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Does Ground Wire Need to be Insulated

Discussion in 'Pickups & Electronics [BG]' started by blipndub, Mar 16, 2010.


  1. I'm using pushback wire it it would be easier just to strip a length and run it along the three pots for my jazz bass, but will not having the wire insulated create additional noise?

    Thanks
     
  2. You just need to make sure that nothing is shorting out.
    If you have uninsulated wire, that creates a greater possibility that the ground wire can touch up against a pot terminal or something and short out the output.

    I have seen plenty of people just run a bare copper wire across the back of pots though. I saw a Les Paul prewired harness that way the other day.

    Where on earth did you get the idea that a bare ground wire would increase noise? It's quite the opposite.

    The entire concept behind a faraday cage is to surround a circuit with something grounded so that any free electrons would be grounded before they can reach the signal.
    That's why people shield their basses.
     
  3. seanm

    seanm I'd kill for a Nobel Peace Prize! Supporting Member

    Feb 19, 2004
    Ottawa, Canada
    No. It should be fine. Just make sure it doesn't come in contact with any of the non-grounded parts. The insulation is to make sure nothing shorts, not for noise.
     
  4. Bassamatic

    Bassamatic keepin' the beat since the 60's

    If I am not mistaken, all the pots on a Jazz are grounded through the mounting plate.
     
  5. Duh, I never thought about it! Of course the covering on the wire has no impact on buzz, I don't even know why I had the notion! Oh, well now I know something I didn't know i didn't know!
     
  6. But they still have to be grounded to the input jack a bridge, right? I assume wiring them together just completes that loop, but I don't know a thing about electrical, obviously.
     
  7. OUTPUT jack!

    The jack does not need to be grounded, as it's already grounded through the control plate, along with the pot chassis'.

    All you need to do is run a ground wire from the bridge to either the back of a pot, or the sleeve terminal of the output jack, if you have difficulty soldering to the back of the pots.
     
  8. Why does every wiring diagram I've ever seen have grounding wire running from the output jack through all of the pots? Are you saying that the ground wires that connect the pots are unnecessary?

    [​IMG]
     
  9. Yep, completely unnecessary.
    They are already grounded though the control plate.

    Seymour Duncan probably includes the ground wires because not everyone has a top routed Jazz bass with a metal control plate.

    If you have an unshielded rear routed bass, or perhaps an unshielded pickguard style control plate, the extra ground wires would be needed.
     
  10. mongo2

    mongo2

    Feb 17, 2008
    Da Shaw
    The only reason I can see to ground the individual pots and jack on a J bass with a controlplate is as a failsafe against the controls/jack loosening or corrosion between the plate the pot casings, either would cause intermittent ground issues. Wiile I don't think it's common I've seen both happen several times over the years.
     
  11. Do the grounding lugs still need to be attached to the back of the pots?
    [​IMG]
    This all started for me when I got some WD pots that had a pretty big gap between the lugs and the pot itself, enough so that I couldn't just fold the lug on to the pot I would have to run a wire and that's when I thought I could just run a single wire through all the lugs/pots.
     
  12. Yes, the third terminals of the volume pots must be grounded, otherwise the volume control cannot do it's job of grounding the signal when you mute a pickup.

    FWIW, I wouldn't reccommend folding the terminal inward and soldering it directly to the pot casing. Use a short length of wire between the third terminal and the back of the pot instead.
    I've learned through personal experience that it's rather difficult to desolder the terminal from the pot casing, should you need to dissassemble the pot...
     
  13. Thank you L6M, I think I'll go back to my original plan of running a single ground between the two vol terminals and the tone pot, it would be neater for me than running small wires from each terminal
    [​IMG]
     
  14. bassbenj

    bassbenj

    Aug 11, 2009
    NOT "completely unnecessary"! Yes, you CAN "get away" with not running a ground wire to the jack, but it is not advised!

    Here's the reason. Instrument makers like to use the backs of the pots as a place to solder ground wires. It's handy and makes sure the pots are covered with a grounded metal shield. BUT the backs are typically just crimped on. So usually they make good contact with shaft part of the pot that grounds the pots to mounting plate if it's metal, but they CAN get loose or corroded and lose that contact.

    Thus the way to insure that everything stays grounded is to run the wire from the backs of the pots to the output jack ground. That makes sure that even if a cover comes loose it's still grounded to the shield ground Just as the SD schematic shows.
     
  15. That's a good point actually.

    I've never had any problems with pot casings losing their continuity to the shafts/control plate, but it might be a good idea to account for that in your grounding scheme.
    Personally, I wouldn't worry about it either way though.
     
  16. mongo2

    mongo2

    Feb 17, 2008
    Da Shaw
    Yes, as a failsafe as I posted earlier.
     
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