Re: Filament Issue

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Mddeming-at-aol-dot-com 

In a message dated 12/4/03 5:50:01 PM Eastern Standard Time, 
tesla-at-pupman-dot-com writes:
As you say, a Class C amp or oscillator with a high Q tank, where the tube
is cutoff most of the time, the plate voltage would be higher than supply,
but then, you'd expect that and design for it.  Low emission wouldn't be any
different than having the tube cutoff.

Actually, there IS a big difference in the life of the tube between having 
a full supply of electrons with most prevented from reaching the plate and 
having only a small supply of electrons from the cathode available.
Also, if you plot the tubes characteristic curves with different filament 
voltages and again with different biases at full filament voltage, you will 
see a family of curves that are roughly similar in shape, but not matching.

Matt D.