Andy Evans wrote:
This is the snag with making obervations without reliable measurements. You
end up having to try things 'at random' in the hope some might seem better,
but not then be sure if or why... (JL)

This is true, but it doesn't rule out trial and error as a legitimate way of
getting results. When you think how many times Beethoven re-wrote the 5th
symphony (a process typical to composition), you can see that the final result
was in fact a process of trial and error. I think it's quite fair to think of
creating a sound system as an act of creativity,

Thing is that when creating a symphony there is no definable goal.

when creating an amp there is only one definable goal, which is
linearity across the audible frequency range.

if you want to go for a 'coloured' amp design, then all bets are off I
guess.