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previous: Brutus To resolve your 120 hum problem, te... -- 10/3/2004 4:35 PM View Thread

Re: DC Heater Wiring

10/5/2004 4:19 PM
Re: DC Heater Wiring
The 120Hz problem could just be a mismatch of the output tubes. Swap them with a known good pair.  
Dynaco used a voltage doubler off of a 6.3V winding using 1N4002 diodes and 1000uF caps to power two 12AX7's. Because of the losses in the doubler, the voltage comes real close to 12V. Problem is you need one side of the 6.3V winding grounded instead of a center tap ground otherwise the filament wires still have 3.15V AC on them.

Ed Thanks guys.I'm measuring the v... -- 10/6/2004 1:33 PM