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
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.
Hi Vince, excellent point about dwindling NOS tubes. . . eventually these animals should be declared endangered species and given a modicum of protection against careless use by heartless audiophiles!

You have good chances of being correct about the future of class D amplification. Yet, it is a lot safer to study evolution with hindsight than using foresight. . . . at least for old and crotchety 'secular humanists' like yours truly. Perhaps 65 millions years from now some bookish techno-paleonthologist will examine the then famous Silicon-boundary layer in ancient petrified garbage dumps an discover an explosive growth in the fossil record of switching amplifiers. And perhaps a fossilized 'organism' with an especially unusual body plan sporting a transformerless combination of pre-silicon B-300 tubes and primitive switching amplification modules will be uncovered. . . a brand new techno-phylum will be assigned to it. . . and the specimen will be named Hallucigenia Atmaspherii by its discoverer--an incredibly distant descendent of Aloysius Qwantz Schmaltzenstein Gavronsky.
It's kind of silly to have to drag out the "dwindling supply of NOS tubes" argument. There are more tube manufacturers than 10 years ago thanks to the music and hifi industries, and MANY manufacturers (basically all) use current production tubes and get excellent sound from them.

Yes, you can likely improve the sound with some pricey NOS tubes, but the costs are going way up and you tend to simply change the sound with differing tube brands and vintage, not always for the better. I have a pretty good stash of NOS tubes, but I could live just as happily if my rig was running current production stuff.

RFG