Can someone tell me what each pre-amp tube is for? I have been swapping tubes in and out not really caring what each one does, only caring about how it sounds. I pull one, listen to it, put the other back to see if it was better and then decide which to keep. Sometimes it's dramatic and sometimes not. I assume V1 & V3 have a lot to do with the lead channel, but I've gotten curious lately as to what slot does what. I've been dying to call Mike at Mesa for years just to talk to him, kinda like talking to the Hendrix of amp builders, in my opinion anyway, and have him give me a little bit of knowledge about my amp. The amp is a C++ with no reverb so where V4 is, there's nothing, kind of like V1-V3, V5 all 12ax7 tubes.