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.
Of course you are correct, Elberoth2. As I said earlier, for any technology there are stereotypical distortions, brand typical distortions, and atypical ones. Where I have problems is characterizing distortions in tube gear as 'benign' as a whole. At RMAF I ran out with 'bleeding ears' of as many tube suites as I did from SS or class D suites. Tube amps sounding classically 'tubey' were definitely a minority.
As for ARC Ref 110, I agree completely that it--and the rest of the current ARC lineup--are darn special amps; I own a Ref 3 and in general I love the new ARC sound; The only reason why I will not even consider a Ref 110 is because. . . tube amps generate too much heat in the ghastly Texas Summer. What switching amps have you evaluated/contrasted against Ref 110 besides Bel Canto Evo 4 and Nuforce? One of the problems I can see with some class D marketing is a tendency to hyperbolic generic claims of the type. . . 'X crushes SS/tube sacred cows costing 4 times as much'. The problem is that such sweeping uncautious claims expose a product to equally uncautious counterargument such as yours, where you contrast a brand new $10K tube design (Ref 110) with a 5 year old $4K switching design (Evo 4) and a current $5K switching design (Nuforce Ref 9 SE) only to apply the old induction step and produce a slightly brave conclusion. Seems to me you are comparing one orange with two clementines. . . and concluding that all oranges are . . . heavier.
What can I say, sadly, I am probably not a member of the species 'Homo sapiens', because 'tubey' distortion do not sound at all priviledged to these poor ears.
You are going to the extreem here. Not all tube amps sound "tubey" and yet, they still have certain distortions characteristics that are more benign to human ear.
To my ears, a good tube amp still sounds much better than current Class-D designs. I have owned BelCanto eVo 4 amp, I have evaluated both ICEpower design (ASP based) and, just recently, the latest NuForce 9V2SE monoblocks IN MY SYSTEM, and all I can tell you, is that the difference between them and my current ARC Reference 110 is so HUGE, that it is almost laughable.
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.
"Consider that because you have heard some tube amps which have coloration does not mean that all of them are like that."
I agree with you Atma. With any technology there exists stereotypical coloration/distortion, there is also brand-typical coloration/distortion, and then there is simply the atypical kind. I suspect it may be a lot easier to eliminate outright distortions than to tame colorations for everyone. We should remember that one audiophile's poison often is someone else's Nirvana. . . or in other words someone's coloration may be someone else's 'neutrality'. For myself I often do not even attempt to define my preference in terms of warm/lean/neutral. . . I will simply describe what I hear in semi-musical terms as well as I can, and explain what I like and what I do not like, and if I am at all capable, why.
Guidocorona, you may not believe this but I agree with you- I don't like 'tube' colorations either. I think many of those colorations have to do with design considerations rather than the tubes themselves.
Consider that because you have heard some tube amps which have coloration does not mean that all of them are like that.
I don't really like *any* colorations (tube or solid state). Spending a lot of time in the studio, hearing the live feed as opposed to the recording, how different mixers, speakers and amps behave will do that to you.
This is one of the intrigues of class D for me as they often lack some of the more heinous colorations that I associate with transistors and tubes. For all that, my experience is that class D amps often have their own unique sonic fingerprint that varies from brand to brand as it does in the scale of execution. Its getting control of those variables that seems to be at the cutting edge of this art.
What can I say, sadly, I am probably not a member of the species 'Homo sapiens', because 'tubey' distortion do not sound at all priviledged to these poor ears. [chuckles!] Oh well, guess there are worse things in life!
Eldartford - the fact is, that some distortions are more easily accepted by human ear than the others. That is where tube designs have their advantage. They may measure as good (or as bad - depending on the point of view) as the SS design, but in the most cases, they will sound much natural to human ear.
Atmasphere...I agree that the specs we measure are intended to verify that a unit is performing as per its design (ain't broken) and do not necessarily correlate with sonic quality. (Although high IM distortion is very anoying to me). However, if the ideal amplifier is a "straight wire with gain" why don't we just compare the output, adjusted for gain, with the input while playing some complex waveform like music, and over a range of amplitudes. "Total Error" would be the parameter...who cares if it's harmonic,IM, or noise. I submit that many SS amps would score well, and many tube amps not. However the tube amp fans would say that the ideal amp is not a straight wire with gain, but rather is a harmonic synthesizer, with gain. To each his own.
Muralman1, I've not checked out all the modules that are out there, and I was careful to comment to that effect.
FWIW though, distortion has nothing to do with what impedances an amplifier will drive. The two issues are unrelated. Neither is THD a good indicator of how an amplifier will sound. The current test and measurement paradigm does not generate specifications that are intended to let us know how an amplifier might perform sonically.
And to the point. As I said my Nuforce 9SE V2's sound better then real music.Hyperrealistic if you will. Uhmmm, go enjoy the music. My amps are great. The music is superb.
