ok, I just got a new head.. it's a Bugera 6262 head with 6 12AX7 preamp tubes and 4 6L6 power amp tubes....... i'm buying all new tubes for it (and I'm switching to EL34 power amp tubes) and was wondering which would make the biggest difference in tone, the preamp or power amp tubes since I can't afford to get all the tubes right now
Depending upon what you put in it, any of them could have an impact. Pick the right brand of 12AX7 and put it in the right socket and you can really change your tone. Same for the EL34s. They're also going to have an impact on your sound. It's one of those "total package" deals. Search the net and have a look at the tube sites. Different brands of preamp tubes will do different things to your tone.