Can a Amp be "timeless" and compete with todays amps?

In addition to what you write, is not the negative in negative feedback, simple because it is subtracted?

If I get your meaning, probably not. In most amplifiers the feedback is applied to a node that has non-linearities, so often feedback signal itself contains distortion not present at the output! For example in a typical solid state amp, the input circuit is a differential amplifier. One of its inputs (differential amplifiers have two, one inverted and the other non-inverted) takes the signal. The other takes the feedback. But the device (transistor) isn't perfectly linear... Of course, if you applied enough feedback, you could overcome this issue...

No I meant in a much more simple fashion, i.e. a portion of the output is subtracted from the input. Literally negative. It would technically be out of phase but that is by definition. 

When @teo_audio writes positive feedback, does he really mean feed forward?

@atmasphere 

Your participation and patience on this Forum is something for which I am truly grateful. Comments from you are always illuminating and helpful.

Thank you.

No I meant in a much more simple fashion, i.e. a portion of the output is subtracted from the input. Literally negative. It would technically be out of phase but that is by definition. 

Yes- we use a resistive divider network to do that in our smaller OTLs (we run 2dB of feedback in the M-60). You either do it that way or thru an active device, such as a tube's cathode while the input signal is applied to the grid.

But the feedback network itself can be simple or complex, depending on (...how well its designed...) the expectations for it, such as keeping unwanted frequencies out of the loop. For example in a class D amp that is self-oscillating, the feedback network defines the oscillation frequency (known as the 'oscillation criteria') since so much feedback is applied that the amp goes into oscillation as soon as its turned on; the amp then uses the oscillation as the switching frequency. That network can be a 4th or 5th order loop with 6 or 7 variables; for that you'll need a computer to sort it out.

What this means is its possible to build a solid state amp that is every bit as smooth in the mids and highs as the best tube amps and leave nothing on the table in terms of detail, sound stage and the like, in such a way that vintage amps simply cannot compete (not that they sound bad, just they don’t sound as good). This is one of those things that is easy to hear and easy to measure.

Bruno Putzeys wrote a wonderful article on feedback.

For example in a class D amp that is self-oscillating,

C'mon folks, apply a little critical reading and thinking skills. Read and see what is clearly between the lines. While I had always admired Ralph and thanked him for his participation here (though disagreeing with his continued insistence that higher cartridge loading is always best unless RFI interferes and that correspondingly, RFI is the chief factor upon which cartridge loading should be chosen), there is clearly a theme here towards promotion of his Class D amps. I have to wonder how a customer of Atma-Sphere who just paid 20K+ for a pair of the MA-1's a month ago must feel when it's principal proclaims his own product to be by nature inferior to his new solid state alternative. 

And I am also surprised and even angry at myself to only now notice that Ralph is so reliant upon that which can be measured.