I recently inherited a non-working gibson scout. I fixed a number of issues, but can't seem to get the trem figured out. It has a cathode bias trem--the problem is that it distorts on the trem peaks. I've replaced the .01 and .022 caps and the 330k and 150k (the one going to the speed, not the plate) resistors in the trem circuit, and tried different tubes.
LFO Plate: 96v
LFO Cathode: 0v (tied to ground)
LFO Node: 176v before the 150k resistor, 96v on the LFO side
The schem says I should expect 118v on the plate.
Any thoughts?
The schem is:
http://www.gibson.com/Files/schematics/ ... 0Scout.pdf
Gibson Scout tremolo distortion
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martin manning
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Re: Gibson Scout tremolo distortion
What is the B+ voltage? Around 305 like the schematic?
What voltage is on the cathodes of the 6AQ5's? Around 17 like the schematic?
Did you check the values of the resistors around the trem output (1M, 150k, and 350k) and also the 220k grid leak resistors on the 6AQ5 tubes? I'm assuming all of these are all CC, and might have drifted up.
What voltage is on the cathodes of the 6AQ5's? Around 17 like the schematic?
Did you check the values of the resistors around the trem output (1M, 150k, and 350k) and also the 220k grid leak resistors on the 6AQ5 tubes? I'm assuming all of these are all CC, and might have drifted up.