Proper grounding method with black conductive-painted cavities?

[Snoogles]

i've re-wired this damn guitar so many times, i can't remember how it was originally grounded.

it has black conductive paint in the control, and pickup cavities (humbucker). and i think at one point it had connector wires that were screwed into the wood, going from the two pickup cavities and the control cavity... to where? i don't remember.

however, i've measured with a multi-meter to random areas in the control cavity. in some spots there is a connection and at other spots there isn't.

the guitar is an old japanese jackson dkmg that had the emg passives in it.

would the cavities be routed to the output jack ground? and would i also need to run a ground wire from all of the pots and switch to the output jack ground as well?

hope i was able to clearly explain the issue. thanks for any help

 

[uOpt]

Re: Proper grounding method with black conductive-painted cavities?

The only rule is that everything needs to be grounded.

If the pots are grounded and sit in the conductive paint you don't need extra ground on the paint.

 

[ItsaBass]

Re: Proper grounding method with black conductive-painted cavities?

In a guitar, there is only one ground in the end: at the jack. As long as everything that needs grounding has a path to the ground lug on the jack, it really doesn't matter to what ground "bus" it is soldered.

So, run the wires to wherever is most convenient...which is probably not the output jack itself.

 

[Ball&Chain]

Re: Proper grounding method with black conductive-painted cavities?

i've re-wired this damn guitar so many times, i can't remember how it was originally grounded.

it has black conductive paint in the control, and pickup cavities (humbucker). and i think at one point it had connector wires that were screwed into the wood, going from the two pickup cavities and the control cavity... to where? i don't remember.

however, i've measured with a multi-meter to random areas in the control cavity. in some spots there is a connection and at other spots there isn't.

the guitar is an old japanese jackson dkmg that had the emg passives in it.

would the cavities be routed to the output jack ground? and would i also need to run a ground wire from all of the pots and switch to the output jack ground as well?

hope i was able to clearly explain the issue. thanks for any help

More that likely where they were screwed into the wood was a sort of junction point for the ground wires. Usually the back of one or more pots is used for that. One of those wires at the junction point should have been connected to the bridge. If its a floyd type bridge, it was probably soldered to the spring claw.

No, you dont need to run all grounds to the output jack. One wire from the output jack to a ground source will suffice. Everything does need to be grounded however.

 

[Grindspine]

Re: Proper grounding method with black conductive-painted cavities?

The only rule is that everything needs to be grounded.

If the pots are grounded and sit in the conductive paint you don't need extra ground on the paint.

Correction: the only rule is that everything needs to be grounded through one common ground. Otherwise, you get ground hum.

 

[ItsaBass]

Re: Proper grounding method with black conductive-painted cavities?

Correction: the only rule is that everything needs to be grounded through one common ground. Otherwise, you get ground hum.

This ground loop thing is a non issue and a myth that is way too prevalent in grounding threads. There's only one way in and one way out of the guitar; everything that's grounded at all must go through the jack eventually. In a mono guitar, there is no way to avoid grounding something to one common ground, if you are grounding it at all. Ground loops just do not exist under those circumstances.

 

[ratherdashing]

Re: Proper grounding method with black conductive-painted cavities?

If the guitar is top routed with a pickguard like a Strat or Tele, there is usually a ground wire screwed into the wood through the shielding paint.

If the guitar is rear routed like a Les Paul, the shielding paint makes contact with the pot housings, which are then grounded.

 

[ratherdashing]

Re: Proper grounding method with black conductive-painted cavities?

Correction: the only rule is that everything needs to be grounded through one common ground. Otherwise, you get ground hum.

Wrong.

This ground loop thing is a non issue and a myth that is way too prevalent in grounding threads. There's only one way in and one way out of the guitar; everything that's grounded at all must go through the jack eventually. In a mono guitar, there is no way to avoid grounding something to one common ground, if you are grounding it at all. Ground loops just do not exist under those circumstances.

Correct.

 

[uOpt]

Re: Proper grounding method with black conductive-painted cavities?

Correction: the only rule is that everything needs to be grounded through one common ground. Otherwise, you get ground hum.

Can you describe more concretely how you would wire a guitar so that this occurs?

 

[Adieu]

Re: Proper grounding method with black conductive-painted cavities?

Can you describe more concretely how you would wire a guitar so that this occurs?

Dunno, the "on a mono guitar" part threw me off - most complex rewires that aren't just swapping two connections on a pot or switch are, after all, stereo jack actives installations. At least for me.

YEah, crap grounding = hum.

When it comes to failed wiring (w/ valid schematic), you really DON'T know how you managed to achieve it - just that something ain't connected right (on actives, semi-bad connection = awful low output and/or hum present). Generally a cold solder joint, mostly on a ground. If you've got a power 100+ watt gunhandle soldering iron, I'd suggest ripping everything out and starting over. Works better in the end.

 

[uOpt]

Re: Proper grounding method with black conductive-painted cavities?

Just for the record, you can't have a "ground loop" in a guitar. It's only grounded once, through your cable.

You can theoretically produce a similar effect to ground loop hum, which is different potential on "mass" (a better word for what people often call ground and I don't care whether that's a normal word to use in the US) if you have broken wiring that connects different pieces of mass so crappily that there is significant resistance and hence a potential difference. You can't do that with regular wiring since even if you use the pickup coil wire no wire that you can work with has enough resistance per length to make this audible. If you cause this you have broken wiring, not a "ground loop".