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Old 08-09-2013, 07:55 PM
bob91343 bob91343 is offline
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Pin 5 on the tube is the screen grid. It shouldn't be such a low voltage; I think 100V or so would be better. I am not looking at the tube data so perhaps I am in error.

In order to get plate current in a normal pentode, the screen voltage needs to be positive, not as high as the plate. If you increase the screen voltage by a series resistor to B+, be sure to decouple the audio from the pot with a coupling capacitor. And bypass the screen for RF with perhaps a 220 pF capacitor.
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