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 9 responses by audioperv

Larryi, on second reading, the 302 is a stereo amp. You seem to be describing monoblocks. Do you remember their very approximate physical size? JRDG has 3 monoblocks in its 1st gen ICE offerings: 201, 501, 301.
"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."

Yes, that is prudent a view indeed. It looks to me like the author seems to have sampled a narrow mixture of usual suspects built to a narrow pricepoint, and not necessarily the latest versions of at least one of them. Obvious holes in the samples are the Spectron Musician 3 Signiture sitting towards the top of the price sampling range, definitely worth a listen. . . or 2, or 3 times )(see Neil Gader's review update in TAS 176); JRDG has a lineup of class D models ranging from $4K to $30K with a proportionally wide spectrum of musical performance characteristics among which the 312 remains my current favorite amp of any class; Genesis has models ranging from under $5K to over $25K; Kharma has 2 models if I recall, one set of monoblocks for under $10K and the other reference level set costing perhaps $40K or so; Mark Levinson is preparing a set of reference level monoblocks in the $40K range. . . . I bet I haven't even scratched the proverbial surface. I venture to suggest that the author may want to consider broadening his reviewing sample starting today. . . he may find some results of current implementations delightfully surprising. . . As for tomorrow, it is in the future and as such is not worth talking about.

Guido D. C.
Atmasphere, which one was in your view the sonically 'best' switching amp you heard 3 years ago?
My admittedly very modest experience is that -- like tubed or classic solid state gear -- tubed amps can sound exceedingly different.
"and luck only determines the sound of the system- no doubt why so many want to know which class D sounds the best!"

Good point Ralph, perhaps that's also why I would really like to know what solid state and what tubed amp sound the best, . . . because with all those technological constraints, compromises, and underlying limitations out there, regardless the underlying technologies, it is my own ever-so-limited experience that results are more often than I would like less than stellar. . . but then, I am admittedly a little hard to please. . . regardless of technology.
"There is a common myth in audio that there is no 'best'. However, the English language tells us that it does exist- else the word 'best' would be meaningless."

Interesting Atma, I did not know you were a nominalist. . . . I thought that particular philosophy had been abandoned a few hundred years ago. By the way, I do not own a switching amp. My amps are 20 years old solid state class A/B JRDG model 7M monos.
Hi Larryi, I concur with a lot of your findings on the 1st generation Rowland 302 amp. I heard it twice at some length at a dealer, but it was not stirring my imagination at all. . . polite to a fault. Totally different experience with the 2nd generation 312 amp from Rowland. I heard it at RMAF both last year and in 2007 in the fabulous Soundings / Rowland / Sumiko suite, driving a pair of Vienna Mahlers. I have enjoyed the sound of the whole system sooo much. . . I have ordered a pair of Mahlers. . . can't afford a JRDG 312, at least this year [chuckles!]. By the way, the system configuration was identical this year and last. . . but last year the system was set up in a much better suite at least twice as large as this year's. Yet, in spite of their acoustic challanges, this year's two little suites of Soundings (of Denver, Co, 303- 759-5505) still were in my opinion two of NOT TOO MANY RMAF suites where I met music that unconditionally moved my soul . Guido D. Corona
Chaz801, in the same general price range as the Nuforce and Red Dragon, you should consider also having a listen to the Spectron Musician 3 Sig, the H2o, and to the Rowland 501 monos. You may find they sound somewhat different from one another. You may love one or more of them. . . or you may very well hate them all. If I am correct, some form of at home auditioning may be available at least from Spectron.
Atma, I am glad you are withdrawing from "it can be expressed in words, therefore it must be true" kind of logic. As for distortions, I hear a lot of distortion in most systems, regardless of underlying technology and -- I should add -- regardless of price point. Yet, whereas my ears may be 'bleeding' when listening to a particular system -- or conversely I may be dying of boredom -- I notice audiophiles as hardened as I am, experiencing true rapturous epiphanies around the very same setup. Am I unable to grok true audioheaven? Or are those other audiophiles getting a little case of 'The Emperor's New Clothes"? Or should we perhaps accept somewhat soberly that we all may be seeking subtly differing things in our private quests for audio Nirvana?
"FWIW there is no audible difference between a damping factor of 60 and that of 1000..."
Thank you Atma for the information Much appreciated.

"the problem with most solid state amps is. . ."

Right on MRT. I should also like to add:

"the problem with most tubed amps is. . ."
"The problem with most OTL amps is. . ."
"the problem with most switching amps is. . ."

Or in other words:

the problem with most amps is. . .that in every technology, there are inherent problems, and not all engineers know how to address them.