Jaguar grounding issue!

[vibrev]

Hi! I recently purchased a 2001 AVRI Jaguar off Reverb. The guitar is great, but it's got a nasty hum that my other Jags don't. It started after I swapped out the pickgaurd for a vintage one and replaced the bridge with a staytrem. I've searched the forum since there are quite a few threads regarding this, but couldnt find a solution. There are two ground wires (one under the bridge pickup and one in the tremolo cavity) and when I hold either with my finger the hum stops. I'm just not sure where to connect these ground ends to.

[Bradley-Jazz]

Hello

The wire in the term cavity should have the bare end trapped under the term plate to make electrical contact, and the one in the pick up cavity should overlap the top to contact the shield on the back of the scratchplate.

Hope that works for you!

[vibrev]

See that's what I thought, but I did that and it hasn't seemed to make a difference. I'll try messing with it a bit more I suppose.

[timtam]

Do you have a multimeter ? Is there continuity between all the metal (control /switch plates, bridge, strings, trem) and the rim of the output jack ?

[alexpigment]

Two questions: Did the guitar previously hum if you didn’t touch the strings? Did you buy a Staytrem with the rubber bushings to prevent rocking?

[Embenny]

Two questions: Did the guitar previously hum if you didn’t touch the strings? Did you buy a Staytrem with the rubber bushings to prevent rocking?

At first I thought it could be a bridge issue with the new one not making good electrical contact with the thimble, but it sounds like the OP's guitar is grounded at the vibrato plate, so the strings should be grounded where they make contact there.

Just thinking out loud here, but OP, did you switch to some type of new, coated string when you swapped the bridge? If the bridge plate is the point that is grounding the strings, and the strings are being insulated from electrical contact where they mount to the tailpiece, maybe that's what is decoupling the strings from ground?

[vibrev]

Two questions: Did the guitar previously hum if you didn’t touch the strings? Did you buy a Staytrem with the rubber bushings to prevent rocking?

Yes, the staytrem has rubber bushings, but I use the same bridge with my 64 Jag and it doesnt have any issues. The guitar would still hum if I touched the strings, but not if I touch any other metal parts. I'll check with a multimeter when I can. I have a Rothstein prewired electronics kit laying around so I'm probably gonna replace all the electronics anyway. Maybe that will fix the issue.

[alexpigment]

To be clear, I was wondering if this guitar hummed when not touching the strings prior to installing the Staytrem. My guess was that you have a grounding issue, but the Staytrem bridge bushings are now preventing you from completing you circuit by touching the strings. I assume your other guitar is properly wired. Anyway good luck - a multimeter should help you narrow it down

[jvin248]

.

Two types of hum...

Does touching the strings sound like you grab the bare end of the guitar cable going to the amp (with the amp on)? Then you have a signal wire, pot tab, or other bit that is touching ground. This is really loud and pretty obvious if you have this issue.

Does it sound like another guitar when you are not touching strings/metal parts (even though on this guitar you do that and the hum remains)? You don't have ground to the bridge/strings. Test externally by using a wire to touch from the output jack to the bridge/strings and touch the strings it should get quiet. If so then you need to figure out where your ground wire was disconnected from (or broken) inside the guitar while replacing parts.
If you have a multi-tester volt/ohm meter you can use that to go around the guitar and check what should be the hot and ground section. Harbor Freight sells a good one for this under $10, or Amazon is probably around that too.

.

[timtam]

To be clear, I was wondering if this guitar hummed when not touching the strings prior to installing the Staytrem. My guess was that you have a grounding issue, but the Staytrem bridge bushings are now preventing you from completing you circuit by touching the strings. I assume your other guitar is properly wired. Anyway good luck - a multimeter should help you narrow it down

I hadn't thought of that possibility before. But I guess that a lack of continuity is theoretically possible between a non-rocking Staytrem bridge (with grounded thimble) - the one with the extra nylon bushings in addition to the stock anti-sink bushings - and the strings. But only if the bridge is decked, such that the height screw does not make contact (and therefore continuity) with the bottom of the thimble. So the bridge would actually have to be resting on nylon (not the screw tip) at the bottom of the post ...


And even then, if the trem is grounded then the strings would be grounded via contact with the trem. So all in all, a non-rocking Staytrem being associated with a lack of string grounding is probably a long-shot.

Non-metallic saddles (like graphtec) can also prevent a grounded bridge from grounding the strings.

[vibrev]

Issue solved!! Thanks for all your help guys. I guess I didn't have a solid ground connection on the bridge so I drilled a small hole from the control cavity to the bridge hole and ran the wire through there. Put the thimble in top and voila! No more ground issue!

[auxiliaryjoel]

Issue solved!! Thanks for all your help guys. I guess I didn't have a solid ground connection on the bridge so I drilled a small hole from the control cavity to the bridge hole and ran the wire through there. Put the thimble in top and voila! No more ground issue!

I have an American original 60s jagaur that has quite a bad hum.
Do you have any tips on how to fix it?