>
>I have a homebrewed PL-172 amp deck I'm working on (someone else's I bought
>cheap...don't throw rocks at me!). In tracing thru the circuit, it's a
>cathode-driven amp with provision for grid bias, but both the screen and
>supressor are DC grounded.
>0V on the supressor causes me no grief (it's even rated there), but 0V on
>screen?
The suppressor is usually operated at the same potential as the cathode.
Grounding the suppressor and grounding the cathode is normal, however,
grounding the suppressor and driving the cathode may cause IMD probs.
> I haven't ever seen a Triode-connected PL-172 in the literature
>(not that it's not there of course).
>Has anyone on the list seen a successful triode-connected PL-172 circuit?
not I
I doubt that the tube has been damaged. The grid is way more rugged than
the grid in a 4cx1000A. . I would be tempted to operate the tube in
Class AB1, grid-driven, Scott. Even if some way could be devised to
operate the PL-172 as a high Mu triode, cathode-driven tuned inputs are
not a piece of cake. Grid-driven tuned inputs are. .
Rich...
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
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