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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
ar_t
165 posts
 
The answer is "yes", but.........boy, am I going to step into it here..........the module that one would expect to be best for that particular speaker, based on its low impedance and power requirements, really doesn't work that well in that appication. (There is a reason that I know that answer.) Long story, and perhaps best not dealt with in detail in a non-technical forum.

Anyone desiring a more detailed answer should contact me privately.
muralman1
1,527 posts
 
That is a good question. Looking into it, B&O does employ class AB amps for mids and highs in their Beolab 7. While their flagship speaker, the Beolab 5, uses all 1CE amps. It's quite a mystery. I sent them a query.

http://www.bang-olufsen.com/UserFiles/File/Products/Technical%20Specifications/BeoLab5_en_na.pdf
muralman1
1,527 posts
 
Mr. Tennis, my system sound has evolved from one matching your experience to one now that is on all day long.

It didn't take me long to realize there were things you can do to bring out the best results. A remedy for your complaint, "solid state amps and class d amps sound uncivilized, raw and aggressive," is do not use over-sampling CDPs, and do not choose a digital power supplied module.

The ribbon speaker cable I switched to worked wonders as well. On the whole, music is dynamic, yet relaxed.
guidocorona
4,298 posts
 
Hi AR_T, please try post here a super simplified version of the explanation as you know it.

MRT, I am terribly sorry to learn about your physical and spiritual suffering caused by panels, solid state, switching amplification, and other such admittedly uncivilized, raw, and aggressive sounding technologies. In a sense I deem myself fortunate that -- being somewhat of an uncivilized and unrefined pragmatist myself -- I seem not to suffer from such horribly insidious and generalized malaises. . . . heck, I am so bad I even find tubed equipment can be delightful and eminently listenable.
atmasphere's avatar
atmasphere
11,931 posts
 
For my ears, Class D amp builders are not trying to achieve a sound like tubes or solid state. They are trying to amplify the truest signal to their ability.

This comment sounds like a strawman to me: I know a fair nubmer of conventional amplifier designers (tube and solid state) who have the same goal- this is nothing unique to class D!
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