The P4's J pickup soloed had the familiar throaty punch of a Jazz, but it sounded a touch more nasal due to its placement - a bit closer to the bridge than our '64. (Roger Gee of Mike Lull's Guitar Works comments: "if the J pickup is placed in the traditional '64 Jazz Bass spot, it is too close to the P pickup and the two pickups interact in a way that sounds not very pleasing to the ear. We have taken this into consideration by having Lindy wind the J pickup to compensate for its placement close to the bridge.") [Close quote.]
I find this interesting, and since I read it I've been paying attention to J pickup placement on P/J basses. I played two last week, Fender's Aerodyne Classic P and Peavey's Zodiac, and found that, with the P pickups on full, the J pickups didn't noticeably alter the tone unless they were turned up all the way. I wonder whether Lull's placement provides a wider range of tones. But I'm sure of one thing -- I have plenty of GAS for a Lull P4!