Class D Amp For 'Stats?

For a number of reasons, I am considering the purchase of a Class D amp (or amps) to drive my Sound Lab A-1s. Most uses of such amps detailed here and elsewhere seem to have been with 'conventional' speakers, which obviously present very different impedance loads than a full range electrostatic (approximately 40 ohms in the bass, dropping to 2 ohms at the highest frequencies). I would be most interested to hear of members' experiences.
I cannot imagine why you would want a Class D amp? Most class D use large amounts of Feedback to deal with transient response. I have not heard a Class D amp that does not sound mechanical except for subs, this is the one acceptable use that I can think of. What type of music do you listen to?
Hi, Check out the Bryston 4BSt or SST. They were designed to drive the hardest speakers I can think of, the Dayton Wright gas filled electrostatics. I've heard these amps on Audiostatics { which I own} and Quad 63's and even Quad 57's and the amp just cruises and sounds great.
Never mind Distephenson. Either he has limited experience with this new genre, or an inhospitable system hindering their proper function.

See my system review, at:
I have a Bel Canto evo-4 and, it sounds outstanding on my Magnepan 3.6's. My favorite amplifier on these speakers. However, I do not like it on Sound Lab U2's as the sound character is thin and bright'ish. Switching amplifiers have an output filter and, this filter will interact to some degree with the load impedance. With Sound Labs, the reactive load impedance varies quite a lot especially in the lower registers. The BC just does not seem happy with the SLs. It's speculation, but I suspect it's not much different with any switching amplifier as they all have have an LC output filter.

The Atmasphere OTL amplifiers are my favorite on the big SL's - the MA-1s and MA-2s in particular. I have spent considerable time with both and, both work great. I have also tried the Wolcott 220s and, the Innersound ESL-300. There is a palpable richness with the Atmasphere's that manage to elude the other amps.
The Innersound ESL amps were designed to drive the capacitive load of electrostatics. They will do so while sounding outstanding and without strain. An electrostatic speaker is a capacitive load which is very difficult for most amps.
Try the Channel Islands D-200s which use UcD modules. These modules take feedback at the speaker terminals and are said to be load independent which would mate particularly well with speakers having large impedance swings. Said to be the best sounding of the class D lot.

Review here:
I too have the SL A1's. Earlier this year I tried the H20 non-signature stereo amp here. Once I got passed the claimed "inapplicability" of these amps with MIT ICs, I had pretty much the same results with NBS ICs....the H20 was fine but not a musical match with the A1s. Resolving, yes......involving it simply was not. An older Counterpoint NPS400 had far more portrayal of space and body even though it lacked the ultimate extension at the frequency extremes. The CAT JL-3 Signature amps took the musicality so far beyond the H20, but of course at a price. The CAT's dynamics and incredible resolution brings out these same strengths of the SL's.

I have also heard the JL-2 with the SL speakers and for the price, it is unbeatable. This on the used market is not too much different from a pair of the fully decked out H20 mono amps and the JL-2 would simply destroy the H20's with the SLs.

And Nealhood brings up another great option with the Atmaspheres. I also heard the MA1's with the SL's and these too are incredibly musical with a more rich and full lower midrange but not quite the dynamics and ultimate resolution of the CAT JL-2. This was a back-to-back comparison of the SL U1's last year.

As for Brystons, before I had the A1's, I had the Magnepan 3.3 and 3.5 for 6 years. Several amps that I owned, ARC VT130, Wolcott 220, even the Counterpoint NPS400 hybrid drove the Magnepans to a musical level the Brystons simply could not touch. Speaker drivability is only part of the equation. Why anyone would use the Bryston amps with Maggies is beyond me and yet that is often what you read about with these speakers. And to consider them on the much more dynamic and resolving SL speakers makes no sense at all.
"Switching amplifiers have an output filter and, this filter will interact to some degree with the load impedance."

I have said this many times before, and I am glad that someone finally concurs.

'Stats are not a purely capacitive load, although they do have a great deal of capacitive reactance. Most of the new Class D amps will handle the capacitance, but the low value of the absolute impedance may present a problem. For reasons stated above.

Anyone who thinks that "all" Class D amps are mechanical have not heard any of the new genre. Period.

Can you tell me what amps you have heard? What you seem to be describing is quite different to my own experiences. thanks.

I fully understand your comments on the Atmas. I have owned both the S-30 and the M-60s in the past (not for the SoundLabs, obviously). However, the biggest single push towards the possibility of the Class D amps is the ability to leave them on at all times. You see, what I did not explain was that, at this time, I'm pretty much forced to listen in short intervals of an hour or less. No amp is going to sound anywhere near its best for least 1/2 hour after a start from cold. I'm just plain tired of having to shut things down at the same time things are starting to sound good.

