, and the left and right channels were reversed because I wired it in a hurry - it is now correct. Sounds very good so far. More extended listening tomorrow, as I am out of time today.
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2 Bi-amping is imposing to keep the pots (to allow for adjusting separately the level for lows and highs),.. therefore connect he 2 XLR symetrical (balanced) inputs in parallel..do yu know whether the position of each pot is modifying the input impedance or not? did anybody measure exactly which is the value of one channel's input impedance in balanced mode?(which will be divided by 2 when paralleled)
I've asked Tom this exact question about input impedance and he said the pots do not modify input impedance of the amp. If I recall properly, the pots are located between the input stage/buffer and output amp. Input impedance is specified as 47k but I don't know if that is for both RCA and XLR. Might want to email Tom a question.
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UPDATE AFTER SOME MORE EXTENSIVE LISTENING:
Some initial listening impressions, comparing the SDS-254 to a set of Bel Canto REF 1000M's:
The Bel Cantos may have a slightly better low end. It is very close though. UPDATE: THEY ARE ACTUALLY PRETTY EVEN HERE.
The ClassD has better mids; the Bel Cantos have some midrange suckout in my system, right in the male voice range. UPDATE: I MUCH PREFER THE CLASSD MIDS. THEY ARE SMOOTHER WITH A LOT LESS GRAIN, AND ARE NOT RECESSED THE WAY THE BEL CANTOS ARE.
The ClassD high end is a touch rolled off, but I actually like that. UPDATE: THIS ROLLOFF IS VERY SLIGHT. IT DOES NOT BOTHER ME AT ALL, AND THE HIGHS SPARKLE WHEN THEY NEED TO.
One thing that a lot of audio systems do that is not real is overemphasize upper mids and highs. The highs are there when they need to be with the ClassD, and are totally silent when there is no information there. I really like the silence of this amp - no hum, no nothing. It also runs very cool in my system, and my speakers are not efficient (84dB).
In terms of soundstage, right now it seems as if the Bel Cantos offer a slightly wider soundstage, but I have not listened enough yet to finalize this. The midrange suckout on the Bel Cantos is making it tough to assess the depth. UPDATE: WITH THE MATERIAL I WAS LISTENING TO THIS AFTERNOON, THE TWO SYSTEMS WERE PRETTY EVEN FOR WIDTH, AND THE CLASSD DID BETTER WITH SOUNDSTAGE FRONT TO BACK DEPTH.
So far, I do not find the ClassD to be fatiguing at all. I will need several weeks of listening to this in my system to finalize this. I also need to adjust the gain slightly, as I started out with it a little low (pots about 3.6K or so). I will end up putting fixed resistors in, likely either 3.3K or 2.2K. My preamp will be able to handle either I think, as right now, it it running at about 11 o'clock with the gain set where it is.
FINAL THOUGHTS. I SET THE GAIN UP FOR 2.2K AND IT IS JUST RIGHT. ALSO, THE MUSIC I USED THIS AFTERNOON IS ONE THAT I AM VERY FAMILIAR WITH; IN FACT, I HAVE PERFORMED WITH ABOUT A 1/4 OF THE PERFORMERS ON THIS DISC. CHICAGO SYMPHONY ORCHESTRA / LEONARD BERNSTEIN SHOSTAKOVICH SYM. 1 & 7, DG 1987
I HAVE TO SAY FOR A LOW COST PROJECT, THIS CLASSD AMP IS A KEEPER IN MY SYSTEM. ESPECIALLY CONSIDERING I DO NOT GET MUCH TIME TO EVEN LISTEN ANYMORE ANYHOW.
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UPDATE AFTER SOME MORE EXTENSIVE LISTENING:
Some initial listening impressions, comparing the SDS-254 to a set of Bel Canto REF 1000M's:
The Bel Cantos may have a slightly better low end. It is very close though. UPDATE: THEY ARE ACTUALLY PRETTY EVEN HERE.
The ClassD has better mids; the Bel Cantos have some midrange suckout in my system, right in the male voice range. UPDATE: I MUCH PREFER THE CLASSD MIDS. THEY ARE SMOOTHER WITH A LOT LESS GRAIN, AND ARE NOT RECESSED THE WAY THE BEL CANTOS ARE.
The ClassD high end is a touch rolled off, but I actually like that. UPDATE: THIS ROLLOFF IS VERY SLIGHT. IT DOES NOT BOTHER ME AT ALL, AND THE HIGHS SPARKLE WHEN THEY NEED TO.
One thing that a lot of audio systems do that is not real is overemphasize upper mids and highs. The highs are there when they need to be with the ClassD, and are totally silent when there is no information there. I really like the silence of this amp - no hum, no nothing. It also runs very cool in my system, and my speakers are not efficient (84dB).
In terms of soundstage, right now it seems as if the Bel Cantos offer a slightly wider soundstage, but I have not listened enough yet to finalize this. The midrange suckout on the Bel Cantos is making it tough to assess the depth. UPDATE: WITH THE MATERIAL I WAS LISTENING TO THIS AFTERNOON, THE TWO SYSTEMS WERE PRETTY EVEN FOR WIDTH, AND THE CLASSD DID BETTER WITH SOUNDSTAGE FRONT TO BACK DEPTH.
So far, I do not find the ClassD to be fatiguing at all. I will need several weeks of listening to this in my system to finalize this. I also need to adjust the gain slightly, as I started out with it a little low (pots about 3.6K or so). I will end up putting fixed resistors in, likely either 3.3K or 2.2K. My preamp will be able to handle either I think, as right now, it it running at about 11 o'clock with the gain set where it is.
FINAL THOUGHTS. I SET THE GAIN UP FOR 2.2K AND IT IS JUST RIGHT. ALSO, THE MUSIC I USED THIS AFTERNOON IS ONE THAT I AM VERY FAMILIAR WITH; IN FACT, I HAVE PERFORMED WITH ABOUT A 1/4 OF THE PERFORMERS ON THIS DISC. CHICAGO SYMPHONY ORCHESTRA / LEONARD BERNSTEIN SHOSTAKOVICH SYM. 1 & 7, DG 1987
I HAVE TO SAY FOR A LOW COST PROJECT, THIS CLASSD AMP IS A KEEPER IN MY SYSTEM. ESPECIALLY CONSIDERING I DO NOT GET MUCH TIME TO EVEN LISTEN ANYMORE ANYHOW.
Hi CYoung234,
Well, get those resistors, the 2.2 KOhm and remove the pots accordingly. What preamp are you using?
Hey Neil, no problem.
I don't have the moola at the moment to build one. A few years back I went through some hell building Greg Ball's SKA amp. This one however seems like it would be easier to build.
I was kinda thinking of getting the smaller version of this amp, since I am going to be switching my priorities to headphones. So I don't really need tons of power. So something like the 224S just might be the ticket to headphone bliss or with use of small speakers.
What do you guys think?
Ray Bronk
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Ray,
Thanks for the advice. I put in some Vishay 1% metal film 2.2K 1/2W resistors, and the soundstage does open up, especially front to back. Very interesting. I sprang for a pair of the Vishay nude 2.2Ks ,and will try them out probably Friday to see if I can hear any difference. BTW, my preamp is an Audible Illusions Modulus 2D with Electro-Harmonix 6922's in it. It is a wonderful preamp, IMHO.
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My first post to say Hi. After reading through all 167pages of this post I decided to jump in and order a couple of the CDA1000 kits for a few projects I'm wanting to start.
I'm no audiophile like the majority of you, but know quality sound because of all my buddies that are! This seems to be a good grouping of knowledge here with very minimal drama.
I took notes along the way from everyone elses experiences so hopefully I'll get it right the first round. If anyone has any lessons learned I'd be glad to take those as well.
Thanks
Enal
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Good luck on the build, and welcome!
It has been noted that the IR boards sound a little sweeter than the TI units. Some of the higher power units are the Texas Instruments boards.
-
+1
I guess my first suggestion would be to verify that the "high" gain on the CDA amps works for you. Tom can lower the stock gain (32 - 33dB???) if that may be too high.
Mike
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Ray,
Thanks for the advice. I put in some Vishay 1% metal film 2.2K 1/2W resistors, and the soundstage does open up, especially front to back. Very interesting. I sprang for a pair of the Vishay nude 2.2Ks ,and will try them out probably Friday to see if I can hear any difference. BTW, my preamp is an Audible Illusions Modulus 2D with Electro-Harmonix 6922's in it. It is a wonderful preamp, IMHO.
Just an update to note that I put in the Vishay 2.2K "naked" resistors, and do not hear any difference. I will listen more, of course, but it looks like I just wasted $30 on them...
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Just an update to note that I put in the Vishay 2.2K "naked" resistors, and do not hear any difference. I will listen more, of course, but it looks like I just wasted $30 on them...
Their still perty to look at, of course hopefully you realize some sonic gains. They do need a little break-in from my experience using in other positions. I never tried the resistor swap as i like the adjustable gain, but that is the "cats meow" in resistors.
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Their still perty to look at, of course hopefully you realize some sonic gains. They do need a little break-in from my experience using in other positions. I never tried the resistor swap as i like the adjustable gain, but that is the "cats meow" in resistors.
They may be the cat's meow in resistors, but in this amp, at least for me, they were pretty dead cats! I changed them back to the regular Vishay 1% metal film 2.2K's , and all is bliss again. THe amp has more air and dynamics with the regular old metal films. Maybe they need break in, but they are likely not going to get it at this point, as I am happy with what I am hearing.
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Well , with the hot summer temps. arrival over the last week, the sauna-like conditions in my NYC apt. has forced me to put my tube amp(power) on extended leave...after an extended leave of absence, my CDA254 build is back in play after a couple modifications, namely installation of an IEC socket and better input wiring...handling the mid/hi freq. above 250Hz.
I ordered a heatsink to attach to the fin-less one on the board, my p/s o/p voltage is slightly higher(+ 6vDC) than the max., causing the amp to run hotter than I would like.
The sound is adequate, clean and clear. Not as spectacular as my tube amps for sure.
(http://www.audiocircle.com/image.php?id=63231)
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Hi all, new here so please be gentle :)
I bought two CDA-1000 Kits a few months ago but only recently got the time to hook them up. Just as a test I measured the DC voltage output of the power supplies, and to my surprise they had an output of 95V instead of the expected 47V. When measuring the AC inputs on either side of the center tap I get around 67V which means the transformer has 33-34V secondaries. When measuring the center tap and one of the inputs on either side I get ~34V, which confirms the above.
According to the ClassDaudio website, the power supply should give me 1.41*33=47V DC output, so why is my output double at 95V? Am I doing something wrong?
The transformers are wired according to the 230V scheme as on Tom's website since I live in Europe.
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Hi all, new here so please be gentle :)
I bought two CDA-1000 Kits a few months ago but only recently got the time to hook them up. Just as a test I measured the DC voltage output of the power supplies, and to my surprise they had an output of 95V instead of the expected 47V. When measuring the AC inputs on either side of the center tap I get around 67V which means the transformer has 33-34V secondaries. When measuring the center tap and one of the inputs on either side I get ~34V, which confirms the above.
According to the ClassDaudio website, the power supply should give me 1.41*33=47V DC output, so why is my output double at 95V? Am I doing something wrong?
The transformers are wired according to the 230V scheme as on Tom's website since I live in Europe.
Okay, Tom just got back to me. Apparently I had to measure ground and + or - to measure the correct voltage. My mistake...
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Hello gentlemen,
My SDS470 amp,bought completed, has been (slightly) tweaked by: removing the wire which feeds the light located in the on/off switch,removing the asymetrical RCA inputs as well as the inverting switch allowing to choose between RCA and XLR.
I will also-in the near future- shorten the wires going to the pots by placing the pots at the RCA's holes location,then replace the short input wires by litz wire and the loudspeaker ones by pure silver (several 0.5mm dia),but the amp is working SO well that i hesitate to pursue tweaking it..Nota:I need to keep the pots since the sensitivity adjustment, with relation to the output level of my Weiss dac, modifies the balance and searching for a good compromise allows to improve further,the position of my pots is about 50%)
A very important improvement has been to bi-wire my Duntech speakers and use for the medium/treble section:litz wire as follows: 8X0.28mm (+) 25X0;05mm which opened up the sound, more "air".Nota:The interconnects going from the dac directly to the amp should better be chosen without shield.
Such mods led to considerably improving the balance (tonal accuracy)and the subjective impression of quality delivered by the SDS470 which ,from "good" ,raised the level of "top level amp".(This is just my personal opinion..)
The reason for my coming today is i compared last saturday my SDS470 amp to an amp which is considered worldwide as equal to the cream's best, the DEVIALET amp.(price :12000 Euros)
For such comparison,i just had to remove the SDS and replace it by the Devialet,sole mod: adding a Neutrik XLR to RCA adaptor to the interconnects since the Devialet has only RCA inputs.
Conclusion: the 2 amps are in the same league as far as transparency and sound quality are concerned.
The SDS has been far from ridiculous and i even wonder whether some audiophiles could always differentiate them in a blind test.
The very small differences of sound are : the Devialet is more "recessed" in the zone 2-4khz, giving him a more "neutral" sound,while the SDS pushes a little bit more forward this "presence zone", may be by 1 (or 1.5) dB(but i think this slight difference could be easily compensated if wished by the choice of interconnects or cables).
My interlocutor, who brought the Devialet at home for such test,has been voiceless since he was not anticipating such a small difference if taking into account the Devialet current worldwide aura..
However, i must emphasize that to obtain the best from an SDS amp,a lot of cable's optimizing is mandatory, INCLUDING the choice of the mains cable.
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However, i must emphasize that to obtain the best from an SDS amp,a lot of cable's optimizing is mandatory, INCLUDING the choice of the mains cable.
Thanks for the report, ive found the power cable makes a big difference also. Increasing the amps capacitance with better quality power caps increased dynamics and mico details considerably.
I first increased to 40k with great results, then bumped to 60k. The difference between 40-60 wasnt as significant but notable.
Might try better board power supply wiring also. Have fun!
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Thanks for the report, ive found the power cable makes a big difference also. Increasing the amps capacitance with better quality power caps increased dynamics and mico details considerably.
I first increased to 40k with great results, then bumped to 60k. The difference between 40-60 wasnt as significant but notable.
Might try better board power supply wiring also. Have fun!
What power cord did you settle on? (you may have stated this earlier, but...).
Thanks, Mike
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What power cord did you settle on? (you may have stated this earlier, but...).
Thanks, Mike
Im using a wywire juice2 power cord with copper connectors. I will be auditioning a Triode Labs (seven plus) in a few weeks, they seem to be very popular.
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To nick77:
Which are the exact references of 60kMicroF caps?(15k each?)and could they replace easily the original ones without modifying the board holes? thanX by advance fr ur reply.
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To nick77:
Which are the exact references of 60kMicroF caps?(15k each?)and could they replace easily the original ones without modifying the board holes? thanX by advance fr ur reply.
Yes they fit the stock board, i used six of these Panasonic. Suppose to be a good bang for the buck. Always wanted to try the Mundorfs but couldn't find a cap to fit.
http://www.diycable.com/main/product_info.php?products_id=602
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To Nick77:
Warm thanX,i will upgrade my caps.
In the same time, i will shorten the pots wires to the minimum possible,and put good input wires (silver or litz) and good speaker ones.
I will inform you after a strict comparison (before/ after mods),made in presence of a friend.
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What distinguishes the difference between the SDS and the CDA series amps other than the larger heat sinks, balanced inputs and adjustable gain?
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What distinguishes the difference between the SDS and the CDA series amps other than the larger heat sinks, balanced inputs and adjustable gain?
A higher input impedance, 47K ohm versus 7K ohm, and "better sound" according to Class D Audio and some of the users who have both (based on what other circuit differences I don't know).
Steve
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Thanks Steve,
I guess I should plow through the entire thread. I see that there are different power supply options as well plus the various mods and how they affect sound quality. I'm mostly concerned with SQ. Power is secondary since I will have very efficient speakers that will be bi amp'd.
..Roy
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Thanks Steve,
I guess I should plow through the entire thread. I see that there are different power supply options as well plus the various mods and how they affect sound quality. I'm mostly concerned with SQ. Power is secondary since I will have very efficient speakers that will be bi amp'd.
..Roy
Roy the SDS series is well worth the extra price of entry, the sonics are a real nice improvment over the CDA. SDS series has a high end input reciever that really lowers distortion. Definitely get the larger PS, and if you like to tinker you could even buy it w/o caps and install the Panasonics which take it to another level.
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Hi all,
Does anyone know if the Class D model (CDA-258) amp allows for easily modding it to accommodate a gain control like the SDS-258 offers? Are there PCB holes where a 3-pin header could be soldered in - after presumably removing a fixed resistor?
Edit: A quick look thru of the manual suggests there are no obvious connections for a gain control so I may have found my answer. Without a schematic of the circuit, and all the SMDs on the underside, it sounds like it would be more than I'm willing to tackle now, but not out of the realm of possibility. :) I'm thinking about this unit to purchase over the SDS model due to the price, but would like the gain control option.
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I have a SDS 258 amp.
Just soldered the speaker wires on the bottom of the board on the screw terminals solder point.
Cheap solution for cleaner, clearer sound top to bottom. Easy to hear the difference.
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I'm about to place an order for one of the SDS amps. I'm vacillating between the SDS-254 and the 224. They're both about the same cost and I'll be using them with very efficient speakers: biamped wave guides SEOS-18's with AE15m woofers and yet to be determined compression drivers for the waveguides. The SDS's will be used for the woofers.
Since the difference in cost is negligible, I'm leaning towards the 254's unless the 224's have better SQ or some other advantage I don't know about. Another reason is if I happen to build some other less efficient speakers in the future the 254's might be a better match.
Are there any faults in my reasoning? Would the 254' s be overkill?
...Roy
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Roy,
Your question is likely best directed to Tom at Class-D Audio. I really doubt many, if any, here have A-B'd the 2 amp boards in question.
My honest opinion is there is no such thing as too much power, having plenty of extra head-room/power available for sudden crescendos is a good way to add life and effortlessness to a system.
Best, Barry
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I'd go for the 254's. $35 for another 3dB ain't bad. Also, don't forget to use ACircle as the promo code...5% off!
Mike
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I'm going for the 254's :D The TD15m's can take a lot of power and I will be using a miniDSP to implement digital crossovers which will eat some of that power. Mike, thanks for the heads up on the promo code. :thumb:
...Roy
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I set out to make 6 channel amp for my home theatre. I have mounted the amps in the following manner. I have designed my equipment console to be kept below the screen, in which this contraption will be put and the transformers will be put just behind it inside the console.
Do you guys think i will run in to any problems with this setup. I did a trial run today and i am getting a lot of hum in my speakers. I am trying to investigate any ground loop problems. But any insight or help from you guys will be greatly appreciated.
(http://www.audiocircle.com/image.php?id=64441)
(http://www.audiocircle.com/image.php?id=64442)
(http://www.audiocircle.com/image.php?id=64443)
(http://www.audiocircle.com/image.php?id=64444)
(http://www.audiocircle.com/image.php?id=64445)
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What kind of speaker binding posts are you using? They look like RCA inputs.
Mike
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What kind of speaker binding posts are you using? They look like RCA inputs.
Mike
+1
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yes they are RCAs. i have terminated my speaker cables with RCA plugs. The idea of designing this mount was to access the amp from above and not from behind as is the usual. May be i will post the whole assembly with the position of the processor as well.
Are RCAs a bad idea?
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I was looking at the photos and scratching my head. My first thought that the reason for the odd layout was to have the shortest possible input and output wiring, but you subsequently said it was for connection access.
I always put rubber grommets in holes in sheet metal that wiring passes through. I'm not sure exactly why you're getting hum, but I will say that I have never seen a layout where the boards are so close as to almost touch each other.
Steve
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Very often cable boxes or Sat / Dish receiver boxes will carry hum into your system. Try disconnecting everything from your AV receiver or pre/pro, and then fire up the AM or FM, and see if your hum is gone. If so, systematically begin connecting sources one at a time until the hum returns... and then you'll know what the culprit is.
