"Rockinghorse Winner"
wrote in message
OK, but your timeline seems to say that by the late '80's
these op amps had improved greatly since the 70's.
However, I have owned a mass market reciever from the mid
90's that I paid about $300 for (not a cheapo amp). The
difference between it and my current tube amp is
profound.
Depending on the tube amp, proper bench measurements could probably explain
why.
True, I have not compared it with a high end SS amp, but
I'm sure the high end amp would sound just as improved
over that crap receiver as mine does.
A mid-90s receiver would now be 16 years old and may be defective.
You can't tell ME that all amps sound the same! 
Nobody is telling you that all amps sound the same. It is just the good ones
that sound the same, and there is good reason to believe that neither of the
amps you are comparing are good amps.