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Old 13th Aug 2022, 9:41 pm   #13
murphyv310
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Join Date: Sep 2006
Location: Kilmarnock, Ayrshire, UK.
Posts: 5,422
Default Re: Band 1 Rod Pentode modulator (Part 2)

Hi.
Well that was interesting. I decided to try anode modulation using the existing output transformer in reverse basically, it sounded good but needed the balancing resistors for left and right from the PC to be reduced from 180 ohms to 47. It sounds nice and I can achieve over 90% modulation. I decided to try a 1ZH18B which reduced the filament, the only thing is the output went through the roof, the G2 is now fed from a PD but to tame the output I had to massively drop the Anode volts, tapping off the filament supply before its dropped to the filaments via the resistors gives superb results, with an anode voltage of 2.8v.
These valves really amaze me!
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