Class D is just Dandy!

There isn't time to read all of this thread, so my apologies if it's already covered the Red Dragon S500, but I've had that for almost two years and am really pleased with it.  Sound is detailed, balanced across the frequency range, bass is deep and articulated, mid-range is clear, treble is also clear and realistic though I sometimes think it might show a little more sparkle.   Certainly it's well ahead of the Class AB monos I had previously, and they'd been well recommended.  

The main partnering equipment is an Esoteric X05 SACD player, Townshend Allegri preamp, and B&W 804S speakers. 

I don't doubt that there may be better Class D power amps.  Some will be better because of their design and the quality of their components.   It's also possible that some Class D modules are better than others.   Living in Britain I don't get much opportunity to compare the sound of different systems.  I did hear one of the first NORD NC500 power amps (it's only an hour's drive to where they are made), but the demo wasn't very successful from my point of view - mainly to do with the circumstances and not necessarily a criticism of the amp itself.   Buying the Red Dragon was something of a risk because although I could return it within 45 days, I wouldn't get the import duty back and there's be expensive carriage costs.   But it's been highly successful and I'd probably have to pay a lot more to get something that performs significantly better; though in five years' time, perhaps, when things have moved on a lot, better quality may be available more cheaply.

I haven't seen much discussion of the NAD M22 outside of general discussion of the Hypex nCore modules, but I've had this amp for the better part of a year. It replaced an Ayre V-5xe which put out too much heat for the hot southern summers I have to endure. While perhaps it doesn't have quite as much depth as the Ayre, it has incredible bass definition and control, a wide soundstage, and a sense of liquidity, propulsion and flow that the Ayre definitely didn't have. It has a pristine clarity and neutrality without seeming anywhere near harsh, dry or boring, and the dynamics are thunderous. I really couldn't ask more from an amp. Considering I see the M22 going for roughly 55% off the MSRP around these parts, I don't think there's a better performance bargain for power amps on the used market.

I'm using a PS Audio HCA 2 with the Cullen mods and I love it. 

I auditioned a variety of amps in my home - a high powered ARC tube amp and a Pass Class A amp at the same time I had the PS Audio.  I think I may have liked the Pass amp about as much as the PS Audio, but I'm inclined to keep my gear turned on all the time I didn't think I'd like the extra heat and energy usage.

Time and innovation march forward so I'm sure there are others that are better, but I'm not feeling any urge to upgrade at this point.

Paul McGowan of PS Audio recently released a really good video on the future of Class D audio.  

https://www.youtube.com/watch?v=98QQ43qgzbg

I still here the same fear obfuscation and doubt thrown at Class D amplifiers, without meaningful research behind it.

One of the biggest: Class D can't be as good as (blah blah) until the switching frequencies are above x Hz.

With zero objective evidence of such a thing. This is a vague, moving goal post.  I've heard a number of Class D designs that equaled or better very expensive Class A designs.

I'm not asking you to like any particular class D design, nor am I saying all Class D amps are going to sound as good as any linear amp with  particular speaker. I am suggesting this is thin techno-fear without research or experience behind it.

Yes, there is ultrasonic noise. So what? All amplifiers have noise. I have seen and heard zero evidence of this being audible. Yes, there will be amplifiers that will move the switching frequency from 450kHz to higher. So what? At what point, exactly, will it be high enough? What measurements, exactly, and what threshold of those measurements, will satisfy you that they have reached audio nirvana?

You do not have to like Class D. That's fine if you do not, but I've read encyclopedia's worth of hogwash on this particular subject here and elsewhere on the net. It's like a scam diet, which proclaims that x protein is the root of all evil. Buy my new book and I'll show you how to avoid and heal your gut... blah blah blah.

I also want to point out, I've been listening to Class D amplifiers since the 1980s. They were horrible, despite overall reasonably good specifications. So I'm not saying you should listen with specs, but rather, find the specs that correlate to audible effects. 400mV of 500kHz noise is measurable, but not audible, and my amps sound a lot better or as good as several Class A amps with all the speakers I've heard. I would gladly trade the size, cost and efficiency in exchange for a measurement that has zero bearing on my experience.

Sorry.  had to vent.

Best,

E