I just ordered and installed a Bartolini 5.4 preamp in my bass. This is like the 7th one I've installed. However, this one has an issue. When I try to boost the bass knob, volume cuts out from the bass. I get no sound at all. All other knobs work like they are supposed to. I can even cut bass. But when I try to add bass, if I turn knob past 2:00 the volume cuts out. I even tried another new pot and had the same results. What the heck could be the problem? I've tried everything. Thanks in advance.