OP has a depth of understanding comparable to that of Julian Hirsch in 1970. Since then a lot has arisen to pique the curiosity of both listeners and amp designers. The effect of global feedback was illustrated by Matti Ottala. Richard Marsh published his findings on capacitors. Bob Carver exposed how protection circuits can intrude on music reproduction. All applied to supposedly transparent SS amps with ruler flat response “from DC to light”. Today, we have D Class surging in the market with Hypex and Purifi. Long live the curious!
Why do amplifiers sound different?
Coming from a electrical engineering background, amplifiers theoretically should all sound alike as when measured into an 8 ohm load, their frequency response is extremely flat.
Usually + or - less than 0.2 dB. Your ears can't detect that.
What makes them sound different is the fact that speaker impedance various with frequency. All solid state amplifiers that do not have output transformers vary their output slightly depending on the impedance they see at each frequency.
That's why matching amplifiers to speaker matters.
All tube amplifiers have output transformers so they aren't affected by impedance fluctuations.
That's one reason they sound better to most people.
Odd vs even order harmonics is another but that's another discussion.
Usually + or - less than 0.2 dB. Your ears can't detect that.
What makes them sound different is the fact that speaker impedance various with frequency. All solid state amplifiers that do not have output transformers vary their output slightly depending on the impedance they see at each frequency.
That's why matching amplifiers to speaker matters.
All tube amplifiers have output transformers so they aren't affected by impedance fluctuations.
That's one reason they sound better to most people.
Odd vs even order harmonics is another but that's another discussion.