#1
Do the power tube brands matter? as how to your tube amp will sound? It just powers the amp up right?

One of my friends was curious, and I didn't know what to say.

He was thinking of getting Jj brands pre amp tubes and sovtek power tubes.
#3
Not just the brand, but the specific model matters too. Sovtek makes 4 diferent new production variations of the 12AX7.