Jack Casady had a Les Paul Signature back in the day, he liked it but he didn't care for the pickup. He helped tweak and refine the Gibson low impedance pickup to sound like he wanted it to.
“In 1985 I was living in New York and happened to stop in a music store one day and saw a goldtop, full scale semi-hollow Les Paul bass. I loved the bass but found the pickup to be deficient…I did a little investigating and found out that only about 400 of the instruments were made in 1972 and because it was kind of an odd duck, it didn’t catch on.”
“I approached Gibson and asked if they would be interested in reproducing the bass with my input. Epiphone’s Jim Rosenberg was very interested, and allowed me to kind of re-make the instrument. I told Jim that I’d like to develop a Jack Casady pickup for it and he hooked me up with the R&D Department at Gibson.”
“I went to work on the pickup and it took almost two years to develop. I think they were getting pretty antsy by this time but I wanted it right. I did a lot of homework and bench testing and finally when it clicked in right, it was great. They blow the old Gibsons to smithereens, even in the construction. As you know, the early 70s weren’t good for cars or guitars (laughs) and the workmanship that’s coming in on these instruments is just super.”
From https://bibliolore.org/2014/04/13/jack-casadys-signature-bass/
"We duplicated the pickups as they were on the old '72 model but then I took the pickup and added more Alnico power to it, another three quarters of an Alnico magnet on the other side. Also I took a page out of a lot of lap steels, I took the windings that were used for those pickups and used a higher gauge wire. I used a 28 gauge wire, very thick. I wanted to thicken the sound up, and they said that I could do anything I want. I could add one pickup, two pickups, three pickups. I said what I want is one great pickup that I can have at any expense."
From https://www.flyguitars.com/interviews/jackCasadySignatureBass.php
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Of course, some people prefer the old Gibson Lo-Z pickup so sometimes you see Epiphone Jack Casady basses out there with the old 70s pickup.