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Class-D amps - a different re view

Martin Colloms, the editor of HiFi Critic (ad-free mag from the UK) have recently published the review of several different Class-D amps, together with an in depth technical analysys and measurments.

His conclusions were not favourable, to say at least:

"I regret that not a single model merits unqualified recommendation. Price is not the issue; the poor listening tests speak for themselves. (...)
At present we have to take the prudent view that good sound might be possible from switching amps, but we haven't heard it yet."

BelCanto REF1000 (ICEpower) - score 10.5 pooints
"The ICE power module used has a dependable reputation, and the design is well built and finished as a whole. While I would not suggest that you shouldn't try this amp, on sound quality grounds alone I cannot recommend it for audiophile use."

Channel Islands D100 (UcD) - score 13 pooints
"While I have reservations about a number of aspects of sound quality, and advise personal audition, given the solid lab results (...) the overall performance and the moderate price, these CA Audio monos do make it to the 'worth considering' cathegory."

NuForce 8.5V2 (proprietary technology) - score 9 pooints
"Yes, the price is good for the power output. Yes it's pretty, light, small and runs cool. However, the sound quality simply does not justify recommendation." (on top of that the NuForce amp measured very poorly - Elb)

Pro-Ject Amp Box (Flying Mole) - score 5 points
"I'm sorry to say that Project (...) was a real disappointment in the listening tests, and can't be recommended."

Just as a point of reference, recently reviewed Krell 700CX scored 100 points, CJ Premier 350 - 110 points and ARC Ref 110 - 135 points.

At least someone have had the balls to say it. This is why HiFi Critic is THE mag to subscribe.
128x128elberoth2
audioperv
18 posts
 
"FWIW there is no audible difference between a damping factor of 60 and that of 1000..."
Thank you Atma for the information Much appreciated.

"the problem with most solid state amps is. . ."

Right on MRT. I should also like to add:

"the problem with most tubed amps is. . ."
"The problem with most OTL amps is. . ."
"the problem with most switching amps is. . ."

Or in other words:

the problem with most amps is. . .that in every technology, there are inherent problems, and not all engineers know how to address them.
gregm
3,399 posts
 
Audioperv:
that in every technology, there are inherent problems, and not all engineers know how to address them
Hmmm, may I paraphrase? "In every topology there are inferent problems, and all engineers (worth their salt) have adressed them, choosing one compromise over another." Cheers.
mrtennis
3,295 posts
 
hi audioperv:

the objections i raised are reasons not to want to listen to solid state amps. what ever faults lie in the design of tube amps do not deter me from wanting to listen to them.

subtractive coloration of some tube designs does not bother me. additive colorations of solid state amps is annoying.

i have heard class d amps at ces many times. i have no desire to listen to them on panel speakers.

ralph, what say you ?
guidocorona
4,298 posts
 
That's interesting MRT. . . roaming the halls and suites at RMAF I was actually dismaied by how so many tube designs at all price points were trying to out-solid-state solid state designers. . . and succeeding admirably, tizziness (additive flaw presumably) and vanishing harmonic structure (subtractive flaw I presume) included. The difference apparently is that. . . if such flaws are heard on classic solid state or switching technology--which I did hear in spades as well--the problem is with the technology or the design, but if any apparent 'solidstatification' of tubes is perceived, the culprit is supposed to be only the wild and utterly uncontrollable acoustics of the suite. . . go figure!
guidocorona
4,298 posts
 
Oh yes, let's not forget that flabby bass, or conversely that magic vanishing bass, or that sudden hard clipping: these are apparently more artifacts that plague room acoustics where some tube designs are featured. . . Yet, if switching amps or solid state amps are present instead, 'tis always safe to point an accusing finger at the designer.
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