A 3-500Z will do c. –45db total IMD without a cathode feedback R.
Adding one will reduce distortion - with the tradeoff of higher drive
requirement.
On Dec 15, 2005, at 7:29 AM, TexasRF@aol.com wrote:
>
> Doesn't grounded grid/cathode driven operation provide much if not all
> of
> the degeneration/negative feedback we are discussing here?
>
> 73,
> K5GW
>
>
>
>
> In a message dated 12/14/2005 11:10:17 P.M. Central Standard Time,
> K1JJ@comcast.net writes:
>
> Correction:
>
> 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.
>
> 73,
> Tom, K1JJ
>
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Richard L. Measures, AG6K, 805.386.3734. www.somis.org
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