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actually i wanted to fit 4 amp modules in 17" space to have a provision for 7.1 setup if i wanted to in the future. That is why i ended up quite tight.
I had sent the photos to Tom as well and he was OK with the layout. As far as my humming is concerned i have the following symptoms.
1) when i switch on the amps with speakers connected and no processor connected. I get a very slight hum from the speakers which i have to have my ears very very close to the speakers to hear it.
2) when i attach RCA interconnects to the Amp the hum increases to the point that i can hear it from 4-5 feet away
3) if hold the hold the negative of the two RCA channels with either of my thumbs the hum is greatly reduced
4) when i connect the interconnects to the Processor and switch it on, the hum does decreases a little bit.
5) when i play something on the bluray player the hum increases dramatically. When i stop it reduces to previous levels after a fraction of a second. If change the volume on the processor the hum level does not change it remains the same.
6) if i switch of the processor the hum increases to a very high level.
I have connected all my equipment to all my equipment to a single belkin powerstrip. The ground is working. i got it checked. the equipment right now connected to the strip is.
Two classdaudio amps connected through single power supply ( the third amp is disconnected)
one behringer amp for the subwoofer
Emotiva umc-1 processor
one sony bdp s590 connected through a 220-110 transformer
1. use umc-1 without ground
2. use claasd amp without ground
3. remove the behringer amp
Doing the above does not make any difference.
I tried the amps with a different power socket, The same pattern of hum occurs.
could braiding of the power lines be a problem? I was reading somewhere that toroidal transformers can also induce hum. Any help will be appreciated.
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3) if hold the hold the negative of the two RCA channels with either of my thumbs the hum is greatly reduced
Are these the input RCA's or the output RCA's?
If you are referring to the output RCA's, and have some extra speaker wire, I'd run one end straight to the amp (taking the RCA's out of the loop).
Are you using very efficient speakers? My Klipshorn's will buzz slightly a foot from the tweeters, but not at listening distance.
Mike
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RCA inputs which go into the amp from the processor to the amp. I hold the negative of the interconnect RCA connected to the amp, without connecting to the processor.
i am running Mirage OMD 15. L/R Sensitivity: 87 dB from 500 Hz to 2 kHz.
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Sorry...running out of ideas. :scratch: Almost sounds like a bad connection, if touching it solves the problem. I tinned the end of the wire before inserting it into the amp input (sometimes needing pliers to flatten the end so it would fit into the input terminal). I also make sure 1/16" or so of bare wire is exposed, just to make sure I'm not clamping down on the wire insulation.
Another thought. Did you use heat shrink tubing on each of the wires you soldered to the input RCA?
Good luck!
Mike
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Has anybody directly compared the Class D SDS amp to the ICEpower 125ASX2? http://app.audiogon.com/listings/icepower-125asx2-diy-kit-assembled-mono-block-550w-am--3
...Roy
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Has anybody directly compared the Class D SDS amp to the ICEpower 125ASX2? http://app.audiogon.com/listings/icepower-125asx2-diy-kit-assembled-mono-block-550w-am--3
...Roy
Mellifluous has both the 125ASX2 and the SDS-254. He prefers the 125ASX2.
http://www.audiocircle.com/index.php?topic=100249.msg1101726#msg1101726
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New mini amp out! Curious as to what the amp chip is. There's also new 4 channel complete amp available.
http://classdaudio.com/class-d-audio-amplifiers-1/mini-class-d-audio-power-amplifier.html (http://classdaudio.com/class-d-audio-amplifiers-1/mini-class-d-audio-power-amplifier.html)
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Hmm.... For those of us with very efficient speakers, I wonder how the sound quality of the mini amp, given it's power constraints, compares to the much higher powered versions. Battery power would eliminate the noisy influence of the power grid. Also the mini amp would be operating in it's sweet spot vs. using a much higher powered amp which would be idling most of the time.
I'm thinking that two of these in bridged mode, battery powered, would provide nice clean 30w/ch for efficient speakers at a very low cost. My current 25w monoblocks hardly ever get past 10 o'clock on the volume control.
Red Wine Audio has been using battery power for years for their well reviewed and modestly powered amps.
Dodd Audio also has some battery powered monoblocks that have been well received.
...Roy
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The Mini Amplifier might be a good fit for that portable DIY boombox/iPod speaker.
Steve
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I like my SDS on a battery for sure...
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I like my SDS on a battery for sure...
Was your battery powered implementation discussed somewhere in this huge thread? I'm curious how you used batteries to come up with the specified 40+ volts. Did you connect a number of 12V batteries in series?
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Battery power supply
http://classdaudio.com/power-sppplies/12v-dc-switching-power-supply-500-watt-car-audio.html (http://classdaudio.com/power-sppplies/12v-dc-switching-power-supply-500-watt-car-audio.html)
(http://classdaudio.com/media/catalog/product/cache/1/image/750x750/9df78eab33525d08d6e5fb8d27136e95/1/2/12v_power_supply.jpg)
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Looks like the "Mini D" runs straight off a 12V battery...perhaps the same battery powering my Dodd preamp??? Hope Tom adds more specs to his website.
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Yes, it should work.
"The amplifier runs from a 10V to 24V DC power supply or Battery"
One is on the way to me. :thumb:
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Ah I see.... a separate board to convert the 12V to ~40V. How does the SQ compare to the stock linear PS boards?
Yes, it should work.
"The amplifier runs from a 10V to 24V DC power supply or Battery"
One is on the way to me. :thumb:
I'll be eagerly awaiting your review. :green:
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+1
Wasn't it Paul Klipsch himself that said (paraphrasing) "What the world needs is a good (1)5 watt amp." ?
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Wasn't it Paul Klipsch himself that said (paraphrasing) "What the world needs is a good (1)5 watt amp." ?
What he actually said was "What this country needs is a good five-watt amplifier" (which was an alteration of an earlier famous quote "What this country needs is a good five-cent cigar").
Of course Paul's quote has to be taken in the context as being from someone who was building and selling a 105dB loudspeaker.
Steve
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Hi gentlemen,
I recently methodically compared three amps,one expensive, and excellent amp, tubed with 8XKT120,the DEVIALET amp,which seems to be recognized as a top performer, and my SDS470 (mods:removed the asymmetric RCA input,removed the wire which allows the led included in the on/off switch to be lighted)(no mods of the caps).
The results show that the three above ones are in the same sound quality league, the differences between them being less than the magnitude when changing some cables.
The tubes one has an euphonic charachter, very pleasant,but after a (long) while,some lack of surprise appears in my mind, the DEVIALET is excellent, gives the impression that it's very quick and uncolored since the mediums are very slightly recessed, the piano notes are excellent,but if the digital message is not perfect,dont account on it to forgive .., and the SDS is fully comparable to both previous ones,the sound is absolutely excellent but under the condition all the cables have been optimized in order to tune as perfectly as possible the complete system.
I planned to upgrade the caps to panasonic's, but the current result is soo good that i dont intend anymore to do it.
I have NO personal interest for which concerns my information,i own (also) the tubed amp, so i have a free choice, and i choose the SDS, but i donot criticize the tubed once since it is really good also,but i am slightly more "disturbed" and awakened when listening to the SDS, this is why i finally prefer it..But other audiophiles might very well prefer the tubed one, this is in the subjective domain.
I formerly thought that the treble (or medium-treble) might be purer with the tubed amp, but finally the difference of purity is not really relevant, all is depending upon the purity of the digital system incl. the dac.
I will let all of you informed about future confirmations of the above conclusions.
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Yes, it should work.
"The amplifier runs from a 10V to 24V DC power supply or Battery"
One is on the way to me. :thumb:
Any news on this? :)
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:thumb:
24V sound very good,and yes, it's a keeper.
I'm still "breaking in" new S/O Mundorf caps on the speakers, 2 more weeks 24/7 to go.
Will move to a metal chassis soon.
(http://www.audiocircle.com/image.php?id=64839)
(http://www.audiocircle.com/image.php?id=64840)
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Do you have one of the higher powered classdamps too? If so, is this mini amp comparable in sound quality? I'm just looking for a general impression of the difference. I realize you're still going through break-in.
Did you try 12V power or just use 24V battery power?
BTW, what kind of speakers are you using?
Thanks,
Roy
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I do have CDA-254 and will bring to a friend setup soon.
Mac Mini , DIY CAT SL1 , Pendragon
:thumb:
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I just ordered one of the mini amps. :D For $55 why not? I really like using batteries to eliminate AC noise issues. If it doesn't work out, I'll have a serviceable backup amp. All of the other amps have much more power than I need.
I'll be using a sealed 12V 9.0 Ah battery that is buffered with multiple caps . If this little amp meets my requirements I'll bridge it and order another one. I might experiment with lithium batteries too, to hear if they affect SQ.
....Roy
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I just put my CDA1000 kit forsale in the swap section if anyone is interested...Still new in the box it came in from CDA.
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6"X6"X4" Electrical box (Free)
:thumb:
(http://www.audiocircle.com/image.php?id=65118)
(http://www.audiocircle.com/image.php?id=65119)
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So you are running it on 24V Trung?
-
^^^^^
Yes, DC DC converter 12v to 24v
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Did you try it with with a 12V battery, no converter?
-
^^^^^
Yes, I think 24V give more everything.
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Hmm...I might try a couple of 12V batteries in series. I also use battery power for my Bolder SB3 and use a 12V to 5V converter. Works well. :)
How's is the SQ compared to your larger amp?
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Hmmm, in the good old cheap/cheerful ideas, I might have to figure out creating a cheap integrated to include using this DAC (http://www.audiocircle.com/index.php?topic=103678.0) with this new amp and some type of cheap preamp that can run on 12V as well and accept a few inputs...
Ideas?
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^^^^^
Yes, I think 24V give more everything.
argh. give more of what?! you're holding back bro! how's it sound?!!! :drool:
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I'm still have one more week to "burn-in" the Mundorf caps.
I can't get the best perform of the speakers.
Only what I can heard now. :scratch:
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Where do you find inexpensive chassies for one of these amps?
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Good place for some nice chassis with a good price:
http://www.sanjosescientific.com/servlet/the-PRINTED-CIRCUIT-BOARD-ENCLOSURES--PCB-BOXES/Categories (http://www.sanjosescientific.com/servlet/the-PRINTED-CIRCUIT-BOARD-ENCLOSURES--PCB-BOXES/Categories)
:thumb:
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I am having humm issues with the amps.
I wanted to know.
The transformer has a ground coming out which goes in to the mains. But there is not ground which goes in to the power supply. Then there is a ground which goes from the power supply to the amp board. So how do the amp and the power supply get grounded?
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I am having humm issues with the amps.
I wanted to know.
The transformer has a ground coming out which goes in to the mains. But there is not ground which goes in to the power supply. Then there is a ground which goes from the power supply to the amp board. So how do the amp and the power supply get grounded?
Hi justd...
Is the hum coming from your amp or your speakers (and what amp/speakers are you using)? Does it go away when you disconnect the inputs?
To quote Tom...
As far as grounding, don’t overdo it. Just put the transformer ground wire to the chassis and the ground from the IEC to chassis ground… that’s all. The mistake many make is trying to ground everything… this only causes problems.
I ran a short wire from IEC earth to the chassis
(http://www.audiocircle.com/image.php?id=60345)
The ground wire from the transformer...I just crimped/soldered a spade to it and attached it under one of the PS standoffs. Nothing else. Anyone else need to do more???
Mike
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Thanks Mboxler,
The hum is coming from the speakers. I am using Mirage speaker OMD 15, OMD 5, OMD C1. Yes it does go away if i remove the interconnects.
I am using a UMC-1 as the pre-amp and processor. I have tried lifting ground on all the equipments and it is not helping at all. in fact the problem is very peculiar. There is very little hum (almost inaudible) when everything is connected. But as soon as i play the source, and the hum volume increases. The volume of this hum is the same irrespective to the volume on the UMC-1. When i pause the source the and the music stops... the humm stops after a 2 seconds.
So it seems to me that a 50hz, signal is superimposing itself on the interconnects between the umc-1 and the amp boards. Or may be the amps are grounding themselves through the interconnects via the UMC-1 since the amps do not have a ground available to them.
To quote Tom...
As far as grounding, don’t overdo it. Just put the transformer ground wire to the chassis and the ground from the IEC to chassis ground… that’s all. The mistake many make is trying to ground everything… this only causes problems.
I ran a short wire from IEC earth to the chassis
Mike
Whats is IEC? is it the power supply board? i actually do not have a body as such for the amp. And i have not grounded it. May be i should do that.
(http://www.audiocircle.com/image.php?id=64442)
In fact i am running all my equipment on an online ups now. So i am getting clean power.
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I have two transformers feeding the two power supply boards. I just checked the larger transformer is giving me a slight buzz/hum
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Sorry...I now recognize your setup from a previous post.
IEC International Electrotechnical Commission is the IEC connector. It's the power inlet for your power cord. Grounding the mains earth to the chassis is a SAFETY procedure. I can't see your power cord connection.
Same problem with different source?
I remember a few of us were concerned about the rca-to-speaker configuration. Do you have chassis mount speaker binding posts that you could attach to the amp to answer that question? Just run wires from the amp, over the top of the chassis, to the posts, then hook your speakers to those. That would rule out the rca to speaker question.
Again, I'd attach the transformer ground wire to a separate bolt/nut on the chassis.
Good Luck!
Mike
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Ya same problem with all sources. Apple TV, sony blurry etc.
Actually i don't have a speaker binding post. But i'll try your suggestions and report back. Thanks again for all the help.
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Thanks Mboxler,
The hum is coming from the speakers. I am using Mirage speaker OMD 15, OMD 5, OMD C1. Yes it does go away if i remove the interconnects.
I am using a UMC-1 as the pre-amp and processor. I have tried lifting ground on all the equipments and it is not helping at all. in fact the problem is very peculiar. There is very little hum (almost inaudible) when everything is connected. But as soon as i play the source, and the hum volume increases. The volume of this hum is the same irrespective to the volume on the UMC-1. When i pause the source the and the music stops... the humm stops after a 2 seconds.
So it seems to me that a 50hz, signal is superimposing itself on the interconnects between the umc-1 and the amp boards. Or may be the amps are grounding themselves through the interconnects via the UMC-1 since the amps do not have a ground available to them."
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It may be an RFI signal, or ground hum, generated by your source or UMC-1 when audio is produced. And your amps without a chassis are picking it up by RF or in the wires.
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I'll consider that. Most probably it is the umc-1. But since i am testing right now. It is some distance away from my amps. So it could only be affecting the interconnects.
I just read through from page 140. Very interesting.
The hum symptoms also keep on changing. There so many variables. I learnt that even amp temperature is an issue.
This driving me crazy:-). I am thinking of making chart of the various scenarios and then posting here.
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I was also thinking of using a connexelectronic power supply, since it generates very little EMI. It is rated for 800w. Do you think a single will good for three CDA254.
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Has anyone replaced the tantalun input caps with high quality films? I understand this will change the cutoff freq but I am using subs and thus can afford to use 1 or even .5 uf caps here. I am concerned abut RF or EMI pick up with the longer leads. Any experience anyone has had would be appreciated. Thanks and kindest regards John Dozier
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Has anyone replaced the tantalun input caps with high quality films? I understand this will change the cutoff freq but I am using subs and thus can afford to use 1 or even .5 uf caps here. I am concerned abut RF or EMI pick up with the longer leads. Any experience anyone has had would be appreciated. Thanks and kindest regards John Dozier
I've done it. The longer leads are indeed an issue. Better to do the PS caps mods discussed a few pages back.
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I have now found that the input caps are niobium oxide and are much better sounding than tantalum-in fact pretty much SOTA. Thanks for the input though. Regards
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I have now found that the input caps are niobium oxide and are much better sounding than tantalum-in fact pretty much SOTA. Thanks for the input though. Regards
Good to know. I really, really wish Tom would just share more info about these boards. Even something like that is an interesting tidbit and good selling point. Sigh.
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I cannot blame Tom, as many other manufacturers are keeping their design and construction techniques as proprietary. There are many countries where patent protection is not worth the paper it is printed on. Intellectual property theft is rampant and if it ever gets on the web, the whole shooting match is down the tubes. Regards
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im sure this info i buried in this thread (probably a million times) but that class d website is a tremendous headache. i have, after hours of trying to search it, yet to find which amp or kit to buy. i would like to find a 4 ohm amp that is either 500 + 500W stereo or 500W mono. i would also like to get the kit (minus chassis and connecting hardware). if i could find one on amazon, that would be even better as i have a line of credit with them. for instance, what is this:
[urlhttp://www.amazon.com/250W-Class-Power-Supply-Transformer/dp/B002E6YXL0/ref=sr_1_5?s=electronics&ie=UTF8&qid=1346544898&sr=1-5][/url]
is this in 4 ohms? i cannot find any kit listed on the website that matches up with this? (of course that would be easier if the kits weren't listed under 17 different places and had any kind of accurate descriptions). :duh:
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im sure this info i buried in this thread (probably a million times) but that class d website is a tremendous headache. i have, after hours of trying to search it, yet to find which amp or kit to buy. i would like to find a 4 ohm amp that is either 500 + 500W stereo or 500W mono. i would also like to get the kit (minus chassis and connecting hardware). if i could find one on amazon, that would be even better as i have a line of credit with them. for instance, what is this:
[urlhttp://www.amazon.com/250W-Class-Power-Supply-Transformer/dp/B002E6YXL0/ref=sr_1_5?s=electronics&ie=UTF8&qid=1346544898&sr=1-5][/url]
is this in 4 ohms? i cannot find any kit listed on the website that matches up with this? (of course that would be easier if the kits weren't listed under 17 different places and had any kind of accurate descriptions). :duh:
Yes 250w into 4 ohms, 125w into 8 ohms, 500w bridged 8 ohms. That is the 254L. I agree, the website is still confusing and some of the amps still don't have full specs listed : (
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Hi all. I own 2 SDS-224, each running in bridge mode. I was playing it in a minute, and then a channel when mute. Upon checking, the amp main board does not have the usual blue LED lit up, and the heat sink is quite warm. The other unit is running fine. When I switch the ON/OFF switch to OFF, the usual amber LED does light up, but when I switch it back to ON, no LED, no sound. I've checked all connection, reconnect them as well, still the same. I initially thought that it was over heating, but I tried it again after a 20 minutes break ( I turn off the main power ) and still the same symptom. Anyone encounter such a problem before?
Thanks
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I just wanted to understand.
All these amps are basically power amps. Most of them do not have volume control.
So if I have preamp. And attach These amps to it. A 120 watt amps will sound twice as loud as a 60 watt amp. For the same volume level of the pre amp.
I have a cda224 and cda254. But I don't seem to get difference in loudness. Am I missing something.
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Twice as much power is only a 3db increase, which is barely audible. To be twice as loud you need a 10db increase which would require a 1000 watt amp in your situation ( and new speakers after you have blown your current ones) Hope this helps explain what is going on. Regards
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Twice as much power is only a 3db increase, which is barely audible. To be twice as loud you need a 10db increase which would require a 1000 watt amp in your situation
10dB is a power ratio of 10X, so compared to a 60W amp, a 600W amp would be twice as loud.
Steve
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Decibels are a log function. Compared to 125 watts, 250watts is a 3db increase, 500 watts is a 6db increase, and 1000 watts is a 9db increase. Regards
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Twice as much power is only a 3db increase, which is barely audible. To be twice as loud you need a 10db increase which would require a 1000 watt amp in your situation ( and new speakers after you have blown your current ones) Hope this helps explain what is going on. Regards
You're right about the 10db increase, but a 3db increase should be quite noticeable. It's about a 30% difference. Typical humans can easily perceive a 1db difference in volume.
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I agree although ear training and frequency also play a part in audibility. I was just replying to a the comment that he could barely hear a difference (if any) between two amps with different power outputs. Regards
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Decibels are a log function. Compared to 125 watts, 250watts is a 3db increase, 500 watts is a 6db increase, and 1000 watts is a 9db increase.
