I have a newer bass with a single pole J pickup. I get a lot of 60 cycle hiss I'm trying to track down.(The P pickup is as quiet as can be.) I practice in a room with the family's wireless router. Since the whole purpose of that device seems to be to radiate an electromagenetic field, is this the likely source of my hiss? Or the computer, or DVR or halogen lamp or ??? If I lay the guitar flat, the hiss goes away; it's worse when the pickup is vertical in playing position, but no better or worse facing one direction or another.