I do not seem to have my data sheet to hand. I wonder what
the optimim screen voltage is for the 4CX250K with 1.6kV
on the anode, for SSB use with 100mA standing bias? Perhaps
it does not matter so much if it is 250V-350v and well
regulated (shunt style). 320-360V is quoted for a 2kV EHT.
The reason for asking is I have come across a TV amplifier
that uses 1200V anode, 250V screen and 180mA bias for 50W
of RF. The circuit is an unusual cavity design with current
feedback to improve linearity and cathode driven. I it happy
giving 100W on 432MHz, but I am sure it can do better if I
raise the EHT using the 1200V ac tap rather than the 1000V ac
tap on the transformer which is 275VA CCS.
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