Understood, but he was comparing the expected volume increase from the 60W amp to the 120W amp, so relative to the 60W amp, 120W = 3dB increase, 240W = 6dB increase, 480W = 9dB increase and 600W = 10dB (twice as loud) increase.
You're right about the 10db increase, but a 3db increase should be quite noticeable. It's about a 30% difference. Typical humans can easily perceive a 1db difference in volume.
I'm not sure about 'easily', but in any case, I can hear a 1dB increase when paying close attention, the majority of people can more easily hear a 2dB increase and certainly most everyone can hear a 3dB increase.
Still, that difference will be harder to discern at lower settings of the volume control than higher ones.
Steve
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Thanks for explaining guys...i thought that a 6db increase would tantamount to doubling of perceived sound level.
Actually i have two 254s and one 224. I am using these to drive my 5 home theatre speakers. The woofer is being powered by behinger pro amp.
Since the rear satellites are smaller speakers i have connected them to 224 and the rest three to the 254. But i have rotated the speakers on the amps without any perceived difference in volume level. But know i know why.
how are other members approaching multi-channel setups.
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Hi all,
I've got an SDS-470 I built, being powered with a Connex SMPS800R power supply (http://connexelectronic.com/product_info.php/cPath/25_46/products_id/124) (i.e., not the standard linear power supply that Tom/Class D Audio uses).
It generally works great, except, I noticed that when I turn it off, there's a "thud" or "thump" that comes out of the speakers. This happens maybe a couple seconds after the power is disconnected. I assume this is the capacitors of the PSU discharging. But I have a second, complete pre-build SDS-470 (which uses the stock linear PSU), and it doesn't do this. Note that when I turn the amp on, there is no such noise. Why would the SMPS do this but the linear PSU not? Note that I've never tried this particular SDS-470 board with a linear PSU, so I suppose it could be a problem with the amp board itself as well.
Some basic web searching on this kind of issues suggests it may not be a real problem, i.e. OK for my speakers. Can anyone confirm this? Even if it's OK for my speakers, it's disconcerting to hear it.
Thoughts?
Thanks,
Matt
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Quick question: I've got a TKD stepped attenuator. Would that work instead of a single-source pre-amp?
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Depends on its impedence. If it is a 10k you would probably be ok. 20k is chancy, but you can try. BTW I too have several of those-IMHO the best stepped attenutor out there. Regards
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Quick question: I've got a TKD stepped attenuator. Would that work instead of a single-source pre-amp?
It would no different than a number of integrated amps that don't have a preamp gain stage but use a passive volume pot or stepped attenuator.
There are several things to be aware of when using a passive "preamp":
1. Interconnects between the preamp and power amp should be as short as possible, and the internal volume pot would be the best possible scenario in that respect.
2. An active preamp provides impedance matching between the source and the power amp. Ideally the output impedance to input impedance would have a ratio of 1:10 or greater. Sources with a high output impedance may not match up as well. Note: The Class D Audio CDA series have an input impedance of 7K Ohm while the SDS series have a higher 47K Ohm input impedance.
3. If you have really low sensitivity speakers and/or low output voltage from your source, you may not have enough gain and might need an active preamp with additional gain.
Steve
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Thanks john and SRB! I will be connecting to a dac as a source. I couldn't find any info on the output impedance for a Music Hall 25.2 cdp.
I imagine that the output impedance for various dac's is similar. Is that right?
I also assume it would work well with a passive setup. Is that right?
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I imagine that the output impedance for various dac's is similar. Is that right?
Most of them have pretty low output impedances, such as Benchmark DAC 1 = 30 Ohms, Cambridge Audio DacMagic Plus = <50 Ohms, Simaudio Moon 300D = 100 Ohms, etc. I have seen some DACs with higher output impedances like 5K Ohm, and those DACs would be a better match with the SDS series 47K Ohm input impedance than the CDA series 7K Ohm input impedance.
I couldn't find any reference to the output impedance of the Music Hall DACs, but you will likely be just fine.
Steve
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Now that I've got the attenuator issue settled for now, I am wondering about transformers.
I've got a few transformers. One from a tubed Cary pre-amp. Could that be used to build a Class D brand amp or should I buy one of their transformers? (I know I am not giving much to go on here, but the answer may be a simple one. I don't know.)
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I've got a few transformers. One from a tubed Cary pre-amp. Could that be used to build a Class D brand amp or should I buy one of their transformers?
It depends on the amplifier board. You will need a transformer with sufficient VA rating of course, then the particular amplifier board you have will determine the AC voltage of the dual secondary windings that will be required.
Steve
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A power transformer from a tubed preamp won't have anything like the voltages (or current rating) needed.
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A power transformer from a tubed preamp won't have anything like the voltages (or current rating) needed.
I was discounting the Cary transformer right off the bat, but he said he had other transformers. But having one with the proper secondary voltages and capacity for a particular board might be a stroke of luck. The CDA and SDS amps will require transformers with dual AC secondaries from the 21V - 28V range to the 44V - 51V range and 300VA to 500VA capacity depending on which Class D Audio amplifier board.
Steve
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Thanks guys. I'll see if I can find out the specs on the transformers. I have three. Two are from an old Cary power amp, the first one they made. And I mean, this amp is probably the first one they made, i.e a prototype.
I'm junking them both. Too much trouble. I'm planning to use the pre's case for the Class D. I've got some good caps in the power amp with very few hours on them. I'll salvage them along with the pre's case and it's connectors.
At the moment, I'm waiting to hear from an AC'er if he wants the transformers. If he doesn't, let me know. I'll be giving them away so packing and shipping is all I'll want. The models are Sweet 807 (one EI laminated core power transformer, one ultralinear output transformer) and SLP 70 (no specs in the manual or on the transformer, custom manufactured by Peter Dahl).
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Does anyone know what the power draw of the SDS amps is or where I can find it? My amp is 12 volt, but I assume the amp draw would be the same for a/c and d/c amps :scratch:.
Thanks, Mike
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Does anyone know what the power draw of the SDS amps is or where I can find it? My amp is 12 volt, but I assume the amp draw would be the same for a/c and d/c amps :scratch:.
Thanks, Mike
Mike..
Do you mean the power supply is the 12 volt DC PS from Class D Audio? All the amps are DC power in, AC signal in, amplified AC signal out. Sorry if I misread your question.
Mike
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Sorry I wasn't clear. Yes 12 volt power supply.
Mike
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Hi all,
I've got an SDS-470 I built, being powered with a Connex SMPS800R power supply (http://connexelectronic.com/product_info.php/cPath/25_46/products_id/124) (i.e., not the standard linear power supply that Tom/Class D Audio uses).
It generally works great, except, I noticed that when I turn it off, there's a "thud" or "thump" that comes out of the speakers. This happens maybe a couple seconds after the power is disconnected. I assume this is the capacitors of the PSU discharging. But I have a second, complete pre-build SDS-470 (which uses the stock linear PSU), and it doesn't do this. Note that when I turn the amp on, there is no such noise. Why would the SMPS do this but the linear PSU not? Note that I've never tried this particular SDS-470 board with a linear PSU, so I suppose it could be a problem with the amp board itself as well.
Some basic web searching on this kind of issues suggests it may not be a real problem, i.e. OK for my speakers. Can anyone confirm this? Even if it's OK for my speakers, it's disconcerting to hear it.
Thoughts?
Thanks,
Matt
Try asking Tom and christi
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I think this has been discussed earlier, but it is not in me right now to scan the 172 pages right now. I want to know if there is a sound quality difference between the CDA and the SDS amps. Or is it just a matter of the balanced inputs and the volume pots.
My pre-pro is unbalanced right now so the balanced inputs will not make any difference to me right now.
Hey matt, I read the christi's reply to your query. But I could not understand it. Could you explain it for the benefit for othe forum members.
Thanks
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IMO, the SDS has a little more depth to the soundstage and more 3D quality to the imaging. YMMV.
Steve
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The SDS series amps also have better cooling through finned heat sinks and have a higher 47K ohm input impedance vs the 7K ohm input impedance of the CDA series, which may provide better matching to some preamps and direct volume controlled source components.
Steve
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Hey matt, I read the christi's reply to your query. But I could not understand it. Could you explain it for the benefit for othe forum members.
Hehe, I'd like to explain it to you, but it's also over my head. :) For what it's worth, I did ask Tom about this. I sent him Cristi's reply for reference as well. He said he could make some adjustments to the amp that should fix the problem. He also said he had one other customer using one of Cristi's SMPSes and had a similar issue.
My original intent with the SMPS was twofold: lower power consumption and small physical footprint. If you read back in this thread, you'll see the first point didn't work out as planned. The idle power consumption of the amp with the SMPS was actually slightly higher (compared to the linear PS). To be fair, it was only a watt or three, and my measurements aren't precise by any means (just using a Kill-a-Watt).
Regarding the small footprint goal: you can also see, earlier in this thread, I was having some overheating issues. Ultimately, I worked with Tom to get a different board. Also, as per his suggestion, I drilled holes in the bottom of my enclosure. Understand that the enclosure was just big enough to contain the SMPS plus SDS-470 amp board, and very little extra space. I ran it for a short while, and didn't have any problems. But the case was pretty warm to the touch; not enough to cause any audio problems, but enough to make me feel uncomfortable.
I do think my SMPS-powered SDS-470 sounds slightly better than my other SDS470, which is a pre-assembled unit. But my DIY version also excludes the input gain pots in favor of fixed resistors (not those fancy/expensive Vishay foil resistors, but regular cheap commodity resistors). I also don't have switchable input, it's XLR only. So there are more differences than just the power supply. Now I think I'm going to mod the the linear PS (original from the DIY SDS470 kit) with bigger capacitors and see how that compares to the SMPS.
To help anyone else interested in the Connex SMPS, here's Cristi's reply from the DIY Audio Forums (http://www.diyaudio.com/forums/connexelectronic/158604-switched-mode-power-supplies-smps-12.html#post3214573):
Matt: The SMPS800R output voltage will slowly decrease during power off sequence to near zero if the amplifier has an idle current draw of at least 50-100mA. If there is no load or the amplifier consume much less, is possible that the output voltage to fall then when reach about half the power supply to restart switching for brief period, increasing the output voltage with 20-30%. this happens because at power down, the capacitors which store the energy for controller and driver section, will discharge much faster than the large caps, because is much smaller, 100 uF at 25V compared with two 1000uF at 200V, and since the large caps are still charged, the small cap will be recharged in about 2-3 seconds and restart the smps for a brief period till most of the stored energy from the large caps is consumed. On board there is a circuit to prevent the power supply restart, there is a resistor divider which supply one pin of the controller ic with a divided voltage from the mains DC bus, so when this voltage drops below ~240V DC the smps will shut-down and will not restart till the power is applied again. However, to be able to work properly in every corner of the world, where the mains voltage can be substantially lower, I decided to reduce this threshold to about 200V. this means that the smps should work also with 180V AC or 90V AC voltage. If the mains supply voltage is stable, over 200V or 100V then the initial values for the divider can be used, so the smps will not restart once is turned off.
On the other hand, the amplifier itself must feature an UVP and OVP protection, not only for this issue but also to prevent erroneous switching frequencies and damage due to excessive bus pumping when is supplied with too low, and too high voltages. The threshold for UVP must be not lower than 70-75% of the nominal supply voltage and the threshold for OVP must be not higher than 120-125% of the nominal supply voltage for safe and reliable operation.
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Power supply capacitor upgrade: I'd like to try upgrading the capacitors in the power supply to the 10,000uF. The Panasonic TSHA series were recommended earlier in this thread, but I can't find a TSHA-series in an 80v value. What about the T-HA series, such as DigiKey part P10645-ND (http://www.digikey.com/product-detail/en/ECE-T1KA103EA/P10645-ND/272785)?
Even those are $12/each. Six of those would run me $72. Whereas I can get a whole new linear power supply using six 10k uF 80v caps for $54 from ConnexElectronic (http://connexelectronic.com/product_info.php/cPath/25_45/products_id/72).
Any reason to do the capacitor mod myself versus just getting a whole new PS?
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Came across this article http://www.hometheater.com/content/anthem-statement-m1-amplifier . Basically they review a $3500 1000watt mono block class d amp, and come way less than impressed.
They say that class D amps are inherently not good at high frequencies. What do the forum members feel about this point of view. Has classdaudio done things differently.
My classDs sound pretty good to me at all frequencies. But i am not an audiophile. At least not as yet.
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Yes, ClassDaudio has done it differently. I have no problems with the highs in my very revealing system.. the devil is in the details. Regards
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Came across this article http://www.hometheater.com/content/anthem-statement-m1-amplifier . Basically they review a $3500 1000watt mono block class d amp, and come way less than impressed.
They say that class D amps are inherently not good at high frequencies. What do the forum members feel about this point of view. Has classdaudio done things differently.
That review was a train wreck. Just a bunch of idiot purple prose that demonstrated a total lack of understanding of the actual issues at play in Class D amplification by MF or his editors. (Or worse, a lack of interest in the actual issues at play.) For more on said issues, see my comment at the bottom of the review.
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Believe nothing Fremer has to say. The man is a complete idiot and an idealogue to boot. Typical of the "audiophile" press. Regards
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Power supply capacitor upgrade: I'd like to try upgrading the capacitors in the power supply to the 10,000uF. The Panasonic TSHA series were recommended earlier in this thread, but I can't find a TSHA-series in an 80v value. What about the T-HA series, such as DigiKey part P10645-ND (http://www.digikey.com/product-detail/en/ECE-T1KA103EA/P10645-ND/272785)?
Even those are $12/each. Six of those would run me $72. Whereas I can get a whole new linear power supply using six 10k uF 80v caps for $54 from ConnexElectronic (http://connexelectronic.com/product_info.php/cPath/25_45/products_id/72).
Any reason to do the capacitor mod myself versus just getting a whole new PS?
Depends if you believe PS caps can affect sound quality. I do and say if you are going to upgrade then spend a little extra and get Nichicon Fine Gold (avaliable from Mouser). Or go all in and get the Mundorfs from partsconnexion.
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Came across this article http://www.hometheater.com/content/anthem-statement-m1-amplifier . Basically they review a $3500 1000watt mono block class d amp, and come way less than impressed.
They say that class D amps are inherently not good at high frequencies. What do the forum members feel about this point of view. Has classdaudio done things differently.
My classDs sound pretty good to me at all frequencies. But i am not an audiophile. At least not as yet.
Not all Class D are the same. Classdaudio amps never exhibited HF issues for me, but the chip it is built around is not being used in retail amps so there is no retail frame of reference.
Michael Fremer is a good reviewer. People who complain about audiophile reviews ought to try cranking out 2500 well written words every couple months based on a subjective experience. His life is audio and he has strong opinions, well good for him.
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Strong and not well based opinions. He is technically illiterate. Regards
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Strong and not well based opinions. He is technically illiterate. Regards
Who reads Michael Fremer for technical expertise?
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I thought he made some rather good points about what to listen for when comparing Class D to Class A and A/B amps. Whether you agree with his conclusions is irrelevant to the points he was making about listening for upper octave decay. He said in his final point, "...listen very carefully, especially to the top octaves and the atmospheric cues on familiar music and movies. Pay particular attention beyond your immediate reaction to instrumental attack, and focus instead on the flow of the sustain and the quality and length of the decay." This is exactly what detractors of Class D are noting, and is what bothers them about fully endorsing the technology. He then says, "If you still love what you hear, don’t pay any attention to me", which is exactly what I would do, listen more critically to that area of reproduction. If you've listened and are satisfied, enjoy the music.
I've been searching for that description as I couldn't pin down what I was hearing while listening to the Ncores, a different amp than we're talking about here of course, but Class D nonetheless. I loved the amps, but funds are being expended elsewhere so purchase was on delay. But thinking back there was something in the high end that was different, not bad, different. The amp was very balanced and I didn't find any obvious fault at the time, however I'd like to go back and listen anew after reading MF's commentary.
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Depends if you believe PS caps can affect sound quality. I do and say if you are going to upgrade then spend a little extra and get Nichicon Fine Gold (avaliable from Mouser). Or go all in and get the Mundorfs from partsconnexion.
My goals are (1) something to play with and (2) increased capacitance. In other words, bigger capacitors, not necessarily better caps. And whatever I do, I don't want to spend a lot of money (and in that regard, the Mundorfs are definitely out of the question!). I wasn't able to find the Nichicon Fine Gold capacitors in 10k uF / 80v value on Mouser, unless I missed them. Do you happen to have a link or part number?
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I really do love my SDS-258 and still think it's a bargain for what I paid. However, in my opinion Fremer isn't wrong. I've noted from the first day of listening to it how warm and easy to listen to the ClassDAudio amp was. But I also noticed exactly what Fremer described was missing. The highs are good but even compared to my modified Dynaco tube amp they're lacking in the highest frequencies, the decay, the room ambiance. If you weren't familiar with seriously good gear out there you may not miss it. I wasn't expecting the best for $600 but it works well enough as a back up for when my tube amps go down. I actually fell asleep listening to it a few nights ago. :thumb:
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He said in his final point, "...listen very carefully, especially to the top octaves and the atmospheric cues on familiar music and movies. Pay particular attention beyond your immediate reaction to instrumental attack, and focus instead on the flow of the sustain and the quality and length of the decay." This is exactly what detractors of Class D are noting, and is what bothers them about fully endorsing the technology.
That's just purple prose nonsense for "the output filter may interact with the load presented by the speaker in the treble."
It's not rocket science. It's just a gain block.
I've been searching for that description as I couldn't pin down what I was hearing while listening to the Ncores, a different amp than we're talking about here of course, but Class D nonetheless.
Equalize the frequency response, and class D doesn't have a "sound."
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+10
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Oh, DS-21 is back. Well, that ends that.
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Oh, DS-21 is back. Well, that ends that.
[video=youtube;1p6fTDGLHGQ]http://www.youtube.com/watch?v=1p6fTDGLHGQ[/video]
http://youtu.be/1p6fTDGLHGQ
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That's just purple prose nonsense for "the output filter may interact with the load presented by the speaker in the treble."
It's not rocket science. It's just a gain block.
Equalize the frequency response, and class D doesn't have a "sound."
Well of course. certainly. I don't know why I didn't think of that myself. It's so simple now, thanks for pointing that out.
And now for something completely different. :thumb:
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I see. So the nuance of sound reproduction - the attack, the decay, the harmonics and their relative phase relationships - can all be made perfect by simple frequency equalization. Brilliant! The physical world is far simpler than I had previously thought!
Steve
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Also note that we may be somewhat unfair to DS-21 because of his, let's say, blunt presentation sometimes. However you cannot deny that the output filter in Class D amps can affect high frequency response that can vary with different speaker loads. Whether this can be solved by equalization is doubtful IMHO. I think phase interleaving the transistors to raise the sampling frequency is a much more effective solution, which is what I believe is done with the Ncores and other Class D amps. The data indicate flat frequency response into varied loads to above 20kHz, so it's not a frequency response problem that equalization can solve.
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Do tripath amps share the same "issue" in re high frequency as the class D amps?
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I see. So the nuance of sound reproduction - the attack, the decay, the harmonics and their relative phase relationships - can all be made perfect by simple frequency equalization. Brilliant! The physical world is far simpler than I had previously thought!
In this case, yes. Point me to a bias-controlled subjective listening evaluation that demonstrates otherwise, and I'll change my mind. Point me to a sighted, un-level-matched listening evaluation, and who cares because such things tell us exactly nothing of any merit or relevance whatsoever in cases of subtle differences.
Also note that we may be somewhat unfair to DS-21 because of his, let's say, blunt presentation sometimes. However you cannot deny that the output filter in Class D amps can affect high frequency response that can vary with different speaker loads. Whether this can be solved by equalization is doubtful IMHO.
Why? Frequency response errors can be corrected.
I think phase interleaving the transistors to raise the sampling frequency is a much more effective solution, which is what I believe is done with the Ncores and other Class D amps. The data indicate flat frequency response into varied loads to above 20kHz, so it's not a frequency response problem that equalization can solve.
