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P bass pup losing magnetic strength?

Discussion in 'Pickups & Electronics [BG]' started by dropbass, Oct 2, 2013.


  1. Had for years. Got some fret work done... pick guard wasn't removed. .. get it home and the g and d seem much louder... when I tap the pups with a screwdriver. . The quieter one doesn't seem to pull as hard...and input is softer... may not have noticed before becaue the pup height was higher before. And may have compensated the loss.... thoughts. . Worth getting recoiled or is the magnet done? Help. This is my baby. Super bummed
     
  2. The magnets can be re magnetized. Not a huge project.
     
  3. And I can do this how?
     
  4. You might not be able to at home. It takes a variety of equipment...

    You could replace magnets instead, easier, really.

    EDIT: If the magnets weren't very strong to start with, you could try pulling a magnet (a strong one) across to remagnetize.
     
  5. They are 70s so prefer to keep orig... will prob just have to get some temp ones and see about getting this one repaired.. just bummed cause I can finally play it after the fret job now the pup ***** out.. waaa
     
  6. Want to elaborate on my edit.
    Dragging a very strong magnet, specifically a rare earth if possible, across a few times in the same direction will help.

    This might have to be done with the magnet out since the direction you do this should be parallel to the poles.
     
  7. Catanova

    Catanova

    Apr 7, 2011
    Golden CO
    Have had a similar problem with the G/D pickup on a Peavey Fury. Checked wiring etc and all was good :confused:

    Note that some types of strings are less magnetic than others. Check and note string heights above pole-pieces for reference before adjustment of pickups. If raising the pickup yields minimal results, try magnets.

    You CAN re-magnetize pickups...

    I used 4 of those super strong toy magnets that my kids have in a kit, they build shapes with them. They were neodymium.

    I stuck one per pole on both pickups (4 poles) and let them sit on the bass for a week. Output was much more even across the poles (strings) after removal.

    Then out of curiosity, I applied a smaller neodymium "disk" to the directly to the top of each polepiece instead. They stuck really strong. Left them on a few days.

    I thought it would be fun to hear what my bass sounded like with the "disks" still on. The magnetism was so strong that the strings has awkward vibration issues, but the volume was HUGE.

    After experimenting with the magnets, I found that my pickups were more balanced and pronounced. I just wonder whether the re-magnetizing works better when the pickups are energized...
     
  8. Interesting... but a week? Seems awful long compared to the less than five seconds it takes when magnets are created.

    But, if it works. . .
     
  9. This is output and mag strength...It doesn't pull as hard on thw screwdrivet....the good one is strong and loud and pulls the screwdrive twd it... wiring is solid and
     
  10. Catanova

    Catanova

    Apr 7, 2011
    Golden CO
    I guess my thinking was at the time that the magnetic field needed serious re-kindling :D

    I'm no scientist, but those polepieces are only able to maintain a certain magnetic field over time, and then will diminish.

    Was just trying to jump-start them I guess. Worst thing that could happen is they are too "hot" for a while.

    Might be a good reason to replace magnets, I don't know.
     
  11. Catanova

    Catanova

    Apr 7, 2011
    Golden CO
    FWIW, there are other sources I have found regarding this problem, where re-magnetizing valuable vintage pickups is preferable to performing surgery on them. Apparently the older toaster/single type Gretsch, Mosrite, Rick, Magnetone pickups have magnetic issues nowadays.
     
  12. Ya I dont know when it happend. Maybe e the tech had a speaker on the counter? Can that demag it? Like a tv or credit card.
     
  13. MPU

    MPU

    Sep 21, 2004
    Valkeala Finland
    You can't replace magnets in Fender style pickups without destroying the pickup.
     
  14. Ya gonna send them to Fralin or duncan for rewind and repair if it is possible..
     
  15. MPU

    MPU

    Sep 21, 2004
    Valkeala Finland
    No need for rewind if the resistance is ok in both coils. Remagnetizing should do the trick.
     
  16. It is just the magnet. Even I'd the coil was broken. It should still pull metal twd it self with tge same strength as the other half of the pup...just mainly want to know what the cause was or could have been?? M. Ive had this bass forever and know it well... I would have noticed this right away as I did once I plugged into a real..amp.. just used a small test amp the tech had to hear it when I picked it up so did notice the drop out in the bass as badly..:confused::(:(
     
  17. I don't know about ceramic and AlNiCo magnets, but neodymium magnets lose .1% of their magnetism every 100 years (don't quote me on that), I somehow doubt other magnets differ very much.
     
  18. So how can a magnet be discharged in a day or two?
     
  19. There are a couple possibilities.
    A. Large impact to a pole. This would cause the magnetic field to weaken.
    B. Heating past the magnets Currie point. Would probably melt the wires first though.
    C. High AC currents, as in a large electromagnetic field.

    Another. .. and you would hope it's not this. .. a crack or break in the magnet.

    All these things cause disorder at the poles, and weaken or kill the magnets.
     
  20. uOpt

    uOpt

    Jul 21, 2008
    Boston, MA, USA
    Looks like fretword dude did cause some mechanical or magnetic disturbance. Anyway.

    You can recharge the magnets with one of those neodymium magnets you can buy everywhere. Instructions can be found e.g. on the seymour duncan forum where people hand-tune their pickup magnets all the time. With such a magnet you won't reach 100% of the full strength, but you won't need that, in most cases slightly aged magnets sound better anyway.

    You will have to remove the pickup and separate the two coils. The two coils have opposite polarity so if you don't separate them you would de-magnetize the other coil while going after the first.

    Exchanging polepieces isn't possible in vintage fender style pickups because the wire is wound directly around the rod magnets.
     

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