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previous: Ken McGill Aaargh Just spoke to my Tech friend... -- 4/13/2000 7:01 PM

Re: Marshall 1987X biasing question

4/13/2000 7:15 PM
Troy	Re: Marshall 1987X biasing question Ken: I'm not familiar with how the reissues are layed out but usually you don't have to desolder anything using the OT shunt method of biasing. Just find where the center tap of the output transformer comes into the board and clip your red lead on that point. Clip your black lead on the plate of the EL34's (pin 3). If your tubes are mismatched (in current) then you'll have to check each individual tube and use the "highest" current tube as your reference. Remember set the Fluke to amps/miliamps. Troy

4/13/2000 7:15 PM

Troy

Re: Marshall 1987X biasing question

Ken: I'm not familiar with how the reissues are layed out but usually you don't have to desolder anything using the OT shunt method of biasing. Just find where the center tap of the output transformer comes into the board and clip your red lead on that point. Clip your black lead on the plate of the EL34's (pin 3). If your tubes are mismatched (in current) then you'll have to check each individual tube and use the "highest" current tube as your reference. Remember set the Fluke to amps/miliamps.

Troy

Replies:

peter Troy, I'm not sure I understand you... -- 4/13/2000 7:44 PM