Ok, so I recently wired up my mess around fretless J-style bass' pickups to be out of phase. I simply swapped the neck pickup's hot and ground wires to do this. I already had a series/parallel switch on this bass, and in series mode it sounds really great, although parallel is good too. when both pickups are full up, the tone thins out a lot and loses a slight amount of output. I kinda like this tone on this fretless, especially since I'm not a big fan of the way the jazz bass pickups "scoop" the tone when both pups are full.
Wondering, do any of you do this and like the sound?