Oh how I wish Class D amps ...

Ralph do you think that a digital amp will ever be able to capture what tubes can do;personally I do not;but it is fun to listen and compare.

One thing to be careful about is reliance on simple measurements such as frequency response, or THD.

Ideally, a measurement such as EVM that is used in the wireless industry would be a more appropriate measure of the quality of the amplifier.

One example of the problem with measurements like THD is that its easy to crank up the amount of feedback to create good THD measurements. However that will smudge out the transients in a signal and cause a dull lifeless sound. That is why on Class A/AB designs the better sounding amps tend to be the ones with zero global feedback.

Going back to Class D designs, my experience with several ICE amplifiers has been they tend to distort the transients - particularly the quieter signal levels. Perhaps this is due to the deadband issue that is described on the Mark Levinson website - I don't know. Its a type of digital nonlinear effect and so can't be described by simple 2nd order/3rd order products.

I recently got a Spectron digital amp, and haven't noticed this issue at all so far, although I have been using it in balanced mode, which perhaps serves to reduce the effect to the point of not being noticeable.

I am also intrigued by the idea of the Devialet amp - which combines class A with a class D to capture accurate transients - although I have yet to hear one.

Dan92075, class D amps need patience to bring out their best. Or, you can copy my recipe. ;-)

I have found what you say is the opposite of truth. That is, A/AB amps, with zero global feedback, distort the transients, not the best class D amps. The well tuned ICE amps will have no audible distortion, and will dig deeper into the CD than ever thought possible.

I think I have been more than patient with ICE amps, including changing around my interconnects, power cables, speaker cables, even preamps to get the ICE amps to sound better! And tried several ICE amps to boot!

Don't get me wrong - the detail was not poor by any means - it was fairly good overall - but somehow there was something missing on higher frequency transients that created an ever-so-slight digital, plasticky sound.
When I did a comparison between the state-of-the art latest Ice amp (Bel Canto 500m) and a 8 year old Sim Audio Class A/AB amp with zero global feed back - there was simply no contest. Especially at low volume levels I found the Bel Canto would compress and sound anything but audiophile, whereas the SimAudio operating in Class A mode managed to retain most of its nuances, just at quieter levels.

I honestly don't know what else I could have done to bring out the best in the ICE amps. . . if you have a special recipe I sure would be interested to know! :)

Ok, Dan92075, what CD players did you try? On my system all oversamplers failed miserably, especially in their highs. I use a 47 Lab Flatfish transport and a much improved Audio Note DAC. I cannot stress how important that is.

All speaker cables that are not nearly bare will flood the signal with noise. All power cords must be fully insulated against EMI. Saying that, only my speaker cables made the ultimate difference for me. They are ultra thin metal ribbons. I use Speltz ICs because what he says on his site is right on.

None but one solid state preamp will do their best with class D. The rest will diminish the music. Tube preamps do much better. It is a mismatch thing. There is one solid state preamp made especially to match class D, and that is the H2O Fire preamp. That is what I use. It will kick ass the sound into a music that shows flow and big impact.

I can go into great detail, but not here. Drop me an email if you are still interested.

See my friend's comments above.