In the 60's a ham friend of mine was experimenting with different tubes in
grounded grid configuration.
One experiment he did was four 4CX250Bs.
He first tried both grids grounded and fried them before he got the output
power he was looking for and
then tried a series resistor in the control grid of each tube to limit the
current but I think it was on the order of
a kOhm or so. Still did not get the results he was looking for and finally
tried connecting the control grids to
the cathodes. It worked but he had low gain and just did not have enough drive
to get the same output power
that he could with the four tubes running with the cathodes grounded.
However, I suspect that if you did run the 4CX250Bs in G-G and had the
control grid connected to the cathode
it would be quite linear. The cathode impedance would be a bit high but the
reason I say this is that I think the
screen current would be very low. However. you would have to swing the cathodes
to a peak negative voltage of
250 to 300 volts. I would like to find time to experiment with this and make
distortion measurements but just don't
have the time.
73
Bill wa4lav
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