Guitar Grounding Common Misconceptions?

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

  1. Raz59

    Raz59 Senior Member

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    The whole metal plate is in itself a ground connection...I don't understand why Gibson opted to do that, it's a really poor design.
     
  2. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    The vintage 50's circuit is also grounded all the way around as you can see here. :D

    [​IMG]
     
  3. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    They quit using them as far as I know and switched over to mounting the controls in PCB boards in some of the current LP models .
     
  4. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    I gotta get some sleep now TTYL ;)
     
  5. lukemacauley

    lukemacauley Mac Guitars Premium Member

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    I put the ground wire from neck tone to bridge tone in usually just to keep the whole harness together, so it is a direct drop in, and the customer isn't left with two separate parts - avoiding confusion of which to put where. :)
     
  6. FourT6and2

    FourT6and2 Senior Member

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    What about the point where all three braided leads from the switch come into contact with the braided leads from the pickups in the routing channel? Isn't that a bad thing as well? Shouldn't they be isolated from each other? Or does that not matter?
     
  7. lukemacauley

    lukemacauley Mac Guitars Premium Member

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    It doesn't matter at all, as the braided wires (from the pickup and from the switch) are still being grounded. It would only pose a problem if there was a live wire touching the braided grounds - which could cause a short, or cause the guitar to work intermittently.

    Basically, if a ground touches a ground anywhere in the circuit it won't matter, since they'll just be grounding to each other.
     
  8. Raz59

    Raz59 Senior Member

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    The braids from the switch are connected to ground, so any signal passing through won't pass through the amp's circuitry - it won't be amplified. So it's a shield against outside interference (I think I already said it, but it's good to know this by heart).

    The braids from the pickups are soldered next to the braids of the switch purely because of aesthetics. The second you solder that braid from the switch to the back of the pot, the pot itself becomes a ground point.
    Aside from the 'hot' lugs of the pickup and switch, you can solder the braids any where on the potentiometer and you'll still get an effective ground connection.

    Ideally, every every element that is supposed to be connected to ground should be connected to it only in one point - not several. In a guitar, the current generated by the pickups is low, but in other high voltage situations, a circuit with ground loops can lead to unexpected/fatal situations.

    It's vintage correct to just make a loopy loop of solid wire and solder it all around the pots, but it's a bad practice electrical-wise.
     
  9. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    Grounding & Fender Metal Control Plates

    It has been common practice since the mid 1940's for companies like Fender to use Metal Control Plates to mount the guitar electronics on. It makes them handy to load into the guitar, provides a Universal "Grounding point" and is also part of the guitar design and gives Tele's, Mustang and Jazz Bass guitars a cool look. Things have remained the same for over 60 years, here are some examples.

    [​IMG]
    Fender Mustang Control Plate


    [​IMG]
    Fender Jazz Bass Control Plate


    [​IMG]
    Fender Telecaster Control Plate


    All these Control Plates were not only designed to mount the controls on, but also to provide a Universal grounding method for the volume and tone pots. The notion that the wiring controls should only be grounded at "One Point Only" is pure nonsense. On all my Tele and Jazz Bass rigs I also solder an additional ground wire between the pots to ensure good grounding, so along with the plate the volume and Tone pots have a solid connection as well. Grounding is a good thing and helps reduce noise and provides a clear signal path.

    [​IMG]

    The switch frame is grounded to the control plate, but all the + positive contacts are isolated from the plate and they handle the hot + signal from the pu's and route it into the volume pot, then on to the input jack.



    Good grounding does several things...

    1. It creates a ground path for the neg. - signal for your volume and tone pots so they work properly.

    2. The hardware is grounded so your switch frame, bridge and strings are all properly grounded which helps reduce noise.

    3. Good grounding also helps get rid of static and additional unwanted signal as it is also sent to ground via the ground loop.

    GROUNDING = GOOD :naughty:
     
  10. Raz59

    Raz59 Senior Member

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    If a ground connection touches another ground connection at a considerable distance, you get a ground loop.

    "What is ground loop ?

    A ground loop occurs when there is more than one ground connection path between two pieces of equipment. The duplicate ground paths form the equivalent of a loop antenna which very efficiently picks up interference currents. Lead resistance transforms these currents into voltage fluctuations. As a consequence of ground-loop induced voltages, the ground reference in the system is no longer a stable potential, so signals ride on the noise. The noise becomes part of the program signal."


