NBD: Univox Professional P bass

[ATLbassist]

However, shielding with copper tape didn't cancel the open tone hum entirely. Had I not carefully positioned the ground wire under the bridge when I removed it for cleaning, it would be main culprit.

Have you tried putting some copper tape on the body under where the ground wire goes? That can help expand the connectivity, especially if the ground wire channel is deep and the wire can't easily make contact with the bridge plate.

 

[Straw_hat]

Not perfect job, but I think I got that covered.

 

[ATLbassist]

I meant under the bridge plate itself. Like this:

Hohner p-bass cleanup by thaddeusthompson, on Flickr

Also, it might help to tape up the underside of the pickguard so all the shielding can touch and create a Faraday cage.

Hohner p-bass shielded pickguard by thaddeusthompson, on Flickr

 

[Straw_hat]

Thanks, I'll do that. I haven't even noticed no shielding on the pickguard