Guitar Grounding Common Misconceptions?

Discussion in 'Tonefreaks' started by jonesy, Jul 23, 2010.

  1. onehippie

    onehippie Senior Member

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    ive reach a moment of clarity Jonesy i think i finally am comfortable about my task
    looking back on your notes i get it :thumb: theres been some helpful info i needed to see got me pondering it all :hmm:
     
  2. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    Like someone posted earlier...(Lampens?)

    I hear and I forget, I see and I understand, I do and I remember :thumb:
     
    onehippie likes this.
  3. onehippie

    onehippie Senior Member

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    true words right on
     
  4. weirdotis

    weirdotis Senior Member

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    I don't know how I missed this thread. Very informative- thanks for posting!
     
  5. Mookakian

    Mookakian Senior Member

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    Heres a boggler, if you put too much solder on the back of pots can this create a resistor of some kind, read it over at ANZLF from the administrator, but i question everything, even my sexuality(kidding) Not that theres anything wrong with that

    [​IMG]
     
  6. Buzzerjim

    Buzzerjim Member

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    Sorry but thats bollox.....:D
     
  7. peaveywolfgang

    peaveywolfgang Member

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    my grounding wire from the bridge to the pot on a Gibson Les Paul Classic has broken at the bridge end so i need to replace it. Do i need to pull the bushings out (totally or just a little) to get a new wire under and press the bushing in on the wire or does the stud screw in deeper than the bushing (the bushing having no bottom) and therefore being sufficient to unscrew the stud to make room for the wire and then screw it back in, pushing on the wire ?

    thank you
     
  8. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    Normally you would pull the bushing completely out, run the new ground wire and be sure that the bottom of the bushing seats firmly on top of the ground wire. The bushing makes contact with the wire not the stud itself since it is raised slightly. But you may be able to just pull up the bushing far enough to get a new wire under it? :hmm:

    Afterwords you can check continuity with a multimeter to make sure you have a good ground path between the ground wire and the bridge.
     
  9. FourT6and2

    FourT6and2 Senior Member

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    Hey jonesy,

    Is there a reason why the pots in a guitar aren't wired this way, with the lugs that go to ground connected with the bus wire, instead of being soldered to the pot casings and then the pot casings all connected with the bus? Doing it this way in an amp eliminates ground-loops and reduces background noise. I may try it in my guitar. Because I still haven't been able to get rid of that noise. I suspect a ground-loop is the cause.

    [​IMG]

    [​IMG]

    Normally, that bus wire is wired up this way (much like in a guitar), where the pot casings are connected and then the lug that needs to go to ground is soldered to the bus. Hello ground loop!

    [​IMG]

    [​IMG]

    Why not separate the ground connections? The lugs that should go to ground get connected by a bus wire, instead of having them soldered to the casing and then connecting the casings.
     
  10. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    Amps deal with high voltages so grounds loops are in issue as far as generating noise. In guitars there is barely any measurable voltage (milli-volts) at all, so as previously discussed ground loops in guitars do not cause noise or humm like they do in amps.

    Guitar wiring has not changed a whole lot in 50 years because grounding to the back of the pots is a simple reliable way to do things. Most all the amps controls and circuits are mounted inside a metal chassis along with the transformers so a universal star ground is commonly used. I highly doubt your noise issue in your LP is caused by a ground loop, it is more likely a bad ground or a partial short that is causing the problem.
     
  11. Core

    Core Senior Member

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    Just changed the bridge saddles to graphite on my '82 LPC. I noticed I'm getting more buzz as I rest my palm on the strings. It doesn't quiet the hum anymore, it adds to it. However if I do touch any of the vol/tone pots it does quite the guitar so I know that's grounded.

    I'm assuming the saddles being graphite are the problem as there is no direct metal connection now. Also on this guitar there appears to be no ground wire coming from the tailpiece to the control cavity, nor is there a hole drilled from the stud hole to the cavity like there is on my '08 LPC. It may have been set up to ground to the bridge but I can't find any evidence of ho or where.

    Jonesy, would you or anyone else know how I might bypass this so the strings can be grounded again?
     
  12. Raz59

    Raz59 Senior Member

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    As far as I know, graphite is electrically conductive...
     
  13. Core

    Core Senior Member

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    ah ok thanks for the info. I noticed it less tonight during practice so maybe there's some other interference going on with the amp or wall outlet.
     
  14. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    Maybe pu one of these testers and check your wall outlet to see if it is grounded properly? :hmm:

    [​IMG]
     
  15. Core

    Core Senior Member

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    Thanks Jonesy, I may have to try that out although since it's an apartment I don't know if my landlord would fix anything if it wasn't grounded properly.
     
  16. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    Your welcome, those little testers are only $6 and handy to use.
     
  17. FourT6and2

    FourT6and2 Senior Member

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    Well, I brought my guitar to a good tech and he said he can't find anything wrong with it either. It's just noisy and that's the way it is. He said maybe try putting the metal grounding plate and can/cover back in as that my filter out any interference if there is some. I did just that–unsoldered the ground bus wire from the pot casings and put the metal plate back in. With the cover on, some of the noise is gone. But not all of it. I guess the bottom line is I'll have to suck it up and drill a hole for a string ground if I want to get the guitar quiet, especially since now I'm playing it thru a cranked Super Lead. And those are noisy amps.
     
  18. onehippie

    onehippie Senior Member

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    youll be glad you did
     
  19. mariosyjp

    mariosyjp Junior Member

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    this is one of the most interesting and informative threads i've read. not even in books there is so much easy to read and practical information.

    i'm dealing with a noise problem:
    i put a push pull switch in my gibson flying v yesterday for out of phase sounds and the guitar is either quiet as stock or uncontrollably noisy!
    it picks up some kind of interference it seems and only volume to 0 makes it stop and i have to change my standing position to get rid of it.
    my guess is that the extra wires and the long box with the lugs of the push pull are to blame.
    what has just occurred to me is that i didn't use a wire from the pot casing to the ground, just it's physical connection touching the back of the pickguard. could this be it?
    do you have any suggestions?

    thanks!
     
  20. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    Glad you found some useful info in this thread. ;)

    I use push pull all the time and don't have any extra problems like that. I would start by grounding the back of that pot to the rest of the circuit with a wire that is soldered on. Not having a solidly attached ground wire may very well be the source of all your noise. :hmm:
     

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