Have you seen any data showing the performance of a Hypex amp into high frequencies with a dummy simulated speaker, such as the Ken Kantor-designed circuit Stereophile uses? While the test is probably too easy, it does do a great job of first-pass sorting amps capable of high-fidelity reproduction from colored-sounding crap. I've not seen such data for a Hypex, but I'd liketo.
Alternately, have you comparative measurements of a speaker driven by an Ncore compared to the same speaker driven by bog standard Class AB amp? If such data does not exist, if anyone wishes to send me an Ncore channel, I'll be happy to take comparative measurements between it and a standard Class AB boat anchor that was very positively reviewed by Dr. David A. Rich, and recently referred to by him as "still state of the art."
Do tripath amps share the same "issue" in re high frequency as the class D amps?
While I don't know why you put "issue" in quotes, my understanding is that Tripath amps have passive high-pass filters just before the binding posts, so yes those crossover components can interact with those in the loudspeakers, as well as the impedance of the tweeter.
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I have been using a CDC 254 to drive the bass panels of my rebuilt maggy IIIa's for about a year now with no problems. I did try it full range when I first got it and did not care for the high freqs. I should go aback and give it another try
(http://www.audiocircle.com/image.php?id=70554)
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As far as Class D and the high end: yes, probably lacking a bit in relationship to the high end of conventional amps. In a few years the frequency of the chips will go to something like 4M instead of 1M, and then the filtering will be so far out of the range of human hearing and overtones that it will have no impact.
That said, Tom's amps are a bargain, and sound as good or better than anything near their price, including in the high frequencies. You have to spend double or triple to get something better, from what I've seen. The NCore seems to be better, but an assembled one will cost you over $2K. I've heard plenty of conventional amps in the $2-3K range that aren't better than my SDS. Some are.
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Thinking of trying to upgrade my standard SDS build. Just for fun. At purchase, Tom said he'd tried all sorts of parts, and the ones he's using give equal SQ to more expensive parts at less cost than some of the audiophile favorites.
In spite of this, I'm sort of a believer in the best hifi starts with the best power section:So I'm wondering: anyone used a better PS, transformer, or regulators?
Did it REALLY make a difference?
Or caps with more capacitance? Anyone turned one of these amps into something with very high current capacity? How did it effect the sound?
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Thinking of trying to upgrade my standard SDS build. Just for fun. At purchase, Tom said he'd tried all sorts of parts, and the ones he's using give equal SQ to more expensive parts at less cost than some of the audiophile favorites.
In spite of this, I'm sort of a believer in the best hifi starts with the best power section:So I'm wondering: anyone used a better PS, transformer, or regulators?
Did it REALLY make a difference?
Or caps with more capacitance? Anyone turned one of these amps into something with very high current capacity? How did it effect the sound?
I just replaced the caps on the power supply board with larger 10k Panasonic TSHA series for a total of 60k capacitance. The result was increased dynamic's and micro details, well worth the $60 entry fee. :green:
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I just replaced the caps on the power supply board with larger 10k Panasonic TSHA series for a total of 60k capacitance. The result was increased dynamic's and micro details, well worth the $60 entry fee. :green:
What voltage are those 10k Panasonic TSHA caps? Where did you get them?
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What voltage are those 10k Panasonic TSHA caps? Where did you get them?
http://www.diycable.com/main/advanced_search_result.php?keywords=panasonic&Cid=6027b26cbb56db7ef1820316e30b5860&x=0&y=0
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http://www.diycable.com/main/advanced_search_result.php?keywords=panasonic&Cid=6027b26cbb56db7ef1820316e30b5860&x=0&y=0
Ahh, you used the 63V ones. I'd like to use 80V, and it appears they don't offer an 80V 10k uF TSHA-series capacitor. Not sure what the next best would be, without spending a fortune.
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Tom approved the 63v.
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Just finished reading that thread. Wow! I may need to read it again. Lots of great information. I have a CDA 254 and a SDS 254. I will be making some tweaks this weekend!
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Work in progress 8 channel power amp using 2 x SDS-258 module, 2 x CDA-258 module using SMPS. The amp is build with space saving concept in vertical position and will be install in a standard desktop PC casing. This project had been pending for almost 2 years. Still waiting for 28 AWG pure silver cable for input.
(http://www.audiocircle.com/image.php?id=70831)
(http://www.audiocircle.com/image.php?id=70832)
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Hi all. I own 2 SDS-224, each running in bridge mode. I was playing it in a minute, and then a channel when mute. Upon checking, the amp main board does not have the usual blue LED lit up, and the heat sink is quite warm. The other unit is running fine. When I switch the ON/OFF switch to OFF, the usual amber LED does light up, but when I switch it back to ON, no LED, no sound. I've checked all connection, reconnect them as well, still the same. I initially thought that it was over heating, but I tried it again after a 20 minutes break ( I turn off the main power ) and still the same symptom. Anyone encounter such a problem before?
Thanks
I dunno where to turn to, so i hope to shed some light here for me. Regarding the issue above, I have sent my amp to Tom, and the courier tracking log does show that the amp has been delivered 2 weeks ago, however, until now, there's no news from Tom.....I have even send follow up messages to him but with no avail. Just been wondering, is Tom still available, or is he on holiday? Cause I am kinda worried since there is no response from him at all.
Please help.
Thanks
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Relax. Tom is a man of very few words.
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Just finished reading that thread. Wow! I may need to read it again. Lots of great information. I have a CDA 254 and a SDS 254. I will be making some tweaks this weekend!
Can you give a comparison of the sound quality between the amps.
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Relax. Tom is a man of very few words.
Well, he should at least reply the emails I sent to him, just for acknowledgment sake.
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Thanks Mboxler,
The hum is coming from the speakers. I am using Mirage speaker OMD 15, OMD 5, OMD C1. Yes it does go away if i remove the interconnects.
I am using a UMC-1 as the pre-amp and processor. I have tried lifting ground on all the equipments and it is not helping at all. in fact the problem is very peculiar. There is very little hum (almost inaudible) when everything is connected. But as soon as i play the source, and the hum volume increases. The volume of this hum is the same irrespective to the volume on the UMC-1. When i pause the source the and the music stops... the humm stops after a 2 seconds.
So it seems to me that a 50hz, signal is superimposing itself on the interconnects between the umc-1 and the amp boards. Or may be the amps are grounding themselves through the interconnects via the UMC-1 since the amps do not have a ground available to them.
Whats is IEC? is it the power supply board? i actually do not have a body as such for the amp. And i have not grounded it. May be i should do that.
(http://www.audiocircle.com/image.php?id=64442)
In fact i am running all my equipment on an online ups now. So i am getting clean power.
I previously had the same electrical buzz. If the source is playing then the buzz go away. I trace the problem to the RCA cabling and high gain. Previously I'm using 2 conductor with grounded shield but somehow the shield pick up EMI/RFI. I change to pure silver 28 AWG wire and a few twist solve the problem. Also change the gain using fix resistor 5kohm and now the amp is dead silence.
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Finally completed the wiring and now testing all channels. My short impression between CDA-258 and SDS-258 are SDS-258 had slightly better separation. For my application, CDA will be use for surround speaker and SDS for Front and Center speaker.
(http://www.audiocircle.com/image.php?id=70928)
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Thanks for chiming in rjyap. My problem was the opposite. I started getting more hum when the source was sending a signal to the amps. In my case the emotive UMC-1. It still remains a mystery, for which i have had not time in the past few months. I had sent the amps back to tom, because one of them had fumed on me. Once i get them back ill try to get put them in a more conventional case and see how it goes from there.
I see that you are using Connex power supplies. How is that working out for you? When you say separation, you mean between the various instruments?
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Connex power supplies doesn't have any noise issue. I like it due to the compact size compare to linear ps which I can't fit into a compact 8 channel amp chassis. Also, separation should be better as each ClassD amp module will run on different transformer. Regarding the separation I mention earlier, I do feel that vocal is more distinct compare to background instrument.
As for your hum issue, it could be the gain is too high that cause the issue. Your build show that you are using CDA series which doesn't allow you to adjust the gain. You might want to try out SDS series and try higher value around 5 kohm and see if this solve your problem. Also need to mention SDS board is slightly longer so it might not fit your existing casing. Tom should be able to do a swap from CDA to SDS. I asked him earlier and he say it is OK as long as your board looks like new.
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Finally completed the wiring and now testing all channels. My short impression between CDA-258 and SDS-258 are SDS-258 had slightly better separation. For my application, CDA will be use for surround speaker and SDS for Front and Center speaker.
(http://www.audiocircle.com/image.php?id=70928)
Nice design and construction!
:thumb:
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Connex power supplies doesn't have any noise issue. I like it due to the compact size compare to linear ps which I can't fit into a compact 8 channel amp chassis. Also, separation should be better as each ClassD amp module will run on different transformer. Regarding the separation I mention earlier, I do feel that vocal is more distinct compare to background instrument.
As for your hum issue, it could be the gain is too high that cause the issue. Your build show that you are using CDA series which doesn't allow you to adjust the gain. You might want to try out SDS series and try higher value around 5 kohm and see if this solve your problem. Also need to mention SDS board is slightly longer so it might not fit your existing casing. Tom should be able to do a swap from CDA to SDS. I asked him earlier and he say it is OK as long as your board looks like new.
Exchanging CDAs for SDS was one of the reasons for sending the amps back to Tom. But as I said earlier, he is a man of very few words. I had a lot of question for him but he chose to answer them as briefly as he could. He told me the basic advantage of the SDS over the CDA was the balanced inputs, for which I had no use as of now. The output impedance of the UMC-1 is 1k ohm, which I thought was a concern given the input impedance of CDA amps is 7k ohms. I asked Tom, as well, but got no response from him. So I stuck to the CDAs for the time being.
I have used the CDAs without an issue also. I will re-investigate everything once the amps come back to me.
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BTW, which power supplies are you using.
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SMPS800R for FL/FR channel and SMPS500R for the rest. My initial design is using a single SMSP2000R but Christi from Connex advice that one power supply with each board is a better design. In the future, if I go for 11 channels, will consider building another 3 channel power amp using nCore 400. The review so far look interesting but far more expensive than ClassDAudio. Each channel would cost around USD 800 while ClassDAudio is 2 channels around USD 360 - 1 channel = USD 180.
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Relax. Tom is a man of very few words.
Hi. Since he is not replying me after such a long period, any advice you can offer me?
Thanks
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Tom has several email addresses on the website. Only one seems to work well. I have forgotten which one, but found it worked well with quick replies. You will just have to try all of them. Regards
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SMPS800R for FL/FR channel and SMPS500R for the rest. My initial design is using a single SMSP2000R but Christi from Connex advice that one power supply with each board is a better design. In the future, if I go for 11 channels, will consider building another 3 channel power amp using nCore 400. The review so far look interesting but far more expensive than ClassDAudio. Each channel would cost around USD 800 while ClassDAudio is 2 channels around USD 360 - 1 channel = USD 180.
toooootally worth it.
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Hi. Since he is not replying me after such a long period, any advice you can offer me?
Thanks
Try sales@classdaudio.com. I had no problem getting a reply from him last 2 weeks.
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toooootally worth it.
I had followed nCore thread and started to plan for the future. Anyway, anyone feel that ClassDAudio amp need some warm up time before sounding the best? In my system, the initial 20 mins sound a bit flat but after that, the vocal start to float out a bit and I can hear good separation of vocal against the background music.
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Pretty much all amps need time to warm up and sound their best.
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I don't really like to do it, by my system sounds best when left on all the time. I think this is generally true for electronics - leave them on and they sound their best.
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Try sales@classdaudio.com. I had no problem getting a reply from him last 2 weeks.
Tried, and no reply...... :bawl: :bawl: :bawl: :bawl: :bawl: :bawl: :bawl: :bawl: :bawl: :bawl: :bawl: :bawl: :bawl: :bawl: :bawl:
What should i do.........
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call on the phone?
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call on the phone?
I am not from the US. Does he have any other contact means other than email? Skype?
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I had no problem getting a response from Tom yesterday. Also found out that the IRS module is inverted amp when running in stereo mode. If you use it with Audyssey, the phase warning will pop out. Just reverse the polarity for speaker output. No problem if you only run with 2 speakers without a sub.
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I had no problem getting a response from Tom yesterday. Also found out that the IRS module is inverted amp when running in stereo mode. If you use it with Audyssey, the phase warning will pop out. Just reverse the polarity for speaker output. No problem if you only run with 2 speakers without a sub.
Oh, so can I assume that he's ignoring me purposely?
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Maybe your email go to spam folder? I don't see why he purposely ignore you? Previously I send back the SDS-4 module due to some issue but he fix that within 2 weeks.
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So, would something like a pure I-20 work with one of these amps?
Or would you still need a separate pre-amp?
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I'm building a SDS 254 amp with the D/C power supply, to run off batteries. On the amp and power supply boards one of the screws that hold the boards to the chassis is labeled chassis gnd , as the screw is not connected to the chassis should I run a wire from the screws to the chassis or is this not necessary because the amp is D/C powered?
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Mike
You do need those ground.
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Thanks Trung, then I can just run a wire from the screws to the chassis?
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If your chassis grounded, Yes.
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So, would something like a pure I-20 work with one of these amps?
Or would you still need a separate pre-amp?
I think it should work...the problem would be with volume control. The remote for my i-20 was crappy at best, and stopped working soon after I bought it. If/When that happens, you'll either be manually adjusting the i-20 volume using your docked device, use BOTH gain controls on the SDS amp, or a combination of the two.
I'll try it tonight and report back.
Mike
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Nothing is grounded because it runs off D/C, as far as I know there is no gnd in D/C gear. If I'm wrong about that were would the GND run to? :scratch:
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Nothing is grounded because it runs off D/C, as far as I know there is no gnd in D/C gear. If I'm wrong about that were would the GND run to? :scratch:
I'm new to this, but here is how I understand it...
Circuit ground should equal the greatest negative potential in the circuit (in your case...-50 volts DC). This way, everything in the circuit will measure a positive voltage from that point.
A metal chassis can have varying effects on components contained within it. By connecting the chassis to the amp, both the chassis and the amp will be at the same potential, reducing unwanted interferance.
I can't remember, but are the standoffs aluminum? As I recall, the chassis ground on the board is also a mounting hole. As long as there is no paint or anything to open the connection, you may have connectivity from the board to the chassis automatically. A DMM will tell. If not, do what Trung says.
Okay, let the corrections to my explanation begin :o
Mike
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Never got around to fusing my SDS monos, but figure I should now that they have become a permanent fixture and I can seal up the chassis.
Any reason, safety or sound quality, I wouldn't want to use these manual reset circuit breakers in lieu of fuses?
http://www.parts-express.com/pe/showdetl.cfm?partnumber=075-154
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Question: I am considering buying the SDS-1000 kit to run the front stage of my system. Would it be OK to run just 3 channels for L/C/R and leave one channel idle with the SDS 254 modules?
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yes resetables can fail shorted and never blow in my experience when a fuse goes its gone.
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Question: I am considering buying the SDS-1000 kit to run the front stage of my system. Would it be OK to run just 3 channels for L/C/R and leave one channel idle with the SDS 254 modules?
That would be okay. However, if your center channel speaker is less efficient than your left/right, you may want to bridge one of the amps to drive the center, and drive the left/right with the other. Is the center channel 8 ohm? Tom's site doesn't show power into a 4 ohm speaker with a bridged SDS 254.
Just a thought.
Mike
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That would be okay. However, if your center channel speaker is less efficient than your left/right, you may want to bridge one of the amps to drive the center, and drive the left/right with the other. Is the center channel 8 ohm? Tom's site doesn't show power into a 4 ohm speaker with a bridged SDS 254.
Just a thought.
Mike
All three speakers are 4 ohm with identical drivers, ( 3 way Swope center and towers.) so if I can run 3 channels that would work great. Maybe use the spare channel for another sub later.
Thanks
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What's up with the classdaudio website? Just tried to look up some info and I get errors and different languages. Anyone else seeing this or is it just me/my browser?
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It's not you, it's the website.
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Looks like they changed the website again. Looks nice but pretty much the same info. No more USPS shipping and the Audio Circle code no longer works.
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I've been lowering the gain on my amps to match my subs better.
Going from 11K resistors to 14K the amps have gained in clarity at a moderate volume. I did not expect any change.
Same brand Vishay resistors.
Anybody else notice this effect?
Speakers: B&C DE 250 tweeter, B&C 10PS26 woofer.
(http://i379.photobucket.com/albums/oo237/nilsonb/FRONT1.jpg)
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I've been lowering the gain on my amps to match my subs better.
Going from 11K resistors to 14K the amps have gained in clarity at a moderate volume. I did not expect any change.
Same brand Vishay resistors.
Anybody else notice this effect?
Speakers: B&C DE 250 tweeter, B&C 10PS26 woofer.
Hi...
Do these resistors replace the 10K pots? I'm not sure how you are getting any volume at all. :scratch: Or do the newer amps have different pot values?
Mike
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Some opinions from a french audiophile:
-I use my SDS470 with Duntech Prince's,i have just removed the RCA inputs which allows to avoid a parasitic capacitance(better)
-The treble precision and balance are highly depending upon the pot's position, the best being around 50% opening (i'ts connected directly to my Weiss DAC2 which has a digital volume adjustment)
-In order to favourize extreme treble,i advise to use litz balanced XLR interconnects, the best for me is (+)8X0,28 (-)4X0,28+25X0.05 ground:1 or 2 AWG24 wrapping wire (silver plated)(dia 0,51),minimum length
The best mains power cable is made with 4 wires, each one having 8X0,28 litz strands,2 are turning clockwise, 2 counterclockwise, in order to reduce inductance to the minimum possible.
The result as obtained when listening can be compared according to my personal opinion) to the best amps available today,( i own also an AYON TRITON II), but a friend allowed me to test also at home a DEVIALET D premier,and i think one couldnt recognize the 2 amps if blind tested.
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I think it's time to move up. I have used a CDA-254 kit for 2 1/2 years, today I ordered the SDS-470 kit. I would like to find a chassis for it that is different than the stock Class D chassis, I really don't like IEC connectors, prefer PowerCon, and I prefer SpeakCon over binding post.
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Hi...
Do these resistors replace the 10K pots? I'm not sure how you are getting any volume at all. :scratch: Or do the newer amps have different pot values?
Mike
I tried 18K for more clarity. The negative feedback sound was, uh, negative to my ears. I think increasing amounts of negative feedback is used to reduce the gain, to a point.
Tried 1k for fun. More gain, a lot more PS and amp noise. Less clarity.
Now using 4.7k and attenuating volume into amp with resistors to match sub level.
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I have the Spiral Groove Mastering amp and found the best sound was obtained by removing the gain fixing resistors. Regards
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I have the Spiral Groove Mastering amp and found the best sound was obtained by removing the gain fixing resistors. Regards
Hi
Is this the Spiral Groove Studio One mixing monitors Amplifier ($600)? There isn't a lot of info regarding this amp, but the review (which could be yours) is stellar.
Mike
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The review is mine. The more I improve the front end of my system, the better the system sounds-real proof of a transparent amp. As you know, class d is not digital, but it is high frequency, needing special design and layout techniques as well as careful choice of components. For example, ClassD audio uses Niobium coupling caps (the only use of them that I know of) This care in selection and layout, I think produces an amp that can compete with the best in the world. There is a great deal of high speed circuitry knowledge in California. Regards John Dozier
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I have the Spiral Groove Mastering amp and found the best sound was obtained by removing the gain fixing resistors. Regards
Does Spiral use the same input opamp, or transistor, as the SDS series?
I'd like to remove my gain R, but would removing it cause instabilities in single ended configuration (versus balanced)?
Did you replace the R with a wire or nothing?
