I was wondering how much of a difference the tubes in your amp make to your sound. I have a B-52 AT-112 with the stock tubes.
With those amps, quite a bit. Give www.dougstubes.com a look.
if you have an idea about what you want from your tubes like more headroom, more gain, tighter low end, whatever, you should try places like eurotubes. bob at eurotubes will find what you're looking for, they test all they're tubes to see how hot and cold they are and what-not.
Bob will only sell you JJ. Thats all he sells. IMO there are better tubes out there.
Depends what sound you after, but changing stock should make alot of difference. If you can stretch it, groove tubes might also be a good option, as they really thicken up your tone, and give it more midrange punch. Very smooth sounding.