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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
branimir
236 posts
 
"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...
muralman1
1,527 posts
 
Rowland and Levinson can read tea leaves it seems. :)
tvad
9,467 posts
 
An analog power supply does make an audible difference in the sound of a chip amp. Channel Islands Audio utilizes an analog power supply in their line of chip amps, and the sound of those amps is slightly more forgiving than other chip amps I have heard with switch mode power supplies. Still, the CI amps sound a little flat and sterile to me.
guidocorona
4,114 posts
 
Branimir, I agree with your finding on the Rowland 302. It is worth pointing out though that the 302 was JRDG 1st venture in class D, and was replaced in 2006 by the 312, which sounds quite a bit different, and to these ears is both more musical and much more exciting.

TVAD says:

"Class D amps are getting attention because they are less expensive to manufacture, purchase and operate than SS and tube amps."

Undeniably, one of the major reasons I am interested in class D amplification is its promise to let me listen to music during the sweltering Austin (TX) summers and I won't have to worry about swapping out exhausted tubes. It is also undeniable that Switching amps have largely debuted on the market with rather minimalistic and relatively inexpensive designs that may have created a perceptional stereotype. I should however point out that they are starting to get the attention of major 1st tear manufacturers, and more ambitious devices having significant price tags are now appearing on the market: Rowland has offerings ranging upwards of $30K, Kharma has introduced new monoblocks likely costing over $40K USD, and so is Mark Levinson. I recently heard that more such manufacturers may be preparing to soon enter the race.

I have not heard any all out assault switching models as yet. But -- already in the habit of keeping an open mind on any tube or classic SS device until I have had the opportunity of a personal audition -- I am simply looking forward to giving any such 'statement' switching devices at least the benefit of doubt ahead of any actual audition. After all, if my modest experience serves me, I do end up liking roughly 20% of what I listen to, regardless of underlying technology.
elberoth2's avatar
elberoth2 OP
1,219 posts
 
Elberoth2 - the H2O is made in America. That should tell you a lot. I have monos. The aluminum plates are made and finished in the USA. There are some 30 or more power caps.

Mularman1 - I asked this question on purpose. The reason is that there are many SS designs that are much more expensive to produce in that price range.

Take $6000 Cary CAD-500MB for example. Also made in the US. Also monos. Thick aluminium front panels. Transformer as big or even bigger than the one one used in the H2O. And so are the PS caps.

On the other hand, H2O uses 150$ ICEpower module and Cary uses full blown Class A/AB output stage which is MUCH more expensive to produce.

My point is, that you cannot uderestimate the cost (and serviceablity) factor in Class-D designs. They are just cheaper to produce (with build-in SMPS power suply the difference is MUCH bigger). That is why so many manufactures are persuing this technology.
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