Sherman wrote:

However since I don't usually go around tapping the tubes while
playing the amp I doubt they make any difference.

You only do this to find out where "bad vibes" couple into your
audio equipment, do you? If you´re listening to vinyls - very
likely with tube amp enthusiasts - you may want to tap the vinyl
itself, stylus down but turntable not rotating...

It is a very good idea to have the vinyl dampened (sought to the
turntable e. g. by some vacuum) - the difference is truely amazing.
It is "microphonic" like nothing else in the reproduction chain.

Cheers

Walther