Hi BC! I have my #3 bass witch i play only for fun at home. Italian hand made D'alessandro (looks like 5 string Fodera emperor II). Electronics 2x crown battery, volume(can be switched to active, passive). treble, mid/freq, bass, 2 pickups blend - neck single coil Bartolini, bridge humbucker Bartolini, knob for humbucker, tone for passive mode. The problem is that when i play it for 1 minute, the sound slowly turns of, after 20 secunds - turn slowly back and all the time. I checked the batteries, seemed ok, but didn't change. Sorry for now pictures, because i am at work and can't acces the bass. After 5 hours will put them in, but i don't think it's preamp problem anyway. The pickups are constructed the way you can't see what's inside them - just black boxes. Please help!