>In message <PKUw4HABVmmzEwFZ@ifwtech.demon.co.uk>, "Ian White, G3SEK"
><G3SEK@ifwtech.demon.co.uk> writes
>>...snip......... Also
>>the 91b has a low-impedance grid bias supply, so small amounts of grid
>>current do not spell IMD "nutsville".
>
>I'm learning a lot here, ...snip,,,
Yes, but does it wash? When a tube with a high output-R (100k ohm) bias
supply is temporarily overdriven by a voice peak, the negative grid bias
voltage temporarily increases due to grid-rectification and the resulting
E=I*R drop across the 100k resistance, so the grid becomes more negative,
so grid current tends to decrease, which limits IMD-genenrating grid
current. OTOH, with a stiff grid bias supply, overdrive produces high
grid current. ....... Does increasing grid current in Class AB1 increase
or decrease IMD?
Rich---
R. L. Measures, 805-386-3734, AG6K
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