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RE: The coating on the cathode is burned off by the filament or either the filament is burned up

Posted by vetmedrobert@gmail.com on March 24, 2012 at 08:41:32:
You are right about the 6bx7, the first one measured 80 volts on one plate and 110 on the other!
As far as gas goes is not that what the getter is supposed to deal with? The tube has abundant silvering so I would imagine there is no problem there.
Heater glows, and the tube gets plenty warm so I imagine this is not a problem.
So I imagine it must be low cathode emission. I am unsure just how this works to lower the plate voltage. Plus this is a relatively new tube not previously used (as far as one can tell from anything coming from Russia). So I am puzzled how it is that the tube could be defective. Anyway, thanks for giving me something to think about.