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So I shielded my single coil Jazz pickups and this happened.....

Discussion in 'Pickups & Electronics [BG]' started by Modern Growl, Sep 19, 2005.

  1. I shielded my jazz pickups as in: covering coil with electric tape, then covering that w/ copper, making sure no copper touched the coil or the output signal, and of course grounding the copper to the ground output. I did a very neat and clean job... I figured all I would loose is a little high end...right.

    Now, I have a HUGE loss in output, and when I engage the S1 switch (Ameri J Bass) I get a VERY LOUD hum ?

  2. Lyle Caldwell

    Lyle Caldwell

    Sep 7, 2004
    Sounds like something is touching that's not supposed to be. Photos, please.
  3. sorry no pics... but everything was connected correctly before I decided to shield the pups....

    I dont know what could be touching... I completely covered the coil wire w/ electrical tape, and even making sure the connections at the leads were clean, and the ground never made contact w/ the hot signal. I'm completely stumped.

    what I'm going to try at my lunch break is to just take off the shielding on the pups and let everything go back to normal and just turn down the treble on the amp.

    now, if I do that, and there's still a problem, then i'm going to be upset! :crying:
  4. Lyle Caldwell

    Lyle Caldwell

    Sep 7, 2004
    How did you attach the copper to ground? Because to make it work in series, you cannot attach the copper to the pickup negative lead. It would have to have a separate connection to ground.
  5. standard single coils... they are not humcancelling.

    I have the ground connected to the copper by using little wire (bare wire, no plastic cover) (perhaps 1 inch) and connected the one end to the ground solder joint, and then had the other end connect to the copper along side the long part of the pickup.
  6. thats exactly what i did. I had it connected to the negative lead.

    hmmmm.......... interesting.

    but on a side note. I hate using the s1 switch in series... I mainly use in parallel.. and in parallel, there's a huge loss in volume... ?

    there was no loud hummm, it sounded fine, but there was the huge volume loss? i shouldn't loose all that output right?
  7. Lyle Caldwell

    Lyle Caldwell

    Sep 7, 2004
    What pickups are in your bass?
  8. lindy fralins, true single coils
  9. Lyle Caldwell

    Lyle Caldwell

    Sep 7, 2004
    When you get to the bass, very carefully disconnect the copper from the pickup negative leads. At that point, if the copper isn't touching anything, it will be out of the circuit and should have no affect on the sound. See if your level comes back (the noise in series mode will disappear too).

    Then run a connection from the copper to the back of a pot. If everything is connected properly and nothing is touching anything it shouldn't, you should have the coil shielding working properly and have normal levels with less noise.
  10. will try, thanks! - later I will let you know how it works out.
  11. alright, so here's the deal. I cut the connection that was made from the negative lead to the copper shielding the pickup. No dice. The output was still tremendously low, and when put into series, the loud buzz was still there!


    The reason why I connected the negative lead directly to the shielding of the pickup is thats the exact way Mike Lull did it to the Lindy Fralins I previously purchased from him. I was just imitating him, exactly the way he did it.

    His worked though, mine, after my shielding job didn't. I guess I didnt' do it wright??? But its such an easy thing to do, I can't see how I screw it up!! But you CAN have the negative lead connected to the pup shielding... I guess I just did it wrong? I could swear that no copper was touching the hot signal lead wire though? So I dont get it.... ?

    Maybe all along I shielded the pickup correctly, having the connection to the negative lead..... but somehow with the grounding I did with the cavities, along w/ the monkey wrench of the S1 switch that I wish I never even had... somehow something went wrong?
  12. shnapper


    May 1, 2005
    I had a huge loss in volume on the vintage pbass pickups I just got.

    Reason: factory wires were not soldered properly and birdcaged. If you moved those wires back and forth and separated the strands you will have problems that are not obvious. Check all stranded wires for proper tinning of leads, restrip and resolder all birdcaged sections. Usually once a stranded section of wire becomes caged individual strands will start to break and create a blind short. I say blind short because most people don't look at that tiny section of wire where the housing ends and the bare wire begins. I really should call it a loss of conductivity, it's not really a short. ;)

    I for one find soldering a highly misunderstood skill, most do not realize how important the little things can be when melting solder, tinning leads and filling thru-hole components.............

    I don't think you did anything wrong, I think something got wiggled the wrong way.........

    Good Luck, let us know.............. :D

    A thought for the day: Never pull rosin core solder apart always cut the amount you need with wire cutters.
  13. Lyle Caldwell

    Lyle Caldwell

    Sep 7, 2004
    You can tie the pickup shields to the pickup negative if you're only running the pickups in parallel, but if you're running them in series you have to separate the ground from the negative lead of whichever pickup will have it's negative lead tied to the positive lead of the other pickup in series.

    So if Mike Lull isn't configuring them in series, he can tie the pickup shields to the pickup negative leads.

    Sounds like you damaged your pickups. In the future, I would suggest painting the inside of the pickup covers rather than using copper foil. Pickups are fragile. The good news is that Lindy Fralin will fix them for not much money.

    I didn't suggest shielding the insides of the pickups in my shielding tutorial in the FAQ, partially because I didn't want to be liable for anyone damaging their pickups. It certainly can be done, but it's not something that can easily be taught over the internet.

    Shielding the cavities won't lead to any of the problems you're having. Don't rip it out just yet.

    And a lot of people demonize the S-1, when all it is is a very nice 4PDT switch incorporated into a pot. In a Jazz, it lets you do series/parallel, which most people like very much. I certainly do.

    But if you don't want it, I'll gladly buy the S-1 switch from you. Just replace the S-1 pot with a standard 250K audio taper CTS/Fender pot and wire it like a standard Jazz Bass, leaving just the parallel mode.

  14. any idea how i did that? I had them in parallel at first before I even switched to series, and the output was a still wisper?

    the in series - BUZZZZZZ!!!!
  15. get thee an OHM meter!

    and checketh thee out the pots for a partial ground...

    after I shielded my cavities (did two basses with my aluminium foil/carpet tape process)...i applied an insulating layer of non-conductive tape around the pots, to prevent the riveted pot lugs from making contact with the foil.

    Try this...lift your pots out of the cavity to that they aren't touching anything and see if the problem goes away...in which case, thou haveth a partial short.

    an ohm meter is quite handy for sniffing these things out in situ
  16. gyancey


    Mar 25, 2002
    Austin, TX
    Did you ground the polepieces? If so remove the grounding element and with an ohmmeter check to make sure there is no connection, resistive or otherwise, to the hot or ground output of the pickup. Sometimes the pickup coil wire can get shorted to one or more of the polepieces.