I'm planning on installing an additional pair of Nord J's into my 6 string bass. I will be keeping my Bart's in also. The question I have is will I have problems with the Bart NTMB pre handling 4 pickups? Will there be a problem with only 9v and 4 pickups, or does it even matter? Do pre's have limitations? I plan on wiring them in pairs with stacked volume/blend knobs. One knob for the Nords, the other for the Barts.