HT 40 safe to swap 12AX7 for 12AT7?

[ht40guy]

Hi all,
Im wondering if anyone on here specifically knows if there would be a problem in swapping the HT 40 OD channel 12AX7 for a 12AT7 (a NOS Telefunken - sounds great!)to tame the gain. Ive read several threads pertaining to the use of AT7's in the PI slot of some amps but I have also read other places online saying you cant just swap them around, yet other places say you can.
Apparently an AT7 draws more current...would this cause any harm to the circuit or power tubes etc or would a straight swap be perfectly ok?

I have an old AY7 that sounds good (but I like the extra oomph the AT7 provides) and I have an old RCA 5751 I havent tried yet, so if the AT7 cannot be used I might use those.

Thanks for your help
Glenn

[Hedgehog]

The official line would probably be don't change valve types at all, but lots of people (me included) are running an AY7 in the drive channel with good results and no apparent bad effects on the amp. I don't think I've heard of anybody using an AT7 though.