Jazz Grounding

[PreCBS]

Hello,
I'm putting new pickups in my MIM Jazz. When I removed the bridge pickup, I saw that the pickup is grounded to a lug in the cavity, and then from there another ground runs out to the volume pot. My new pickup has a ground, and then another ground on the shielding plate that the foam is attached to. How should I be grounding this pickup?

 

[Matt Liebenau]

Run all the grounds to whatever ground point in the control cavity is convenient. Typically the back(s) of one or more potentiometers is used. If there are several ground wires I’ll often pigtail them together, ie solder and heat shrink all the wires together with one additional wire to solder to the output jack ground. Don’t forget to ground any shielding.

 

[PreCBS]

Run all the grounds to whatever ground point in the control cavity is convenient. Typically the back(s) of one or more potentiometers is used. If there are several ground wires I’ll often pigtail them together, ie solder and heat shrink all the wires together with one additional wire to solder to the output jack ground. Don’t forget to ground any shielding.

The only shield ing seems to be the paint. Does this mean I can ignore the lug in the pickup cavity?

 

[Karl Kaminski]

you should see 'at least one' wire connecting the lug to the ground on the jack. As Matt stated the traditional method would be to run all ground to a single point (usually one pot shell), the other method 'Star' is to run everything to a single point (a lug in the cavity) and then a single wire to ground on jack.

having a 'shield plate' under the pickup vs shielding the cavity with copper is another debate. Basically, as long as all the 'grounds' are connected you're good.

so... make sure both shield plates and the bridge ground connect to the ground on the control plate

 

[Matt Liebenau]

The only shield ing seems to be the paint. Does this mean I can ignore the lug in the pickup cavity?

I didn’t look at the pictures earlier. If you’re using the brass plate you should be able to remove the lug in the pickup cavity and just connect the plate to ground. If the shielding paint in the cavity is properly conductive it will connect to ground through the brass plate. If things end up noisy you can always run a separate connection to ground.

 

[sunbeast]

You don't really need the shielding plate that came with the pickup if there is shielding paint in the cavity- it won't hurt anything to use it but probably won't add anything either (the shielding paint appears to be a more thorough coverage assuming it was adequately applied), in any case though don't remove the ground from the cavity that is grounding the shielding paint. Carbon paint like that often doesn't have great surface conductivity (and sometimes Fender even clear coats over the shielding paint), so simple contact with the metal plate that came with the pickup may well not be an adequate way to ground it (in this case it is being grounded by having a metal screw run through it rather than via surface conduction which is a much more reliable way to ground shielding paint)- and shielding that is left ungrounded will actually increase noise. I would either mimic the current wiring by running your ground(s) through that screw in the cavity so you only have a single ground wire to run into the control cavity, or if the hole from pickup cavity to control cavity is large enough for a 3rd wire you can run the pickup ground independently from the shielding ground (if you want to use the plate then ground that through the screw in the cavity).