hi.. i got a question - just to be sure. amp needs to be rebiased only when I change power tubes, not when i want to change preamp tubes, or PI tube? do i have to look for preamp tubes or PI tube with some special parameters, or just any ecc83 or 12ax7 will work in preamp section or PI slot? sorry for that stupid question but i need to be sure - i don't want to damage the amp
