Sam Goldwasser wrote:

"Bob Shuman" writes:


The diodes were my thought as well, but this may not give the necessary
control since voltage drop must be a multiple of the bias voltage. But this
will certainly get you closer and help determine if you have another problem
that is causing the filaments to glow so red hot.


He said the plates are glowing red. That's not a filament voltage
problem.

sounds like a Tank miss match or not enought on the grid verses the
plate current
maybe even both!