[Amps] Cathode (filament potential to ground)

[HENRY PFIZENMAYER]

OK Gurus -- What is the DC voltage from a good 3-500z  filament to ground
with its grid grounded for DC and 3000 volts on the plate ? I remember the
cathode voltage on cathode keyed tube stages approached the plate voltage
key up , but never keyed a grounded grid stage in the cathode.

Hank K7HP