Shielding/Grounding Query

Discussion in 'Tele Home Depot' started by MarcoCee, Sep 30, 2019.

  1. MarcoCee

    MarcoCee TDPRI Member

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    Hi Folks

    I've just finished shielding the cavities.

    As I understand it, I need to connect them all, and plan on doing so by soldering wires from each cavity to the control plate cavity.

    The bridge plate will be connected via the copper strip that is extended to make contact with it, removing the necessity for an additional wire.

    Assuming this is sound, do I only need one ground wire to ground this circuit directly to the output jack? I know I can also ground to the volume pot, along with the ground wires from the pick-ups.

    Appreciate the advice.

    IMG_3939 wires.JPG
     
  2. Ronkirn

    Ronkirn Doctor of Teleocity Vendor Member

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    yes what you have illustrated will be perfect.

    rk
     
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  3. ale.istotle

    ale.istotle Tele-Meister

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    In what is surely a non-standard solution I used the copper shielding tape as my ground connector between cavities. I cut a thin strip - about 1/4" wide - peeled the backing and fed it through the hole between the control cavity and bridge cavity then pressed it down. I did the same between the control cavity and the connector cavity. For the connector to the neck cavity I put the tape over the top to contact the foil on the back of the pickguard. I also used the same surface tape to contact the bridge that you used. I actually didn't solder any ground wires to the foil. The control plate is grounded and contacts the foil in the control cavity. Continuity rings out fine with meter from socket to bridge to pickup cavities. This is certainly not better than soldered, but it's clean and it works as well in my case.

    upload_2019-9-30_8-11-16.png
     
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  4. hemingway

    hemingway Poster Extraordinaire

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    Hmm, this would explain why the shielding job I did didn't make any difference.

    Looks like a need to add a few more details.
     
  5. kbold

    kbold Tele-Holic Silver Supporter

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    Nice job.
    Grounding to the pot would be the easiest IMO. I would take all the shielding wires to one common ground on the pot. As ale-istotle mentioned, because the control plate is grounded via the pot casing, you don't need a wire to the control cavity shielding.
    Don't forget shielding under the pickguard to fully cover the neck pickup area.
    You could cover more of the pickguard to prevent the possibility of "pickguard crackle" (static crackle).
     
    Last edited: Sep 30, 2019
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  6. Ronkirn

    Ronkirn Doctor of Teleocity Vendor Member

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    remember, it doesn't matter what with or how continuity between the shielded cavities is achieved... the voltages are so very extremely low that if you could keep it from drying, salt water would suffice...

    You just want a way for electrons to be able to scary between the shielded cavities... how?? it could matter less... I use a bare wire, about 24 ga.. you can just barely see it coming through the bridge pickup leads hole..


    DSC_7426.jpeg
     
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  7. MarcoCee

    MarcoCee TDPRI Member

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    Great! Good to know.

    Not a bad idea, although (and despite their being an open cavity) I mean still go with a neck pickup mount and not have a scratchplate, meaning I wouldn't be able to hide it, but definitely a good idea.

    As for the bridge cavity, I'd maybe be a little concerned as to the tape splitting and being a bit more difficult to remove than a soldered wire, although if it works, it works!
     
  8. MarcoCee

    MarcoCee TDPRI Member

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    I may well do that, although, do I really need to connect all the wires to the pot? If they are connected at the same point in the control cavity, can I not simply use a single wire to connect them all to the pot?
     
  9. Ronkirn

    Ronkirn Doctor of Teleocity Vendor Member

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    not really they will be connected by virtue of the mechanical connection when you mount the pot through the shielding. BUT! I like to NOT depend on mechanical connections... such can shake loose.. if that happens, nasty crackling and other noises result...

    I always make a soldered connection from the shield to a pot case

    rk
     
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  10. tfarny

    tfarny Friend of Leo's

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    As stated, what you have will work. For me, I don't like soldering to the back of pots, I have ruined too many pots that way and in general it causes me problems - I get cold joints, the solder lifts off, etc.. If the tele control cover is grounded, the pots themselves will all be grounded. I have used a star ground approach many times with success. Screw a little eyelet into the side of the control cavity, connect every single ground point to it, then go from the eyelet to the output jack.
     
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  11. ale.istotle

    ale.istotle Tele-Meister

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    I have had some cold solder joints with my 40w iron. Probably I'm just not that practiced with it. The consensus on this site is to bring a lot of heat fast then get off the pot', so to speak. To that end I heated a 1/4" wide cold chisel with a mapp torch and used that as my soldering iron for the back of pots. Heated the pot back very quickly and let me get good solder flow, then let me lay off fast before the heat went to the internals. Also, I sanded and tinned the pot first, let it cool, then went back with the torch to add ground wires. Probably not my best idea, but it worked and I got to use open flame.
     
