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PO Shielded cavity with active preamp, Neck P still hums

Discussion in 'Basses [BG]' started by c3powil, Nov 7, 2016.

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  1. Nov 7, 2016 #1
    c3powil

    c3powil

    Apr 18, 2008
    North of ATL, GA
    I have an ESP rb1005, it's a PJ setup with a passive hum canceling J and passive P.

    Not sure if the bass hummed before, but the PO installed an active Seymour Duncan three band EQ and decided to shield the electronics cavity. The bass hums when I'm not touching metal/the bridge, so I know it's a grounding issue. When I blend the bridge (J) pickup all the way on the hum goes away. The more of the P I blend in, the more buzz.

    Should I just ground the preamp cavity? I'm not sure how to do this, but I know there are lots of threads on it. I just don't want to go through the effort without making sure that's what I need to do.
     
  2. Nov 7, 2016 #2
    c3powil

    c3powil

    Apr 18, 2008
    North of ATL, GA
    Whoops, looks like the wrong forum. Can't figure out how to delete.
     
  3. Nov 7, 2016 #3
    bholder

    bholder Affable Sociopath Gold Supporting Member Supporting Member

    Sep 2, 2001
    Vestal, NY
    Received a gift from Sire* (see sig)
    Sounds to me like PO wired or positioned the P pickup wrong, such that the 2 halves are both "facing the same way", killing any hum-cancelling effect. Try flipping one side 180 degrees and see if that changes anything, maybe?
     
  4. Nov 7, 2016 #4
    bholder

    bholder Affable Sociopath Gold Supporting Member Supporting Member

    Sep 2, 2001
    Vestal, NY
    Received a gift from Sire* (see sig)
    Ask mods to move it.