>rich asks:
>>How much grid current do you have to run to see an improvement in IMD,
>>Peter?
>
>It peaks about 25mA, as I remember it.
>From Eimac's curves for the 4-250A, minimal amounts of grid current
result in a substantive bend in the constant-current curves for the
grid-driven configuration. The flatter the curve, the less distortion.
>As the amp was built for AB1, and
>changed after I put a spec an on it and had a fit, I don't have a grid
>current meter. It has negative feedback with 8.2 ohm carbon resistors in
>the filament returns, ...
It seems to me that putting a cathode RF negative feedback R in the
filament return (center tap) would result in no distortion-reducing RF
negative feedback whatsoever, Peter.
Rich---
R. L. Measures, 805-386-3734, AG6K
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