60hz hum develops after 6-8 hrs, and HOT

[aroide]

Thanks for the advice.  I did find some tubes when searching  for p vs pi.  I ordered 2.

While I had the preamp out for replacing my loose 300b socket, I put everything back and checked voltages.  Sure enough, terminal 6 is 185V (with the dead EL84 on that side) while terminal 11 is 146V.  If I swap EL84s, the voltage imbalance follows.  I must have been operating this way for a 8-15 hours or so (I know last week both EL84s were glowing).  And the preamp sounds great.

Have I been hurting anything operating this way?  I'm sure I've stressed the circuits around.  But they work with a working tube so all is well as far as I can see.

[Doc B.]

If it's working, it's working. If parts were stressed to the point of failure they would have failed. Now you can sit back and enjoy.

[aroide]

Thanks Doc!  As soon as the new EL84s arrive, I'll pop one in and let the toe tapping begin again.