....tubes have to be biased in order to operate. There is a bias mod for 5150s that some people have to make them a bit hotter. Perhaps you misunderstood something involving this? You are also talking like changing tubes will change the tone completely...different types of tubes in the same amp will do very little to the sound. Yes it will change, but not THAT much.
Youre mis understanding my take on tube swap.
I think it will smooth out the harsh mids.
And a 12at7 in the V2 will tame some of the shit
going on with the amp. Im not looking for a different
tone, Mainly looking for less upper midrange harshness.
And You dont have to rebias an amp, Machine head supposably
didnt have any "bias mods". Which is what i was referring to.
Sry for the confusion here.