I am totally ripping my hair out on this one. Now usually I am pretty good at wiring up guitars, but this one's outsmarted me.
I picked up a project semi hollow body guitar and finished it up a couple days ago.
Strung it up and I am getting tons of noise & hum. It quiets down when I touch any of the metal parts, so I was believing it's a ground issue.
All my grounds are joining at a single point, and I have continuity between all parts (both humbucker pickups, the single volume pot, the single tone pot, the bridge, the switch and the jack.)
I pulled it all back out and re-checked all my wiring and solder points, and everything is as it should be.
So I came to the conclusion it must be a shielding issue, since it's in a semi-hollow, there's no shielding paint/tape. So I ordered a good length of shielded wire (the single conductor style with the metal braided sleeve like used in a lot of vintage guitars) and completely rewired the entire guitar with it (including removing the original pickup leads and replacing them with the shielded wire.)
I don't have another actual set of pickupsto try, but I did try hooking up a Seymour Duncan 59 in the neck and still had the same issue with it too.
These are the pickups from my Carvin (C22 pickups) and they sound fantastic, outside of the crackling and hum.
Also, I should mention it does this through my POD HD and my Spider III half stack, so I don't think it's the amp either...
The noise is still there! These are new Bournes 500K pots (though I also tried some known good used Gibson 500K pots to eliminate them as the culprit) and a Switchcraft 3-way toggle and Switchcraft jack. The capacitor is a Vitamin Q 0.22 cap. I have tried a different output jack, but I not a different switch (I don't have any other switches, but have tested the continuity of the switch and it shows good.) I have tried removing the tone pot completely from the circuit as well. I don't know what else it could be. Anyone got any ideas? What am I missing?
Are you using the guitar with high gain amp models on pod and spider? Maybe some styrofoam in the f-holes might the feedback and hum.