I've come into a pair of 4-400A's. I'm thinking about building an amplifier
with one tube
and using the other for a spare. Looking at the data sheet for class-C CW, the
maximum
rated plate current is 350 ma. This means that at 3 kV on the plate I can
expect to get
only about 750-800 watts output. This does not come close to utilizing the
400-watt plate
dissipation of the tube.
At 4 kV, I could get 1400 watts input and about 1050-1100 out. That's a lot
better. But it
means a lot of extra expense -- the power supply, tuning capacitor, etc. need
to be bigger.
Is this correct? Why is the plate current limited to 350 maA? Is it a
limitation on
filament emission?
Of course I can use both tubes and get full legal power. But then I need
another socket,
chimney, etc. Or maybe I can use the "SB220 cooling method" and cheaper sockets.
--
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/
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