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In Reply to: RE: I get no music out of mynewly built amp posted by Tre' on October 19, 2016 at 14:23:13:
Actually, the driver stage is an "RH" type , i.e., there is plate fb from the output tube anode to the anode of the 6j5. The fb resistor is also 100k. So, wont that make the plate load 1/2 of just the single 100k resistor?
Significantly, when i touch the input grid of the 6j5 with my DMM probe there is no sound. nothing, no click, hum, or buzz. zip, zilch, nada. I measured about 60vdc on the plate, and IIRC, 2vdc on the cathode, but i can't find my notes about that measurement, so not sure.
The odd thing is that i built this same circuit with 6sn7 instead of 2 6j5 and it worked fine. Pretty much the same part values and the same circuit but , that amp did not have fixed bias, it was cathode biased.
Edits: 10/19/16 10/19/16
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Follow Ups
- RE: I get no music out of mynewly built amp - DAK 14:36:10 10/19/16 (3)
- RE: I get no music out of mynewly built amp - Tre' 18:21:44 10/19/16 (2)
- RE: I get no music out of mynewly built amp - DAK 20:22:49 10/19/16 (1)
- RE: I get no music out of mynewly built amp - Tre' 07:02:17 10/20/16 (0)