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Help, no volume in middle blend position

Discussion in 'Pickups & Electronics [BG]' started by scotch, Nov 19, 2010.


  1. scotch

    scotch It's not rocket science! Supporting Member

    Nov 12, 2006
    Albany, NY USA
    Please see Profile for Endorsement disclosures
    I'm having a problem with a 2 pickup bass that I'm wiring. Both pickups work fine when solo'ed, but I get zero volume when they are set in the middle (detent) blended position. Have I grounded something weird? I attempted star grounding, with all grounds connecting to a common lug - then a lead to the jack ground.
     
  2. FunkMetalBass

    FunkMetalBass

    Aug 5, 2005
    Phoenix, Arizona 85029
    Endorsing Artist: J.C. Basses
    They're out of phase. Switch the leads on one of the pickups.
     
  3. scotch

    scotch It's not rocket science! Supporting Member

    Nov 12, 2006
    Albany, NY USA
    Please see Profile for Endorsement disclosures
    Makes sense. So switch the 'hot' and ground?
     
  4. FunkMetalBass

    FunkMetalBass

    Aug 5, 2005
    Phoenix, Arizona 85029
    Endorsing Artist: J.C. Basses
    That's correct.

    If that doesn't solve it, you've somehow managed to wire up something very funky. :p
     
  5. walterw

    walterw Supportive Fender Gold Supporting Member Commercial User

    Feb 20, 2009
    alpha-music.com
    that's not it. out-of-phase pickups would sound thin and weird in the middle, but they would still make sound.

    i suspect you have the blend pot wired mirror-image to how it should be. do that, and it will indeed give you silence in the middle setting.
     
  6. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Yep.
     
  7. scotch

    scotch It's not rocket science! Supporting Member

    Nov 12, 2006
    Albany, NY USA
    Please see Profile for Endorsement disclosures
    Hmmm,... double checked and everything is normal. Is it possible the pot itself is inverted?
     
  8. VinKreepo

    VinKreepo

    Nov 13, 2009
    NOTE: when you splice a pick up wire, the tiny insulated wire in the middle is your hot wire, the threads surrounding that one is your ground

    Here's how the pot should be wired...

    You have three contacts... the middle should be the output (hot wire leading to your tone or volume pot). The two outer contacts should be the inputs (the hot wires of the pickups). Then ground the pickups to the pot casing or wherever your ground is. If that doesn't work, your pot is shot.

    Blend pots basically select how much of each pickup hot wire is going to the output hot wire.
     
  9. 3506string

    3506string

    Nov 18, 2004
    Lawton, OK
    I've done this twice actually. What happens is you will have zero vol at center and as you blend to one side it will act like a vol knob raising the vol of the pickup your blending to. It is supposed to be the other way around, full volume at center and as you blend to the neck you are turning the bridge down, vice-versa.

    You have two wires switched, but I can't for the life of me remember what lugs that I kept switching around. Give me a second I may be able to find one my old diagrams.

    I'm thinking it might be something as simple as the output and ground switched but I am not sure.
     
  10. maurilio

    maurilio Musician - Owner Mo's Shop & MBD - Tech Nordstrand Commercial User

    May 25, 2003
    Redlands, CA
  11. Jazz Ad

    Jazz Ad Mi la ré sol

    Are you sure you bought a 100-100 blend pot? And you crossed the wiring of the volumes?
     
  12. scotch

    scotch It's not rocket science! Supporting Member

    Nov 12, 2006
    Albany, NY USA
    Please see Profile for Endorsement disclosures
    Well, "mirror imaging" the pot worked. But, I discovered that one of the middle tabs has an intermittent short (after much fiddling around!). Thats what I get for buying a an eBay cheap-o pot!

    Not only were the hot & ground inverted from 'normal', but the thing must be cracked somewhere as well. Nice.
     
  13. scotch

    scotch It's not rocket science! Supporting Member

    Nov 12, 2006
    Albany, NY USA
    Please see Profile for Endorsement disclosures
    Swapped out for an Alpha blend pot. All problems solved. Thanks folks!
     

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