Interference, hissy sound when I play my fender roscoe beck! The bass is passive, when I went to the studio the producer noticed this interference. But the interference desappears after some seconds. I dont know how to explain it well, but when I put my fingers close to the strings the noise start to get louder, I take off my hand of the strings, the noise is still there, then suddenly dessapears. It is different than the hiss of the ground, sometimes the noise appears when I am playing, lasts for some seconds and then go away. I keep quiet and the noise appears and dessapears, so it has nothing to do with a bad wire that moves and make the noise. I could record that day cause the noise dessapeared, now I think it is making that noise more often. Now I realize the pole pieces are more sensitive than before. Next week I will go to the luthier, but can somebody give any advice of what is the problem?? Thanks pd: To add more info; both pickups are in humcancelling mode in series.