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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.
128x128elberoth2
larryi
4,126 posts
 
The Rowlands I heard, were huge monoblocs (what happened here to compact size of Class D?). I have not heard the later iteration of this design. I am not surprised that it is much better. Typical of any relatively new technology is that the learning curve is pretty steep at the beginning.

The issue will be where that curve tops out and how long will it take to get there. It is really impossible to know now what the ultimate capabilities of any technology will be. Take phono reproduction as an example. To me, there is NO question that modern cartridges keep getting better. On other fronts things are not so clear. Some of the best speakers I've heard use drivers and other components from the 1930's and so very old amps are absolutely amazing when hooked up to modern front end gear (Western Electric amps, Brooks, etc.).
chaz801's avatar
chaz801
77 posts
 
Thanks Audioperv
For the recomendations.
I will check out those amps listed a little closer.
guidocorona
4,298 posts
 
Thank you larryi, the only larger class D monoblocks Rowland makes are the model 301. Here are the dymensions:
10.6" x 15.5" x 18.3". Weight is 80Lbs each.  
One probs they have is to have a relatively low damping factor of only 60, which is likely to create problems on low impedance speakers. Model 312 has damping factor of 1000 instead.
Does this size sound right. . . not exactly huge. . . actually less than typical full size amps. They are rather narrower than the typical amps. Cost is $30K for the pair. I have not heard them so I can't comment on their sound. JRDG makes much more compact models like the 501 and 201. The little ones are built to a price point and are not in the same league as the 312. I wish I have heard more switching amps than I have. For the moment my favs are the 312 and the Spectron Musician 3 Signature. It is also worth pointing out that I heard only a very unbroken Spectron this far on a system that had a few other challenges. As such I can't make a real comparison with 312. . . but what I heard was extremely PROMISING and is DEFINITELY worth further serious auditioning.
jw94055
125 posts
 
Guidocorona, I have a custom made 12au7 pre amp and an Audiosource Amp Seven T. This is a Tripath based amp, 200watts at 8 ohms. Got it off E-bay. The rumor is Audiosource had problems with FCC and radio interference. I hear nothing but black quiet from mine, even with the tube pre. It has a large torridal transformer and probably the Bel Canto Evo would be the closest well known equivalent. I wanted to try the Class D technology after reading reviews that one could have SET sound with high power output. All I know is that my combo of tube and Class D produces a musical experience that is excellent. I can not comment on the differences between Nuforce, ICE and Tripath as I have not heard them compared head to head. I have heard Class D systems without tubes and my system with tubes and IMHO, mine provides a superior sound. I have no interest in having a system using Class D that doesn't have a tube pre-amp and I can not imagine a system now that doesn't have a Class D power amp. Rest of system:Harmon Kardon CD player, Scott Nixon DAC and custom speakers using the full size Heil ATM, Peerless Mids and sub-woofer using KEF bass drivers. Good listening.
atmasphere's avatar
atmasphere
11,979 posts
 
I am glad you are withdrawing from "it can be expressed in words, therefore it must be true" kind of logic.

From my own perspective I have merely been dealing with what is.

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?

I think 'The Emperor's New Clothes' is a powerful issue in audio, perhaps because humans are more visually oriented than aurally. We get told that something is state-of-the-art (like a Yamaha receiver) and we pay the money and are so investing in the belief. But knowledge and belief are not the same thing despite how as humans we persist in trying to live our lives as if they *are* the same!

So the result is a disparity, I think the result of one individual listening with their ears as opposed to another listening with the filter of 'status symbol'. How many times have we been sold 'new' as 'better'?? I am not saying that because class D is new that it is worse, nor am I giving it a whitewash: just from reviewing the comments of this thread, there is quite a range of experience. I think in the end that fact that an amp is 'class D' will not be enough for one to judge what it sounds like. Ultimately if an amp is sounding really right, it should sound like any other amp that is also sounding really right, shouldn't it?
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