12AX7 vs 12AT7

Hey folks,

Just wanted the opinion of a few experts here. What are your thoughts on replacing a 12AT7 input tube with a 12AX7? I know there is different plate voltage and the AT has less gain. I recall one of the Cary amps that actually states it can be done. Is it worth trying or should one take a close look at the schematics first?

thanks in advance!

I wouldn't do it; each tube is different electrically; the 12AX7 has higher gain but the 12AT7 has higher current.
Bobgates is right. If you want to tailor the sound, get the best NOS 12AT7 you can afford or have a knowledgable technician change the resistors so that the circuit is optimized for a 12AX7 if you really want to go that route.
Some circuits can use both.. Also the lowest gain of the series is the 12Au7's but make sure you can use any of this family first..

Beyond that 12AT7's for the most part are easier to find in better quality these days, even some of the new productions are pretty decent..

12AX7s are higher gain, which also in many applications equals much more Noisey but un-needed cause you can just turn the volume up a little on a AT7 and get better sound and quiter background.. This is just in my experience thats all.
I guess it is not s good idea at this point.

thanks for the help!