I have the J99A pickups in my Carvin B40 bass kit. Passive controls. When I have both pickups volume and tone turned up all the way, they don't make any unwanted noise. As soon as I roll back either volume knob, I get a static/hissing noise from the amp. Wondering what it might be? A shielding issue? I checked continuity and it all seemed fine. Even rechecked the ground wire under the bridge. I did notice if I have the tone knob turned up, the static noise is louder, but when the tone knob is turned down all the way, it is barely audible. Is it possible there is a bad solder joint in the wiring harness? Sorry for all the questions. Hopefully I can get to the bottom of this.