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High Frequency Pickup Noise

Discussion in 'Pickups & Electronics [BG]' started by LeonD, Jan 30, 2006.


  1. LeonD

    LeonD Supporting Member

    Prior to rewiring my Peavey Palaedium, I had a high frequency noise coming from my bridge pickup. I would hear the noise with the pickup either soloed or blended but not with just the neck pickup on. And it didn't change if I touched the bass / strings or not.

    Well, after rewiring the bass, the noise is still there. The pickup is a quad coil humbucker running through passive electronics.

    Could it be something with the wiring or is it internal to the pickup? Any suggestions on how to diagnose and repair?

    Thanks,
    LeonD
     
  2. CentralCoastBass

    CentralCoastBass Supporting Member

    Feb 4, 2004
    San Luis Obispo, CA
    National Reso-Phonic Guitars
    do a search on single coil pickups, here or on the web. they are noisy.
     
  3. LeonD

    LeonD Supporting Member

    Thanks for the reply.

    The pickup is a quad coil humbucker. The neck pickup is dead silent.

    LeonD
     
  4. CentralCoastBass

    CentralCoastBass Supporting Member

    Feb 4, 2004
    San Luis Obispo, CA
    National Reso-Phonic Guitars
    oops, my bad. what model is the quad coil humbucker? one of the bartolini mm quad coil models has numerous wiring options, you can run it in single coil mode. if it is a stock peavey pickup, though, and its bothering you, replace it.
     
  5. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    FWIW:

    Hum, buzz, tubular, squeal? Is the noise a change or has it's always been there? Does it do it no matter where (as in New York or Detroit) you play the bass? How may leads does the pup have? Is it epoxy potted? Is the bass shielded? Is the ground wire connected (as in contact with the bridge)? Are you trebling the bass up? Is the neck the same pup?
     
  6. LeonD

    LeonD Supporting Member

    I'd call it a very high frequency whine. It's definitely not a hum or buzz. It wasn't always there but I'm not sure what changed to create it; I don't remember doing anything specific to the bass when it started. I've only played the bass in my basement so that's probably something I should try.

    It's a four lead pickup with two of the leads connected and appears to be potted. The bass is not shielded and the ground wire is connected. I have my amp set flat and the tweeter off on my cabinet.

    The neck pickup is identical to the bridge pickup and it doesn't whine. I recently rewired the bass partially in hopes of fixing this but it didn't seem to help.

    Thanks for asking. Hopefully, this info can help.

    LeonD


     
  7. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    FWIW:

    I would try another location since it didn't occur before and there was no defining change that brought it about. Even just some place else in the house for starters. Sounds more like it may be external interference than internal. The neck would be less likely to put out the higher frequency.

    Even so, an epoxy potted humbucker should be pretty impervious to issues internal or external.
     
  8. fretlessrock

    fretlessrock Supporting Member

    Aug 8, 2002
    Corrupticut
    What I'd do is unwire the pickup and test both coils. If it is 4-wire it is probably a regular dual coil humbucker, not a quad coil. The 4 wires are each end of the two coils. If it is a quad coil then it is two humbuckers side by side that have been pre-wired, probably in series, breaking out to two pairs of wires. Either way you have the potential for a problem with one coil that might not be easily seen.

    When you have it wired where two wires are spliced and two are free, that is series wiring. You are seeing the IN end of one coil, and the OUT end of the second coil. The other OUT and IN are spliced. Check the series wiring on each, then check each coil separately. Use an Ohm meter and note the resistance of each coil. Also, label the ends. For any one of the 4 wires only one of the other three should show continuity. Make a diagram of how it was wired before you take it apart.

    You should see the resistances being very similar. Also, the color coding should match between the neck and bridge.

    What I'd be looking for is a bad coil. Either an open circuit, or a short. Open would show no continuity, or very little. Short would show a lot less, but not none. Less being anything from 80% to 20% of the sister coil.

    Good Luck,
    Pete