High end Class D amps?

Ralph, if GFi is right, that you are close to releasing your class D, I volunteer to compare/comment on it vs my much beloved EVS 1200, dual mono IcePower AS 1200 modules with lots of Rics pixie dust. My speakers are EP 3.4s 12' concentric driver with polyester tweeter. Digital is a Oppo 105 with upgraded LPM, Furutech rhodium IEC with silver tail to LPM and ground, plus jumper to replace 110/220 switch. Series 8 WireWorld ICs and Series 7 speaker cables. CorePower 1800 into 20 amp dedicated line

George is correct. Lack of switching bandwidth is the problem. I know Bruno Putzeys claimed differently in an old interview, but he's mostly a self-promotor so no one should take what he says as gospel truth.

For the record, Bruno Putzeys is the one that made self-oscillating class D amplifiers a reality, a practical thing. That's a pretty big deal; if you work out the math for that you are doing quite well. You better be good at calculus with multiple variables! He also is able to show the measurements to back up what he says about how the technology works. Attacking Bruno is really done at your own peril!

By 'switching bandwidth' I think you must mean 'switching frequency' since 'switching bandwidth' isn't a thing. And in this regard your statement is false. Based on the rest of your comments I would venture that you simply haven't heard everything that's out there, and just like traditional solid state amps and tube amps, there is a tremendous variance in class D implementation!


You might think of it this way: digital has come a long ways since 1981 when it first started showing up. Its common now to see scan frequencies of 192KHz; class D amps are commonly switching well over double of that. At the current state of affairs, the practical upper limit is around 600-700KHz before you really start to get into troubles with radiation and oscillation issues- the fact that Technics seems to have gone well past that says a lot about their engineering expertise. But Technics has to switch faster, since (if their claims are correct) their circuit is zero feedback, so they have to raise their filter frequency quite a lot in order to avoid phase shift at audio frequencies. Also for the record, self oscillating class D amps don't have to do this- their filter frequency can be lower since they can run so much feedback that it is able to correct for phase shift. 
@tweak1 Thanks for your offer!

@atmasphere, and @tweak1, Tweak1 is also getting Walter's Voyager GaN amp as well as having Ric's modded 1200AS amps, Ralph he deserves to be in your Beta testing.

Here are the class D I tried.
Old ICEPower: Unlistenable junk. To be fair I didn't burn it in much (didn't know about burn-in back then).
DriveCore 2: Very poor.
Pascal (newer version forget the designation): Very tight control good imaging but also empty and not pleasing. MAYBE it needed more burn-in but I was running into the return widow.
Cherry: Decent in some ways, couldn't compete with my linear amp. Actually I just moved it back into my main system to contrast and compare again now that I have new pre and source gear.
Technics GaNFET: Dry, sterile, boring. Burned it in for over a month. The cheap integrated unit.

I haven't owned any Hypex amps. I've listened to some at shows but I do realize those are poor environments for critical listening.  There was one nCore 1200-based unit I thought MAYBE warranted further listening but that was based on the "wow" factor of high-end class D's first impression.

How many class D do I have to listen to? Is there a The class D which disproves the "myth"? Did I just happen to miss the good ones?

The way to tell people who know and don't know what they are talking about is by the detail and depth of their posts.  Ralph, jaytoy, and I talk about architectural specifics about Class-D, even where the filter is placed. We talk about device operating region. We talk in numbers specific to Class-D.   One other person here who has a bugaboo and about Class-D and I think Ralph in general does not.  I would argue that he cannot, and if he educated himself, he still would not be able as he would see his errors.

As Ralph has pointed out, there are many ways to skin the Class-D cat. High frequency open loop is just one method. Claiming it is the best is like claiming tubes of solid state is the best.  We know many do it, but it is purely dogmatic.  Implementation details can push either in a direction of like or dislike for a given person.

Tim also clearly laid out what I would agree w.r.t. modern high end class-D. It is targeted towards very neutral. Many don't like that.  I am finding the Cherry very neutral. It does appear to have a better supply than what you are using.  I have heard your present Odyssey a few times, one of my friends bought on reviews and did not keep it.  I can see the allure, but it was not for him and and if you like that sound, the Cherry may not be your cup of tea, and I can't recommend one that will be, though they may be out there.