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Electronic Guru's - i need your help!

Discussion in 'Pickups & Electronics [BG]' started by BassBert104, Nov 17, 2015.


  1. I have (2) mini-humbucker pickups that are for the Gretsch 220 short scale bass. I installed them in a Dean Stylist B2 ''Cabbie" model bass that already has two pickups. I kept the existing control wiring intact with Volume / Tone knobs and a single toggle switch for pickup selection. Each pickup has just (2) wires - a ground wire and one white. These are the same as the pickups I removed and I just cut & spliced/soldered them exactly the same. Both new pickups are dead quiet after installation, and with very good output when soloed. However, when the toggle switch is used to engage both pickups, the output drops significantly - still no hum, but a lot less output - almost anemic sounding. Not sure what is going on and I need some help!
    In Summary:
    1) Both pickups are the same - i.e. not neck or bridge specific. They are the mini-humbuckers that came out of the early Gretch g-220 single pickup basses - I just have 2 of them.
    2) I did not take the controls out of the Dean bass to verify how the toggle switch is wired, but connected each pickup exactly as the previous ones were wired (only 2 wires per pickup - white and ground) by splicing them to the existing pickup wires once pickups were cut and removed.
    3) Both pickups sound normal when soloed. When played together, they are anemic and very low in output.
    Any help you can give via instructions on how to correct and / or wiring diagrams would be appreciated!
    Thanks in advance for any and all suggestions - Mark
     
  2. Anyone with an idea on this?
     
  3. JustForSport

    JustForSport

    Nov 17, 2011
    Try switching/swapping the wires on only one pickup.
     
    JackANSI likes this.
  4. Thanks - will try that and see if it helps!
     
  5. bholder

    bholder Affable Sociopath Supporting Member

    Sep 2, 2001
    Vestal, NY
    Received a gift from Sire* (see sig)
    The pickups can appear the same on the outside and not be the same on the inside. Have you measured their resistance? You want the hotter one (higher resistance) in the bridge position. The loss of volume with both on sounds like phase cancellation - swapping the wires on one should indeed fix that, if that's the problem. Being that they're mini-humbuckers, messing with the phasing between pickups shouldn't affect noise levels as on single coils.

    The problem may be more due to positioning of the new pickups rather than the electronics - if the new spots are relatively different (compared to string length and proportional distance from nut/bridge), you may have changed their physical spacing from a "reinforcing" configuration to a more "cancelling" one. Flipping the electrical polarity of one should still fix it, I would think.

    A very long way of agreeing with JustForSport. :D
     
  6. Crater

    Crater

    Oct 12, 2011
    Dallas, TX area
    Classic symptom of out-of-phase pickups. Especially if the tone is very thin and trebly, like playing through transistor radio or telephone.

    This is the fix for it.
     
    Growlmonkee likes this.
  7. IMG_3025.JPG
     
    Growlmonkee likes this.
  8. Thanks guy's - that was it!
     
  9. Growlmonkee

    Growlmonkee

    Jan 30, 2013
    Florida, U.S.
    That bass is sweet Bert!
     
  10. One more issue: Now that I reversed wires on the bridge pickup, I get a really loud hum when I touch the pickup. Seems like it's no longer grounded. When I try to ground the pickup body to anywhere on the bass (bridge, etc.) it cuts off output from the pickup entirely. This is a 2 wire pickup so not sure how to properly ground it. Maybe I should not connect the braided wire to the toggle switch and only use the white?


    PS - Thanks Growlmonkee! Not sure I like the sticker on the bass. Any thoughts?
     
  11. mech

    mech In Memoriam

    Jun 20, 2008
    Meridian, MS, USA
    Unfortunately, the only way I know of to cure this is to go inside the pickup and reverse the wiring there. But just in case, can you post a pic of the back of the pickup??
     
  12. bholder

    bholder Affable Sociopath Supporting Member

    Sep 2, 2001
    Vestal, NY
    Received a gift from Sire* (see sig)
    that might be cool to use intentionally as an effect - ok, after the 3rd chorus, we do the break in 60s Japanese AM Radio mode! ;)
     
  13. bholder

    bholder Affable Sociopath Supporting Member

    Sep 2, 2001
    Vestal, NY
    Received a gift from Sire* (see sig)
    Well, or reverse the magnet(s), but that usually means completely demolishing and rebuilding the pickup. But it might be there's a separate (or separable) case ground, which could solve it without messing with the pickup's insides. Still, tricky business, really need closeups of the back of these Gretsch pickups.
     
  14. bholder

    bholder Affable Sociopath Supporting Member

    Sep 2, 2001
    Vestal, NY
    Received a gift from Sire* (see sig)
    The sticker is a bit over the top, perhaps, but if that's the look you're going for, it's perfect. I have a couple of sets of the other stickers, haven't quite figured where to put them yet. Hadn't considered the cabbie, that works, though I'd choose a different big sticker, myself. ;)
     
  15. Growlmonkee

    Growlmonkee

    Jan 30, 2013
    Florida, U.S.
    What's happening is the pickups are now phased correctly, however, the covers are connected to, or at least touching ground, on the one you didn't change, the cover is grounded, and the pickup is grounded, all good, on the one you switched, that cover isn't ground any more, it's the hot side now...the bass probably sounds like it should, but, any time you touch the cover your hand is touching a live wire, (not near enough to shock you, but it still shorts out.) As Mech, and Bholder said it may be complicated to fix, it's not as simple as awitching the wires soldered to the pickups, (that would make things exactly how it used to be, (bad). it's almost as you have 2 left shoes, flipping a coil, and magnets would be great, , but may be destructive depending on their design, and the skill of the tech. Wring the bass in series would work, but it lose all it's flexability, and might not sound good at all. My bet is a good tech could fix things, or buying a reverse wound pickup would surely fix things, as long as the seller knew which way the ones you have are wound, and sold you reverse
     
  16. bholder

    bholder Affable Sociopath Supporting Member

    Sep 2, 2001
    Vestal, NY
    Received a gift from Sire* (see sig)
    Yup, and a case that's intended to be a ground that is instead hot becomes a big noise antenna. I just wonder why the original Gretsch didn't suffer from these issues. May have been different pickup positioning affecting the phase relationship.

    Any pics of the original Gretsch the pickups came from?

    Anyway, I think we all agree, starting to get tricky, new pickup or tech trip....
     
  17. Growlmonkee

    Growlmonkee

    Jan 30, 2013
    Florida, U.S.
    If they are both designed for a single pickup bass, they are most likely wound the same, because the covers are grounded, that's a problem. but only if using 2 of them, even though it's a better design to have the covers grounded, (something you would expect from a quality manufacturer like Gretsch.)
     
  18. Thanks Guys for all your help! Many great ideas and suggestions here. At the suggestion of JustForSport, I ended up swapping the pickups and moving the noisy one to the neck position as I very rarely touch this one, and sometimes use the bridge pickup as a thumb rest. The back of the pickup was soldered to the case, and i'm not sure if I would be able to execute the surgery needed to separate it to install a separate ground wire or reverse coils (see pic).

    Once again, I am indebted to you guys - such a simple and straightforward solution would have eluded me for days! Also - after much consideration I removed the "High Rollers" Dcal and think the bass looks much classier for it - Thanks for all the suggestions! Mark

    PU.JPG Dean Bass.JPG
     
  19. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
    Apr 13, 2021

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