Hi I have installed a set of Dimarzio Model J DP123 jazz bass pickups on my bass. I have bought it from eBay. I have followed the Installation Instruction that came with the set, doing the alternative wiring of "Two (2) Push/Pull volume control for Dual Sound", with a regular pot for tone control. I notice that each pickup when soloed sounds great and the series/parallel switch for each pickup is really evident. The series (push) sounds thicker and the parallel (pull) brighter. When I have both pickups open, the sound from the strings G and D is much thinner than the sound from the A and E strings. When playing the same phrase on each pair of strings, the difference in gain and tone is huge. The same test performed with each pickup soloed does not present that difference. If I do another test, varying from a soloed pickup and opening the other to 100%, volume and tone in the G and D strings vanishes gradually. If I do the same the lower strings, the behavior is much more subtle on the volume and the tone is always rich. Both pickups are installed with the DiMarzio mark under the G string and, by using a compass, I can tell that both pickups have their poles in the same orientation. I wonder if there is something wrong with the coils phases the way it is and if it could be solved through wiring. This is my first time messing with my bass internals and I really can't know for sure what to expect. I can upload some pics of my wiring or some audio for the tones I'm getting, please let me know if that would help you help me! Looking forward for your inputs! Best Regards!