Vince, tell you the truth. . . I am all for hyperrealism in recordings and in playback. . . I honestly love it and so many times I can hardly have enough of it. Yet. . . you and I know exactly what it is. . . a particular mediated view of reality, and will love it for its very nature. I fear that If I ever got in a position where I could hear Larah St. John's Stradivari the same way I can listen to it on her recording of J. S. Bach Sonata No. 3, appreciating her fiddling the fiddle may end up being the very least thing on my fuddling brain. . . .
Guido, I love your writing style. - read the above post. I have untampered recordings, and I love that. A close miced guitar is wonderful, because most of us have heard guitars up close. As annoying it is to hear the string squeaks you do want to hear the string windings when the player slides his/her fingers along them. When Kottke really gets going, his manipulations of each string and each fret are simply awesome.
People with poor hearing do miss a lot. I know fellows like that. Mids and lows are everything to them. I have that great recording, Windham Hill '84 on now. That is a good one for detail. During one song (on now) the drummer is constantly tickling the high hat. It is a panoply of high frequencies not enjoyed by the hearing challenged.
You know real when you hear it, regardless of your hearing ability. There are clues.
Tvad, I have a Royer's Microphone demonstration disc. It covers the different microphone positions, and their affect on the final sound. Recording is an art in itself.
On solo acoustic instruments, with a uber-resolving system, you can indeed hear the rosin's stickiness, and those faint bow angle tonal tickles. That is what I want to hear, and that is what I have.
Orchestral staging is quite different. I am careful to choose a volume level that is compensatory to the distance between my speakers, 7.5 feet. That puts me on first balcony.
Hi Vince, that's exactly my point. The sound of rosin for example is extremely faint and can be heard clearly only if you 'are' a microphone, or you are sitting/standing so close to the performer to be socially unacceptable under most circumstances. most concert goers will never hear the rasp of rosyn from the 4th, 12, 30th, or 50th row behind that plynth. . , particularly if they are surrounded by other listeners wearing sound absorbing winter clothing. Besides, what is 'real'? What I can hear when in a good day without tinnitus I can outperform audiometric equipment? or what's real is what the average middle age listener hears with a 12,000Hz cutoff, or what my dog can hear with a bandwidth of perhaps 50Khz. Or perhaps the perfect ears are those of a microphone? Which one? How sensitive? With ewhat dispersion, with what kind of bandwidth? Even the most perfect recording is by necessity just a cropped, filtered, an edited 'view' of reality containing selective enhancements. Nothing wrong with that, provided that we realize that our own perception IS NOT reality, but merely a useful and partial interpretation of it.
I have grown wearie of reading the black&white cartoonesque audio manifests of those who seem to be wanting to ram facile editions of some kind of Audiophile Pravda down my unwilling gullet. When I really want to hear the 'Truth' I'll find me a Church. . . for the time being, music and the quest for beauty may suffice.
Muralman1, you're in a good position to record that viola- and then play it back. *Thats* what I'm talking about. You already *know* what the instrument sounds like.
That's the technique I use when I am auditioning anything- speaker, a tweak in one of our products, a class D ampilfier- whatever. Sure, I play a variety of recordings, but its always useful to be able to play one where you were at the recording session.
To address an earlier comment- the distortion that a tube makes is not something that is cast in concrete. I have found that quite a bit rests on design consideration as well as materials. Not all tube amps have a predominant 2nd order harmonic- that's really a character of SETs. Push-pull amplifiers have even-order cancellation.
If you look at the distortion makeup of a lot of the class D modules, the distortion can be quite high for a 'transistor' amplifier. We have a module here that is 10% at full power. We've not measured the spectra, but I can tell you that the distortion is under 0.5% or so to about 50% of full power. The IM is actually higher than measured on our own production amps. Of the two, IM is usually more audible than THD. The appearance is very much (in the case of this module) that the ear is ignoring a lot of the THD, i.e. it appears to be even-ordered. IOW it seems to have a lot in common with SET amplifiers! I thought you might find that interesting...
By no means is the module that we have (Phillips) representative of the entire field. It would be interesting to see if there is a correlation either negative or positive with what we hear in these amplifiers as opposed to what is measured! A negative correlation, FWIW would put the behavior in the same realm as tubes, where much of the distortions made are ignored by the human ear.
Thank you, Atmasphere. If I were building amps, I would go that route. The closest thing I have to having that capability is a remarkable CD produced by the Royer microphone company. They purportedly transposed master tape recording to CD. I know, it isn't the tape.
The point I am attempting to make, is knowing what a live musical instrument sounds like, you don't need an intermediary such as a tape. Take my daughter's viola, for instance. If, on your playback, you cannot hear the subtle roll of horse hairs from on edge, to flat, and all points between, you are missing a whole lot in musical phrasing. You will also learn to look for the proper amount of resin.
I can see where a master tape could come in useful. The sound of the viola is indeterminate. They all sound a bit different from each other. There is no one tonal indicator.
It should go without saying, no matter the recording, wires and speakers play an enormous part in bridging the performance with a system's There is not a speaker made that can sound absolutely real. The closest I have heard is my own.
Muralman1, I am sorry you took offense at my comment, but if you look at my last post and your initial reaction, it will be obvious that you attached meaning where none existed.
