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
>>10-31-07: Mrtennis
a class d amp will never sound like a vintage tube amp.
Mrtennis

10-31-07: Dazzdax
Mrtennis: And a vintage tube amp will never sound like a class D amp
Dazzdax<<

Wow, this is really deep thinking. Maybe you guys should take the MENSA test.
Hi Atma, I do grant you that these show hotels seem to have lucky spaces and very very unlucky ones. Trying to Tame the wildness of some suite I am sure must be a frustratingly thankless task. . . . perhaps as easy as herding cats?! Is one of the problems that you manufacturers end up having to select a room from a floor-plan without having the opportunity of sonically testing the space ahead of time? Perhaps RMAF organizers should be encouraged to assign some of the odder sounding rooms to the admittedly few static displays. . . do not need good acoustics to select LPs from a bin, after all.

Back now to the discussion of artifacts and stereotypical audible flaws in switching amps, without here pointing fingers to models/brands in particular, I observe that that there are a number of such amps today that do still sound stereotypically 'digital' to a slight or greater extent. Among 'non stereotypical' switching amps, I have already waxed poetic on this and other threads about the two switching amps that I truly like as of the end of 2007. I should also point out though, that I have heard switching amps that did not seem to have any audible 'digititis', and still I was not able to like. In one particular case, the sound of one seemed overly dark to a fault, almost if the designer were attempting to overcompensate for expected stereotypical flaws. not sure if I was having a bad audio moment or I was perhaps in a 'dark' sounding suite. I did discuss the device with other audiophiles that have listened to it under various circumstances and received confirmation of my cursory impression.

As you said, the switching technology is young and evolving rapidly. It's certainly worth watching with an open mind. It is equally true that it may in the end turn out into the proverbial flash in the pan. . . and 10 years from now, instead of having grown to broader maturity, it may be simply remembered as a valiant experiment. We will have to wait and see.
Guidocorona, just what will be the standard, if class D never ascends to superiority? Solid state, with it's manufactured. "Body," and smeared highs?
Or is it to be NOS tube amps, with their rapidly dwindling stocks of tubes, and their cloying delivery, the worst of which sound gooey with caramel?

My class D amp. augmented with the perfect preamp. is deeply detailed. hugely dynamic, sweetly extended, and lifelike, superseding every SET or any other tube system I have heard. Solid state might as well skip the party.

B&O has announced a new generation of digital power supply modules that purport to have have distinctly improved stats. Someday their modular amp will succeed in making even the now so necessary analog power supply superfluous.

The future is here. It's just the learning curve on how to implement class D amps that is in it's infancy.
high muralman:

the alleged superiority of class d over tubes or tubes over class d cannot be confirmed unequivocally.

i cannot corroborate your perceptions, you cannot confirm my perceptions and what is better or worse is a matter of opinion. we can agree to disagree.
hi guidocorona:

i have attended ces shows since 1992. i have yet to hear a class d or solid state amp that i would want to own.

i have not heard any class d amp i would characterize as dark. of course the sources that i used to evaluate stereo systems were probably different from what you auditioned.

i am still curious as to which brand(s) you found "dark" sounding. in addition, i am also interested in the names of other components and stereo systems which you consider to be "dark" sounding.