Not to hijack this thread.. What harm will it do to an Amp that runs only on one type power tubes (6L6/EL34?) and does not have a bias pot or switch, if I put different tube? let's say 6v6, KT66,KT77 etc..
I bought a used line 6 spider valve (6L6) :mrgreen: & I've been tempted to put EH6CA7 on it.