Fender '57 Twin-Amp

[Eddie B.]

I just tried substituting NOS GE JAN 6072A's(12AY7)in V1,V2, and V3 of my new '57 Twin-Amp. The resulting drop in gain is just what I'm looking for, however the bright channel now has a fairly loud hum. The normal channel is dead quiet. Substituting any of the other 6072A's into V2 has no effect on the hum level of the bright channel. But if I put the 12AX7 back in, the hum disappears. Any thoughts??????

[voxworld]

I'm speculating because no one else has posted.
Have you got another 12AY7 to try? I'm not sure but maybe one half of the 12AY7 is shared with the bright channal and that half of your tube is not functioning correctly?
Just a thought.
I have a 12AY7 in the first position of my Victoria Low Power Twin and it's staying for sure.
A 5751 is real nice too.

[Eddie B.]

Thanks for the reply. I tried three different 12AY7s in V2. I even tried it with no tube in V1. The hum was present each time. I settled on a 12AX7 in V2 (no hum), but I like the way the amp sounds better with the 12AY7 in V2. Anyone else have comments?