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Princeton vibrato problem

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  • #31
    The 25µ cathode cap I mentioned connects between V4 pin3 and the ground point I mean on the other side of the board where 7 wires in total connect to one eyelet (one of them being a yellow wire that goes to a pot case). Connect the blue wire to the eyelet with the 7 wires..
    - Own Opinions Only -

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    • #32
      Sorry I still don’t follow… could you mark in the photo Where i should attach it?

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      • #33
        Click image for larger version

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        "Take two placebos, works twice as well." Enzo

        "Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas

        "If you're not interested in opinions and the experience of others, why even start a thread?
        You can't just expect consent." Helmholtz

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        • #34
          Chuck H Thank you! I’ll do this tomorrow

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          • #35
            I'll mention this for the others here, the reason I questioned the 'caterpillar' (post #27) where the black wire is wrapped around the others, those are the 2 yellow wires that go to grid and cathode of trem tube (pins 2 and 3). Not sure where the 2 ends of the black wire are going (maybe speaker jack ground?) but I wondered about oscillation when trem is disabled.
            Probably a long shot but everything else seems to be checking out.
            Originally posted by Enzo
            I have a sign in my shop that says, "Never think up reasons not to check something."


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            • #36
              Originally posted by g1 View Post
              I'll mention this for the others here, the reason I questioned the 'caterpillar' (post #27) where the black wire is wrapped around the others, those are the 2 yellow wires that go to grid and cathode of trem tube (pins 2 and 3). Not sure where the 2 ends of the black wire are going (maybe speaker jack ground?) but I wondered about oscillation when trem is disabled.
              I agree that bundling the "wrong" wires may cause unwanted coupling and even oscillation.
              So it can't hurt to separate the wires and do some chopsticking.

              But I just can't see how (AC -) grounding the LFO grid would allow the tube to oscillate.
              This is assuming that it's the LFO tube which generates the noise.
              - Own Opinions Only -

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              • #37
                Hey everyone! Just to get back to you all on this. I had put the amp back together and just thought f@ck it. But yesterday, when changing some tubes I noticed when I changed the V.4 tube, it solved a ticking tremolo noise. And guess what: it also solved the manic drill sound. So the problem was a valve that was excessively microphonic. Blows my mind it could be something this simple but it was. Thanks again for your time!

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