>I've heard that applying regulated 3-400 volts to the screen of a cathode
>driven 4-1000 in grounded grid will lower the drive requirements. Any
>comments?
>
- This is yet another old wives' tale, Bob. In order for screen
amplification to take place, the signal must be applied between the grid
and the screen - which is why the screen is bypassed or grounded. Adding
screen voltage to a g-g amplifier shifts the ZSAC, but does not change
the drive requirements because no signal voltage exists between the
screen and the grid in a g-g tetrode amplifier. . . To reduce the
drive requirements for a 4-1000A, drive the grid, apply at least 6kV
anode and 1kV to the screen. The grid needs to be fed through a 1 to 4
bifilar step-up broadband transformer, and the grid needs to be
terminated in 200-ohms.
Rich...
R. L. Measures, 805-386-3734, AG6K
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