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Both amps use a special opamp designed for professional use by the head of Jensen Transformers. There are two versions, however, differing in common mode rejection. I do not know if they use the same version. I have "hot wired" mine, but I am running balanced and had the designer of my Anedio Dac reduce the output gain. As to whether there would be instability in running single ended, that is a Tom question. Regards John Dozier
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I think it's time to move up. I have used a CDA-254 kit for 2 1/2 years, today I ordered the SDS-470 kit. I would like to find a chassis for it that is different than the stock Class D chassis, I really don't like IEC connectors, prefer PowerCon, and I prefer SpeakCon over binding post.
I used a couple Par-Metal cases to build my monos with PowerCon and SpeakOn connectors. Not sure if they are still selling since they had a fire, but I got mine through ebay since they were a bit cheaper that way (Antek/Par-Metal are under user name johnango).
(http://www.audiocircle.com/image.php?id=54915)
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I just experienced a decisive improvement of the sound of my SDS470 amp,further to very simple mods:
The basic principle of mods is to reduce the parasitic capacitance of modulation cables, and replace the 4 loudspeaker internal wires by more transparent ones.The list of mods is:
1 Remove the RCA inputs with all their wires, and use only the XLR ones
2 Shorten drastically the wires going to the pots,by locating the pots at the holes made for the RCA inputs,then such wires have only about 4cm(separate them from proximity of other wires)
3 Separate the (+) wire from the (-) wire for each XLR input (5mm instead of sticked)
4 Replace the 4 speaker wires by: Mass(-)=2X rigid wires copper silver plated of 0,9mmdia (+) 3Xwrapping wires copper silver plated of 0,6 or 0,5mmdia + litz 8 strandX0,28mmdia
Time necessary=about 1 hour max cost=nothing
Result=dynamics further improved,definition &details further improved.
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Both amps use a special opamp designed for professional use by the head of Jensen Transformers. There are two versions, however, differing in common mode rejection. I do not know if they use the same version. I have "hot wired" mine, but I am running balanced and had the designer of my Anedio Dac reduce the output gain. As to whether there would be instability in running single ended, that is a Tom question. Regards John Dozier
Tom emailed back that eliminating the gain R is fine, but to replace it with a jumper wire. For my single ended input SDS amp.
Sounds much better, more relaxed, really reduced the negative feedback sound.
Very good for a free mod.
Of course I had to reduce the input to match the subs with 2 resistors. And there is a little bit more noise with my 95db speakers. 86db speakers probably won't hear the noise.
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I recently purchased a SDS-470 kit and assembled it today but I have a problem and I hope someone here will have an idea as to what is wrong. I built a CDA-254 2 years ago and a few other kits so I'm not brand new to the experience. The two red LED's on the power supply board are light up and I measured +- 71VDC from the power supply board and also at the power input on the amp board. The two LED's on the amp board are light indicating power "OFF". When I switch the amp "ON" with the remote power switch nothing happens, the power "ON" LED's never turn on and the power "OFF" LED's remain light. I also checked the amp board for proper connection at the remote power switch points and all appears ok. Hope someone has run into this before.
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I'dont know the SDS470 Board. But at the border on the bottom side of the SDS254 is a small switch mounted which could be use to turn the board on / off without remote switch..
Is the switch also available on the SDS470 Board ? May be you could try to disconnect the remote and use the on board switch.
Did you connect anything to the board, may be there could be that the on board protection circuit raise..
Regards
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I recently stumbled across these kits and I have a few questions.
1) My front speakers are MartinLogan ElectroMotion ESL's that are 6ohm and dip down to 1.6ohms at 20khz (which I know is rarish for material to really get up there) and my rear speakers are MartinLogan Source that are 5ohm and just like my fronts dip down to 1.6ohms at 20khz. Is the CDA-254 module robust enough for impedance swings of ESL's?
2) Is the toroidal transformer in the CDA-1000 Kit enough to run three heavy duty power supplies, three CDA-254 modules and a CDA-258 module? My goal would be an all-in-one chassis for my 5.1 system.
Thanks!
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I'm finally going to finish wiring up my SDS 254.
Would appreciate a quick bit of advice on the input wiring (mine came without PCB Phono Sockets).
There are three connections per input socket (+,-,G) but I only have two wires from my socket. Can you tell what goes where?
(http://www.audiocircle.com/image.php?id=78374)
(http://www.audiocircle.com/image.php?id=78375)
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The center post from your phono socket goes to the "+" and the tag from your phono goes to the "G".
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Thanks SL_1800, appreciate the super quick response! Presume it's the same for the right hand channel (i.e. I don't use the negative for that channel either)?
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Thanks SL_1800, appreciate the super quick response! Presume it's the same for the right hand channel (i.e. I don't use the negative for that channel either)?
Negative is used for balanced sources. Make sure your on-board jumpers are set for single-ended connections.
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Great. Thanks Krikor! I wondered what the other connection was for. Much appreciated.
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rarem, how does it sound now?
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sl_1800 - so I like it a lot! I was using a little T-Amp from AutoConstruire before. The T-Amp was also really nice little amp but it felt very underpowered because as soon as I remotely cranked up the volume it would max out and cut off. The ClassD on the other hand feels like it has acres of headroom.
I'd really like to thank all the major contributors to this forum. The great postings really enthused me and pushed me over the edge to trying the build. You know what? - it's really not that hard to do!
I feel like I need to tune it a bit though. At the moment it sounds pretty similar to the AutoConstruire Amp, though much more punchy, but that was running through digital room correction via an Ultracurve DEQ2496. If the Class D Amp sounds so good now prior to correction, I can't wait to see what it will sound like after!
There are a couple of issues that I think are probably down to build issues (all views or fix suggestions welcomed).
- Firstly, I am hearing the odd bit of distortion. I think this will be down to imperfect connections from the amp along to the speakers. For the initial setup, I made a number of intermediate connections for ease of testing.
- Secondly, I get the odd intereference 'crack' every now and again. The amp is not grounded yet and is in a plastic case. Could that be a cause?
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Hi recently entered the DIY world, and for my first amp kit I chose a SDS-470. I plan to use the amp to power two 4 ohm subs. Unfortunately the amp is not working as intended, so I'm looking for some advice because I'm not sure how to go about troubleshooting the issue.
The amp is wired up correctly from what I can tell, lights are on, but it barely puts out any sound. Currently I have only 1 sub connected using an unbalanced input. I get the same weak output on either channel and with either gain pot. Gain wired left to right - Black, White, Red when gain knob is pointed toward me and leads pointing down.
Perhaps the LFE output from my receiver is too low? I have an older Harman Kardon AVR254. Would something like this work as a signal booster: http://www.musiciansfriend.com/pro-audio/art-tube-mp-studio-mic-preamp (http://www.musiciansfriend.com/pro-audio/art-tube-mp-studio-mic-preamp) to test that idea?
Some blurry shots:
(http://www.audiocircle.com/image.php?id=79068)
(http://www.audiocircle.com/image.php?id=79069)
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Update from my last post:
Per Tom's instructions, I jumpered the gain and got the same output as with the gain control, so I did have it wired correctly, but then I remembered my AVR's Sub level was set very low at -9db, so I maxed it out at +10db, and then I got good output with the amp gain maxed as well. Still not as loud as I was expecting, but usable.
A couple odd things that I noticed: first, when I played the test tone from the AVR to set sub level, instead of the usual rumbling,low frequency pink noise, I got a high frequency sounding white noise. Does anyone have an idea why the test tone wouldn't play normally through the amp?
I also have 2 other powered subs I'm running from the same LFE output and the test tone comes through normally for them. I swapped sub cables, tried the other input and output without success.
The second odd thing is that the weird sounding test tone comes through very loud with the gain maxed, but when I turn down the gain until I get a 80db reading, then the gain is too low to hear anything I play. That's not the case with my other subs, where the test tone comes through normally, I set the 80db level, and then everything plays back at that level. For some reason, the test tone is loud through amp, but anything I try to play is quiet unless I max the gain out.
Thanks,
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Hi recently entered the DIY world, and for my first amp kit I chose a SDS-470. I plan to use the amp to power two 4 ohm subs. Unfortunately the amp is not working as intended, so I'm looking for some advice because I'm not sure how to go about troubleshooting the issue.
The amp is wired up correctly from what I can tell, lights are on, but it barely puts out any sound. Currently I have only 1 sub connected using an unbalanced input. I get the same weak output on either channel and with either gain pot. Gain wired left to right - Black, White, Red when gain knob is pointed toward me and leads pointing down.
Perhaps the LFE output from my receiver is too low? I have an older Harman Kardon AVR254. Would something like this work as a signal booster: http://www.musiciansfriend.com/pro-audio/art-tube-mp-studio-mic-preamp (http://www.musiciansfriend.com/pro-audio/art-tube-mp-studio-mic-preamp) to test that idea?
Some blurry shots:
(http://www.audiocircle.com/image.php?id=79068)
(http://www.audiocircle.com/image.php?id=79069)
It looks like you have the amp board set up for balanced operation but are using an unbalanced source. You need jumpers J1 and J2 in place across pins 2 & 3 if i recall correctly.
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A couple odd things that I noticed: first, when I played the test tone from the AVR to set sub level, instead of the usual rumbling,low frequency pink noise, I got a high frequency sounding white noise. Does anyone have an idea why the test tone wouldn't play normally through the amp?
I also have 2 other powered subs I'm running from the same LFE output and the test tone comes through normally for them. I swapped sub cables, tried the other input and output without success.
Would those 2 other subs be types with plate amps that have a low pass filter? On the ones I've seen that filter isn't defeatable, only adjustable. Could be you're hearing the full range of pink noise through your sub on the Class D amp as opposed to a low pass filtered pink noise through the others. That will make the sound quite different.
If this isn't the case or your AVR is doing the filtering then carry on :roll:
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Would those 2 other subs be types with plate amps that have a low pass filter? On the ones I've seen that filter isn't defeatable, only adjustable. Could be you're hearing the full range of pink noise through your sub on the Class D amp as opposed to a low pass filtered pink noise through the others. That will make the sound quite different.
If this isn't the case or your AVR is doing the filtering then carry on :roll:
Thanks for the response.
Yes, plate amps with the low pass disabled. And I couldn't find an option on the AVR for any kind of pass filtering for the sub.
I got the same white noise and complete lack of low tone when I swapped the amp with a little tripath amp, and even when I tried a different sub with the tripath amp. So I'm a bit perplexed why the DIY amps are not playing back the sub test tone normally.
Kirkor - you've good eyes spotting the missing jumpers in those blurry pics. Had taken the pic prior to installing the jumpers, so all good in that respect.
Movies and music sound good, so I don't think there's anything wrong with the amp, but it is disconcerting that there is still an issue with the test tone. Tom suggested the issue is with the input signal from the AVR, which I would tend to agree since the swapping amps and drivers netted the same result - even though my other two subs play the tone correctly.
Any suggestions on a good device that could "fix" the signal?
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Update:
It was the input signal from the receiver causing the issues. I upgraded to a new Denon receiver, and everything works perfectly.
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would be grateful if some could help me quickly. Does it matter if the wire to the speaker binding posts are close to the torroidal transformer inside the amp case.
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would be grateful if some could help me quickly. Does it matter if the wire to the speaker binding posts are close to the torroidal transformer inside the amp case.
To be honest, some will say "Yes" others "No", but distance between power and audio carrying cables can't hurt ;)
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Thanks Barry. Actually the toroids and the speaker wire will be in different boxes. Only they will have a 12mm wood ply between them. A a situation might occur that the speaker wire might be going right over the core of the transformer.( though I can easily avoid it)
So was thinking if the magnetic feild of the transformer will affect the speaker wire.
Also I could line the transformer box will aluminium foil and connect it to earth. Would that help ?
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the toroids and the speaker wire will be in different boxes. Only they will have a 12mm wood ply between them. A a situation might occur that the speaker wire might be going right over the core of the transformer.( though I can easily avoid it)
So was thinking if the magnetic feild of the transformer will affect the speaker wire.
Also I could line the transformer box will aluminium foil and connect it to earth. Would that help ?
AFAIK, plywood does not provide any shielding. As regards EMI from the toroid, due to the construction of the toroid, it would be 'Y' plane of the toroid (perpendicular to the toroid), extending above and below the hole of the doughnut. So avoid routing the speaker wire over the toroid. Routing it adjacent should not matter IMO.
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Always twist speaker cables and always twist power cables for that matter. The exceptions being, pre-twisted cable and shielded cables.
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Hey there I have the SDS-254 which i am building for these http://www.audioheuristics.org/projects_gallery/ER18DXT/ER18DXT.htm# (http://www.audioheuristics.org/projects_gallery/ER18DXT/ER18DXT.htm#)
I am now adding another speaker as the center channel and need a mono amp to drive it. Which series would you recommend? Tom said I could use either the CDA254 or SDS254 in bridged mode.
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Hey there I have the SDS-254 which i am building for these http://www.audioheuristics.org/projects_gallery/ER18DXT/ER18DXT.htm# (http://www.audioheuristics.org/projects_gallery/ER18DXT/ER18DXT.htm#)
I am now adding another speaker as the center channel and need a mono amp to drive it. Which series would you recommend? Tom said I could use either the CDA254 or SDS254 in bridged mode.
I'd say go with another SDS-254 since it will match your main amp and you can adjust the gain to match (CDA has fixed gain). Just a thought.
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Thanks krikor that's a lot of money for a mono amp :( oh well
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Thanks krikor that's a lot of money for a mono amp :( oh well
Yeah, I wasn't thinking about price. You can save a few bucks going with the 224 (instead of the 254) since that will put out all the power you need when bridged. I also suppose you could just go with the CDA version and adjust the SDS amps to match the mono CDA. That saves you quite a bit. I assume you are looking to stay with ClassDaudio amps (that way you at least have the same family sound).
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How do you wire the classD amp remote? It is probably somewhere in this post but being a computer idiot I have almost never been able to find anything using the search function :scratch: .The way I wired it was obviously wrong because all I got was smoke and fire :duh: :duh:, thankfully it was only the remote wire that burned not the amp which is still working.
Thanks, Mike
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How do you wire the classD amp remote? It is probably somewhere in this post but being a computer idiot I have almost never been able to find anything using the search function :scratch: .The way I wired it was obviously wrong because all I got was smoke and fire :duh: :duh:, thankfully it was only the remote wire that burned not the amp which is still working.
Thanks, Mike
Hey Mike
I couldn't find anything previously posted in this thread (Click on the PRINT button...this will format the entire thread into one document. Then you can use your browser's find function). Is this for power on/off only? What remote control brand/model are you trying to install?
Mike
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I'm not using a remote control, I just want to turn amps on and off using a relay connected to the amps remote on off. Thanks for advice on using print and browser search function, but you missed the computer idiot comment I made, how do you do a browser search :scratch:
Thanks, Mike
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Thanks for advice on using print and browser search function, but you missed the computer idiot comment I made, how do you do a browser search :scratch:
Firefox: Edit > Find (Ctrl + F)
Internet Explorer: Edit > Find on this page (Ctrl + F)
Chrome: Menu Button > Find (Ctrl + F)
Safari: Edit > Find > Find (Ctrl + F)
Steve
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Thanks srb for computer info, but still can't find anything on how to wire a remote on off switch.
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Thanks srb for computer info, but still can't find anything on how to wire a remote on off switch.
Hi Mike
I think we may have a terminology issue (well, I have a lot of other issues, but..). Is this to add/replace a toggle switch before the power supply, or are you trying to wire to the on/off holes on the SDS amplifier boards?
Mike
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On my PS board the is a 2 slot connector that says remote, that is what I'm was trying to connect to, but if the on off hole will work that fine. What I want to do is connect the remote on off to a relay that I can activate from my bed.
Thanks, Mike
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I have had a CDA 224 since Oct 2010 and it has preformed brilliantly. I did beef up the PS by replacing the 4700mf caps with 10000mf caps.
I have just purchased a CDA 258 for another system and want to beef up its caps also. I do not remember where I got them from. does anybody have a good (cheap) source for these.
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Check out Apex Jr (http://www.apexjr.com/capacitorsR.html)
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Thanks TrungT
great lead
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i Have two CDA 254s running of a single power supply. One one amp....i have the left and right channels and on the other i just have the centre channel using one channel. Some times during playing music the centre channel goes yellow and stops playing....do i need a separate power supply?
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If you bridge the center channel board, the center speaker must be 8 ohms.
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If you bridge the center channel board, the center speaker must be 8 ohms.
It sounds like justd is using only one of the channels in normal stereo (unbridged) configuration.
..... on the other i just have the centre channel using one channel.
Steve
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Thanks Steve. ;)
May check the voltage to the board when it goes yellow.
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It sounds like justd is using only one of the channels in normal stereo (unbridged) configuration.
Steve
yes...
any ideas?
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I would send an email to Tom at Class D Audio. He's usually quite helpful. Just don't expect an immediate reply, it's clear to me that he's quite busy!
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Dear all,
I've just purchased two SDS-470 modules.
I intend to bridge them each and wire them as monoblocks.
I'm planning to replace the gain pots with TX2575 resistors - would anyone know if I still need a pair of resistors per module, or can i just use a single resistor per module, now that I'm bridging them?
Thanks!
Mike
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Dear all,
I've just purchased two SDS-470 modules.
I intend to bridge them each and wire them as monoblocks.
I'm planning to replace the gain pots with TX2575 resistors - would anyone know if I still need a pair of resistors per module, or can i just use a single resistor per module, now that I'm bridging them?
Thanks!
Mike
No, you don't need the resistors for the other "unused" channel. I've got a pair of SDS-450 boards running as monoblocks and only have a single gain pot attached to each. I keep thinking about replacing them with resistors but I've never got around to that project.
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No, you don't need the resistors for the other "unused" channel. I've got a pair of SDS-450 boards running as monoblocks and only have a single gain pot attached to each. I keep thinking about replacing them with resistors but I've never got around to that project.
Very much appreciated Krikor. Just didn't know if the both channels in the output stage were engaged when the modules were bridged.
Glad to have cleared that up.
Thanks!
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FYI, the US warehouse (based in Oregon) of Hifimediy now stocks Connexlectronic SMPS's. No more awkward emails and long shipping times from China. For those who don't know both Hifimediy and Connex are longtime respected diyaudio members. These power supplies come with 10% adjustable range AND an auxiliary power of 10-12v at 500ma for say a preamp. I've mentioned being extremely impressed with the Connex earlier in this thread. So if your power demands fit I highly recommend them, especiallyas they are only 4x4 and weigh nothing compared to the toroid and cap bank that comes stock with CDA amps.
And you guys do know that there are much cheaper versions on Ebay now, right? Not that I'm knocking CDA - the reliability is worth the cost - but for anyone wanting a secondary setup or want to play around there are *many* boards on ebay now.
http://us.hifimediy.com/index.php?route=product/product&path=68&product_id=64 (http://us.hifimediy.com/index.php?route=product/product&path=68&product_id=64)
http://www.ebay.com/sch/i.html?_trksid=p2047675.m570.l1313.TR2.TRC1.A0.Xirs2092&_nkw=irs2092&_sacat=0&_from=R40 (http://www.ebay.com/sch/i.html?_trksid=p2047675.m570.l1313.TR2.TRC1.A0.Xirs2092&_nkw=irs2092&_sacat=0&_from=R40)
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No one else uses the quality of components that ClassD uses. No one else achieves their sota sound quality either. You get what you pay for and with Tom's product, you get some of the best out there. Nothing to be taken away from the ebay offerings, they are good cheap amps, but hardly even close to sota. Regards
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No one else uses the quality of components that ClassD uses. No one else achieves their sota sound quality either. You get what you pay for and with Tom's product, you get some of the best out there. Nothing to be taken away from the ebay offerings, they are good cheap amps, but hardly even close to sota. Regards
Actually Connexelectronic would probably beg to differ. He has several IRS2092 as well and they look pretty freakin' good - but Hifimediy doesn't carry those so be prepared for the 30 day shipping time.
http://connexelectronic.com/product_info.php/products_id/145?osCsid=uq1cv8sl85ti6re7evdtc3q3r1 (http://connexelectronic.com/product_info.php/products_id/145?osCsid=uq1cv8sl85ti6re7evdtc3q3r1)
And in what way exactly are Tom's boards SOTA vs. ebay offerings? (just want some clarification).
