How do Digital Amps Mfrs. compare in sound?

I was able to spend a few weeks directly comparing a pair of ICE-based monoblocks with a Mark Levinson ML-9. I found the ICE amp to be a very good amp overall, with no obvous weaknesses. I find it quite puzzling that there is such vehment opposition to "Clas D" from people who have either never done a direct comparison or only listened in passing years ago.

Truth be told, I returned the ICE amps because of two minor things my friend and I both noticed. One was that the ML-9 had tighter bass. No, the ICE amp wasn't "boomy" by any means. I'd say the ML-9 probably has tighter bass than most SS amps, so this shouldn't be an indictment of class D.

The other reason was that there was a slight veil of the high frequencies, as compared to the ML-9. I want to emphasize that it was very subtle and not noticeable most of the time. If I had not been doing a direct comparison, I probably would not have noticed it. Judging by the popularity of the various ICE amps, I'd say most people do not notice these issues.

Btw, based on a few days of diect comparison between the ML-9 and a Spectron Musician III SE Mk 2, I'd say the Spectron compares very well with the ML-9. My friend and I are not able to say for certain if there is or isn't high frequency veil, and the bass extension may be slightly better with the Spectron. It weighs 20 lbs less and uses less than half the electricity of the ML-9, which to me are "good" things. I think I may have found a keeper and can finally return my father's ML-9 :)

Nospam, which class D amp suffered of the slight loose bass problem? and on what speakers? Thanks, Guido

Nice thread.

The comparisons of specific Class D amps is of great interest to me.

My local dealer sells the small Rowland Class D stereo amp along side Audio Research and Rogue tube amps. I need to go give a listen sometime soon and hear for myself.

Guido,

I want to reiterate that the class D amp did NOT have "loose bass". In fact, I would not be surprised if its bass is tighter than most other amps.

The ML simply was a little "better". That's it.

I have not had a chance to compare all the various ICE amps out there, but I am a bit dubious that the various tweaks different manufacturers claim to do actually make much of an audible difference, especially as far as the veiled highs go. That is something that seems to be an inherent problem with the ICE modules.

Has anyone been able to compare different ICE amps?

Thank you Nospam for the clarification. I would still like to know which ICEpower based amp you evaluated. Your assertion that recent production ICE amps have veiled highs across the board is an interesting proposition which I have not been able to verify. There are certainly some ICE-based amps that I heard at shows which sounded shrill to my ears, like there are SS and even tube amps that I feel the same about. There is one amp (Red Dragon) which I perceived to have limited yet ragged treble. On the other hand, I did not experience these to be generalized problems across all ICE amps.

I am currently evaluating a pair of Bel Canto Ref 1000 Mk.2s, which I experience to be extended in the treble and harmonically textured without sounding 'in my face'.

It is worth pointing out that ICE modules are not amps per se. . . they can be used to create very subtle sounding amps, or very basic ones, depending on the designers preference and philosophy. This is really the same as designing amps around 64550C or KT88 tubes. . . you do not tweak around these tubes. . . you use them as component pieces of a whole.

To give you an idea of the sonic differences I perceived within a single manufacturer, here are some capsule observations about a few Rowland amps based on ICEpower:

201 monos -- graceful but a little matter of fact and can run out of steam quickly on congested passages, in which case they turn a little 'glassy', particularly in the treble. They are fine on smaller speakers (Maggie 1.6, Vienna Baby grands), but run out of steam quickly on larger ones (Maggie 3.6, Vienna Mahlers) even on very moderate 'forte' of a chamber music piece.

501 monos -- No problem with power and authority here. . . no chance of them clipping and sounding glassy, even on difficult loads like the Vienna Mahlers. On the other hand, 501 may not yield the ultimate harmonic texture, nor the ultimate low level nuance, as such it is fair to say that they do not always draw me into the music.

302 stereo (withdrawn) -- same power/authority as the 501, but with grace and refinement in low level harmonic texture, giving the impression of an extended and musical treble. With this amp I also noticed a great deal of micro dynamics, which yield very musical string vibratos, even on pianissimo. Where this amp did not quite shine was paradoxically in macro dynamics, which IMO did not sound quite as extended as the 501, giving me an overall impression of 'politeness'. It draws me into the music somewhat, but does not quite excite me.

312 Stereo (current model) -- All the positive traits of the older 302, but with excellent macro dynamics and transient response, which make for me this amp both musically subtle, involving, and exciting to listen to. 312 is one of my very preferred amps, regardless of underlying technology. I have written a short article on the 312 for issue 188 (December 2008) of The Absolute Sound. It is a sidebar in the Vienna Mahler speakers review. . . I believe on page 88.

Hope this helps, G.