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  12. kbold

    kbold Tele-Holic Silver Supporter

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    As RonKirn mentioned, connecting to the shielding would not be as reliable or as sturdy as pot connection. You could secure (screw) a lug through the shielding and connect to the lug, but that would not be my preference.
    Also, it's common practice to connect all grounds to a common point, not multiple points, to stop ground loop noise.
    So .... soldering all grounds to a pot is best practice. Otherwise connect all grounds to the lug if that is your preference.
    You do need good soldering technique to have a good pot case connection.
     
    Last edited: Sep 30, 2019
  13. TimTam

    TimTam Tele-Holic

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    Just remember to test for continuity with a multimeter between the farthest end of each cavity and the output jack. It's easy to think you've used the copper tape with conductive adhesive when maybe you haven't. ;)

    With copper tape you should get ~0 ohms between test points. With conductive paint it may be over 100 ohms. That's perfectly fine as far as we know (no one has done a comparison of relative shielding effects AFAIK).
     
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  14. moosie

    moosie Doctor of Teleocity Ad Free Member

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    All good advice here. In case it has not been made clear... If you don't shield at all, you get RF noise, and static. If you do shield, and don't ground every little bit of it, then you stand a very good chance of having a (sometimes intermittent) 'haunting' of your guitar. Weird, weird noises, often loud. Make sure all shields, and any other little metallic bits, are grounded, and will stay that way.

    You can buy copper tape with electrically conductive adhesive, which is supposed to give continuity by simply overlapping the pieces. The foil is OK to use, but don't rely on the adhesive. Solder the overlaps. After 2-3 years in my guitars, the conductivity failed, and I started having strange noise problems. Clean the foil, and apply a single drop of solder across each joint - problem solved. Permanently.


    That one was very difficult to diagnose. I also bought a new Les Paul with a factory flaw. It was even harder to diagnose, and the problem was intermittent, and nasty. With the guitar on a bench, plugged in, I could 'play' it by holding my hand in the air 6-12" above the body or the neck. By moving my hand back and forth, I could get the guitar to HOWL. Almost like playing a theremin...

    After tearing every single other thing apart, I found the problem was the four-wire humbucker lead from the neck pickup. It was the kind that has the black rubbery outer insulation, and inside are the four wires, each insulated, plus a bare wire for grounding the pickup frame. The cable is shielded by a thin (conductive) mylar wrap between the wire bundle and the outer insulation. But wait, how is that mylar shield grounded? Well, you ground the bare wire, and the assumption is that it's going to touch the mylar sheath at some point over it's length, thereby grounding the shield. But in this lead, the bare wire was buried inside the other four, for it's whole length. And maybe sometimes it wasn't, because the problem seemed to go away for a while, and then come back...

    Save yourself a real headache, and ground that shielding.
     
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  15. MarcoCee

    MarcoCee TDPRI Member

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    Hi Folks

    Another update from me...

    A rookie error on my part, but, with this being a new body, I hadn't considered it may need a bit of sanding down in the cavity areas, especially those that had paint and gloss on them. The end result is the the control plate/components and the neck pickup didn't fit.

    I've removed the copper shielding and sanded down enough to give space for me to reapply and allow things to fit.

    It did get me wondering about the neck pickup I have. I think it's going to be inevitable, unless I sand away a great deal more, that the crimps on the pickup casing will contact the shielding. Will this result in the pickup grounding out? Here is a picture:

    IMG_3940.jpg

    I'm half tempted to wire up without shielding the cavity, but will hold my horses until the verdict is in.

    All being well, by the weekend, I hope to have this up and running :)
     
  16. MarcoCee

    MarcoCee TDPRI Member

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    I bought the shielding for a guitar builder supply store, so I very much hope it is fully conductive!

    I have my multimeter on hand, nonetheless...
     
  17. MarcoCee

    MarcoCee TDPRI Member

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    It should end up looking a bit like this... Can't wait!

    IMG_3960 (2).JPG
     
  18. mkdaws32

    mkdaws32 Tele-Meister Ad Free Member

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    I usually star ground to the volume pot using one of these between the control plate and the volume pot (these ones are a bit big - the smaller blue ones work better):

    upload_2019-10-2_17-13-53.jpeg

    I cleanly run, strip and twist all my grounds together, crimp them in the ring connector and then run some solder to “glue” it altogether. It’s true that the connector under the volume pot is a mechanical connection, but it’s under significant pressure and not in danger of disconnecting.

    The nice thing is that I can test everything before I run the solder into the ring connector sleeve so if there are any phase issues with pickups or other problem, I don’t have to unsolder/resolder a glob of wires to the back of a pot. It also means you don’t have to put a bunch of heat on the pot to solder to it.
     
  19. I_build_my_own

    I_build_my_own Friend of Leo's

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    Per Ron’s picture above - you would always want to solder pieces together. The solder joint will obviously outlast the more or less conducting adhesive of the copper. Plan for the years / decades to come.
     
  20. moosie

    moosie Doctor of Teleocity Ad Free Member

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    It won't be a problem. The pickup case is grounded, as is the shielding. All same.

    Do not rely on conductive adhesive, special guitar copper or not. You have been warned. ;)
     
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