Furthermore, just so it's clear I'm really promoting the Connex power supplies not looking to argue about the amps -I think we can agree that Tom's power supplies are NOT sota.
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No one else uses the quality of components that ClassD uses
I'd like some clarification about that statement in particular.
Steve
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Tom uses Niobium oxide caps (I think the only manufacturer who does) and a special input IC designed by the head of Jensen transformers. Again, one of the very few manufacturers to use this device and all others are extremely expensive. Regards
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Tom uses Niobium oxide caps (I think the only manufacturer who does) and a special input IC designed by the head of Jensen transformers. Again, one of the very few manufacturers to use this device and all others are extremely expensive. Regards
For ALL of his amps or just SDS?
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I think only the SDS series, but you would have to ask Tom. Regards
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I think only the SDS series, but you would have to ask Tom. Regards
Right, that's what I remember. That's a $200+ difference between SDS and the ebay amps. Hence my recommending as a secondary or for playing around. Goes without saying any amp off ebay is a risky proposition. No free lunch.
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Right, that's what I remember. That's a $200+ difference between SDS and the ebay amps. Hence my recommending as a secondary or for playing around. Goes without saying any amp off ebay is a risky proposition. No free lunch.
And I would add that Tom has always provided excellent, generous, high-quality customer service. I suspect he's a one-man or at least very small shop, and presumably he's super busy. I'd wager that this thread has probably been both a blessing and a curse for him. :)
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Since I know of at least two people (myself included) who have replace mega buck amps with ClassD Audio, needless to say I recommend them highly. Regards
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I'm still happy with mine but I do think they are very system specific. I've heard my amps in other systems with poorer results than in my system. Something to be said about system synergy.
steve :thumb:
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Both of us have sota systems and find the ClassD to be so transparent that even small changes in the rest of the system are clearaly audible.. Regards
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FYI, the US warehouse (based in Oregon) of Hifimediy now stocks Connexlectronic SMPS's.
That's really interesting!
I've mentioned being extremely impressed with the Connex earlier in this thread. So if your power demands fit I highly recommend them, especiallyas they are only 4x4 and weigh nothing compared to the toroid and cap bank that comes stock with CDA amps
Just some notes on my experience with this, for anyone who's interested.
I have two SDS-470 amps, one was completely done by Tom/Class D Audio, i.e. shipped in fully finished & working condition. The other is a DIY that I put together myself (although in a case from Class D Audio, so it looks like a pre-built one).
The DIY version uses the Connex SMPS800R power supply (actually recommended by Tom when I asked him what switch-mode PSU I should use). My DIY version also supports only XLR inputs, and I didn't use the gain pots, but opted for fixed resistors (not those fancy/expensive metal film resistors mentioned earlier in this thread, but cheapies from Mouser). To me the DIY amp sounds a little better than the stock. But I haven't done a true blind A-B test, and in fact, I suspect if put to the test, I wouldn't be able to tell the difference. But there is some non-tangible benefit to running a DIY rig. :)
Downsides to the Connex SMPS: my original goal was to have a very small, lightweight but high power amp. I tried putting the SMPS and SDS-470 in a case that was just big enough for the two boards. That resulted in overheating issues (my experiences are documented somewhere in this thread actually). Tom was super helpful through all this. Ultimately, though, my conclusion was that the SMPS800R puts off some heat, and a larger, better-ventilated case is necessary. I've since replaced that case with the "official" Class D Audio chassis (which really isn't that big), and haven't had any heat problems.
If I had the time (and was more motivated) I might try to revisit the small case setup, but this time with a slow-running (i.e. silent) fan. Note also that the SDS-470 is the highest powered Class D Audio amp, and the SMPS800R is one of the highest-power Connex SMPS modules, so going with lower power components might be all that I need.
One other small nit with the Connex SMPS: it makes a whining sound when there is no load, i.e. when there is no music playing. It's a pretty quiet whining sound (my wife can't hear it unless she's physically close to the amp and I point it out to her). And it goes away when playing music anyway. I asked Christi (the "Tom" of Connex) about this on the DIY Audio forum, and he said it's to be expected (he explained why it's so, but the technicalities were over my head).
I believe that both Tom at Class D Audio and Christi at Connex are continually revising and tweaking their boards. It's possible that a newer version of the SMPS may not whine. It's also possible that either (or both) boards have had their efficiency increased and/or heat-sinking improved.
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Not very expensive Niobium Oxide Caps from Digikey http://www.digikey.com/product-search/en/capacitors/niobium-oxide-capacitors/131747 (http://www.digikey.com/product-search/en/capacitors/niobium-oxide-capacitors/131747)
I use a Connex smps with my sds 258 amp. They sound great together.
For another project I'm going to try a Sure amp board off ebay using the IRS2092.
http://www.ebay.com/sch/m.html?_nkw=&_armrs=1&_from=&_ssn=sure-hifi&rt=nc (http://www.ebay.com/sch/m.html?_nkw=&_armrs=1&_from=&_ssn=sure-hifi&rt=nc)
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Niobium caps are not expensive, just great SQ. State of the art material and construction-more expensive does not always mean better SQ-it depends on the application. Regards
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I am looking at the SMPS 500 (http://us.hifimediy.com/index.php?route=product/product&product_id=72) as a PS for an SDS 254 amp.
That power supply has 500 watts continuous and 650 watts peak power available.
My sense is that given an input voltage range of 40-50vdc for the amp board, output from the PS of 45vdc is a solid choice.
Given that peak output power of the SDS 254 is 500 watts, I'm curious as to if this power supply has enough power available if I have sustained 500 watt demand. I don't actually expect that kind of demand, but would prefer to buy a slightly beefier PS if necessary and avoid the issue entirely.
Seems like it will, but want to confirm before I pull the trigger.
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Well, it has been a couple of years since I built my Class D amp. I have an SDS 254 kit with two amp boards (passively bi-amping at the moment, hope one day to actively do it). I am still quite happy with it. Currently, it is housed in an empty Peachtree Audio Nova-type box with custom front and back plates. I use my Nova now as a DAC and pre-amp.
(http://www.audiocircle.com/image.php?id=50069)
For awhile I tried a NAD C390DD direct digital amp. It has great clarity and a dead silent background. However, when I returned to my Class D amp, I realized I was missing quite a bit in the way of dynamics. I'm not sure if this is just because mine had more power, or if there really is something about Class D audio class D amps vs. the class D DAC/amp configuration and power supply NAD has.
It does make me wonder if I should try a NAD M51 DD DAC/digital pre-amp with the Class D Audio amp. Any suggestions?
Also, has anyone directly compared Class D audio amps to Hypex Ncore nc400?
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Also, has anyone directly compared Class D audio amps to Hypex Ncore nc400?
I got too, the Ncore was clearly a step up in overall resolution and dynamics, bass is a stand out. But i slightly preferred the more musical ClassD amp in my audition. My ClassD amp is a premium build with 60k Panasonic capacitance. The Ncore was a baseline build, I believe had it been built with premium parts it would have killed the ClassD. Hope to upgrade someday, but the ClassD is a great performer.
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It does make me wonder if I should try a NAD M51 DD DAC/digital pre-amp with the Class D Audio amp. Any suggestions?
I've been running an NAD M51 balanced into a stock Class D SDS-470C into Magnepan 1.7's for over a year now and the sound is fantastic. The NAD & Class D are great individually and they compliment each other well.
I can't believe I'm getting sound like this from such a modestly priced amp. I was prepared to spend more (and have in the past) but I've never had sound this good before.
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Well, it has been a couple of years since I built my Class D amp. I have an SDS 254 kit with two amp boards (passively bi-amping at the moment, hope one day to actively do it). I am still quite happy with it. Currently, it is housed in an empty Peachtree Audio Nova-type box with custom front and back plates. I use my Nova now as a DAC and pre-amp.
(http://www.audiocircle.com/image.php?id=50069)
Nice enclosure! I really like that look... so where do you get empty Peachtree Audio Nova-type boxes? Was that from a unit that went kaput?
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They sold me an extra. I told them what I wanted to do, and they were kind enough to do it.
Now they sell their own Class D amp. I wonder if I planted a seed ... ?
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Would I benefit from putting the toroid and the power supply board in a separate, metal enclosure, perhaps directly behind the current box which would continue to house the two amp modules? Right now everything is really crammed in there. I do hear a faint amount of hiss when nothing is playing, if my ear is within say 6" of the speakers. It is no big deal, but I wouldn't mind getting rid of it. Also, when I turn it on, I get two pops, presumably one per amp board. Is there a way to prevent that? When I have only one amp board connected, I don't get any pops.
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I just have recently even further improved the sound of my system using one SDS470 amp connected to Duntech Prince speakers.
The sound is as good as with a DEVIALET D Premier amp, costing about 12000Euros..I am not even interested into listening to the N-CORE in comparison since the sound i get is (according to my own opinion) really close to the ideal..
The essential improvements /tweaks of the SDS are concerning the Linear Power Supply and the cables, NOTABLY the Mains power cable to which the amp is extremely sensible.And the interconnects and loudspeaker cables.=
-switching to 6X Panasonic caps (60kMuF instead of 28.2kMuF)is better but not sufficient, i added 2X3 1800MuF panasonic caps at the amp board input, aiming at decreasing further the internal resistance of the PS.The result is good, the amp becomes "imperial" means seems to operate with more "ease".
-The Mains power cable is of great importance, notably for the extreme treble,which can be understood when looking at the current impulses entering the PS, which need fast transitories to be conveyed by the cable.I copied the principle of Shunyata by making a cable with 4 standsX(12X0,28 litz wire) but 2 strands are turning clockwise and two counterclockwise in order to reduce the cable inductance.This cable helps for the high frequencies,("air")
-i think the pots must be conserved since allow to tweak the slight difference of channel sensitivity, BUT the pot's wires must be shortened to 4cm instead of about 25 , i located the pots below the XLR inputs, by removing the RCA plugs as well as the (useless) switch for my own case.(removing useless wires brought an improvement in purity by decreasing the useless cable capacitance)
-the loudspeaker internal wires are of bad quality, i replaced by good ones, silver plated and litz.
NOW, about the interconnects and speaker wires:
-use UNSHIELDED interconnects seems to me a must.
-reduce the section of cables going to the woofers since the natural tendency of this amp is to give a little too much "high-lows"
-use litz wires for the treble in order to "purify" the sound and help for the extreme treble
Some hesitation and tests will lead at the end to clearly improved balanced results,if patience is used....
The shortcoming of this amp is to be extremely sensible to its environment, which leads to anticipating that if the user is not ready to tune it slowly and correctly with the system's remainder,the final result can be a lot lower than the maximum
attainable.
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i added 2X3 1800MuF panasonic caps at the amp board input,
Can you please add more detail on this mod. Are you referring to the 4 large caps next to the heat sink? What was their value before switching to pannys? What panasonic cap "FC"??
I also have 60uf on PS and very interested in your board mod. :wink:
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3 FC panasonic caps of 1800MuF each, in parallel, are connected between de (+) and the earth input screw
(http://www.audiocircle.com/image.php?id=91032)
pins, 3 other ones between the earth and the (-) pins.The mod is very simple to complete,one hour work is really a maximum.
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Can i use the SDS-470 rated at 300watt@8ohms and 600watts@4ohms to drive mirage OMD 15 (nominal 6ohm, and minimum 4ohm) rated at 25-250watts. Or will these blow them up.
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Can i use the SDS-470 rated at 300watt@8ohms and 600watts@4ohms to drive mirage OMD 15 (nominal 6ohm, and minimum 4ohm) rated at 25-250watts. Or will these blow them up.
I use that exact same amp with my 4-Ohm Salk Songtowers, with similar power ratings. I haven't blown them up yet. I believe it's possible that I could destroy the speakers if I tried... but I'd have to go out of my way to do that, including torturing myself with ridiculously loud volume.
The extra amp power is nice for dynamics in your source material. We're talking very brief peaks of power draw. If your typical listening levels are obscenely loud, I suppose those dynamic peaks could conceivably get into the danger zone for your drivers and possibly harm them. But I'm willing to bet that such a listening level would be quite unpleasant (unless you happen to live in a sports arena ;)).
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Thanks Matt,
I already have a pair of CDA 254s and a CDA 224. I am using them as a 5 channel amp in my home theatre. The problem is that in case of some brief highs, the amp is clipping. Also i feel that the rear surrounds are not as loud as they should be. Thirdly, to get to the desired level of volume i have to often go to 65 on my emotive UMC-1 ( max volume is eighty). earlier it was loud enough at 50 or 55. So i don't know, if that is the problem with UMC-1 itself.
I am thinking of migrating entirely to three SDS-470 for the five channels and go for the Connex power supplies. Thanks again for the insight.
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Hello to alls!!! Im from Croatia and im new in DIY, but i have nice friends who are monst...masters in that 8) so im not scared of answers! The question is what classDamp + preamp fits for my quads 11L, 86db speakers? Music is....... everything except classic (for now), and budget is 400-500$! Any suggestion is welcome! Thnx in advance!
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I would run this kit and a Grant Fidelity DAC-11 preamp. I run this combo with my Magnepan MMg's in my second system and it sounds great. The stock tube in the Grant is not that good. I run an early 1960's telefunken 6DJ8 or a 1960 Amprex non aframe with the halo getter.
http://classdaudio.com/amplifier-kits/cda-254l-kit.html
http://shop.grantfidelity.com/Grant-Fidelity-TubeDAC-11-D-A-Converter.html
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Thnx a lot!!! it looks very promissing, i hope it only would not be overkill for my quads, cause they are spec. with max 130wat!!
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Thnx a lot!!! it looks very promissing, i hope it only would not be overkill for my quads, cause they are spec. with max 130wat!!
Ignore that spec. You can do more damage to your speakers with an under powered amp.
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Ignore that spec. You can do more damage to your speakers with an under powered amp.
+1
btw.. i bought my sds 254 in the year 2012 and i'm still stoked about the sound. Especially since i run new speakers.. this amp have a lot potential for sound very superb.. additional i recommend to do some tweaks as described in this thread..
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Hi all. I'm a new comer to not only the thread but to hifi in general. I've never really owned anything that someone would think sounds nice, myself included. It's time to get wet though.
I've been reading like crazy over the last month and just need to start ordering stuff and get off the darn computer. haha
This system will be used for music off of my iphone for the foreseeable future.
So I have decided on the Gr-research X-MTM for my speakers. http://gr-research.com/x-csclassic.aspx
The classd cda254 for the amp http://classdaudio.com/amplifier-modules/cda-254-audio-amplifier-125w-x-2-8-ohm-250w-x-2-4-ohm.html
and I'm not sure about the preamp.
I'm leaning towards the passB1 http://www.audiocircle.com/index.php?topic=78312.0
But as wushilu points out a page or 2 from the end of the thread. The buffer is kind of old news and lots have come out since then.
If you all could help me decide on the buffer/pre I would be grateful. I have looked at too many designs. At this point in my education, I don't even know what will really work and what wont.
My goals for build sakes would be that I could power from the wall and not batteries.
That I can put in a box not bigger then 8x14" wide
That the cost comes in under $300. Much closer to $200 or less would be preferable.
Should I just go with the pass B1 and get on with things?
Lastly, I plan on going with the recommended PS from Wushilu http://us.hifimediy.com/index.php?route=product/product&path=68&product_id=64 and would really like it if I could power the pre and the amp off of the one power supply.
This is actually lastly. As I know enough to fill a tea cup at this point. If you see anything that just doesn't make sense in this post, please point it out.
Thanks all, Mike
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Mike, I have a CDA 254 driving a spare pair of Magnepan MMG's. I recommend using a warm sounding tube preamp. The amp leans a little on the sunny side of neutral. I use a Grant Fidelity DAC/Preamp (DAC-11). It uses a single tube as a tube buffer. I run it with a warmer sounding 6DJ8 1960 telefunken tube and it sounds great.
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Thanks, I appreciate the info. While it's pretty much double what I was looking to spend. I like the idea that it can also help with sound quality as I'll be using my phone and ipod as a music source most of the time.
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This thread is over 4 years old now. I myself have been following it for over three years. I was just thinking. Are these amps still the best quality for money.
I had searched for alternatives some time back but it seems doesn't seem to be any balanced input amps boards. I may be wrong and would love to be enlightened.
i am wanting to upgrade my CDA series amps to SDS series.
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Only aware of Hypex Ncore at about 3+ times the cost.
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This thread is over 4 years old now. I myself have been following it for over three years. I was just thinking. Are these amps still the best quality for money.
I had searched for alternatives some time back but it seems doesn't seem to be any balanced input amps boards. I may be wrong and would love to be enlightened.
i am wanting to upgrade my CDA series amps to SDS series.
Hi,
you could also take a look at
ALC0300-1300 (http://www.profusionplc.com/pro/gex/pcatdtl0?ipartno=ALC0300-1300)
Manufacture Data Sheet (http://www.anaview.com/sites/default/files/PDS%20ALC0300-1300-E.pdf)
There are about $300 for two mono blocks (300W each channel) with power supply integrated, so very easy to build.
They have balanced inputs also.
People report they sound very nice (also compared to ncore) .. anyway i guess a good quality/price ratio. The Class D chip is the same as used by SDS / CDA series (IRS2092). But the circuit design is different from the general reference design of the IRS2092. Therefor they use a 'custom Version' of the IRS2092 and a patented (http://was.prv.se/spd/pdf/7-H_QEPxhl_WS3oljenFlQ/SE536297.C2.pdf) circuit design.
Regards
Marcus
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I am changing my SDS254 from single-ended to balanced but have misplaced the manual. Anyone have a link to the SDS manuals (I found the CDS are on the Classd website but no balanced info in there). Alternatively if there is a wiring diagram with the jumper info that would be great. Might add a switch for he jumper if this is straight ahead as well....
Thanks,
Jeff
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I am changing my SDS254 from single-ended to balanced but have misplaced the manual. Anyone have a link to the SDS manuals (I found the CDS are on the Classd website but no balanced info in there). Alternatively if there is a wiring diagram with the jumper info that would be great. Might add a switch for he jumper if this is straight ahead as well....
Thanks,
Jeff
Details are buried in this thread, but if I recall, the single-ended/balance jumpers for the two channels are J1 and J2. Pins 2 and 3 shorted with the jumper gives you single-ended, open (no jumper) gives you balanced (you can move the jumper to pins 1 and 2 to store the jumper). Switch can be added across pins 2 and 3 per the following:
http://www.audiocircle.com/index.php?topic=76400.msg983417#msg983417
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Only aware of Hypex Ncore at about 3+ times the cost.
NCore yeah, but the UcD line has a balanced input stage as well for less $$$
I've got 4 UcD180HGs running my horns right now, and a Class D Audio SDS-470 on the woofers. I'm impressed with them both. The adjustable gain on the SDS line almost won me over for my horn amps, but I found a way to modify the Hypex boards to lower the gain.
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but I found a way to modify the Hypex boards to lower the gain.
Could you please expand on how you do that in the Hypex thread?
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What Hypex thread? It's simple, you just remove a resistor and it changes the gain from about 29 to 4.4dB. SMD resistor of course so you need a good magnifying glass. Hypex has the info in a little white paper on their website.
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What Hypex thread? It's simple, you just remove a resistor and it changes the gain from about 29 to 4.4dB. SMD resistor of course so you need a good magnifying glass. Hypex has the info in a little white paper on their website.
Its under the Owners Circle with a heading of Hypex.
http://www.audiocircle.com/index.php?board=197.0
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I still suggest the Class D Mastering Amp. It recently allowed me to hear the difference between 1m and 1ft cables. Both Gore (very difficult to obtain, but superb) The rest of the system- Anedio d2 and Paradigm sig1v3. Regards
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Just curious if anyone is having heat issues (thermal shut down) with modules and/or evaluation boards.....
Sound-wise, is there a clear winner for low-cost DIY Class-D?
