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.
elberoth2

Showing 4 responses by branimir

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...
"Branimir, class D is not going to suit everyone."

Muralman1, that is the truth.

Interesting point that you mentioned in one of your previous posts in this thread is about power supply in Class D amps. All Class D amps that I personally audition features switch power supply(Rowland 302&201, Nuforce REF9V2) so, could this be a reason for sound signature of this amps in your opinion?

Your H20 amps use analogue power supply AFAIK. New Mark Levinson No.53 will also use Class D modul with analogue power supply...
I agree with Elberoth2.

I personally audition Jeff Rowland Model 302/Concerto Pre combo and it was not up to my liking... To my ears both Krell Evolution One/Evolution Two and ARC HD220/REF3 combos sounded better. Krell was more extended and top and bottom with tighter and more defined bass(it also want deeper), it was also way more musical to my ears. ARC was warmer overall with bigger soundstage(almost Krell size) and more midrange presence(specially on male vocals).

But, honestly Jeff Rowland combo was not that bad either, in fact Model 302 sounded much better then Model 201. Rowland 201 sounded better for me then Nuforce REF9V2 so go figure...

Speakers were Avalon Isis and Escalante Fremont. Both not very demanding to drive...

I guess that for both Elberoth2 and me current Class D(switching) amps are not our "cup of tea"...

What I truly do not understand is how "die hard" are Class D fans...
Guido,

Honestly, I would like to truly love Jeff Rowland sound. New Jeff Rowland Criterion preamp(will be fully introduces on CES2008, double chassis, battery powered!) with Model 301 monos(new version with 600w/8ohms) could be very nice solution despite big price tag...

BUT, is it really better then simillary priced solid state offerings? For example:

-Hovland Stratos/HP200
-Krell Evolution One/Evolution Two
-Krell Evolution 900/Evolution 202
-Vitus SM-101/SL-100

Interesting thing is that Hovland and Vitus use UI core power supply transformers, not toroidal one like Krell. Both Hovland and Vitus claim that these UI Core transformers are much, much better(of course, they are costum mode for both manufactures and are really very expensive) then toroidal one...

So, development in "normal" solid state world in still in progress...