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

Showing 16 responses by mrtennis

the problem with most solid state amps is the unrealistic presentation of detail. the sound of an instrument is usually represented as highly timbrally inaccurate, compared to some of the classic tube designs.

there is something very unnatural about solid state.

yes, you get the speed, control and resolution, but there is no bloom and the sound seems forced, rather than liquid.

it would be nice to meet some audiophiles at ces, visit soem rooms and compare perceptions.
hi audioperv:

the objections i raised are reasons not to want to listen to solid state amps. what ever faults lie in the design of tube amps do not deter me from wanting to listen to them.

subtractive coloration of some tube designs does not bother me. additive colorations of solid state amps is annoying.

i have heard class d amps at ces many times. i have no desire to listen to them on panel speakers.

ralph, what say you ?
hi muralman1 what panel speakers do you have ?

as i have said , i have heard several class d designs. my friend owns an expensive pair of piega speakers. i have heard them driven by a class d amp. i was not impressed.

class d is not the sound of classic tubes, or many set amps.

we all have our preferences. i prefer the vintage tube sound. many current production tube amps sound too sterile for me.
high muralman:

i prefer the vintage tube sound. the conrad johnson mv 125 is my favorite amp. no class d amp will resemble the mv 125.

a class d amp will never sound like a vintage tube amp.
high muralman:

the alleged superiority of class d over tubes or tubes over class d cannot be confirmed unequivocally.

i cannot corroborate your perceptions, you cannot confirm my perceptions and what is better or worse is a matter of opinion. we can agree to disagree.
hi guidocorona:

i have attended ces shows since 1992. i have yet to hear a class d or solid state amp that i would want to own.

i have not heard any class d amp i would characterize as dark. of course the sources that i used to evaluate stereo systems were probably different from what you auditioned.

i am still curious as to which brand(s) you found "dark" sounding. in addition, i am also interested in the names of other components and stereo systems which you consider to be "dark" sounding.
the satisfaction of an owner of a component is not a predictor of the satisfaction of a potential owner of that product.
hi eldartford:

an opinion is very subjective. i don't think that popularity or the satisfaction of other owners is a reason to buy something.

as has been said many times, your ears are more important than any opinions.

the only question is, how to minimize the number of components to evaluate.

i'm afraid one should audition every component in one's price range, depending upon preference for, say, tubes or ss.
why is there such an obsession with class d amps?

i am not aware of any other class of amplifiers which has garnered such interest or generated so many posts.

what am i missing ? is class d an infinite pursuit ?
there are a number of amps that will drive a difficult load, say under 2 ohms. just because an amp can drive a speaker doesn't mean one wants to listen to that speaker with a particular amp which drives it.

as i have said i find pnels and solid state difficult to enjoy for more than about a half an hour.

i am so accustomed to euphonic tube colorations that solid state amps and class d amps sound uncivilized, raw and aggressive by comparison.
hi mr g:

enjoying solid state and class d amps seems to be an acquired taste. i have not as yet acquired the taste.
perhaps you can enlighten me as to how i might acquire the taste.

then again if i acquire the taste i may not like the taste.
however it may be worth the effort.
on sunday i attended a chamber music concert of a string quartet at my local library.

what i heard was not remotely similiar to the sound of any stereo system.
hi ralph:

the recording was made in a den at a friend's house. the purpose of the recording was to make a comparison between the timbre of the cymbal and the timbre reproduced by a stereo system using the cymbal recording as the source.

i would hope the comparison is valid. the cymbal was not near any room boundaries.
all amplifiers have some consistent sonic characteristic which is detectable after audition, for some period of time by a well-trained listener, given a variety of recordings.

if amplifiers had inaudible levels of coloration it would be almost impossible to distinguish one from another.

what does this mean ? find an amp that you like and the quality and quantity of imperfection should not matter.
given all of the observations about class d amps, it seems odd that after all of the relecant points are made, this thread continues.

there can be as many observations about other products as have been generated about this product class. yet, posts continue.
this subject has received more posts than most other threads on the forum. i wonder why.

at what point does the light dim and what remains is just heat ? is there more enlightenment regarding this subject yet to be revealed ?