What is meant exactly by the description 'more musical'?

and IF you can’t hear how an amplifier destroys temporal information, try getting your system in phase… and or considering a speaker that passes the impulse test… Since getting the electronics in phase is free, start there….

@wyoboy My comment

So if you want the amp to be musical, its important that the distortion vs frequency is a flat line across the audio band (or nearly so- 10KHz is probably acceptable since harmonics at 20KHz won't get a lot of attention). Tube amps with little or no feedback have no problem doing this

has the answer, if its a bit obtuse. Any amp with zero feedback will have distortion vs frequency as a flat line. So it will have a good chance at being musical whether tube or solid state. There are other factors relating to topology of course so this isn't sure fire.

Interesting , some people can hear negative feedback = TIM and simple temporal distortion in addition to the various forms of harmonic distortion Ralph and a FEW ear/brain centric designers ( very rightly but not completely ) focus on.

@tomic601 Timing usually isn’t a problem with negative feedback. Phase shift is (and can look like a timing problem if you’re only using a ’scope to see what’s going on). TIM really isn’t a problem with feedback so much as it was a problem associated with part of the (high feedback, solid state) amplifier that was outside the feedback loop: the base of the input transistor or perhaps the entire transistor, depending on the design... which would easily distort on transients.

Norman Crowhurst pointed to the problem of a non-linear feedback point (node) in an amplifier, such as the cathode of the input tube 65 years ago. He points out that due to that non-linearity, the feedback causes a noise floor of higher ordered harmonics as well as inharmonic (intermodulation) distortions. He did not propose a fix. Later, Peter Baxandall pointed to the same problem in solid state amps and simply proposed more feedback as a fix, which does not work; any signal distorted by that non-linearity (in this case, the base of a transistor) will not somehow magically be healed by more feedback.

The solution is to mix the feedback with the incoming signal using a resistor divider network, before the signal gets to the input of the amp (the way opamps do it). In that way the feedback signal is not distorted and so can do its job more effectively. FWIW this is how we’ve applied feedback in our OTLs for the last 35 years or so.

Since most people believed Baxandall and don’t remember Crowhurst talking about the same problem 20 years earlier, we wound up with a lot of amps that were less than musical in the last 70 years. The issue of increasing distortion with frequency really didn’t show up for decades after! So now you have something to look for in the measurements that relates directly to that mysterious ’musical’ aspect some amps have and some don’t.

For those who want to dig into more details about this feed back problem which atmasphere explain just above :

Read the first 24 pages article titled

The sneaky pitfalls of feedback and feedback theory

https://www.temporalcoherence.nl/cms/en/pyra

It will give you a gist about the complexities of the problem...

I myself cannot make any wise observation about amplifier design at all ..

We are lucky to have atmasphere here regularly for answering questions ...

Ralph, I have to believe that musicality, immersion, involvement and, ultimately, suspension of disbelief has much to do with an amp designer’s taste and ear than simply harmonics and distortion.

I would say that your sensibilities as a musician have as much, or more, to do with your amp’s andpreamp’s sound as your technical abilities.