So I get the Ibanez BTB1206. Awesome instrument. I bring it home, and when I plug it in and turn up the treble I get an oscillating squeal. I try it in two separate amps, and get the problem in both. I try other instruments, including ones with similar Bartolini pup/preamp configurations, at similar volumes and get no such noise. Must be the BTB1206, right? The shop called me just now: They cannot duplicate the problem. I will go there this weekend and try to duplicate it there. In the meantime, I will try my best to duplicate it at my home studio with other basses.