If you have questions about Class-D in general, I'm open. I've been designing Class-D amps since the 1980s, and it's so nice to see them getting more and more acceptance for high performance applications! Thanks, and have a great weekend.
-Tommy O
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Just curious if anyone is having heat issues (thermal shut down) with modules and/or evaluation boards.....
With regards to the Class D Audio amps... if you take the time to read through this whole thread, you can get all the details on the issues I had, but the summary version is this: I was trying to stuff the SDS-470 (the most powerful/high current amp he offers) into a small, un-vented case with a Connex SMPS800R (the case was just big enough for those two PCBs). In this configuration, in the summer, the amp would get too hot and shut down. Since then, two changes have been made: Tom (of Class D Audio) revised the board with a much larger heatsink (includes "slugs" that contact the chassis), and I moved everything into a larger, vented case (the ones sold directly by Class D Audio). This setup has been running fine for a couple years now (daily use).
Sound-wise, is there a clear winner for low-cost DIY Class-D?
I believe the Texas Instruments TPA311x chips meet this criteria. I see you posted over in that thread. There is a similarly long (maybe longer) thread on these chips over at DIYAudio.com (and a similar one on AudioKarma).
I'm sure there are better amps (class D or otherwise) in absolute performance terms. But at $20, I think you'd be hard-pressed to find anything better. If you're willing to DIY, maybe do a simple mod or two, you can get really good performance for less than $100. Even at this price, if there's something better, well, I'd like to know about it! :)
The only potential drawback to the tpa311x amps is their relatively low power: about 50 watts max per channel at 4 ohms. Although, I put one of the tpa3116 amps (with a 24V PSU) on my Salk Songtowers in a huge room, and had no problem reaching my normal listening levels (which are admittedly fairly modest), with headroom to spare.
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Just curious if anyone is having heat issues (thermal shut down) with modules and/or evaluation boards.....
I have the 470 also and it runs quite hot compared to Tom's lower powered amps but I've never had a thermal shutdown. Mine is in a ventilated wooden case (one of my original cases at the beginning of this thread). Tom recommended using a metal case since the heatsink sheds heat better into the metal case bottom but I've never had the need to do that.
steve
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I recently picked up the 400C from ClassD which is the lower power version of the 470 and it sounds great. I would say its sound is very similar to the Peachtree and Wyred offerings (owned them both) at a better price point. The "ACircle" discount code still works too.
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Bad news when placing an order just now :cry::
Coupon code "ACircle" is not valid
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Been following this thread from the beginning. My NAD C 275 BEE gave up the ghost recently so I ordered a CDA 258 kit. Going to bread board it before I go to the trouble of putting it in a case. Will be pushing it with a NAD C 165 BEE preamp at least initially. Has adjustable output and tone controls. Should be here Tuesday. I'll post my impressions after a few weeks with it.
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Just curious if anyone is having heat issues (thermal shut down) with modules and/or evaluation boards.....
Sound-wise, is there a clear winner for low-cost DIY Class-D?
-Tommy O
I did have a problem with my SDS-470 overheating ,, just one channel. I believe the amp was properly assembled with heat transfer tape. I installed a computer fan right over the amp modules,, ran it on 5 volts and that fixed the problem. The fan was very quiet. The drive in my bluray player made more noise!
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Got my cda 258 kit bread boarded and energized. Dead quiet, no harshness noted on the highs and no fm interference. Sounds great with all my sources. I'm happy with the purchase. These offerings from Class D Audio represent high value.
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Got my cda 258 kit bread boarded and energized. Dead quiet, no harshness noted on the highs and no fm interference. Sounds great with all my sources. I'm happy with the purchase. These offerings from Class D Audio represent high value.
Congratulations! What speakers are you driving?
I'm still driving my Klipsch RF-83's with the SDS-224 amp. Wonderful combo :D
Mike
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Right now a pair of Paul Carmody's Classix 2's. They would definately qualify as "cheap and cheerful". Yesterday I had John Busch's Manzanitas hooked up. The amp is plush and quick, no rough edges. The folks who have noted a harshness to the highs must have impedance issues upstream. All the jibberish about special wires and cables is just that. I would like to try one of Emotiva's Control Freak volume potentiometers between my dac and the amp just to see how it sounds without an active pre when I'm using my pc as a source.
Also, none of my speakers are very efficient. 84 db max. So my next build will remedy that. Now I need to get it in some kind of case. Maybe just an ammo can with the tranny on top of the lid. The price certainty would be right.
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I need some help/input regarding 2 persistent problems I've been having with my CDA-254S amp. I am using the amp in stereo mode fed by the pre-outs from my Yamaha RXV-1700 receiver.
Problem 1 is that the left channel has a hiss when the CDA amp is first plugged in and turned on. My preference would be to plug the CDA amp into the AC output on the Yamaha 1700. This way I can leave the CDA amp's power switch on and when the receiver turns on, the amp turns on, and when the receiver turns off, the amp turns off. The hiss goes away on its own after the amp has been plugged in for 5-7 minutes, and then the speakers are dead quiet. I am guessing that it has to do with charging the capacitors or transformer, or bringing certain components up to operating temperature. However, for now, the solution has been to plug the CDA amp directly into the wall and leave it turn on 24/7. However, this work-around is not my preference if there is an effective way to solve the problem. I've tried the CDA amp in bridged mode and with other speakers the same problem exists.
Problem 2 is that the amplifier causes distortion or a buzz in the tweeter when sound is being played at above average (but not excessive) volume, particularly when the song or audio track includes heavy bass. I've tried connecting the CDA amp to different speakers and tried both stereo and bridged mode. I've also tried connecting the source directly to the amp bypassing the preamp/receiver. None of those efforts have solved the problem.
Any ideas/suggestions on how to remedy? Because of the above, the CDA amp has never found a home in my main system. I keep it around as a utility amp when needed for speakers at the office, or in secondary zones. Apart from the above issues, I've generally liked the clean sound it produces.
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I would contact Tom at Class D Audio. Maybe you have defective amp module. Mine has worked flawlessly and is dead quiet.
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My preference would be to plug the CDA amp into the AC output on the Yamaha 1700. This way I can leave the CDA amp's power switch on and when the receiver turns on, the amp turns on, and when the receiver turns off, the amp turns off.
The switched AC convenience outlets on the Yamaha RX-V1700 are low-capacity 100W / .8A total designed for low-wattage components, like a CD player, turntable, etc.
I assume you've tried the amplifier plugged directly into the wall, but even if they are not restricting the operation of the power amplifier plugged into them current-wise, the receiver's power switch / relay / convenience outlet circuit is not designed for a power amplifier's load of that wattage, even being a relatively efficient Class D.
Steve
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The switched AC convenience outlets on the Yamaha RX-V1700 are low-capacity 100W / .8A total designed for low-wattage components, like a CD player, turntable, etc.
I assume you've tried the amplifier plugged directly into the wall, but even if they are not restricting the operation of the power amplifier plugged into them current-wise, the receiver's power switch / relay / convenience outlet circuit is not designed for a power amplifier's load of that wattage, even being a relatively efficient Class D.
For years now I've been using this Smart Strip 4941 Energy Saving Surge Protector with Autoswitching Technology, 7-Outlet (http://www.amazon.com/Smart-Strip-4941-Autoswitching-Technology/dp/B000P1QJXQ/) as a poor-man's relay. I have my DAC setup as the blue master on the smart strip, and my power amp (used to be SDS-470, now replaced by a TPA3116 amp) on one of the green auto-switched outlets.
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I would contact Tom at Class D Audio. Maybe you have defective amp module. Mine has worked flawlessly and is dead quiet.
Have any members here sent their Class D Audio in for repair/adjustment ? And if so, what was the turn around time ?
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Thanks all for the responses.
Yes, as mentioned, I now use the CDA-254S solely plugged into the wall. When initially plugged in, it has a hiss in the left channel for about 5 minutes, which then goes away. Therefore, I leave it plugged in and on all the time (since it does not seem to consume much electricity when idle).
I mailed the amp back to Tom at Classdaudio after first experiencing the problem. He sent it back to me with a note that they didn't find any problem with it. Unfortunately, when I received it back the same problem existed. In response to SCM's question, I received the amp back about 3.5 weeks after I sent it (I paid for priority shipping when I sent it).
When I first noticed the tweeter distortion, my thought was that I over-drove the tweeter, so I purchased a replacement tweeter from the speaker manufacturer and installed it. But the same tweeter distortion existed. So, I connected other receivers and amps to the speakers and tried both the new and old tweeter, and the problem was gone, thereby identifying the issue as coming from the CDA amp.
So while I was able to work around the initial hiss when power is connected (by leaving the amp plugged in at all times), the remaining problem of distortion in the high frequency range (when a track that also has heavy bass is being played at an above average volume) remains. Unfortunately, at this point, I somewhat regret the purchase and wish there was more that I could do to help fix the issue.
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PM sent
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The most common complaint of class d is that the highs sound off. I don't know why that would be but I have my suspicions, and it has as much to do with what people are used to hearing.
The only class D amp I have powers my personal computer audio. It is the bass that sounds a little off to me. Perhaps it is designed to have bass boost for driving small speakers. I don't know. I do use a subwoofer with bookshelf speakers for the computer so it is a full range setup.
My impression is that comments about class D technology as a group probably depend more about when the comments were made rather than what they say. Early class D amps were questionable. The new ones really seem to be pretty good. This little thing certainly provides high fidelity sound from my computer while I work.
(http://www.fredwhitlock.com/images/smslfront.jpg)
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Thanks all for the responses.
Yes, as mentioned, I now use the CDA-254S solely plugged into the wall. When initially plugged in, it has a hiss in the left channel for about 5 minutes, which then goes away. Therefore, I leave it plugged in and on all the time (since it does not seem to consume much electricity when idle).
I mailed the amp back to Tom at Classdaudio after first experiencing the problem. He sent it back to me with a note that they didn't find any problem with it. Unfortunately, when I received it back the same problem existed. In response to SCM's question, I received the amp back about 3.5 weeks after I sent it (I paid for priority shipping when I sent it).
When I first noticed the tweeter distortion, my thought was that I over-drove the tweeter, so I purchased a replacement tweeter from the speaker manufacturer and installed it. But the same tweeter distortion existed. So, I connected other receivers and amps to the speakers and tried both the new and old tweeter, and the problem was gone, thereby identifying the issue as coming from the CDA amp.
So while I was able to work around the initial hiss when power is connected (by leaving the amp plugged in at all times), the remaining problem of distortion in the high frequency range (when a track that also has heavy bass is being played at an above average volume) remains. Unfortunately, at this point, I somewhat regret the purchase and wish there was more that I could do to help fix the issue.
I would email Tom and see if he would exchange the amp for a new one. He should given the circumstances if his customer service is top notch.
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For years now I've been using this Smart Strip 4941 Energy Saving Surge Protector with Autoswitching Technology, 7-Outlet (http://www.amazon.com/Smart-Strip-4941-Autoswitching-Technology/dp/B000P1QJXQ/) as a poor-man's relay. I have my DAC setup as the blue master on the smart strip, and my power amp (used to be SDS-470, now replaced by a TPA3116 amp) on one of the green auto-switched outlets.
I am using the same thing with my Class D Audio amp.
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Have any members here sent their Class D Audio in for repair/adjustment ? And if so, what was the turn around time ?
Yes. I can't remember exactly, but it was fast.
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Hi guys,
It's been a wile since I came over here.... I'm the proud owner of a SDS-254. I recently bought an other 6 channels for an active loudspeaker.
I would like to use a fix resistor on all of my amps and replace the adjustable gain. Is there a "consensus" for the value that sound the best??? or is it simply a jumper that sound the best???
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I would like to use a fix resistor on all of my amps and replace the adjustable gain. Is there a "consensus" for the value that sound the best??? or is it simply a jumper that sound the best???
Here is the table for resistance versus gain:
resistance (ohms) versus gain (db)
560 31
1000 30
2200 27
5200 23
6200 18
7500 16
I don't think there is any consensus, and in general, I believe input gain is a matter of personal preference and/or impedance matching with source components.
In my case, I simply used the pots to dial in what I liked best ("tune by ear"), then used an ohm meter to measure the resistance, and purchased fixed resistors accordingly.
There was a lengthy discussion on type of resistor a ways back in this thread. A lot of people reported success with those expensive thin film (I think?) resistors. IIRC, they're around $30/each. A bit too much for my wallet. :)
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Hi guys,
Does anyone know a way to contact Tom directly? I need to inquire about an amplifier repair. If you have a phone number, please PM me.
thanks!
-v
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I've managed to wade through this entire thread and would like to thank all the generous contributors.
One thing that doesn't make sense to me is some of the complaints I've seen that Tom at CDA doesn't answer emails or takes a long time to do so. I've emailed Tom several times over the last several months and he has always gotten back to me within the hour. Exceptional support. I use the support@classdaudio.com email.
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dr_skoobie,
Use this email, support@classdaudio.com, to contact Tom and see if he's willing to give you his phone number.
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I'm from Malaysia, currently having a pair of Wharfedale Denton 80th Anniversary, amplified via Marantz PM6005, distort when volume pass 12 o'clock, also feel that the speakers need more juice, thus I have ordered SDS-400C since got offer price, I'm using JDS Labs ODAC, no preamp yet, any to recommend? What happen if I drive directly using ODAC?
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SOLD:
I read the posting guidelines and don't think this is against forum rules (its non-commercial and not linked outside of this site). If this is not cool, please let me know and or remove post at once:
Class D kit for sale:
http://www.audiocircle.com/index.php?topic=134492.0 (http://www.audiocircle.com/index.php?topic=134492.0)
Thanks!
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While not specifically forbidden, it's sort of bad form to link your for sale ad in the middle of someone else's thread. That's what the for sale section is for. However it's not an egregious offence and could actually help someone that might be looking for a kit, so I wouldn't ask that you remove it. In fact if it was a completed kit I might have been interested, lol. No worries.
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While not specifically forbidden, it's sort of bad form to link your for sale ad in the middle of someone else's thread. That's what the for sale section is for. However it's not an egregious offence and could actually help someone that might be looking for a kit, so I wouldn't ask that you remove it. In fact if it was a completed kit I might have been interested, lol. No worries.
Well the item in question *is* the subject of the thread, and indeed helped someone out here. All good.
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I'm from Malaysia, currently having a pair of Wharfedale Denton 80th Anniversary, amplified via Marantz PM6005, distort when volume pass 12 o'clock, also feel that the speakers need more juice, thus I have ordered SDS-400C since got offer price, I'm using JDS Labs ODAC, no preamp yet, any to recommend? What happen if I drive directly using ODAC?
Hi guys, I had bought Class D Audio SDS 400C, overall I'm very impressed with it, but I have some "fan" noise coming from the amp, from time to time, though not often, and it just comes out for like few minutes? Any thoughts? Can guide me how to fix this? I've try to contact Class D Audio, but there is no response, anybody know what's going on? :duh:
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Hi guys, I had bought Class D Audio SDS 400C, overall I'm very impressed with it, but I have some "fan" noise coming from the amp, from time to time, though not often, and it just comes out for like few minutes? Any thoughts? Can guide me how to fix this? I've try to contact Class D Audio, but there is no response, anybody know what's going on? :duh:
Are you saying there is a "fan" noise coming from amp chassis? Or is it a fan-like noise coming from you speakers? Curious, since I don' t believe the amp has a fan. If coming from the chassis it could be some transformer noise. I get this from the toroid transformers my subwoofer amps whenever my wife has her hair iron plugged in... drove me nuts trying to troubleshoot since the iron turns on/off to maintain temp. Doesn't really sound like a fan, but makes a buzzing sound that I suppose might sound fan-like in your case.
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Are you saying there is a "fan" noise coming from amp chassis? Or is it a fan-like noise coming from you speakers? Curious, since I don' t believe the amp has a fan. If coming from the chassis it could be some transformer noise. I get this from the toroid transformers my subwoofer amps whenever my wife has her hair iron plugged in... drove me nuts trying to troubleshoot since the iron turns on/off to maintain temp. Doesn't really sound like a fan, but makes a buzzing sound that I suppose might sound fan-like in your case.
Yes, exactly :P How do you solve that? :duh: :D
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Yes, exactly :P How do you solve that? :duh: :D
I usually go in the basement and trip the circuit breaker for the upstairs bathroom, then tell my wife she needs to stop using that hair iron :icon_twisted:
Just kidding of course. You need to kill the source or use a "humbuster" of some sort, such as:
Audio by Van Alstine "HumDinger": http://avahifi.com/index.php?option=com_content&view=article&id=270&Itemid=239
or
Emotiva CMX-2: https://emotiva.com/products/accessories/cmx-2
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I have an SDS-440C and recently tried shorting plugs on the unused RCA inputs, a tweak that's supposed to keep out unwanted EMF/RF. It seemed the worst that could happen would be no detectable sonic benefit, but instead it seemed to degrade the sound and require increased output from the preamp to maintain volume. Has anyone else experienced this, and does the toggle switch for balanced/unbalanced make this totally unnecessary in the first place?
Thanks.
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I have an SDS-440C and recently tried shorting plugs on the unused RCA inputs, a tweak that's supposed to keep out unwanted EMF/RF. It seemed the worst that could happen would be no detectable sonic benefit, but instead it seemed to degrade the sound and require increased output from the preamp to maintain volume. Has anyone else experienced this, and does the toggle switch for balanced/unbalanced make this totally unnecessary in the first place?
Thanks.
hmm, recently I have found some more problems with my SDS-440C, some weird hiss hum from the speakers, the toroidal sound still appear from time to time, the hiss hum is hearable, something serious happen here, but I dunno what to do, as I'm order from Malaysia, if to send it back :duh:, also the problem does not happen so often, but it did pop out from time to time, I'll continue use see what next. Anybody can advice what to do? Something related to power? Power cable?
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If any of you guys have single driver or very sensitive speakers Temple Audio use the Analog devise module which use 8 mosfets per channel .25 wpc in their Bantam Gold 40 into 4 or 2 ohms
High quality sound . They have the dual mono bantam 1 amps with passive preamp and a pre out.
Just. Wanted to mention hand built made in the U.K quality and later in the year. You will
See more products .the is especially geared to the single driver guys.
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Sorry I'l late to this party.
Whose class D chips do the classdaudio.com guys use?
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addendum: I see one of their beefier ones use TI.
Do they use others' as well?
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addendum: I see one of their beefier ones use TI.
Do they use others' as well?
The CDA and SDS amps are generally regarded as their best-sounding designs and are based on IR chips.
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Hi guys, I think that the SDS-400C is working just fine, instead is my speakers the problem, though I still got the minor hum problem from the toroidal transformer, should I change to a better toroidal transformer? This amp is so deadly pinpoint accurate about what's wrong with our system, especially mostly will be speakers is the limitation. Also should I use a preamp to do some filter like roll off, noise reduction etc?
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3 FC panasonic caps of 1800MuF each, in parallel, are connected between de (+) and the earth input screw
(http://www.audiocircle.com/image.php?id=91032)
pins, 3 other ones between the earth and the (-) pins.The mod is very simple to complete,one hour work is really a maximum.
Has anyone else done this mod and how is it holding up?
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I've sent several emails, still no reply from Class D Audio. I dun want to say this, but it's horrible service. The toroidal transformer hum problem still there. I've lost faith in Class D Audio, totally helpless :duh:, I'll have to look else where, good sound but bad service is just what I can said :duh:
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I've sent several emails, still no reply from Class D Audio. I dun want to say this, but it's horrible service. The toroidal transformer hum problem still there. I've lost faith in Class D Audio, totally helpless :duh:, I'll have to look else where, good sound but bad service is just what I can said :duh:
Question: have you tried taking the amp to a different location (friend's house, work, etc.) and plugging it in to see if the hum is present? That way you know if the issue is with the transformer or something in your home power/wiring.
