Ok so I'm trying to figure this out and stuck. I think it might be shielding but my friend I bought it from never had this issue.........so I'm really confused. To start from the beginning......bass came stock......tonepump with EMG HZs in it. It is a Spector Zebop. I had this noise terrible with the HZs in it and it would pick up cell phone transmissions if the phone was even NEAR the bass. I took the tonepump out and tried a EMG BQC and the noise was there with the EMG preamp too.....so I put the tonepump back in (actually like it better). I tried playing out with it last weekend and the sound engineer said it had a hum coming through the channel.....tried to lift the ground no help.....changed basses and dead quiet......so the Spector was causing a hum through his equipment too. I did not hear the noise at that point through the amp itself though? So then I changed the pickups to active EMGs (35CS and 35DC) as I have had zero problems with them in other basses. Now the bass makes the noise much less but it's still there! It gets worse if I tip the bass toward the ceiling and even worse if I point the rear strap lock button at the amp or speaker? It's not nearly as loud but still there and just the right frequency that its super annoying (to my ears anyway). I can plug it into other amps....still there......kill power to everything in my basement including turning off the cell phone......still there. I put together a video to see what some of you might think it is or if anyone has ever seen this before. Note since the active EMG swap I have not played it out (just did it this week.....I have gigs this weekend though). Let me know if anyone has any ideas. Thanks all.