My point was that if you go ahead and make good quality master tapes, you will be in a position to use those recordings as reference tools, for all the reasons that I outlined earlier.
Will the results mean something? I have no idea. All I know is that these tools were invaluable for me personally and others who have done the same thing.
IOW, a system may sound great, but its always in respect to what. When you have master tapes, now you have an absolute.
Tvad, I agree... We are not carving new territory, or supplying grand insights.
I just cannot abide anyone telling us they know there system captured the night because they taped the night. What they hear back at the lab is the tape on their system, not the music that was captured by the tape. Do you get my meaning? We are asked to take their word for it. The Von Schweikert demo is no more convincing. We weren't at the recording. The smart thing was to use a master tape.
You have not convinced me. Knowing what a family of acoustic instruments sound like in real life should be one's gauge, not the recording. Besides Atmasphere is no more likely to remember whether his playback sounds like the performance. He still has to rely on his memory.
When I clicked your system I found you use Bose! :)
Tvad, you are walking right into that bravado I just tried to debunk. Any master tape is going to be more accurate to the performance than that which is tortured through processing. There are great recordings and a lot more bad.
Saying that only the chosen few who follow the recording from the performance can ascertain their system is the closest thing is crazy in my view.
I have sat just a few feet away from guitar maestro Leo Kottke. Do you really think I should have recorded that incident to have any recollection of what it sounded like?
My daughter stood just as close as she practiced her very fine viola daily. It is live, why would I need to record that?
Oh, so that means only you know your system is top dog? I believe if a person of good hearing is familiar with acoustic music, they can tell if a recording is doing a good job representing acoustic music. I know the sound of a guitar, so I know if a recording does it right.
I know string instruments, horns, and pianos as they are all played by my family. I have worked musical theatres for years. We have attended symphonic performances from Carnegie to Sunday at the park.
I know this too, tubes are infamous for their coloring, and oversized helping of second order distortion. People steeped in the land of valves are so righteous they can't accept clear musical feedback when they hear it. I know that for sure, because the only disagreement I have had concerns such folks, good friends of mine by the way.
Muralman1, I appreciate that you like what you hear. My point is that to really know if it is right, it is very useful to do on location recordings with professional recording gear (and with the intention to do a good job...).
The master tapes then are very useful in letting you know how a system really sounds, because you were there at the recording. You know what the hall sounds like, where the instruments were placed, how far the mics were from the musicians, that sort of thing. This is assuming that you have good recording technique and the equipment is up to snuff...
Hmmm, If I had only done my homework. . . I would have been able to answer my own question. MC20 from Halcro is a class D amp indeed. And here is its Stereophile review: http://www.stereophile.com/solidpoweramps/406halcro/
Hi Lucey, I have no info on the sound or technology of the Halcro MC20 (is it a digital amp?). Red Dragon in my experience does not have stereotypical 'digital amp' artifacts, but to my ears it may be somewaht dark. I Also remember I was hoping to hear a little more of harmonic development and microdynamics when I listened to it last year at RMAF.
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.
Hey Atmasphere, reference sir? my Scintillas can bring all the thunder of four antiphonal organs complete with reverberations, off the walls of the Cathedral of Freidburg to life in my listening room.
Mrtennis, by any chance do you have a recording made in the space that you just heard? My experience has been that its apples to oranges comparing live to recorded unless you are familiar with the space that the recording was made in.
I've done a lot of local recording with nice microphones and a portable tube recorder. Some of those recordings have made it to LP and CD. If I hear them played back properly I can always hear the hall- they easily remind me of where they were made. I've come to the conclusion that this is a major part of having a 'reference'.
Bingo MRT, I am very familiar with the problem. . . original live purely unamplified music does not usually sound terribly similar to the recorded product of the same. . . from humble local libraries or world-famous superannuated concert halls alike. Yet, they can be both differently wonderful. . . or even differently awful.
I am not sure MRT how to acquire a taste for a particular technology. . . I sure do not have a 'taste' for switching amps in cprinciple, same as I do not have a 'taste' for tube amps or classic solid state amps. . . . . I simply try to keep an open mind to all. Within switching amps I have listened to only a few and -- at the cost of sounding tedious -- I very much enjoyed the Spectron Musician 3 Sig and the Rowland 312. Other switching amps that I have had the priviledge to listen to I enjoyed partially or not at all. . . but so many switching amps I have 0 experience with. This situation is identical for me to tube amps or solid state amps. . . after careful removal of large chip on shoulder, I listened to all I managed. . . out of these I enjoy some. . . most amps unfortunately I have not heard yet.
Yes! If we all could be weekly attendees to live acoustic events, from grand pianos to grand sweeps of an orchestra, we would largely have the same reference to draw upon.
Among my visitors, those folks with a good deal of that experience see the value in a well developed class D sound.
We go on and on about the subtle "sonic character" of amps, but it is all insignificant compared with the great variability of microphones, about which we can do nothing on playback. (Well maybe a bit with an equalizer).
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.
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