Buzzing after installing new pre-wired pickups

NelsonP

A friend of mine bought one of these...
https://www.siglermusiconline.com/products/seymour-duncan-p-rails-hsh-loaded-pickguard-for-musicman-silhouette

He has installed it but it buzzes and I'm not sure it's earthed properly.

The buzz goes away if you touch the jack socket, selector switch or (metal) pots, but not when you touch the bridge or strings.

He did connect a wire from the bridge to an earthing point, but i'm not sure that point is actually earthed itself.

Is it just a simple case of needing to connect that to an earth?

ICBM

Yes, there’s a break in the ground connection to the bridge somewhere. If that’s connected to the body shielding then the shielding is no longer grounded either, which will make it even noisier.

NelsonP

Thanks for your help @ICBM ; :-)

Will let you know the outcome.

Funkfingers

Don't forget that some of the P-Rails pickup modes are single coil and, hence, not hum-cancelling.

NelsonP

Quick update from my friend....

So when I took it apart it was clear the volume pot was being used as the main earthing point. Everything was earthing correctly except for the bridge so I put a wire in from the volume pot to the main guitar earthing point and tested.

You can see in the pic where I did it. I also twisted the earths round the Jack lead coming in. So much better now! A bit of a buzz still on single coil but no more that I would expect. Still got some shielding to do because it buzzes if my hands aren't on the strings but I can live with that for the mo.

http://imgur.com/gallery/TvT7kXN

ICBM

*Some* buzz when you're not touching the strings is inevitable with any passive electric guitar, even with thorough shielding. But without that wire from the volume pot to the cavity ground then there would have been no connection to either the cavity shielding or the bridge.

NelsonP

Yep, looks like the problem is fixed.

Thank you once again @ICBM :-)