Guitar Grounding Common Misconceptions?

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

  1. Raz59

    Raz59 Senior Member

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    With braided shielded wire or without? :naughty:
     
  2. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    Ok I have highlighted the ground path in Blue to make it easier for you to see. What does that look to you? Looks like a slight variation on the "C" type ground path to me. He must not be concerned that it is going to cause any potential grounding problems.

    [​IMG]
     
  3. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    Your choice. ;)
     
  4. Raz59

    Raz59 Senior Member

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    Excellent.

    First, let me call on your foul play on your earliest example:

    That diagram is set-up without the use of braided shield wire. As you can see, it's simple wire, and that simple wire doesn't have a metal braid nor do you see it magically soldered to the pots.
    Do you usually ground the braid from the jack to the bridge tone? No, you don't, you cover with plastic until it reaches the toggleswitch.
    Without braided shielded wire, you can see that there are no ground loops what-so-ever. With it, you'd introduce a ground loop between volume pots and the toggleswitch. So it would be set up differently if you wanted to add vintage wire.

    So no, that's not a valid example. You can phone Mr.Duncan on this issue too. While it's not too serious of a problem in the guitar cavity, it's not good practice to add unnecessary connections.

    Now, for the Jimmy Page wiring. I'll even specify that it is wired with independent volume controls and that the capacitors are placed so that the tone controls act before the signal is submitted to the resistance of the potentiometer (in other words, 50's style wiring).

    Since you let me choose, I'll just stick with normal wire. This way I can do a "C" shape and not cause any ground loops:

    [​IMG]

    All pots see the ground only once, pickup bodies and toggle switch frame is also grounded. Would this work correctly?
    EDIT: There IS a ground loop when both pups are connected in series though...wait...no it's not, the bodies are separate from the pickup itself, sorry bout that.
     
  5. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    No the way you have the "C" grounding shown for the Original Jimmy Page diagram that I posted is not correct, only about half of it will work. You will get dead spots on several of the push pull functions and they will act like a kill switch instead of working properly.

    Maybe you can explain to me why that would happen?
     
  6. FourT6and2

    FourT6and2 Senior Member

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    You cover the lead from toggle switch to output jack with plastic tubing the whole way?

    Once it reaches the jack don't you solder the outter braid to one terminal and the inner wire to the other? There's no need to solder a ground back to a pot, right?
     
  7. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    No you just need to put about 6" of tubing over the lead from the switch to the input jack inside the cavity so the vintage braided wire does not short out on the hot lugs of you pots or cap leads.

    Yeah then you solder the braided to the ground lug on the jack and the inner hot lead to the hot lug on the input jack. No need to solder the braided to any of the pots.

    The braided ground on the switch leads that are soldered to the back of the volume pots complete the ground to the input jack lead where they are soldered up at the switch.
     
  8. Raz59

    Raz59 Senior Member

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    If you use the braids from the toggle switch to ground both volume pots, then you only need to put two wires bridging each volume pot to the corresponding tone pot. You agree, right?

    I honestly can't see where the pitfall is...if you don't mind, please go ahead and explain.
     
  9. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    Well it's pretty simple (kinda) when you send hot to ground and it is suppose to go somewhere else in the signal chain what happens? Kill switch engaged.
     
  10. Raz59

    Raz59 Senior Member

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    Wait. So is this a problem about the how the grounds are wired to the pots or is there a problem with the a problem as to how the switches work?
     
  11. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    Well in the original Duncan diagram is it is the lack of grounding that causes the problem.

    In the grounding method you posted it is improper grounding that is causing the problem.

    It is nothing to do with the way the switches are wired, that is fine, and I have never tried wiring the caps the way you have shown on the Duncan diagram but that should not be an issue as far as grounding goes.

    I actually use a totally different diagram for my 21 Jimmy page rigs and they are not based on the Seymour Duncan version.

    And don't just guess at it, if you are going to a University studying engineering or electronics then you should be able to explain what is needed, and why ;)
     
  12. Raz59

    Raz59 Senior Member

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    We're having a double standard then. If I don't ground it, volume and tone controls won't work. If I ground it, push/pulls don't work properly.
    Why is this up on Seymour Duncan's site if it's not correct?

    Lucky for me, the schematic I used for my LP was supervised by good and talented people...but here's the totally off-topic part - I did post a modified SD version of it on the Wiring Library thread and asked for help, you replied "I don't know, tell us if it works?".

