High end Class D amps?

@twoleftears  - I am thinking about trying an input buffer using tubes.

I don't think I would consider using the Korg NuTube like ATM does. This is a pretty high-distortion device - specifically designed to add distortion for synthesizer special effects. It also has a bad reputation for microphonics, and is hard to swap in and out. 

The 6DJ8/6922 tube that VTV uses is much better, but I'm not sure it's the ideal tube to use with the relatively low voltages I have available (approx +/-65v if I use the main supply for the Purifi module). I don't want to add another high voltage supply to drive a tube section, although I could consider a DC-DC converter as part of the buffer board design if I have to.

At any rate, I'd prefer to avoid the hassles of tubes, so I'm going to see what's possible with various solid state approaches first.

George - you obviously aren't interested in class D, so why do you keep bothering to post on this and other class D threads?

George - you obviously aren't interested in class D, so why do you keep bothering to post on this and other class D threads?

Really, you need to look a bit deeper sunshine, before ragging on someone.

https://forum.audiogon.com/posts/2062498

YOU are not one of the best designers. You are not even a designer. I would highly doubt you are an engineer.

Rules that apply to linear amps, do not apply to Class-D. As well, how well feedback works is a matter of amount of feedback, loop gain, and gain bandwidth.

The "best" designers are few and far between and they say things like this as generalities AND to sell THEIR amplifiers. They also only say them about non-class D amplifiers.

It is NOT used just locally either, it is used locally or globally, and both. Both work. Depends what sound you are trying to achieve and what your design parameters are.

Most discrete linear audio amplifiers are really quite simple. You think your music was recorded through low, local only feedback amplification chains after the microphone? Get real.

It is not 1973 or 1974 any more and no one is talking about Kenwood, but your ideas and knowledge seem to come from 1974.

And yes, throwing speakers in the loop is exactly where this is all going. Subwoofers with position and velocity feedback are already here and research is moving this up the frequency spectrum.

George see's one graph, or reads one article and he thinks that automatically applies to everything with the same basic name. That is technical ignorance talking.

georgehifi7,965 posts12-02-2020 5:53pm
Problems with any amps shouldn’t be fixed by using even more feedback as a fix, it’s a added by the best designers to clean thing up a little and usually just local not global in an already well designed amp.

All the greatest amp designers say it. An amp should be reasonably good spec’d, and to use it just as a clean up tool.
And the preference with the best is to use "local feedback" only by the best designers. Not global as being talked about here, and then even including the Class-D output filter in the global loop, what next throw the speaker wire and the speaker in the loop as well, like Trio/Kenwood tried all those years ago, utter sterilized disaster sound.

And using tube buffers with the capacitor coupling that’s needed. Is just colorized HF coverup softening job for the more serious Class-D sound problem.

Cheers George

You have no idea and do nothing but put **** on anything that's not "pro" Class-D.
It still has problems sunshine, compared to the better linear amplifiers I and many other still say so.

You are nothing but a Class-D flag waver, that I believe probably has an commercial interest either now, soon or in the future with it.