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
Hi Deshapiro, very interesting, please tell us more once your eval is complete. In particular Spectron/Boulder comparative findings about extension/delicacy of treble, bass extension/tunefulness and control, overall harmonic development and decay across the range, low level microdynamics. staging, hall ambiance, headroom.
I'm happy that John & Toni are finally getting the recognition they deserve. They are a class act! I had the Musician II, which I had some problems with and they were very accommodating and made me upgrade to the then new Musician III for a very good price. I guess after all the good press that the Musician III SE is getting ,it's time for an upgrade! Damn, I got to stop reading these forums.
hi eldartford:

an opinion is very subjective. i don't think that popularity or the satisfaction of other owners is a reason to buy something.

as has been said many times, your ears are more important than any opinions.

the only question is, how to minimize the number of components to evaluate.

i'm afraid one should audition every component in one's price range, depending upon preference for, say, tubes or ss.
Guidocorona - Hi-Fi critic is wrong on all 17 points he presents. Class D produces only about 1% of the carrier (usually 0.5MHz) on the speaker and practically no switching noise (zobel network). My Rowland 102 is directly under TV - no problem. At 0.5MHz speaker cable needs to be 150m long to be 1/4 wave antena. Class D Amps cannot be "unstable" (big advantage) because by definition they oscillate (analog modulator). They are in reality high power sigma delta modulators. It is important to realize that most of modern dacs (sigma-delta) are working on principles of class D (PWM) - same with SACD (PWM at 2.8MHz). I read a little bit of Karsten Nielsen doctorate work on Icepower (University of Denmark) - very interesting.