Power tube selection, types and brands, make a big difference in sound, especially the types, i.e. KT88 vs LL34 and all varients.. For the small tubes the tubes that make the biggest difference is the center two tubes.
But it all depends on what you are hearing now and what you want to hear, tht is you need to have a sonic goal in mind before you start rolling tubes.
But it all depends on what you are hearing now and what you want to hear, tht is you need to have a sonic goal in mind before you start rolling tubes.