Hi Gang,
I have been trying to find the issue with this amp since I finished wiring it! The amp has very low output volume and it is distorted. I have changed all the tubes and traced all the wiring which seems fine. I actually traded out the OT for another one I knew was good and still the same problem. I tested the preamp plate resistors and they all checked out fine. The plate voltage on the V1-12AX7 is 140vdc on pin 1, and pin 3 is .89 dcv, pin 2 is 0. 6,7,8 is also 136,0,.94 respectively. B+ is 200vdc coming to the plate resistors and the 100k resistors drop it to 140v going into the tube. Isn't this too low? I can't seem to find any voltage charts on the Princeton Blackface Reverb, so I am a little lost. The dropping resistors by the filter cap can all check good. V3-12AX7 is also at the same voltages and it also seems low. The 6v6's seem fine with 310 vdc plate, 304 vdc screen grids, and -26 vdc on the control grid. What am I missing and what should I suspect?
Help!
Tim
I have been trying to find the issue with this amp since I finished wiring it! The amp has very low output volume and it is distorted. I have changed all the tubes and traced all the wiring which seems fine. I actually traded out the OT for another one I knew was good and still the same problem. I tested the preamp plate resistors and they all checked out fine. The plate voltage on the V1-12AX7 is 140vdc on pin 1, and pin 3 is .89 dcv, pin 2 is 0. 6,7,8 is also 136,0,.94 respectively. B+ is 200vdc coming to the plate resistors and the 100k resistors drop it to 140v going into the tube. Isn't this too low? I can't seem to find any voltage charts on the Princeton Blackface Reverb, so I am a little lost. The dropping resistors by the filter cap can all check good. V3-12AX7 is also at the same voltages and it also seems low. The 6v6's seem fine with 310 vdc plate, 304 vdc screen grids, and -26 vdc on the control grid. What am I missing and what should I suspect?
Help!
Tim
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