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
Kijank, I want to thank you for taking the time to unmask this pretender, Cplloms.

I am just a listener. One critic of class D, and tube lover extraordinaire, told me recently he can hear class D sampling. When I questioned how, he used the example of upsampling DACs vs. non-upsampling. I had to agree with him on the difference of those two. I also had to tell him I cannot hear any similar sampling distortion in the ICE amp I am using, H2O.

From what I think I understand from what you said, ICE modules do not sample. Am I correct here? That would explain why I do not hear anything.

I can put my ear directly to my drivers and hear nothing but pure music. There is no noise.

Another question I'd like to put to you is whether you have found everything inserted into the best class D amps has to be as faultless as possible?

Thanks again for your input.
Kijanki, FWIW your comment:

My Icepower being smallest of the series has peak current 11A. Larger 201 has 20A and largest 501 has about 50A.

has an ambiguity. The 50A peak current you mention- is that the output? Assuming a 1 ohm load and 50Amps, that's 2500 Watts. Assuming a 2 ohm load that's 5000 watts... So into what impedance does this spec occur or is it 'marketing'?
Kijanki, thank you for your clear explanation. I'm affraid Martin Colloms should go back to school. If he is not chicken he should also give his response! :)

Chris
I paired the MBL 101Bs with the Spectron Musician III signature. It was great. So good in fact. that a friend purchased both items from me and is thrilled. I moved on to the MBL 101Es and MBL 9008 mono amps. But, for the money, the Spectron/111 combo is tough to beat. If you get 2 and run them balanced in mono you ought to really have something special.

David
Hmm...
I had a chance to audtiton Jeff Rowland Model 302 with Synergy IIi preamp and did not like it.

It sounds like comparison between LCD and Plasma displays. Rowland is average LCD and very good solid state or tube amp is Pioneer Kuro HD Plasma IMO.

BTW, here a a link to Italian Audio Review Jeff Rowland Model 312 review with full measurements:

http://www.audiogamma.it/upload/prove_pdf/AR274%20-%20Jeff%20Rowland.pdf

Just check out 10kHz damping factor...