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Hi Guys,
I have this old Pepco Riviera 725 that I converted to a Princeton AA964 clone (added tremolo as well although it is too fast for my taste).
Everything was fine until I added the feedback resistor (2K7). I had a high frequency squeal that would not go away. I then replaced the 2K7 with a pot and found that the squeal went away when the pot was at 10-12K. If I cranked the volume all the way up I could hear it coming back although not as loud as when the 2K7 was in there.
After some research I found that a possible cause could be that instead of (-) feedback, I was sending (+) feedback. The cure for this (if this is the case) is to reverse the output wires to the OT. So I have a couple of questions.
1) Is the (+) feedback a possible cause.
2) Would reversing the output to OT cause any harm (as a diagnostic).
3) Which .01uf cap (or both) should be changed to .02uf to slow down the tremolo speed.
Thanks and Happy New Year to all.
I have this old Pepco Riviera 725 that I converted to a Princeton AA964 clone (added tremolo as well although it is too fast for my taste).
Everything was fine until I added the feedback resistor (2K7). I had a high frequency squeal that would not go away. I then replaced the 2K7 with a pot and found that the squeal went away when the pot was at 10-12K. If I cranked the volume all the way up I could hear it coming back although not as loud as when the 2K7 was in there.
After some research I found that a possible cause could be that instead of (-) feedback, I was sending (+) feedback. The cure for this (if this is the case) is to reverse the output wires to the OT. So I have a couple of questions.
1) Is the (+) feedback a possible cause.
2) Would reversing the output to OT cause any harm (as a diagnostic).
3) Which .01uf cap (or both) should be changed to .02uf to slow down the tremolo speed.
Thanks and Happy New Year to all.
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