I have also owned the Innersound ESL (driving the Eros, as a matter of fact). I think it's a very good amp, and - especially used - a fantastic value. What I never got from the ESL was the harmonic richness of tubes, something I value highly. A couple of reviews of the various Class D amps have suggested that that richness is characteristic to a degree. Here, I'm specifically thinking of Srajan Ebaen's review of the H2Os. Coming from a long time tube addict such as Srajan, I found his comments to be rather striking.

Now that's what I needed - a directly applicable opinion. I wonder if the H2O M250 Signatures would be better? These are actually my top contenders at the moment. The CATs are great amps, but they have the same downside as any other tube amp for me at this point in time (see above). With all due respect to Harrahlv, Bryston is not my particular cup of tea either. I actually have 3 'conventional' solid state candidates for amplification as well - Ayre V-1xe, Edge NL-12, and McCormack DNA-500. This may be a long road.....
One will run into a lot of pitfalls when trying to implement the H2O (I have the Sig monos). For me, there is no doubt they are the best amps I have ever had in my system.

I have found any speaker cable that has anything but minimal insulation coating will cause dielectric polluting of the signal. Also, I am a fast non-upsampling convert. Preamps with a strong power supply do better.

This is a new technology, and that applies to all digital, and class D amps. It requires a rethink of system priorities to bring out the best. The potential is there.
Caveat, I have no business offering any advise here. I've never heard the Sound Labs. I've very little experience with digital amps. Many seem to think that the digital amps can be bright. I just wonder if the traditional Rowland house sound still exists in their digital offerings. A_rt of Analog Research Technologies has mentioned something about offering an option to customize the frequency response of his amps to match a given load. There may be options. Perhaps now that there are quite a few manufactureres offering digital amps we should start respecting them as individual products rather than lumping them by technology.

I have owned many amps similar or perhaps parallel to what your tastes may be. I have owned McCormack DNA-2 Deluxe, Quicksilver V4 monos, auditioned the Ayre, as well as the Rogue Zeus. I now own the H20 Signature Monoblocks. Srajan's review is on the money. I would also take note of Srajan's review on the Nuforce, in specific where he states, almost all ICE powered class D amps sound a certain way... EXCEPT the H20 Signature monos. That is not a coincidence.

The H20 Signature Mono's are the real deal. Are they the best amp out there? I will never claim that. Everyone has sonic "preferences", however, they do carry themselves with the heft of a true class A solid state, with the liquidity of tubes, yet without the harshness or grain at high levels of solid state, and without the euphoric coloration of tubes.

As for system matching, I have had no problem. I have my system posted here on A'gon and there should be a clickable link by my moniker.

If you are seriously considering a new amp, I would try those you are interested in, in your home, in your system.

I would also make certain to audition the H20 Sig Mono's as Henry offers a trial. For what they do, at their price point, they will get the respect they deserve sooner or later when people hear them.
The UcD based amps do have a slight interaction. Less than ICEpower based amps. I have extensive experience with both.

The gang at Hypex is confident that it will handle low-Z loads. Tell the truth, I have never tested them that way. (We only offer the UcD version for HT applications, and you most likely won't find 'stats or Apogees there.)
Art, I imagine you forgot my speakers have an impedance of eight tenths of an ohm. One H2O owning fellow I know is trying out his on new ultra light ribbons at .4 ohms, and likes very much what he is hearing.
The NuForce Reference 9 amps sound extremely natural and musical with conventional speakers and have no problem driving loads well under 1 ohm. That said, I believe the NuForce and probably a lot of the other amps (even analog amps) sound somewhat different when hooked up to a large capacitive load. I believe that Jason at NuForce has had some experience using NuForce amps to drive SoundLabs speakers. So you might want to contact him to see how that experiment turned out.
Here I go speculating again (it's a bad habit you know), but I blieve that if you have an Atmasphere or CAT, and any of the switching amps (as good as they are, and they are quite good) for 3 weeks of audition on your Sound Labs you will find yourself willing to put up with the heat, the warm up, the hassel, the expense, the pain, etc., due to the more immediate and palpable soundfield that will emanate from you panels. Call it body, richness, bloom or whatever but, the excitment and "you are there" experience is arresting.

