1. Win a Broadcaster or one of 3 Teles! The annual Supporting Member Giveaway is on. To enter Click Here. To see all the prizes and full details Click Here. To view the thread about the giveaway Click Here.

Fix a microphonic pickup?

Discussion in 'Just Pickups' started by AJBaker, Feb 26, 2021.

  1. AJBaker

    AJBaker Friend of Leo's

    Age:
    33
    Posts:
    4,087
    Joined:
    Oct 3, 2010
    Location:
    Switzerland
    I have a microphonic strat pickup that needs some attention.

    Normally I like a pickup to be a bit microphonic, but this one squeals when turned up, and makes a very loud sound when I tap it.

    What are my options?

    (I don't need full on vacuum potting, I just need for it not to squeal.)

    Dipping in wax would be the obvious solution, but are there easier fixes?

    For example, could I heat it up with a hairdryer, pour some candle wax onto the coil, and melt the wax into the coil?

    Or dipping the pickup into a can of varnish?

    Thanks!
     
  2. EsquireBoy

    EsquireBoy Friend of Leo's

    Age:
    40
    Posts:
    2,228
    Joined:
    Jun 21, 2019
    Location:
    Paris, France
    I've tried the candle wax thing, and I can tell you it does not work well. And it was not even to wax the pickup, just to secure the rope around my tele bridge pickup.

    You can lacquer pot the pickup (I've had one like that): it's a bit less efficient than wax and can become microphonic again in the future if the lacquer cracks, but it's a bit more lively than wax potted.
    But you'll have to wait for several days for the lacquer to cure.
     
    JL_LI likes this.
  3. hamerfan

    hamerfan Tele-Meister

    Age:
    59
    Posts:
    281
    Joined:
    Dec 8, 2018
    Location:
    Germany, Bavaria
    Does the pickup have a backplate or a back magnet? Is there anything made of iron on the pickup? Has the pickup been wax potted before - any signs of wax residues?
     
  4. AJBaker

    AJBaker Friend of Leo's

    Age:
    33
    Posts:
    4,087
    Joined:
    Oct 3, 2010
    Location:
    Switzerland
    Just a plain bog standard strat pickup: six alnico rods, fibre top and bottom, no base plate.

    I imagine it was potted when it was made, there's some residue.
     
  5. hamerfan

    hamerfan Tele-Meister

    Age:
    59
    Posts:
    281
    Joined:
    Dec 8, 2018
    Location:
    Germany, Bavaria
    Okay then lacquer doesn't work.
    First option: reheat the pickup gently and for quite a time with a heatgun or in a oven. If this doesn't work, you can send it to a professional winder like bootstrap or cavalier pickups for repotting in a vacuum wax pot.
     
  6. Antoon

    Antoon Tele-Afflicted

    Posts:
    1,339
    Joined:
    Feb 10, 2010
    Location:
    Low Lands
    It is usually the outer windings. If you melt a bit of wax you can brush it carefully on the coil with a small brush, at the spots you suspect of causing the squeal. Then use a hair dryer.
     
    Doctorx33 likes this.
  7. AJBaker

    AJBaker Friend of Leo's

    Age:
    33
    Posts:
    4,087
    Joined:
    Oct 3, 2010
    Location:
    Switzerland
    Why wouldn't lacquer work? I've come across Fender style pickups that are only lacquer potted.

    Otherwise yes, I'll take it to a pro. It was actually made in Switzerland, but on the other side of the country, otherwise I would drive there.
     
  8. Antoon

    Antoon Tele-Afflicted

    Posts:
    1,339
    Joined:
    Feb 10, 2010
    Location:
    Low Lands
    It may work but a lacquer drop deforms when it dries. Some magnet wire insulation layers are not resistant to solvents in lacquer (so I found out). What does the coil look like? Any loose parts?

    If you want to be sure the repair works, you can also submerge the whole pickup in wax (50/50 candle and bees wax mixture gives a tough wax that does not melt too easily and is not too brittle).
     
    Last edited: Feb 26, 2021
  9. AJBaker

    AJBaker Friend of Leo's

    Age:
    33
    Posts:
    4,087
    Joined:
    Oct 3, 2010
    Location:
    Switzerland
    Ok, I didn't know that, thanks.

    I haven't looked at the coil yet, it's still in the guitar unfortunately.
     
  10. Antoon

    Antoon Tele-Afflicted

    Posts:
    1,339
    Joined:
    Feb 10, 2010
    Location:
    Low Lands
    If you take it out and look at it under a magnifier you will probably see where the problem is. Can't you just mail it to the one who made it and have it repaired?
     
