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RE: 20B

I took some measurements using a 1k sine wave input at 0.683VAC. FYI: instead of 100k ohms, there is a 220k ohm resistor at the RCA input (I have been playing with different input resistors, FWIW).

Here are the results:

Input signal: 0.683V

6C6
grid 145Vdc
plate 145Vdc (grid and plate are tied together for triode)
filament 4Vdc

2A3
grid 8.77Vac (using signal tone input)
plate 286Vdc
filament 2.6VAC
VDC P-K 237Vdc (target should be 250-265)


The 2A3 plate voltage is low at 286Vdc, typically I see it at 300Vdc.

The 6C6 grid voltage is 145Vdc, I typically see 175-180Vdc when in pentode mode.

I am unsure why the 2a3 plate voltage is so low and is the 6C6 grid 145V voltage OK since this is triode strapped?

Pat

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