hum when I touch the cover of a humbucker

[Orpheo]

when I play, I touch the humbuckerring, as a reference, but I also touch a bit of the cover of the humbucker. whenever I touch that part, I get a big noisy hum.

1: where does it come from?
2: how can I get rid of it?

 

[Orpheo]

one more thing. when i connect the cover to earth and I play, I get no sound at all...

 

[Funky Phil]

hmmm...

Do the pickups have 4 conductor wiring?
What make are they?
Do they both do this?

 

[Orpheo]

hmmm...

Do the pickups have 4 conductor wiring?
What make are they?
Do they both do this?

gibson. 2 conductor. all the pickups I have in this guitar...

 

[Orpheo]

just found the problem.gibson made a wiring-mistake.