  11. hamerfan

    hamerfan Tele-Meister

    Age:
    59
    Posts:
    281
    Joined:
    Dec 8, 2018
    Location:
    Germany, Bavaria
    Just to make it clear: The reheating should reflow to the wax and make it sticky. But the wax should not flow out of the pickup. Then let it cool down over night.
     
  12. Old Deaf Roadie

    Old Deaf Roadie Friend of Leo's Silver Supporter

    Posts:
    2,754
    Joined:
    Oct 11, 2017
    Location:
    Oregon Coast
    I would shy away from heating the pickup, as it raises a chance to damage the insulated coating on the winding wire. I suspect that is one reason they get dipped.
     
  13. jvin248

    jvin248 Doctor of Teleocity

    Posts:
    10,286
    Joined:
    Apr 18, 2014
    Location:
    Lions & Tigers oh Mi !
    .

    Hair drier/heat gun will be problematic.

    Assuming the pickup was once wax potted:

    Remove the plastic pickup cover.

    Put the pickup on a paper towel on a cookie sheet and put it in the oven set for the lowest temp it will go (typically 180-200 deg F) and start with leaving the oven door open a crack. This will allow slow heating and the surface tension of the wax to pull itself together inside the coil. Stay around there to monitor what is happening. Don't leave it too long in excessive heat. Take it out and let it cool slow on the outside of the oven.

    Otherwise, get a pickle jar (wide mouth), put canning wax in there, put the jar in a water bath inside a pan to heat it (never heat wax directly as it can ignite and burn your house down). Dip the pickup in the wax then lay it on a paper towel to solidify. Don't let it 'cook' for too long even though the water will protect against over-heating.

    Wax dipping tends to only coat the outer "20%"-ish of the bobbin, but it works because most of the squealing windings that move around are on the outer layers. Vacuum wax potting drives the wax deep into the coil and stops more of the squealing.

    As far as the wax mix ... I found going from pure 'canning wax' to adding 20% bees wax that the wax jar when cooled shrank a lot more (deep center void when cooling) -- which is problematic as it can pull away from the wires inside a pickup bobbin and not fix the problem. When you are canning you don't want much shrinkage as that cracks the seal and lets bacteria into your jams/jelly spoiling it -- so pure canning wax, while not as 'romantic' as bees wax mixes, may actually perform better. More controlled testing is needed but it indicated a potential risk.

    .
     
    AJBaker and Doctorx33 like this.
  14. Doctorx33

    Doctorx33 Tele-Afflicted

    Age:
    65
    Posts:
    1,994
    Joined:
    Jun 8, 2014
    Location:
    Atlanta
    I bought a used crock pot at a thrift store and use that to pot pickups. 20% beeswax, 80% candle wax.

    I have a friend that does the "Brushing the coil with hot wax" trick, he says it works.
     
  15. AJBaker

    AJBaker Friend of Leo's

    Age:
    33
    Posts:
    4,087
    Joined:
    Oct 3, 2010
    Location:
    Switzerland
    Thanks for the detailed write up!
     
  16. AJBaker

    AJBaker Friend of Leo's

    Age:
    33
    Posts:
    4,087
    Joined:
    Oct 3, 2010
    Location:
    Switzerland
    I think I found the culprit:
    Last time I opened the guitar I added a metal baseplate I had lying around to the pickup.

    I forgot about that.


    I've done in the past by just letting the magnets hold it in place, but this time it appears to have caused squealing.

    The pickup otherwise looks fine and well made.
     

    Attached Files:

  17. Doctorx33

    Doctorx33 Tele-Afflicted

    Age:
    65
    Posts:
    1,994
    Joined:
    Jun 8, 2014
    Location:
    Atlanta
    Ok then. Melt some wax and paint the bottom of the pickup with it. Squish the baseplate to it while it's still soft, then paint the plate itself with wax.
     
  18. Rob DiStefano

    Rob DiStefano Doctor of Teleocity Vendor Member

    Age:
    75
    Posts:
    10,288
    Joined:
    Mar 3, 2003
    Location:
    NJ via TX
    To tame coil wire microphonics, wick in hobby shop quality water thin CA glue to the bobbin. If the bobbin is string wrapped, the CA will still wick right into all the coil wires. Flood it reasonably well and watch out for those CA fumes!

    For base plates, allow the plate to magnetically attract to the rod magnets (it might help to also add the mounting screws as well), dunk into a 160*F wax bath for a minute, done.

    ... or ...

    Use 3m Scotch double sided outdoor tape to bond the plate to the bobbin's fiberboard bottom.
     
IMPORTANT: Treat everyone here with respect, no matter how difficult!
No sex, drug, political, religion or hate discussion permitted here.