Star Grounding ?

Discussion in 'The Custom Shop' started by Superlead777, Jan 2, 2009.

  1. Superlead777

    Superlead777 Junior Member

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    ...so I can get my Paul dead quiet. Diagram?
     
  2. Dino

    Dino Senior Member

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    Star grounding is when you run a ground wire from each component (pot, switch, pickup, bridge, etc..) and ground them all to the ground wire coming off your input jack.

    I usually solder a terminal at the end of my input ground to where all the other ground wires will be soldered.

    I saved some pics of "star grounding" that I did on a custom tele.
    This pic shows all my individual ground wires going to a terminal that I soldered on the ground wire of my input jack.

    [​IMG]

    Then I used shrink tubing to insulate it.

    [​IMG]

    Then I just simply tucked it out of the way for a neater appearance.

    [​IMG]

    If you remember to run a ground from each component, you really shouldn't need an actual diagram.
     
  3. eddie_bowers

    eddie_bowers Senior Member

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    Call me a skeptic, but I don't see how this quiets a guitar. As long as everything has a good ground connection you should be fine.
    So called "Ground Loops" can create noise on AC power lines, but that is not at all what your dealing with in the electronics of a guitar.

    I'm open to being wrong, so if I am educate me.
     
  4. derraj06

    derraj06 Senior Member

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    I don't know much about guitar electronics but I do know you can get ground loop effects in car audio, which is DC power so I would assume it is possible to do the same for guitar?
     
  5. eddie_bowers

    eddie_bowers Senior Member

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    A car has an alternator and not just a battery which creates most of the noise, but this is still talking about avoiding noise induced from a power source, not the passive electronics in a guitar.
     
  6. Tone Seeker

    Tone Seeker Senior Member

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    When you have more than one physical ground point in a circuit, and those ground points are at a different electrical potential, you have a ground loop (AC or DC circuits). The difference in electrical potential causes a current to flow, which is what creates the noise.

    It seems that few guitars come wired with star grounding. I have not converted my instruments so I can't comment on the real-world impact, but it is considered to be a best-practice.

    You can read more about ground loops in general here. . .

    http://en.wikipedia.org/wiki/Ground_loop_(electricity)

    Terry.
     
  7. eddie_bowers

    eddie_bowers Senior Member

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    (don't take this as being belligerent, I just want to understand)

    You don't really have more than one physical ground point in a guitar. OK, if your touching the strings YOU can be another physical ground, but the way you wire your guitar wont change that.

    Wikipedia is still talking about ground loops in supplied Power, not passive electronics like in a guitar.
     
  8. Tone Seeker

    Tone Seeker Senior Member

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    No problem.

    There is a power supply in a guitar, the pickups and a moving string. Striking a string causes a voltage to be generated by the pickups, causing current to flow through your volume / tone controls and caps, to ground in your guitar.

    Now let's plug in the guitar cable. This connects your guitar circuit to your amps input circuit. Your cable, with it's shield and centre conductor, and the associated ground points at your guitar jack and amp jack, are part of the same circuit, as is the cable capacitance and cable resistance (yes, cable quality does matter ;-). Now the current created in your guitar flows to your amp.

    Moving back to the guitar, it's common practice to solder the back of all the pots together, often using the shield from the pickup wire. Strictly speaking, this creates the potential for a ground loop between the controls. It also creates the potential for a ground loop between the controls and the pickups themselves, and along the shielded cable runs where they touch.

    Now, theoretically the resistance of a wire is zero ohms. For short runs of wire this is, for all intents and purposes, the case. But let's say you have a bad solder joint on the back of one of those pots. (It takes a bit to heat those suckers up sometimes, and it's not hard to create a "cold" solder joint.) This creates a resistor in the circuit, between ground points. Now you now have a ground loop.

    But what if everything is properly soldered and good cable / wire is used in the guitar? For all practical purposes a star ground would likely make little, if any, difference. However, as I mentioned in my last post, I have never wired a guitar both ways to see what the real world impact is. But, if I were to put a partscaster together (and I'm thinking of doing that) I would wire it using a star ground (it's the purist in me!).

    Hope that helps!

    Terry.
     
  9. Tone Seeker

    Tone Seeker Senior Member

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  10. eddie_bowers

    eddie_bowers Senior Member

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    Agreed, but there is A difference. Hum from power is infecting your signal and being heard. Since your signal IS the generator of the current in the guitar then any current flow on ground would not be a problem. Right? Wrong?
     
  11. SABLE

    SABLE Banned

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    i would rewire all the wires with high quality wires, and look into upgrading your amp.
     
  12. Tone Seeker

    Tone Seeker Senior Member

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    Wrong. Any time you have a faulty ground in your circuit you have the potential for a problem. You're right in that it would not be 60Hz hum from other connected equipment, but instead your guitar might pick up the local radio station or your fluorescence lights. Perhaps the poor ground will simply cause a tone control to function improperly.

    Terry.
     
  13. eddie_bowers

    eddie_bowers Senior Member

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    I guess i'm assuming all grounds are good, you just might have two paths to ground, one having ever so little more resistance than the other. Anyway, this is a good discussion and helps clarify things in my mind. Ultimately star grounding can never be a bad thing.
     
  14. Tone Seeker

    Tone Seeker Senior Member

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    That's a great summary statement! :naughty:

    Terry.
     
  15. Redfish

    Redfish Senior Member

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    My Strat had a noise problem that I couldn't seem to clear up. I did the copper shielding of the cavity and the pickguard but it didn't help. Star grounding was a last resort and it worked like a charm. I don't think it's necessary in most cases but it can be a great thing for a problem guitar. It's definitely easy and worth a try if you have a ground problem.
     
  16. xsouldriverx

    xsouldriverx V.I.P. Member

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    ok so let me get this straight...
    instead of grounding to the wire coming from my tailpiece, you just run a wire from each component to the ground of the input jack when you plug your cable in?
    so you dont need the tailpiece ground at all then?
     
  17. xsouldriverx

    xsouldriverx V.I.P. Member

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  18. Tone Seeker

    Tone Seeker Senior Member

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    Your tailpiece will still need grounding, to the same ground point as everything else.

    Terry.
     
  19. xsouldriverx

    xsouldriverx V.I.P. Member

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    oh ok, i see now. thank you.
     
  20. Tone Seeker

    Tone Seeker Senior Member

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    Good luck with your wiring!

    Terry.
     

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