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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
elberoth2's avatar
elberoth2 OP
1,223 posts
 
What can I say, sadly, I am probably not a member of the species 'Homo sapiens', because 'tubey' distortion do not sound at all priviledged to these poor ears.

You are going to the extreem here. Not all tube amps sound "tubey" and yet, they still have certain distortions characteristics that are more benign to human ear.

To my ears, a good tube amp still sounds much better than current Class-D designs. I have owned BelCanto eVo 4 amp, I have evaluated both ICEpower design (ASP based) and, just recently, the latest NuForce 9V2SE monoblocks IN MY SYSTEM, and all I can tell you, is that the difference between them and my current ARC Reference 110 is so HUGE, that it is almost laughable.
mrtennis
3,295 posts
 
all amplifiers have some consistent sonic characteristic which is detectable after audition, for some period of time by a well-trained listener, given a variety of recordings.

if amplifiers had inaudible levels of coloration it would be almost impossible to distinguish one from another.

what does this mean ? find an amp that you like and the quality and quantity of imperfection should not matter.
guidocorona
4,298 posts
 
Of course you are correct, Elberoth2. As I said earlier, for any technology there are stereotypical distortions, brand typical distortions, and atypical ones. Where I have problems is characterizing distortions in tube gear as 'benign' as a whole. At RMAF I ran out with 'bleeding ears' of as many tube suites as I did from SS or class D suites. Tube amps sounding classically 'tubey' were definitely a minority.

As for ARC Ref 110, I agree completely that it--and the rest of the current ARC lineup--are darn special amps; I own a Ref 3 and in general I love the new ARC sound; The only reason why I will not even consider a Ref 110 is because. . . tube amps generate too much heat in the ghastly Texas Summer. What switching amps have you evaluated/contrasted against Ref 110 besides Bel Canto Evo 4 and Nuforce? One of the problems I can see with some class D marketing is a tendency to hyperbolic generic claims of the type. . . 'X crushes SS/tube sacred cows costing 4 times as much'. The problem is that such sweeping uncautious claims expose a product to equally uncautious counterargument such as yours, where you contrast a brand new $10K tube design (Ref 110) with a 5 year old $4K switching design (Evo 4) and a current $5K switching design (Nuforce Ref 9 SE) only to apply the old induction step and produce a slightly brave conclusion. Seems to me you are comparing one orange with two clementines. . . and concluding that all oranges are . . . heavier.
muralman1
1,527 posts
 
ARC 110? You mean the ones I heard triamped on panel speakers run active? Oh well, to each his own.
elberoth2's avatar
elberoth2 OP
1,223 posts
 
(...) class D marketing is a tendency to hyperbolic generic claims of the type. . . 'X crushes SS/tube sacred cows costing 4 times as much'

You hit the nail o the head, Guido. This is the reason I gave this example.

Class-D ppl are trying to persuade everyone that Class-D amps are SOTA. They are not. They may compare favourably to other SS/tube designs in their price range, but only provided that you like this kind of sound.

As I said before - I have owned and evaluated varoius class-D designs, and they were quite good for the price, but I never considered them to be SOTA or significantly better than competing SS/tube designs.

I just wanted to make it clear.
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