High end Class D amps?

You have absolutely no idea, your burying your self with your own brand of **** ****

@audio2design Okay what class D amp today can beat my Stratos? I can’t have fatiguing sound. Does the little Cherry just lack juice? My speakers are ProAc D30R.

Edit: it's a Stereo Maraschino with an external power brick, less than the 48V listed on the website but I forget the exact value.

madavid0:
" I don't think you guys really appreciate how deadly to euphonics that traditional class D output filter is. I didn't start out hating class D I developed that position after being burned many times being told this or that class D module was the revolutionary savior of the topology. I remain interested in GaNFET because it seems like that is what will finally be able to pull class D into the realm of quality audio."

Hello madavid0.

     I believe the most prominent characteristic of the newer, good quality class D amps is neutrality, with no euphonics or anything else added or subtracted.  In my experience, this high degree of neutrality is very revealing of everything upstream, even interconnect and power cable quality levels and differences are more easily detected.  
     I know that Bruno Putzeys, the inventor and designer of the Phillips ucd, Hypex Ncore and the most recently the Purifi class D modules, has stated that he has steadfastly maintained a goal of optimum neutrality in all his modules in order to appeal to the largest number of potential customers.  Based on my experience, the designers of most other class D amp modules, such as TI, Anaview/Abletec and Pascal, have apparently maintained the same neutral presentation goal.
     As to your statement " I don't think you guys really appreciate how deadly to euphonics that traditional class D output filter is.", I don't know where you read this, why you believe it or what class D amps you've listened to, but it's definitely not true with my class D monoblocks.  These are good quality units and, as I stated above, their primary characteristic is a completely honest neutrality, like the traditional audio ideal of a 'straight wire with gain'. 
     It is definitely true that this level of neutrality very distinctly and articulately portrays the quality level of both the recording and the music but there's absolutely no elimination or theft of 2nd or 3rd harmonics and euphonics taking place.  If the music contains these euphonic qualities, and the recording is of sufficient quality to have captured them, then they are faithfully amplified and reproduced.
     I happen to appreciate and prefer utilizing very neutral and revealing  amps in my system while understanding that numerous others seem to prefer a bit of flavoring.  However, I believe this is a topic best left for a separate thread.

Tim

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!