[Amps] 813's question

[jerome schatten]

I'm running a pair of gg 813's with both the screen and control grids
bonded directly to chassis ground.  I meter the combined grid currents
from chassis to the CT of the filament transformer with a 0-1 ma meter
with a shunt. B- is not at chassis ground but is returned to the CT
through the plate meter.

My question is this: at 50ma/tube of grid current (2000v Ebb @ 350ma
Ip), what percentage of the total grid current would likely be control
grid current and what percentage would be screen current? What should
the maximum combined grid currents be held to in this configuration?

My good old RCA transmitting tube manual give an ICAS grid #1 rating of
30ma for a single tube in a class C configuration.

Although this beast has been running fine for 40 years, I'm just getting
around to wondering about the grid current.

73'
Jerome - va7vv
Vancouver