I am having an issue with my Jackson JS3 Concert bass. I bought it as a floor model since I am just getting started in bass. I have been playing it with a small practice amp at home with no issue to my knowledge. I was able to play with our church worship team a few times, and when I did our sound guy says my bass had a constant hiss coming through. When I got home, I checked and was able to hear the hiss through my practice amp. I got my guitar from Sweetwater. I got in contact with them, and they offered my a brand new replacement guitar. I picked up the new guitar and plugged it in at home, AND the hiss is still there. The volume of the hiss adjusts when I adjust the treble on my amp at home. Not sure what to do, if I can do anything at all. Any help would be appreicated.