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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
 
Guido,

Honestly, I would like to truly love Jeff Rowland sound. New Jeff Rowland Criterion preamp(will be fully introduces on CES2008, double chassis, battery powered!) with Model 301 monos(new version with 600w/8ohms) could be very nice solution despite big price tag...

BUT, is it really better then simillary priced solid state offerings? For example:

-Hovland Stratos/HP200
-Krell Evolution One/Evolution Two
-Krell Evolution 900/Evolution 202
-Vitus SM-101/SL-100

Interesting thing is that Hovland and Vitus use UI core power supply transformers, not toroidal one like Krell. Both Hovland and Vitus claim that these UI Core transformers are much, much better(of course, they are costum mode for both manufactures and are really very expensive) then toroidal one...

So, development in "normal" solid state world in still in progress...
guidocorona
4,114 posts
 
Hi Branimir, I have not heard the JRDG 301s so I cannot comment about their sound, and can even less venture tu guess on whether I would prefer them over other comparably priced designs, which I have also not auditioned. On spec only, I am slightly concerned about the 301's low nominal damping factor of 60, which may make their application difficult to some speakers. I do not know if damping has changed in the new version.

I am though even more intrigued about the upcoming JRDG Criterion Pre -- being a completely new reference level design -- and how it may compare to the 'usual suspects' in its price range--tubes hybrids, and SS alike.
tvad
9,467 posts
 
Rowland has offerings ranging upwards of $30K, Kharma has introduced new monoblocks likely costing over $40K USD

It's all based on the same inexpensive technology. Bentley offers autos based on the same basic technology as Kia, yet the Bentley costs 1500% more.

There are enough consumers eager to purchase fancily packaged status goods to fuel any new inexpensive development. Witness the diamond encrusted cell phone.
guidocorona
4,114 posts
 
Very true TVAD, almost as inexpensive as 6550 tubes or just about any transistor or cap used in traditional designs ranging from a couple of hundred dollars up to stratospheric prices.. . . To tell the truth, I do not really care about the cost of any underlying building block. Nor in fact I care in principle about the cost of a component per se. What matters to me is how all of these chips/modules/tubes are put together to form a component that will in turn contribute to make music in my loft. If it measures up, that's fine and good, if it doesn't, no amount of mil -specced Tantalium-doped machined Aluminium fascias, 0-feedback pangalactic design, 60-year-old-tubes used to decode WW2 German cyphers, 128bit asymptotic hadro-stochastic processors, 3160 transistors, class A/B/D/T, Doppler elimination, poplar or mpingo sidings, or otherwise mouthwatering old or new real or imaginary technology is going to matter to me a single half bit.
muralman1
1,527 posts
 
There you go guys, what makes those amps so expensive? The monos I bought cost me $5k.

Henry's amps are superb when matched with appropriate gear. Kharma's amps need the same care in matching.
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