Posted this in a thread in BST, but thought others might like an interesting read. Miles is awesome:
//http://www.guitaramplifierblueprinting.com/Primers.html
Check out the Part 1 pdf. Lots of great tube info on that site. Guy makes a living customizing amps to a guitarist's liking (and other things, I'm sure). Not affiliated. Just an admirer of a dedicated data collector.