12ax7 in place of 12at7 driver tube?

[kent]

i have a fender 64 vibroverb custom, can i swap these out without damage to anything? for tonal options

[Rich M]

12AX7's have a lower plate dissipation that 12AT7's so it is generally a bad idea to sub an X7 for a T7. The other was around is o.k.. If you haven't tried it, I would put a Mullard CV4024 in (NOT the reissues). Seems sonically different from most T7's I've tried and seems to have lots of gain.

[Blue Strat]

What Rich said. Mullard CV4024s are the s&*T!