HELP needed from tube amp gurus! b15n distortion and fade problem

[agedhorse]

Agreed, tossing in a new set of output tubes is a way to ruin a tube if the fault is in fact within the supporting circuitry.

 

[whitelines]

All good tips peeps. When the tech tested my tubes, he did the old bang them with a chopstick test, and they still tested ok. That being said, what is working at the moment can all change 5 minutes from now if there is a flaw. Side story: My day job is writing code to control electrochromic (electrically tinting) windows (www.halioglass.com). The bane of my existence are windows that worked when they were installed, then fail intermittently months later due to thermal stresses.
I actually wish my amp would fail more often, it would be easier to fix.
@beans-on-toast Checking out the standby switch is an interesting point. Thank you. I will check it's impedance I've a bunch of switches while unpowered. I suppose I could try getting it into fail mode while it's running by toggling it back and forth slowly and listening for hum.
@agedhorse trying new tubes will be a last resort for sure.

 

[beans-on-toast]

@beans-on-toast Checking out the standby switch is an interesting point. Thank you. I will check it's impedance I've a bunch of switches while unpowered. I suppose I could try getting it into fail mode while it's running by toggling it back and forth slowly and listening for hum.

Those type of windows are the future. Interesting technology.

It would be easier simply to patch in a different standby switch to test. Temove one leg of the installed switch.