Can anyone tell me what controls the gain of a vacuum
tube ( other than someone that actually worked with these )?
Er, I thought it was related to the distance of the grid from the cathode?
Can anyone tell me how the grids must be placed for an
electrometer
preamp tube and why?
If I knew what an "electrometer" was, I'd be doing better :-).
My tube background consists of taking television repair in high school. We
used tubes, but we sure didn't make them.
Actually, far and away the most common "repair" consisted of plugging them
back into the wall :-).
Those that understand these things will always be in
demand.
Those that think they can ignore these kinds of things will
wonder why things are beyond understanding.
In my experience, most people take it for granted that most things are
"beyond understanding".
Vince