Ah, grounding issue. Few different causes, hopefully someone smarter than me can chime in.


So there’s two potential problems. Firstly would be a shielding issue. The way you tell this from a grounding issue is if it goes away when touching the strings it’s shielding, if it gets worse touching the strings it’s grounding. The pickup is another thing. I had that issue on a p bass pickup that was a cheap piece of shit that someone put into a vintage bass after selling it to me (oops) so I’m not sure which issue I had but the consensus online was that A) it wasn’t potted correctly or B) the hot wire which is connected to the terminal on the pot or pickup selector is connected to the beginning of the coil instead of the end. If it’s b and you’re confident with a soldering iron you could try swapping the wires but if like mine it’s a p bass or some other humbucker wired in series you may also have to reconnect the pickups if the wire connecting the two was from the wrong end as well. If not or if that doesn’t help take it to a tech probably. If you need it immediately and can’t wait for a tech you can put some clear nail polish over the pole pieces to stop your finger from making contact with the pole piece (or something else that could act as a barrier that’s just what the internet recommended). I’d also say if it’s a cheap pickup it’s probably not worth the cost to take it to a guy to figure out what’s wrong with it vs just getting a new one but that’s just my opinion and it’s your bass not mine.