Bob Latham wrote:

Don't anyone ever tell me all good amps sound the same, they
simply don't, unless of course these amps are both not good.

Or one of them was good and the other wasnt.

Or the listener imagined it (you didnt say anyone else heard that, only
the listener)

All good amps will produce the *exact same* voltage pattern on their
outouts. hence if theres a different sound, at least one of the amps is
'not good'.

You are also unclear on the point of wether any other parts of the
signal path changed - did you use the same source on both amps or not?