    Why would you knowingly send me on a wild goose chase? I know tinkering, frustration is part of the learning curve, but isn't that a bit mean spirited, jonesy?

    And yeah, since this is wrong, I'll just build it from scratch. I'll provide a working version on my gallery.
     
  13. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    Yeah now that's the spirit bro, you do that. I hope you can actually get one of these 21 Tone Jimmy Page rigs and up and running. :thumb:
     
  14. Raz59

    Raz59 Senior Member

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    It's an updated version of Borsanova's 22 mix tone...lots of funky stuff going on there, the diagram's in my gallery as well, I can testify that it works. The grounds on top of the push/pulls form a nice old "C"...

    Sorry for the off-topic, and please continue what I think is a good thread.
     
  15. jonesy

    jonesy GLOBAL WIRING GURU MLP Vendor

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    Well there you go then, gotta love that "C" ground. Rock on! ;)
     
  16. Mookakian

    Mookakian Senior Member

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    :thumb: Hows this look:naughty:

    Sorry, miss a whole page of posts:laugh2: :slap:
    But if you ground the Neck volume pot to the Neck Tone Pot on the JP wiring, as soon as you reverse the phase/run in series, the hot lead will also go to ground, aka killswitch

    Does that sound right? I always hit a wall in my head trying to understand why leaving this ground out is so crutial to the JP rig!
     
  17. Raz59

    Raz59 Senior Member

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    For whom may concern: I edited, the post where I displayed faulty JP rig...theoretically, it should do what it is advertised to do now. So the volume pots work, the switches do their job, grounding's good and we're all happy campers.

    Hope it helps!
     
  18. onehippie

    onehippie Senior Member

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  19. b3john

    b3john Senior Member

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    Against my own better judgment, I'm going to wade in here. I admit I haven't spent much time working on this stuff in the past 25 years, but it seems like something basic is getting overlooked.

    If this were a high amperage circuit, like in a guitar amp, would you accept a ground loop in your circuit? Of course not, you would never sign off on that design. But you would never route that critical ground through the body of a LP to the switch cavity either. Maybe in the '50s, but not today. No, you'd have some sort of a low voltage control circuit to handle the remote switching between treble/both/rhythm, completely separate from your critical potential voltages.

    Now, is that something you want in your Les Paul? Probably not, I know my guitar is the last place I want harboring a microprocessor. (Paradoxically, it's OK if I don't have to lug around a Hammond and Leslie, and it's even OK if I don't have to lug around a half stack, but it's not OK in my guitar. I'm inconsistent; so sue me. :laugh2:)

    So to get worked up over ground loops on a very low amp circuit in the spirit of correctness might actually make real-world troubleshooting much harder if the search for a ground loop-free circuit means the ideal single ground circuit has to extend all the way into the switch cavity and back again. :shock: And God help you if you got seduced by a Les Paul Supreme, with no access plates into the control cavities! :wow:

    Looked at another way: The developers I work with always seem to be looking for textbook answers to database tuning problems. But many times their little test cases with 100 rows react very differently from a production dataset with 100 thousand rows which itself is very different from the data warehouse with 100 million rows. Not even the access methods are similar. Sometimes the textbook answer is, "There is no textbook answer to fit all cases". Thankfully, we just don't have +400V plate voltages or large electrolytic caps in our guitars.

    Sometimes the low tech answer is the right one, even if it doesn't "scale", because it's solving a low tech problem.

    Now I think I'll go crawl back under my rock.
     
  20. Raz59

    Raz59 Senior Member

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    This will seem like adding wood to the fire, but bare with me.

    Jonesy, out of curiosity I did try following the signal's path along the switches and it SEEMED that the phase switch would be the problem.
    But no, that switch only alternates between which end goes to the series/parallel switch - and that switch alternates between connecting the end of the bridge (chosen by the phase switch) to ground or perform a series link with the neck humbucker.

    Both humbuckers still pass through the corresponding volume pots and through the switches; in series mode, the neck volume/tone pots become master controls of the circuit because the bridge humbucker no longer passes through the bridge volume pot.
    So - and I'm sorry for being a bother - the switches work fine and so does the grounding I posted.
    So please refute my claims and be specific; I know that sending the signal directly to ground is a killswitch, but the only killswitch that is present is when you put the toggleswitch in the bridge position WHEN you are in series mode.
    EDIT: And you can't coil split the neck and be in series mode at the same time either...but the controls still do what they advertise. So two dead spots found.
     

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