Put the resistor in series with the input coupling capacitor.
If you want to experiment with negative feedback with multiple GG
drivers you might try link coupling between stages. You can reverse the
link at the feedback point to get the out of phase signal. You will need
at least a 2 stage amp to do this. Maybe an 811A in GG as a driver for
Put a small coil at the bottom of the input link of the 811A to lift it
slightly above ground. Couple the plate of the 4-1000 to that point
through a small capacitor.
Tom Cathey wrote:
> It was pointed out to me that the cathode resistor for negative feedback is
> to be used only for a grid driven [grounded cathode] amplifier to generate
> degenerative [negative] feedback.
> In a cathode driven [GG] amplifier, the cathode is in phase with the plate
> and it will not work. A different method must be used for neg feedback.
> This is why my GG triode did not show any diffence in drive when I tried
> the cathode resistor.
> I saw the idea in the archives and must have missed the fact that they were
> talking about grid driven amps at the time.
> Tom, K1JJ
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