Whistle in bypass?

Discussion in 'Burnt Fingers DIY Effects' started by Mark the Moose, Apr 15, 2019 at 6:25 PM.

  1. Mark the Moose

    Mark the Moose Tele-Meister

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    just finished an OCD and it sounds great...except...when I click the effect off (it’s true bypass) I get a whistle kind of like a digital pedal starved for power. Any bright ideas?
     
  2. Mark the Moose

    Mark the Moose Tele-Meister

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    Update: if I place a buffer in front of the OCD the whistle is gone but I get a huge pop when I click the footswitch on and bypass.
     
  3. tubejockey

    tubejockey Tele-Meister

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    rewire your stomp switch like this. Make sure you keep wires short or shielded. You are getting oscillation from an open input.
     

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  4. jimilee

    jimilee Tele-Holic Silver Supporter

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    Got pictures of your stomp switch wiring?


    Sent from my iPhone using Tapatalk
     
  5. tubejockey

    tubejockey Tele-Meister

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  6. Mark the Moose

    Mark the Moose Tele-Meister

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    I'll get a pic. I've built several dozen pedals and never heard this! I'm suspicious of the switch itself.
     
  7. Mark the Moose

    Mark the Moose Tele-Meister

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    I rewired the switch to ground the circuit board input when in bypass. Seems to have solved the problem. Is this a common issue for higher gain pedals? I’ve only built low gainers, delays and verbs and have never encountered this issue.
     
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  8. Mark the Moose

    Mark the Moose Tele-Meister

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    And thanks to all of you who chimed in!
     
  9. tubejockey

    tubejockey Tele-Meister

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    High gain pedals are far more likely to have this problem due to capacitive coupling of signals forming a feedback loop. Keeping your leads short and separating input leads from output leads is important.
     
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