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
"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.
Sajran has quality sources, keen knowledge of what actually works in given systems, and an open mind. Read his review of Henry's H20 amps done a couple years ago.

I have monos of his that have a B&O improved ICE module, and much better bypass caps. The sound just got better.

Class D amps, the great ones, must be fed impeccable signal. Any source, wire, and pre-amp negatives will be exposed, much to the listener's discomfort.
Absolutely agree!!!!
Nuforce Ref 8.5 was quite an old piece of hardware, even the difference between Ref 9 and Ref 9V2 is huge.
So the comparison between D-class models should be done with the current amps version that is Ref9V2.

I recently added the Nuforce Pre P9 to the chain...

Never ever heard something like that!!!!!
but you do not have to believe me!
Listen to a Nuforce chain to a dealer near you!!!!

pls look at the Nuforce site under the award and review menu....the quantity of enthusiastic reviews by TAS, 6moon, Stereotimes etc is embarassing!!!!
but listen before judging!
"pls look at the Nuforce site under the award and review menu....the quantity of enthusiastic reviews by TAS, 6moon, Stereotimes etc is embarassing!!!!"

Drooling is embarassing indeed. If you look again into TAS review - it is compilation of three different reviewers. two gave excellent review and one terrible.

Why? Is this one professional reviewer is deaf? No, read again TAS it gave NuForce Editor Choice Award but with the caveat - ineractions with cables (and obvuously speakers).

I know this amp cannot drive electrastatic Martin-Logan speakers (not poorly drive but not at all - coming the the region of difficult impedance and shut itself (v1 for the record).

Without going into engineering as to why let me simply state that despite multiple positive resonse and even drooling ==> BUYER-BEWARE !!!! Good amplifier but not for every speaker!