[I.Greyhound Fan]

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.

[.Marcus.]

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..

[flavo]

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

[I.Greyhound Fan]

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.

[flavo]

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.

[justd]

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.

[Nick77]

Only aware of Hypex Ncore at about 3+ times the cost.

[.Marcus.]

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

Manufacture Data Sheet

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 circuit design.

Regards
Marcus

[yardbird]

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

[krikor]

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

[Nate Hansen]

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.

[santacore]

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?

[Nate Hansen]

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.

[Nick77]

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

[john dozier]

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

[AmpDesigner333]

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

[matt_garman]

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.

[steve k]

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

[sealkojac]

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.

[rvsixer]

Bad news when placing an order just now  :

Coupon code "ACircle" is not valid