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RE: 6BG6G mono amp sounds great but

Thanks, I was wondering if that was the calculation. The spec is supposed to be 1.2V at cathode, which would be 1.2 divided by 25ohm = .048, about right.

If I turn my bias adjust all the way to the other extreme, I had -26.6v on the grid, the cathode read .660v and the plate voltage plummets down to 294V. But cathode reading was moving in the right direction

Solved it mostly, by bypassing a dropping R in the pi filter which bumped up the B+ and now I can adjust for 1.2V at the OP tube cathode. I can raise B+ further if I go from 5R4 to 5V4 rectifier.
Thanks to responders.

Edit: The Sams Photofact schematic said -45V on grid which must be wrong, but it was what I had to go by. -33V is dialed in nicely.

Pete



Edits: 06/13/17 06/14/17

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  • RE: 6BG6G mono amp sounds great but - PeterI 20:47:08 06/13/17 (0)

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