About a year ago I did a active to passive conversion on my Sandberg California VS (P bass). I replaced the big pole peace delano style pickups with more aggressive sounding Lollar PB90s. As I already have a Fender P bass I decided a few months ago to put a set of LaBella low tension flats on this bass and keep rounds on the P bass. Absolutely love the sound, a lovely warm thump, not suitable for all genres of music but I sometimes play with a New Orleans type jazz band and its fits in like a glove, its almost 'upright bass' sounding. Funnily enough I prefer rounds on a fretless, despite the 'chews up the fretboard' mythology.