Here is something to consider; most, if not all, switching amplifiers being mentioned in this thread are available from the vendor for audition with a full money back guarantee. It's a sign of confidence in their products and, a credit to the manufacturers offering this policy. You have one of the best speakers on the market. Go to the trouble of finding the one that makes hay in your system. You will ultimately be far happier. Every one wants to be on easy street and live the simple life but, the life of an audiophile was never meant to be easy.
It's been suggested that speaker impedance variation with frequency might affect operation of the output filter of digital amps. Perhaps that explains why Magneplanar speakers, with their flat resistive impedance, respond so well to powerful digital amplifiers.
Eldartdford, I wonder if there might be more to it than that. My Thiels have a rather steady resistive lower impedance load, yet, I don't know of anyone touting these amps with those speakers. A_rt has suggested that these amps tend to get bright into lower impedances. We are all very much aware of Muralman1's enthusiam for his H2O's on his notoriously low impedance Appogge's. I suspect that Muralman1 might disagree with me here, but, my experience with the Appogges have demonstrated a distinctive downward sonic tilt (the opposite of my Thiels). This just might explain why he is experiencing such joyus synergy.
Unsound, you may have a good point. Apogees have historically been known as downward tilting sounding speakers, especially the Scintilla.

However, "bright" is a symptom I can't abide. I detest any sort of distortion. My speaker's highs are as sweet as a soft center Sees candy.

Unsound...Muralman1 enthusiastic for the H2O?

I hadn't noticed :-)
Muralman1, Distortion is distortion, whether it's tilting up, down, or elsewhere. Now if you find particular distortions either more or less objectionable, well, that's something else and all together more understandable. After all that's probably the basis that we all use to put our systems together in the first place. The point I was trying to make was that if digital amps are bright into low impedance loads then in your case it was unlikely to exacerbate the problem and could even help to neutralize one. It may just demonstrate that though opinons vary they may all be correct within given circumstances. It may be that digital amps like other technologies may be specificaly appropriate. Eldartford and A_rt may have identified specific attributes that currently may help in deciding whether or not this technology may be appropriate. Furthermore since this is a relatively new technonlogy we may not have seen all that digital amps have to offer. The future certainly looks interesting.
The whole issue of low impedance Apogee speakers and the H2O's ability is irrelevant. Since this is not the case for the A1's, discussing an amp that handles sub 1-ohm loads is a "don't care" issue in this thread.

Pure and simple, if you have invested in a $15k speaker like the A1, you need to put the same amount of attention to find an amp of the same calibre to hear what you paid for with the speaker. Again, pure and simple - the H20 does not cut it to convey the many awesome strengths of the SoundLab speakers. We can talk all we want about driveability, but again, this has nothing to do with musicality - the portrayal of space, silence between the notes, dynamic contrasts, ability to play material with a high level of low frequency extension and not have the mids and trebles crumble at the same time, etc., etc., etc.

The CAT amp is not euphonic at all, and the one JL-2 will not generate that much heat. You really should try to hear this to get an idea as to what your speakers are capable of. And try to get the H20 on loan so you can even more greatly appreciate the CAT's ability. Once you hear it, the H20's will be gone.

Thanks to all of you who responded to my questions. The problem has been resolved - at least for now. This morning, I arranged to purchase Bob Crump's personal pair of JC-1s from his estate. For those of you who don't know, Bob lived in Houston, about 40 miles from my home.
Currient11, Enjoy your Soundlabs. If there is anything I have learned, there are many avenues to enjoyment of music.

Brian at EssentialAudio (also his A'gon name) has much experience with the JC-1s driving the SL speakers. He also has a lot of experience with the Atmaspheres and the CAT's. So I suspect he would be a good source of advice to get the most out of these.
My experience is limited when it comes to Class D equipment. In the mid 80s I used a ML and enjoyed it, then replaced it with more power, as the dealer that I worked with suggested and traded to a Silver Seven. I really did not notice a change but was happy for quite a while. Just this year I sold all my equipment after listening to a VERY inexpensive Tube amp that was a SE class A. It just sounded more musical, but reality tells me that my hearing is less acute in my late 40s than it was when I was 20. After doing some research on how each class of Amplification works, I can understand why I felt that this tube amp seemed more musical – not more accurate.

Now the real question is why Class D? Perhaps to drive a very difficult load? Perhaps to bring enough power to a large listening room? Or I like the new Rock and Roll?

My question still stands. I really do not understand. But if you would like to give me your reasons for selecting your equipment then I can understand better.

I am certainly outclassed by your GIGA BUCKS system. I would guess it sounds absolutely unbelievable. My experience with SS equipment is obviously less high end. But that does not mean my opinion is less valuable. My object is not to offend but to participate in order to become more Knowledgeable.