Re: Tube watts & volts
"How is the figure of about 3X for 75% efficiency arrived at? I recall
that most class-C amplifiers run at about 80% efficiency... is that
I'm trying to decide how to find the current I'll need from the plate
transformer. Is that equal to the plate current, with the grid current
added in somehow? (How is that done?)"
That 75% was just conservative, that's all. If you put 100 watts in,
the power output would be 75 watts and the dissipation 25, for a ratio
of 3:1. It's certainly possible to get higher efficiencies with a
well-designed amplifier, and probably with an oscillator in spite of the
fact that the grid drive has to come from the output.
I'd probably be inclined to just put the full unrectified voltage on it
and see what happened.