[Nick77]

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.

[praedet]

I am using a 15 amp fuse on my battery powered SDS-254...

[corndog71]

I use a 6 amp fuse for my SDS-258.

[roymail]

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.

[corndog71]

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.

[jseymour]

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.

[guest1632]

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

[jseymour]

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.

[matt_garman]

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:







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

[mcgsxr]

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.

[roymail]

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.

[mickster1972]

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...







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 ...

[maxitonus]

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.

[roymail]

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!

[krikor]

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 

[firedog]

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?

[maxitonus]

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.

[wushuliu]

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

[roymail]

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.

[wushuliu]

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