[AMPS] Peak reading vs True peak

[Peter Chadwick]

Jon says:

	>How much does gain typically get reduced by?

I maintain that in grounded cathode, it doesn't. We have the complication
here that I'm talking in terms of the plate swing during the RF cycle. As
the grid goes positive, the plate current increases, and the plate voltage
drops. At the peak of positive grid volts, plate current is a maximum and
plate voltage is at a minimum. That voltage is set by the load impedance and
the plate current at the peak of the cycle - which is fixed by the grid
volts. The gain isn't directly related to the plate volts, but to the drop
in signal handling - the gain compression point has come down. At lower
inputs, the gain will be much the same - especially with a tetrode, where gm
is very loosely related to plate volts.

Looking at GG, that will be appear to be a bit different, because if the
drive and fed through power are the same, but the tube is producing less
output because there's less plate swing, then the total output power is
less. Effectively, the gain appears to be less.

Still, hell has frozen over, as you say, Jon!

73

Peter G3RZP


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