PJ Pickups humming/buzzing

Discussion in 'Basses [BG]' started by TjMetalhead, Jul 25, 2020.


  1. TjMetalhead

    TjMetalhead

    Oct 19, 2011
    New Mexico
    About a month ago I had a local luthier wire up and set up a custom fender pj build I pieced together. I had just moved into a new apartment recently I was able to set up my amp for the first time in over a month. I had been playing through a digitech bp90 with headphones while I was staying at a friends place until my apartment was ready. When I finally had the chance to fire up my amp my custom pj had a loud humming noise coming through the amp. I tried my pedal and same thing. Thinking it could be the grounding of my new place I tried my regular P bass and it was fine. No hum at all, silence. So know I know for sure it's my PJ bass. Here's some pics of the wiring and pickups. Now the pickups are a bit mismatched. The ps are fender 62s and the J a stock mim pup. Any one have any idea what the humming could be?
    20200725_211057.jpg 20200725_205519.jpg
     
  2. CallMeAl

    CallMeAl Supporting Member

    Dec 2, 2016
    Ithaca Ny
    Does it stop when you touch the strings?
    Get worse when you touch the strings?
    Any change when you rotate 360 in the room?
    Hum remains when P pickup is solo’d?
     
    Reedt2000 likes this.
  3. JavierFarias

    JavierFarias

    Feb 9, 2011
    Chile
    Hi!!

    Does the bass hums when you have the P solo? If the J pickup is a standard single coil, it is normal to have some hum when that pickup volume is on.
    I have a PJ Jazz Bass that started with a Seymour Duncan Quarter Pound set. I ended up replacing the J pickup (because of the hum) for a Dimarzio Ultra Jazz (which is a split coil J Pickup, with no noise) and never looked back. I have owned this bass for like 10 years:

    Fender PJ bass.jpg

    Cheers!
     
    zie, Doner Designs, Ggeorges and 4 others like this.
  4. TjMetalhead

    TjMetalhead

    Oct 19, 2011
    New Mexico
    No it doesn't stop when I touch the strings. Touching the strings and pickups have no effect and it still hums when either knob is full or soloed. It changes a little bit when I face my amp.
     
    alanloomis1980 likes this.
  5. TjMetalhead

    TjMetalhead

    Oct 19, 2011
    New Mexico
    Ooh! Killer bass that's pretty. But no, it hums with either pup.
     
  6. JavierFarias

    JavierFarias

    Feb 9, 2011
    Chile
    Oh, It might be a problem with other electrical stuff plugged in the place, or worst-case scenario, a problem in the apartment electrical setup, hopefully just in the room or outlet you're using.

    I'm having a similar issue, actually... My roomate works in the healthcare system, so due to the pandemic thing I moved to my girlfriend house with all my recording stuff (my girlfriend is VERY happy about this [joking]). And most of the time that I record music in our room I get this annoying buzz...

    At first I though it was something in my effects chain, but sometimes without doing anything the buzz just stops. One day I noticed that when unplugging my laptops charger the buzz stopped. But next time, this didn't make any changes.

    Maybe you could try different wall-outlets in the room, or if using a multi-outlet, try to avoid overcharging it with many things.

    I wish I could help more, but I'm not too technical in this field.

    EDIT! I forgot one simple question: Does the amp hums when you turn the volume up, without any instrument plugged in??

    Good luck!
     
  7. CallMeAl

    CallMeAl Supporting Member

    Dec 2, 2016
    Ithaca Ny
    Sounds like it could be RF interference. I had a p bass that buzzed worse than my j bass; until I shielded it. Getting worse when you change direction is a symptom...

    Also could be the grounding of the outlets...

    I’d experiment wit all the variables; try as many amps as you have, different outlets/ rooms, turn off computers/ lights (especially fluorescent)

    Good luck!
     
