Les Paul, Feedback and Pickup Covers

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by UconnJack, Oct 14, 2005.

  1. UconnJack

    UconnJack Member

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    Hi,

    Forgive me if this is beaten to death, I did a quick search.

    My 83 all original Lespaul Standard feeds back like crazy with any type of gain. Bassman and TS set to mid it just screams (In a bad way). I'm constantly turning down my guitar volume.

    Had my tech go thru it and check the wiring, grounding etc. He even tightened up the pickup covers. But it's still bad.

    Question: Can removing the covers resolve the problem? If so, is there any special procedure, or wire removal I must follow? I'd like to do this myself.

    Thanks,

    UJ.
     
  2. pedalpat

    pedalpat Guest

    removing the covers is a good way to start. sometimes the wax potting seal will come undone and cause some microphonics feedback to happen. also, maybe you just need to get your pickups repotted. did it always feedback like that or just recently happen?
     
  3. UconnJack

    UconnJack Member

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    Only recently started playing in a covers band which demands some higher gain stuff at gig volumes, so I'm not really sure if the issue was always there. It is an unplesant kind of squeal! I hate it!

    Not sure how to pot the pickups, or if these stock pups are even potted to begin with. Is this something I can do myself?

    THanx
     
  4. Gadowguitars

    Gadowguitars Member

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    send them to lindy fralin to get them potted...it will cure the problem.
     
  5. Jim Collins

    Jim Collins Member

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    Potting pickups is messy, and not without danger. Paraffin is highly flammable, and, if you are not careful, you can set the house on fire. You can also burn yourself pretty badly.

    A pickup can be potted by immersing it in liquid paraffin, for a while, but pickup manufacturers might be a little more sophisticated about it. I believe Seymour Duncan has some type of vacuum treatment which sucks the molten wax into more of the open spaces.

    Removing the covers from humbuckers often takes care of all but the nastiest cases of microphonics, as it is frequently the addition of the covers that creates the microphonics, in the first place.
     
  6. Leonc

    Leonc Wild Gear Hearder Gold Supporting Member

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    I've got an old Guild Thunderbird with their smallish humbuckers. The pickups sound absolutely fantastic...but they tend to be a bit microphonic. I imagine this is part of what makes them sound so great...but can be irritating too if I have to play a bit loud or gainy here and there.

    I know I can remove the covers. I know you can have them potted. But I'm rather reluctant to do anything that alters the originality in a permanent way. Are there other alternatives that might help tame the micorphonics a little? Do I remember something about cotton between the cover and the bobbins...?
     
  7. uOpt

    uOpt Member

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    It can be any of the following:
    • magnet vibrating on base
    • coils vinbrating on magnet
    • cover vibrating against base
    • cover vibrating against coils
    • base vibrating in screw/spring mount towards the pickup ring

    The best way to debug these things is let it howl while the pickup (with ring) is not inside the guitar and then use a cotton tip (q-tip) or whatever to press against individual parts to determine which part is at fault.
     
  8. Leonc

    Leonc Wild Gear Hearder Gold Supporting Member

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    I've never looked under the pickguard on this guitar or had the pickups off. But this sounds like a logical/reasonable way to start debugging. Thanks for the tip.
     
  9. levelfrets

    levelfrets Member

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    Hello,

    Did the pickups always have feedback problems or did this just begin? Chances are they are already fully potted unless someone installed covers later. I had a customer bring me a late 70's LP once with a super high output dime bucker and it squealed like a pig. The pickups were fine and everything was wired correctly. It ended up being the pots that were worn out but weren't scratchy. They were just old and causing micro phonic issues. I replaced them with some new 500k pots and the problem was solved immediately.
     
  10. Leonc

    Leonc Wild Gear Hearder Gold Supporting Member

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    The pickups have had this problem for the year and a half that I've owned it. But it's a '65 guitar, i.e., quite old. The pickups are 100% stock and the covers have not been removed/re-installed, near as I can tell. These are lowish output pickups; the smaller, older Guild humbuckers. I doubt if it's the pots...I'll report back once I get this figured out.
     

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