Ron has expressed his disdain for the electric bass in numerous interviews, stating that he didn’t consider it the “real bass” and making it clear that he played at the request of various bandleaders and producers, not as an artistic choice. Because of that I don’t think you’ll find much of electric playing from him on records that is nearly as remarkable as his upright work.
The first recorded electric bass from Ron that I was aware of was the Miles in the Sky album, where he played it on the track “Stuff.” Ron also used the electric on the subsequent Miles album (Filles de Kilimanjaro) on all but the two tracks Dave Holland played on. Reportedly it was Miles demanding that Ron play electric bass that at least partially led to him quitting the band.
Ron can be heard on electric on lots of albums from the early ’70’s that came out on the CTI label. One that comes to mind is Freddie Hubbard’s Red Clay, which contains some fairly inspired bass playing. Ron plays a bit of electric with a pretty nice tone and touch on an album from Tony Williams called “Ego” (although it is an uncredited Jack Bruce playing on the track “Two Worlds.”) I haven’t heard it in a while, but another record with Ron playing pretty nicely on electric is the Gato Barbieri album “Fenix” from 1971.
I have actually seen Ron play electric bass live (on a sunburst P-bass), in the CTI Summer Jazz concert at the Hollywood Bowl in 1972, along with Jack DeJohnette on drums, backing up a variety of CTI artists like Hubbard, Hubert Laws, Stanley Turrentine, and Deodato (debuting his version of “2001”). A live album was released from that concert.
I’ve also had the fortunate experience of hearing Ron playing acoustic in small club (Fat Tuesday’s in NYC with Airto), sitting close enough to hear the acoustic tone of his bass, and that is something I will always treasure.