I finally scored a set of AVRI 62 JM pickups and I'm considering doing the whole shielding-the-cavities-with-copper-tape thing while I have it apart. I'm not gigging in any noisy spots but I'm tired of hearing my TV whenever I'm not using the middle switch position...

Does anyone have a good concise guide?

Any tips or tricks? Any common mistakes I should look out for?

Any links to the proper copper tape with conductive adhesive?

I get the general principal but I'm a little iffy on how to ground/how many grounds I need).

Any info is appreciated, thanks!

You can ground numerous wires screwed to the sidewalls using a spade terminal ends soldered on.
Don't forget to shield the entire back of the pickguard too.

I did this awesome concept recently about a central ground wire bus made out of super heavy solid copper wire.
All other ground wires were soldered to the central bus.
It's the quietest Jaguar build I have done.

Ground Bus wire

Last edited: Nov 22, 2024 18:21:26

AgentClaret wrote:

Thanks so much, I appreciate the advice! The central ground is a cool idea, I might try it! It sounds more elegant than just adding one more ground to a pot.

I should get the 2 inch tape, right?

Yes the 2" is perfect.
Some of the longer flat sides of cavities you can cut a longer piece of copper for. But there are a lot of small corners to do and using narrow strips are better.
On other tip. I mentioned how it's tricky to peel back the paper, because it's then far too easy to get the foil rolled and stuck to itself. You can never unstuck this either.
So I got in the practice to cut this rolled part off with scissors and sacrifice it ti then have a clean foil edge ready to apply, lay nice and flat.

One more question... what do I do with the old ground wire coming from the bridge thimble if I put a new ground through the tape in the central cavity? Do I still use it or remove it?

I try and connect as many grounds as possible.
The bridge thimble is usually the one that sometimes gets lost because of how it's wedged between the thimble and body with the strand unwound.
If you have continuity from the wire to inside the thimble, then I would use it.

Last edited: Nov 24, 2024 18:01:57

AgentClaret wrote:

Yeah, it's still intact. I just replaced the thimbles a couple months ago when I got a Mastery bridge.

So I would just tape around the existing ground?

Here’s the thing with grounds, as I see it. If you terminate every ground to a common point, and then connect that common point to the ground lug on the output jack, you should have excellent performance. Where people get into trouble so if they have several paths to ground.

If you have a good ground wire to the bridge thimbles, make sure that gets connected to a solid ground. The hassle is when that wire isn’t properly contacting the bridge thimbles, but if that is intact, ground the other end of that wire and your strings will be properly grounded. In many cases, grounds are concentrated to the back of one of the pots, assuming that the wire is long enough.

If you are grounding the strings at the tailpiece, then there’s no advantage to having a ground on both the tailpiece and the thimbles. I’d choose one or the other. It probably won’t hurt anything if you have grounds at both points, but if you have two paths to ground that are not of equal resistance, it’s possible to pickup some hum. That’s called a “ground loop”, and is worth avoiding.

Iceratz is correct, plenty of grounds is a good thing, but, it’s important that you utilize a common ground point so that every item has a low resistance path to a common point.

The artist formerly known as: Synchro

When Surf Guitar is outlawed only outlaws will play Surf Guitar.

AgentClaret wrote:

I wasn't talking about doing both the tail piece and thimbles, only the the thimbles have the ground in mine. I was just thinking of running an extra ground somewhere under the pickguard, but it sounds like maybe I should just keep the stock ground setup.

If the strings are grounded by the thimble, that should work just fine.

The artist formerly known as: Synchro

When Surf Guitar is outlawed only outlaws will play Surf Guitar.

IceratzSurf wrote:

When you overlap the shielding from the cavities to the top surface, and then shield the back of the pickguard, you get conductivity when you screw the pickguard back on.
I think for official Jazzmaster wiring there is a ground wire from the jack to the tone pot, then other grounds to the tone pot.
On a Jaguar there are no grounds directly to the tone pot. Instead, the jack goes to a central ground shield, which leads everywhere else.
This is why I came up with the central bus terminal.

I agree with Synchro, need to be careful of a ground loop. And the more ground leads you make increase this unwanted situation.

IMHO, the Jaguar system makes a lot of sense. When I built my Partscaster Jaguar, I bought the brass shields, bonded them to one another and used them as a centralized ground point. On the rhythm circuit panel, I used a soldering lug and bonded that the the brass shield. The guitar came out hum free.

The Jaguar and Jazzmaster circuits are much more complex than what you would see on a Strat or Tele. I have a lot of respect for the ingenuity behind these designs. I know that Freddie Tavares had some influence in the design, and I would assume that Leo Fender was knee deep specific design. It’s truly a masterpiece, but nonetheless, there are a lot of components to keep track of.

The artist formerly known as: Synchro

When Surf Guitar is outlawed only outlaws will play Surf Guitar.

Thanks again, guys! I'm definitely just gonna stick with the thimble ground.

I'll be trying to get this all done on Thursday since I'll have it off for Thanksgiving.