It's annoying when I'm in between songs when I practice. It's not loud but it's there. it's my new xs fretless p bass. That sucks! What do I do. This is the only issue I have with my bass. Other then that, it's perfect....
I can at LEAST get it to sing in key dee dee dee dee dee, gee gee gee gee gee...eff eff eff efff... seriously tho, are you sure the bass is properly grounded? If not, does the hum go away when you touch the bass?
it could very well be a shielding issue...how well is your cavity shielded?... it's amazing how many people will put in $100 worth of pickups and not get rid of the noise, because...that ain't i-it... start with simple, effective, inexpensive solutions and work your way forward...
When I took it to the shop, they said it was the pick ups...but I took it to a seperate shop to have new pick ups installed....I mean it's an SX Fretless, the bass screams "up grade me" and keeps me up at night.....LOL