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Question: have you tried taking the amp to a different location (friend's house, work, etc.) and plugging it in to see if the hum is present? That way you know if the issue is with the transformer or something in your home power/wiring.
hmm maybe I can't blame the amp, I've read that all toroidal transformer did hum, even good ones, if I'm not doing nearfield critical listening, I won't bother ask for help, yes I've tried at my hometown, the problem pop out whenever it want, no particular logic when it happen, so random, I'm out of idea...my Marantz PM6005 with no DAC input has very very low noise when I hear closely the tweeter, but when it sing, kinda suck compare to Class D Audio in some ways, and the Class D Audio when no DAC input, did has a higher hiss near the tweeter, then I've read that all solid state got this "unhearable" minor hiss, unless some mechanism to reduce that...what can I do now? Don't bother I guess... :duh:
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I've got my Class D amp powered by an SMPS, and there is no hum (that I can hear) generated by that. I don't remember the model number (I think maybe 500R?), or much in the way of details about it (I ordered it from somewhere in Europe I think, quite a while back), but it was easy to install and hook up. Maybe that would solve your issue?(http://[img]http://www.audiocircle.com/image.php?id=123058)
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Do you have any fluorescent lights nearby? Sometimes when the ballast goes bad, the ballast hums and introduces hum into the circuit. My SDS amps were humming and Tom brought this up as a possibility. I typically don't use my fluorecscent lights while listening to music. About a month later, I have a small flurorescent lit sign over my turntable that started to mum audibily. When I shut it off, the amp hum hasn't been back since. The sign wasn't making any noise shen I talked to Tom but I have to bellieve the ballast was going bad and addiing noise to the amps anyway.
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Could also be dc on your line. Some amps and toroids are more sensitive to this than others. Maybe take it to a buddy's place. There are devices that treat this.
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I've got my Class D amp powered by an SMPS, and there is no hum (that I can hear) generated by that. I don't remember the model number (I think maybe 500R?), or much in the way of details about it (I ordered it from somewhere in Europe I think, quite a while back), but it was easy to install and hook up. Maybe that would solve your issue?(http://[img]http://www.audiocircle.com/image.php?id=123058)
So my one is linear PSU? How much you bought? Is it this one?
http://connexelectronic.com/product_info.php/products_id/118
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Do you have any fluorescent lights nearby? Sometimes when the ballast goes bad, the ballast hums and introduces hum into the circuit. My SDS amps were humming and Tom brought this up as a possibility. I typically don't use my fluorecscent lights while listening to music. About a month later, I have a small flurorescent lit sign over my turntable that started to mum audibily. When I shut it off, the amp hum hasn't been back since. The sign wasn't making any noise shen I talked to Tom but I have to bellieve the ballast was going bad and addiing noise to the amps anyway.
Yup there is one fluorescent light on the wall, on top of the amp. I'll do some experiment when the hum coming back again, coz I have no idea when it come, it takes a while for the hum to goes away. Thanks!
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Could also be dc on your line. Some amps and toroids are more sensitive to this than others. Maybe take it to a buddy's place. There are devices that treat this.
To me an amp should not be treated like that. It should just work with a simple power chord. To buy other treatment products, I also not sure whether it works, could end in give more problems than solving it.
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I'll do some experiment when the hum coming back again, coz I have no idea when it come, it takes a while for the hum to goes away. Thanks!
It might also be related to an appliance with a motor that cycles on and off, like a refrigerator or an air conditioner.
Steve
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To me an amp should not be treated like that. It should just work with a simple power chord. To buy other treatment products, I also not sure whether it works, could end in give more problems than solving it.
Lots of appliances are known for causing DC offset: computer printers, blow driers, refrigerators, lighting. It can also originate with a neighbor. In the Van Alstine forum there's a thread that discusses it a little bit, since they make a DC Blocker called the "Humdinger". If you have enough DC offset on the line, lots of well made amps will be susceptible.
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So my one is linear PSU? How much you bought? Is it this one?
http://connexelectronic.com/product_info.php/products_id/118
Yep... that's the one. I don't know which Class D amp module you have, so make sure the output voltage of that SMPS is correct for your module (I think mine is the SDS 254). It is adjustable from a low of + or - 24 V (which is too little) up to 72V (which is too much). I believe I have mine set at + and - 45V.
(http://[img]http://www.audiocircle.com/image.php?id=123098)
[/img]
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To me an amp should not be treated like that. It should just work with a simple power chord. To buy other treatment products, I also not sure whether it works, could end in give more problems than solving it.
Problem is your power, not the amp. Maybe another household device is putting dc on the line, or it is something from your home's wiring or the power coming into your house. If everything is up to spec, DC should not be on the line.
Have you tried it on other outlets in your house, or at a friend's house?
Also make sure the toroid is sufficiently tightened down.
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Problem is your power, not the amp. Maybe another household device is putting dc on the line, or it is something from your home's wiring or the power coming into your house. If everything is up to spec, DC should not be on the line.
Have you tried it on other outlets in your house, or at a friend's house?
Also make sure the toroid is sufficiently tightened down.
Guess I can live with it. It's not happening so often, very rare, just that someitme pop up disturb my near field critical listening and judgement. Actually is it all Class D Audio power amp using that toroidal transformer? I thought I heard sth like SMPS from Class D Audio Website?
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Something like the Humdinger from Van Alstine can fix the problem. If it doesn't work, there is a 30 day return policy.
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Something like the Humdinger from Van Alstine can fix the problem. If it doesn't work, there is a 30 day return policy.
Now that when I complain, the hum problem does not happen again :duh:
Guess it's ok now, thanks for you guys, I see that Class D Audio Web site got some revamp, still look no further but Class D Audio power amp, the price just so nice :green:
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I want to share a mod which i done recently.
I highly recommend this mod, it's a real improvement in more music details :thumb:
Technical :
The input stage (balanced line receiver) is supplied by an on-board power supply. This supply is an very basic concept by using and Resistor and Z-Diode to generate +-15V.
Mod :
Replace this R/Z-Diode Supply Stage by an external low noise +-12V or +-15V power supply board. If the ClassDAudio Kit Transformer (Antek) is used than the unused 12V and 18V winding of the transformer could connected to supply the external board, so no extra transformer is required.
Regards
Marcus
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Has anyone changed over from unbalanced to balanced input, and if so, was the improvement audible and significant? Is it just a matter of removing the two jumpers next to the input terminals (and using XLR inputs)?
Also, has anyone directly compared the SDS to Hypex NC-400?
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Has anyone changed over from unbalanced to balanced input, and if so, was the improvement audible and significant? Is it just a matter of removing the two jumpers next to the input terminals (and using XLR inputs)?
Well, i had changed from unbalanced to balanced.. but i my case i also changed some other things, so it is not meaningful.
The input Stage of the SDS Board (THAT1200, Balanced Line Receiver) will do a nice job with balanced and unbalanced input signals. So it depends mainly on your source. As first approximation i would chose the connection depend on your source build, is it balanced or not, to eliminate additional converting.
May be you are interessted to do some mod's. I do a lot of mod's on the SDS Boards, here is my list starting with most audible mod :
1. Replace R/C Power supply of input stage by external low noise power supply !
2. Replace couple capacitor between Input Stage and IRS2092 by Audio Caps (Elna Silmic II)
3. Replace Bootstrap Capacitor of THAT1200 by Audio Caps (Elna Silmic II)
3. Upgrade all on-board supply capacitors by Low ESR Types with higher capacitor values (Panasonic FC /FR)
3. Replace all Resistors in Signal Path (4x 100 Ohm / 2x 3.3KOhm) by high graded resistors (Texas Components ASM2575)
(Yes 3x position 3 :-) )
Also, has anyone directly compared the SDS to Hypex NC-400?
There are some people who comared both, most say NCore is better.. i brood over buying ncore's for a year now, but I'm actual very impressed by my SDS254 include all the mod's so ..
But I'm also interested about reports / reviews about comparing both systems directly..
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Bellow a picture of my latest setup with external Power Supply, additional Transformer and motorized ALPS Pot as Volume Control :
I highly recommend an external Power Supply, it's not that much difficult to implement. I could never live without again :)
(http://www.audiocircle.com/image.php?id=136106)
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Looks awesome, Marcus, thanks for posting! Kinda makes me wish I hadn't sold my ClassDAudio amps! :)
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Looks awesome, Marcus, thanks for posting! Kinda makes me wish I hadn't sold my ClassDAudio amps! :)
Why do you sold the ClassDAudio Amps ? What's your actual amps ?
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Why do you sold the ClassDAudio Amps ? What's your actual amps ?
I had two SDS-470 amps, one was a DIY job that I put together myself, and the other was purchased finished from ClassDAudio.
I only needed one. I got the pre-made one so I could have a known good/working one while I tinkered with the DIY one. But eventually my DIY one reached a good working state (where I wasn't compelled to constantly tweak it), so I sold the pre-made one. (Note: I never did anything nearly as fancy as what you've done, as at this time, I was literally just getting started with DIY.)
Later, I started building amps based on the tpa311x chip. While my SDS-470 was working just fine, I built a dual-mono tpa3116 amp that was smaller, lighter, and more energy efficient than the SDS-470 (see here for pics (http://www.diyaudio.com/forums/group-buys/257996-gb-tpa3116-8-pbtl-bare-pcb-41.html#post4198031)). I didn't really do any extensive A-B testing for sound quality, but with a quick check, I didn't hear any obvious downgrade. This was for my living room, and by this time, I wasn't really doing any "serious" listening on this rig anyway.
A little more rambling info: I believe the SDS-470 is ClassDAudio's most powerful amp, and in hindsight, I realize it was ridiculous overkill for my needs. There was a thread on AVS Forums talking about using super high power pro power amps for improved sound quality, and I jumped on the bandwagon with a QSC RMX2450, in all its big, heavy and power-hungry glory. Then I read about class d amps (in general, not ClassDAudio specifically), and how they were far more energy efficient. That plus this thread right here, led me to ClassDAudio. At that time I still thought I needed ludicrous wattage, so that's why I bought the SDS-470.
I tried to cram my DIY SDS-470 into a case that was just big enough for the amp board plus a Connex SMPS800R power supply. I think there are pictures buried in this thread somewhere. But that caused me to run into overheating issues. Eventually, Tom (at ClassDAudio) gave me a new revision of the SDS-470 board with a bigger, fancier heatsink, and I moved everything in a larger enclosure with better ventilation. That cured the heating issues.
But then I became so enamored with the tpa311x amps that I felt compelled to build one to replace the SDS-470, mainly for size and power-efficiency reasons.
So, in short, I really only sold them due to "new toy syndrome". I wish I realized back when I first got into those ClassDAudio amps that I didn't need so much power, and probably would have been better served with something like an SDS-254. Lower power means less heat and less wasted electricity.
Having said all that, I'm tempted to build another irs2092-based amp using the LMJ boards (example: L15D), as these are cheaper than the ClassDAudio boards ($80 for a mono pair on ebay) and have a good reputation on diyaudio.
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I know this is an old thread but I need some help. I have a Class D Audio CDA-254 kit amp that I want to upgrade. It has the 300VA torroidal transformer and I want to upgrade to the Antek 400VA. Does any one know which model that I need as there are several with different specs? The amp just does not seem to have enough drive for being 250wpc. It did not seem to drive a pair of MMG's that well. It has been sitting in my basement not being used. My Adcom AVR sounds better.
Also, I have been thinking about swapping out the 4 resistors, 2 on each board for Carbon Riken or Audio Note Tantalums to see if I can warm things up a bit. I doubt that they would change the sound but it is worth a try. I used these resistors in the Pass B1 preamp that I built and they sure made things sound warm and smooth.
Thanks for the help!
Larry
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Do you know the output voltage of your current tranny? This one is 34 volts, which will give you around a 48 volt supply. Seems they have changed the amp names...the CDA-254 is no longer listed. The CDA-250 must be the new CDA-254???
http://www.antekinc.com/as-4434-400va-34v-transformer/
Mike
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My current transformer is an AN-3332 300VA and the outputs are as follows-
115v
115v
32v
32v
18v
So I assume I need a 400VA with the same voltage?
I found these 2-
http://www.antekinc.com/as-4435-400va-35v-transformer/
http://www.antekinc.com/as-4434-400va-34v-transformer/
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The new CDA-250 requires +- 42 to +- 52 volt supply. I assume the old CDA-254 is the same.
Your 32 volt tranny will rectify to 32 * 1.414 or around +- 45 volts. A 34 volt tranny will give you around +- 48 volts.
I like to split the difference, so the AS-4435 would work. The AS series is shielded, the AN series is not. Don't know if the makes a difference.
It would be interesting to check the output voltage from your current setup, to make sure it is around 45 volts DC. Home voltages do vary!
Hope that helps!
Mike
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Thanks for the help. I will go with the AS-4435. Hopefully the upgrade will yield a little more oomph!
The amp can definitely use a little more gain as well.
Has anyone changed any of the Resistors or Caps?
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Thanks for the help. I will go with the AS-4435. Hopefully the upgrade will yield a little more oomph!
The amp can definitely use a little more gain as well.
Has anyone changed any of the Resistors or Caps?
Hm, I dunno 5.5A cap for your Maggies sounds kind of low from what I've read about them. I seem to recall them needing more power earlier in the thread. I have a feeling you need either a MUCH bigger transformer or a higher power CDA amp, or both. Probably need to beef up the caps too if you have the stock ones.
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Hm, I dunno 5.5A cap for your Maggies sounds kind of low from what I've read about them. I seem to recall them needing more power earlier in the thread. I have a feeling you need either a MUCH bigger transformer or a higher power CDA amp, or both. Probably need to beef up the caps too if you have the stock ones.
Do you think jumping up to a 500VA or 600VA transformer would help?
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Its important that you have the larger power supply or buy the blank and add your own to increase capacitance. TSHA Pannys.
http://www.classdaudio.com/power-supplies/upgrade-power-supply/
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Do you think jumping up to a 500VA or 600VA transformer would help?
yes. also what Nick said. the power supply is the weak spot for cda amps. even my old two ways benefited when I had those amps.
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If I wanted to replace the caps in my current power supply, what values do you recommend? Are there any caps with a warmer sound for this application? I have no problem soldering. Or I just may buy the bare power supply board for $40.
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If I wanted to replace the caps in my current power supply, what values do you recommend? Are there any caps with a warmer sound for this application? I have no problem soldering. Or I just may buy the bare power supply board for $40.
I used 6800uf panasonic thsa. 8200 as well I think. Been awhile. As long as they are rated for your voltage get as much as you can. I think I had 90k at one point. The board is easy to desolder iirc.
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The cda site offers 60k I see so that makes me feel a little better about my recommendation as I try to be conservative. Do at least 60.
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Would the 6800uf 63v caps be ok with this Antek transformer for the CDA or do I need lower voltage caps?
http://www.antekinc.com/as-4435-400va-35v-transformer/
https://www.banzaimusic.com/Panasonic-TSHA-6800uF-63V.html
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That's the maximum voltage for the capacitor, there isn't a problem using one rated higher and in fact is good practice to de-rate them for safety margin and longevity.
Steve
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Would the 6800uf 63v caps be ok with this Antek transformer for the CDA or do I need lower voltage caps?
http://www.antekinc.com/as-4435-400va-35v-transformer/
https://www.banzaimusic.com/Panasonic-TSHA-6800uF-63V.html
Yes 63 is fine.
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Much thanks!
Larry
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It might also be related to an appliance with a motor that cycles on and off, like a refrigerator or an air conditioner.
Steve
good advice, these amps are as sensitive as any out there, I know there are many kinds all under the heading of Class d, mine is the 12 pounds and only 25 watts per channel kind and I had a lamp next to it with incandescent bulb and it made the amp buzz, and traditionally that is a great thing, good equipment is very sensitive, mine is a sigma 7th order 1 bit, with over 2 million x over sampling, if anyone knows about it please pm me.
PS a iron choke on the power chord really effects the sound for the better, smoother, sometimes
Ruby
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To me an amp should not be treated like that. It should just work with a simple power chord. To buy other treatment products, I also not sure whether it works, could end in give more problems than solving it.
Hi WIM
my cardas power line turns my D amp into a whole new machine, there is a difference anyone can hear.
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I'm from Malaysia, currently having a pair of Wharfedale Denton 80th Anniversary, amplified via Marantz PM6005, distort when volume pass 12 o'clock, also feel that the speakers need more juice, thus I have ordered SDS-400C since got offer price, I'm using JDS Labs ODAC, no preamp yet, any to recommend? What happen if I drive directly using ODAC?
the Denton's have a very layed back sound, try thermostat cable (solid 5 wire) non OFC, this is very fast wire
and good luck
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Hi guys, recently doing some experiments, and cut off some wires, but dunno how to put back, I would like to configure to use RCA single ended input only, but I'm not able to figure how to, here's the pic, it seem there is no jumper to set RCA or Balanced XLR? Hmm, it takes me sometimes but still cannot figure out how the RCA/Balanced XLR switch works, there are 4 wires initially from the switch, white yellow white yellow, the connections very complicated even I check back my pictures, do I need to install jumper ports on nearby the bridge port?
(http://www.audiocircle.com/image.php?id=159641)
(http://www.audiocircle.com/image.php?id=159642)
Can give me clear details how to use RCA input only? For max gain, I just need to desolder left and right gain jumper parts, then put a jumper right?
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Hey just wanted to put this here. Im selling my CDA-254 with 12vdc/battery power supply on the marketplace if anyone is interested.
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"...
This amp does not use the ICE chip or the hypex BTW. Tripath is not a Class D amp it is Class T.
steve
Just nitpicking, steve ... don't take it personally ;-)
Posted for clarity in case someone searches this thread for information:
Tripath is a Class D topology; they do use a unconventional driver circuit but they use a Class D output stage (which is what amplifier class designations refer to).
"Class T" is a marketing term, a registered trademark of Tripath, Inc (and owned now by whomever ended up with their IP after bankruptcy), so any reference to it should be:
Class T®.
There is no actual Class T as recognized by bodies like the Audio Engineering Society (AES).
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Hi guys, recently doing some experiments, and cut off some wires, but dunno how to put back, I would like to configure to use RCA single ended input only, but I'm not able to figure how to, here's the pic, it seem there is no jumper to set RCA or Balanced XLR? Hmm, it takes me sometimes but still cannot figure out how the RCA/Balanced XLR switch works, there are 4 wires initially from the switch, white yellow white yellow, the connections very complicated even I check back my pictures, do I need to install jumper ports on nearby the bridge port?
(http://www.audiocircle.com/image.php?id=159641)
(http://www.audiocircle.com/image.php?id=159642)
Can give me clear details how to use RCA input only? For max gain, I just need to desolder left and right gain jumper parts, then put a jumper right?
Please take a look on the picture. It shows RCA Input connected with Jumper in place for Full Gain.
(http://www.audiocircle.com/image.php?id=160809)
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1. Replace R/C Power supply of input stage by external low noise power supply !
(https://image.noelshack.com/fichiers/2018/29/3/1531943116-replace-r-c-power-supply.jpg)
=> That's right ?
2. Replace couple capacitor between Input Stage and IRS2092 by Audio Caps (Elna Silmic II)
=> What are capacitors numbers and the value and voltage of these ?
3. Replace Bootstrap Capacitor of THAT1200 by Audio Caps (Elna Silmic II)
(https://image.noelshack.com/fichiers/2018/29/3/1531943437-condensateur-cms-polarise.jpg)
=> What's the value and voltage of this ?
3. Upgrade all on-board supply capacitors by Low ESR Types with higher capacitor values (Panasonic FC /FR)
=> Ok
3. Replace all Resistors in Signal Path (4x 100 Ohm / 2x 3.3KOhm) by high graded resistors (Texas Components ASM2575)
=> 2x 3.3KOhm (R32 and R75) + 4x 100 Ohm (R78, R79, R80 and R81)
=> That's right ?
Bellow a picture of my latest setup with external Power Supply, additional Transformer and motorized ALPS Pot as Volume Control :
I highly recommend an external Power Supply, it's not that much difficult to implement. I could never live without again :)
=> Could you explain to me how this one is built ?
=> What's the difference between original power supply with news low ESR capacitors and your power supply ?