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Shielding Properly

Discussion in 'Hardware, Setup & Repair [BG]' started by Klaxxi, Nov 21, 2018.


  1. Klaxxi

    Klaxxi Supporting Member

    Mar 6, 2017
    Beaumont, TX
    Alright so after asking for advice on fitting my pickups into the cavity, many people were pointing out I needed to do a shielding job on my bass. I planned to do one anyway and now ive gotten around to doing so. Just a few questions. Here are the results of the shielding work. This is copper tape with conductive adhesive so it should be fine that pieces overlap.
    20181121_124737. 20181121_124749. 20181121_124805.

    Do I need to connect the shielding from one cavity to the other? Ive heard you should solder a wire between each one to make them connect. If this is the case couldn't I just run more tape under the pickguard between them and connect them that way?

    Also I know it needs to touch the foil on the back of the pickguard, and the control cavity does. Should I put some on the back of the pickguard over the pickup route too so that its similarly touching?
     
  2. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician, and Contractor to Club Bass and Guitar - Toronto
    Yes you need to connect the pickup cavity shield with the control cavity shield. You can do this my extending the foil on the pickguard so that it touches the pickups cavity foil when the pickguard is screwed down. One of the screws should go through the foil the pickguard and through the foil on both the cavities to ensure good contact. You should also shield the channel that the pickup wires go through. Be sure to install a wire from the shield to the ground connection on the jack - don't rely on a frame connection between the jack and the foil on the pickguard.
     
  3. Klaxxi

    Klaxxi Supporting Member

    Mar 6, 2017
    Beaumont, TX
    Noted .How should I go about shielding inside the wire route? It seems like it would be almost impossible to get the tape in there and actually stick without rolling up on itself.
     
  4. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician, and Contractor to Club Bass and Guitar - Toronto
    Get a largish plastic straw and wrap the tape on the outside. Push it through the hole and cut it off a bit oversize. Then peel back a bit of the foil at the end of the straw on each end a stick that to the foil in the cavity. You can trim the excess straw then if you want or leave it if it's not in the way.
     
    JMarkD, Axstar, Gilmourisgod and 3 others like this.
  5. Keith Guitars

    Keith Guitars Supporting Member Commercial User

    Aug 25, 2004
    Woodstock, NY
    Builder: Martin Keith Guitars, Veillette Guitars
    IMO shielding the channel is only necessary if your pickup doesn't have a shielded lead.
    Many do, check before you take the time/energy.
    If you do choose to do it, Turnaround had a nice tip with the straw.

    +1 on using foil under the guard to bridge the pickup route shielding to the cavity.
    Also - think strategically about which contacts may get shorted if your shielding comes loose.
    It never hurts to put a bit of electrical tape in any of those spots.
    I tack solder the shielding together inside corners and at overlaps to minimize the risk of loose foil
    if the adhesive gives up. I've seen plenty of older basses where the foil was really loose.
     
  6. byacey

    byacey

    May 16, 2008
    Alberta, Canada
    Another option is to take a chunk of RG/59 coax cable with a copper braided shield, take the outer insulation off, and slide the inner dielectric and conductor out, leaving an empty tube of copper braid. Pull the pickup conductors into the tube. Then the tube can be stretched lengthwise to tighten up the braid.
     
    Gilmourisgod likes this.
  7. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician, and Contractor to Club Bass and Guitar - Toronto
    It's worth noting, too, that the conductive adhesive on some foils loses its conductivity after a while. Then you may lose connection from the various pieces of foil in the cavity and thus lose the shielding effect. Best spot solder all pieces together.
     
    Lesfunk likes this.
  8. DiabolusInMusic

    DiabolusInMusic Functionless Art is Merely Tolerated Vandalism Supporting Member

    If your pickups have exposed magnets, shielding the wire route is pointless. You will have more exposed surface area from the magnets than two wire route holes. I also wouldn't bother with spot soldering your tape together. If you are that concerned about conductivity in the future, do the job in paint. People warn about tape losing it's conductivity over time, myself included, but I have yet to actually see this occur in the wild. I'm sure it happens but it is hardly a common occurrence.

    Your job looks good although the pickguard could probably use some around the pickup hole. You really just need to come out of the cavity, no need to cover the body in tape. Pretty much everything I know on the subject can be read in the link in my signature.
     
    CentralCoastBass likes this.
  9. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician, and Contractor to Club Bass and Guitar - Toronto
    I have seen the problem many times. Happened on two of my basses before I switched to conductive paint. Now I am convinced that the paint is overall better than copper foil.

    Single-coil Jazz pups usually don't have shielded leads and I always felt it best to shield the wiring channel. It's really easy to do either with copper, paint, or braided shielding as suggested by @byacey and completes the shielding. FWIW, I tend to shield the pickups and ground the poles.

    Think of the shielding as a complete metal box (top, bottom and all sides) that contains all of the wiring and electrical components with just the magnet poles sticking out (in fact they don't actually have to stick outside of the box to work), and a point where you can connect to retrieve the electrical signal. That's the most effective shielding.
     
    Last edited: Nov 23, 2018
  10. DiabolusInMusic

    DiabolusInMusic Functionless Art is Merely Tolerated Vandalism Supporting Member

    I completely agree that the best shielding is fully sealed. However, that is overkill for our application in my experience. I like to think of shielding as a submarine. If there are any holes, there will be leaks. With exposed magnets, there are bigger holes to worry about than the small wire route. My Stingray, for example, has substantially more area exposed than any wire routes. I have never had noise issues on any of my jobs without coating the wire channels. If the OP has a sealed pickup, then it matters but, in that case, the pickup would most likely already be shielded prior to being epoxied in the casing.
     
  11. Turnaround

    Turnaround Commercial User

    May 6, 2004
    Toronto Canada
    Independent Instrument Technician, and Contractor to Club Bass and Guitar - Toronto
    I guess, in my view, the more holes you can plug the better. And since so little effort is involved, why not go ahead and shield the wire channels? Perhaps it's overkill, but I prefer to overdo than under-do.

    An alternative is to twist the signal wires going through the channel. That helps to reject some of the noise, but especially when using shielding paint, it's so easy to shield the channel that I can't think of a good reason for not doing it.
     
    safikex likes this.
  12. Lesfunk

    Lesfunk Supporting Member

    Anything worth doing is worth doing right
     
  13. I did a similar thing with this heavily-modded Squier VM Precision, using 3M copper foil to shield pickup and control cavities as well as most of the scratchplate. I also used insulation tape to prevent any inadvertant short-circuits as the full-size CTS pots are a very tight fit in that cavity!

    1502674_1502811080003591_7183970484143394490_o.
     
    Last edited: Nov 23, 2018
  14. walterw

    walterw Supportive Fender Gold Supporting Member Commercial User

    Feb 20, 2009
    alpha-music.com
    just remember, all that any of this accomplishes is reducing that extra buzz you might get when you let go of the strings with the volume knob still left up, something a pro player knows never to do anyway.
     

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