[corndog71]

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.

[Feanor]

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.

[roymail]

Thanks for that evaluation.  I'd be interested in what speakers it's feeding and their impedance.  Nice job and much appreciated. 

[Feanor]

Thanks for that evaluation.  I'd be interested in what speakers it's feeding and their impedance.  Nice job and much appreciated. 

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.

[roymail]

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!

[hottuner]

O-M-G thought I'd never reach the end of the thread! I've been obsessed! Literally spent days getting here.

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...

[Feanor]

Folks,

My final review of the SDS-258 as posted at Audio Asylum ...

http://www.audioasylum.com/forums/amp/messages/15/157758.html

I think its a positive review. 

[wushuliu]

Folks,

My final review of the SDS-258 as posted at Audio Asylum ...

http://www.audioasylum.com/forums/amp/messages/15/157758.html

I think its a positive review. 

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!

[hottuner]

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!

[toxteth ogrady]

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

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.

[guest1632]

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

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

[toxteth ogrady]

Anyone try the Grounded Grid preamp with these amps? I think I'm going to build one and try it out.

[roymail]

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.

[corndog71]

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!

[toxteth ogrady]

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.

[soundnoob]

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!

[srb]

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

[nwboater]

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

[soundnoob]

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.

[usp1]

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.