    Ground loop basics
     
  11. Mookakian

    Mookakian Senior Member

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    Nice thread jonsey ;)
     
  12. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    Fender Stratocaster wiring controls are mounted on plastic pick guards. This LH Strat Assembly I just built this week has the foil shielding on the inside of the pick guard to help with grounding and noise reduction.

    The black wires from the pickups are all grounded to the volume pot (circle). The volume pot and both Tone pots are linked by a ground wire that is soldered to the back of the pots, the ground to the input jack is also soldered to the back of the volume pot.

    The arrow is pointing to the ground wire that is also soldered to the volume pot and it get's soldered to the trem claw which in turns provides a ground path through the trem springs to the bridge and guitar strings.


    [​IMG]
     
  13. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    Thanks bro :thumb:
     
  14. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    Leo Fender went to school and was an accountant before he started Fender Music Corp. building amps and guitars. Les Paul learned everything he knew about electronics at the public library and went on to invent multi-track recording.

    No amount of education can buy you commons sense, that is something you are born with not taught. So you are probably not going to get that at the University you attend. I started this thread to provide information about guitar grounding. And that is exactly what I am trying to do here.

    Fender and Gibson have been using these grounding methods ever since they have been in business because they work. Maybe you should send them a letter about how you feel instead of constantly being distracting, and trying to debate it here on this thread with me?

     
  15. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    Gibson Metal Mounting Plates in LP's

    [​IMG]

    These plates were used to install the long shaft pots in many of the LP Customs, Standards and Studios because it made it easier for the factory to mount the controls into the guitars.

    If you look there is center post with a place for a positive + and negative - connection. The braided lead from the input jack solder to the lug with the grounding tab and then the hot center lead goes through it and solder to the other tab.

    [​IMG]

    The braided ground from the input jack then grounds to the metal plate which the plates are mounted to. The plate grounds all 4 pots together.

    The black hot wire from the switch solders to the other tab and connects to the inner hot lead wire to the input jack completing the connection.

    [​IMG]


    Removing The Metal Plate

    Many people decide to remove the metal plate when they upgrade their pots and IMO this is probably a good idea. But you will have to do a little rewiring because when you remove the metal plate the center post will no longer be there to make those connections for you.

    If you remove the metal plate you can solder the braided ground from the input jack to the back of one of the Tone pots. You will also have to run the ground wire shown in previous pics to the back of the pots to complete the grounding since the metal plate is gone.

    If you are using the old switch wires you will also have to solder the hot lead from the switch to the hot inner lead of the input jack splicing them together. If you install a new pre-wired switch you can run that lead right to the input jack and just solder it directly to it without having to splice the two together.
     
  16. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    I thought most of the material has been presented in a pretty straight forward clear fashion. I used a lot of examples of different types of wiring with lot's of pics. And several people posted that they thought it was a good thread and did not seem to have issues with how I had explained it like you and Raz have. Seems like I often attract a lot of controversy in these threads when all I am trying to do is help out. :hmm:
     
  17. Mookakian

    Mookakian Senior Member

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    Ok, the only way to see through this is to test both ways back to back and record, This ones on you Raz, id do it but im happy with the suggested loop method, great tone, low noise :D If it Aint broke, dont fix it.

    Id be very surprised if your grounding Method(Raz) created a stronger signal/less humm, but you need to put ur Theory to the test now ;) Show us
     
  18. FourT6and2

    FourT6and2 Senior Member

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    Now my question is, what would happen if you were to remove the portion of ground-bus wire connecting the neck and bridge tone pots? So, instead of a grounding-wire connecting the backs of all the pots in a "C" shape, it's just neck volume to neck tone and bridge volume to bridge tone.

    One person said the only reason it's wired in a "C" (connecting all the pots) is that it's easier for installation, as all the components are connected.

    If that's the only reason, then is really a need for all four pots to be connected to each other? And if the don't really need to be connected to each other, schematically-speaking, then is there a downside (no matter how insignificant) to doing it this way?

    As I said earlier, I've seen pre-wired kits that are wired both ways. For example, RS sells kits wired either way. What's the difference? It can't possibly just be for variety's sake. Right?
     
  19. Raz59

    Raz59 Senior Member

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    Like you said, ease of installation. It's also vintage correct. You can't question vintage in these parts lest ye be shot by a bullet named Page/Clapton/Frampton/Slush.
     
  20. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    OK, I went back and cleaned up my earlier posts and removed the word "loop" I hope that adds some clarity about "Grounding" and puts an end to the whining and crying about the terminology I used earlier.
     

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