On Thu, 4 Sep 1997 00:38:19 +0000 w8jitom@postoffice.worldnet.att.net
writes:
>> To: amps@contesting.com
>
>Hi Rod,
>
>The most important thing you can do to insure stability is to use a
>very low impedance grid lead, and be sure the anode does not resonate
>on the same frequency where the grid has a high impedance.
>
>It's easy to measure the grids impedance by doing a measurement of
>transmission loss through the tube, from anode to cathode. Any
>sharp increase in power through the tube indicates the grid is
>offering a high impedance, and that sets you up for having a
>tuned-plate tuned-grid oscillator!
Would you please outline the procedure required in an existing amp, not a
lab jig. If it can be done with simple equipment as you describe, I
should think we would all benefit.
3-500Z's for instance usually use a Johnson socket, not some special
shielded version.
Tnx....Carl KM1H
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