    GodPlayedBass likes this.
  8. TjMetalhead

    TjMetalhead

    Oct 19, 2011
    New Mexico
    Nope, I tried all of that. I tried a different outlet with just my digitech alone with the headphones plugged in and I still got the buzzing/humming. I tried my regular precision bass and there was no hum, dead silence. I turned on my amp with nothing plugged in and no hum/buzz. I know for sure it's the bass. I just don't know what.
     
  9. TjMetalhead

    TjMetalhead

    Oct 19, 2011
    New Mexico
    I'm thinking the shielding may be the problem. I have copper shieling running around somewhere. I'm not an expert on shielding so how should I go about it? Should I also place shielding on the bottom of the control plate as well?
     
    alanloomis1980 likes this.
  10. CallMeAl

    CallMeAl Supporting Member

    Dec 2, 2016
    Ithaca Ny
    I’ve only done a P bass, never a PJ or J... I’d poke around the forum, I’ve seen some very thorough threads on the subject- good luck! :)

    I will say the process was fairly easy, and rather enjoyable!
     
  11. TjMetalhead

    TjMetalhead

    Oct 19, 2011
    New Mexico
    I shielded the cavities and control plate and still no avail. I even disconnected the J pickup just to see if it had any effect and still buzzing. Idk what the heck is going on, I'm gonna take it to the tech and see what he has to say.
     
    alanloomis1980 likes this.
  12. CallMeAl

    CallMeAl Supporting Member

    Dec 2, 2016
    Ithaca Ny
    Well that stinks! o_O Hope the tech gets to the bottom of it, and you have a positive outcome
     
  13. Ric5

    Ric5 Supporting Member

    Jan 29, 2008
    Colorado
    I disclose nothing
    isolate the p pickup and it should be quiet

    the j pickup is the problem because it is single coil
     
  14. Nighttrain1127

    Nighttrain1127 Supporting Member

    Nov 27, 2004
    Near Worcester MA
    If you shielded the cavity you need to leave a small amount of shielding wrapped above the cavity for the control plate to contact. Also you need to make sure you soldered a ground wire from the back of the pots to the shielding and if you used more than one piece of shielding they need to be solder connected otherwise you just installed a bigger antenna
     
    Funkdified likes this.
  15. fourstringburn

    fourstringburn Supporting Member

    Jun 30, 2009
    New Mexico
    Is there a ground wire coming from the bridge? It doesn't look like it from your pic. That'll cause buzz. If your Bass doesn't have a pre-drilled hole from underneath the bridge to the body cavity, have your Luthier drill one or use a external ground strap like you see on some vintage Jazz Basses.

    I do "star" grounding meaning all grounds eventually come to a single point to a small ring terminal screwed into the shielded body cavity. I prefer shield paint over foil tape but both do work.

    Good luck!

    I also use Fender foam ground plates under each pickups and ground those to the Star point.
     
    Funkdified and Engle like this.
  16. TjMetalhead

    TjMetalhead

    Oct 19, 2011
    New Mexico
    I actually disconnected the J pup and theres still buzzing. It makes no difference if I isolate the p or the j.
     
  17. TjMetalhead

    TjMetalhead

    Oct 19, 2011
    New Mexico
    Yes there is a ground wire that's underneath the bridge. I may have to try shield paint because I tried everything I could last night and nothing worked.
     
  18. Make sure you have a ground wire to each cavity and soldered to the shielding and back of a pot.

     
    Last edited: Jul 26, 2020
    zie likes this.
  19. bumperbass

    bumperbass

    Jun 19, 2012
    What happens when you disconnect the P pickup?
    Disconnect it by removing the wire on the bottom lug of the pot. Do the same with the J pup.

    Try wiring each pickup directly to the jack.
     
    Last edited: Jul 26, 2020
    Christophe C likes this.
  20. I hate to mention it, but where is your phone? I played a gig a while back and watched a guy about pull his hair out chasing weird noises from the PA and his amp. Between poorly grounded main wiring and the cell phone sitting on top of his amp, he had a symphony.
     
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