Hello all,
I've noticed a few discussions about JPJ's tone online, and analysis of his tone doesn't really ever get beyond his use of rounds and flats on various cuts. The general consensus is that he used a Jazz bass in the early-to-mid era, then swapped that out for the Becvar and Alembic basses we see from 1977 onwards. He also used a fretless CBS-era Precision bass, a stripped finish Tele bass and some sort of electric upright bass live, and that is that!
However I've listened to the intro to Dazed and Confused a lot over the years, and I cannot hear a Jazz bass in that tone at all. To my ears it sounds like an EB0/EB1/EB2 with flatwounds, played with a pick and hitting an oldschool studio compressor quite hard. The notes are pillowy, but the attach is percussive with a bit of a 'click' present.
My fan theory is that Jimmy Page picked up his more experimental studio chops in the latter days of the Yardbirds, and when he knew he had to record tracks quickly and economically for LZ1 he remembered how easily the Rivoli went onto tape on the Yardies tunes. That sort of bass wouldn't really fug up the middle frequencies like a Fender bass would, so he could separate the instruments out quite easily and quickly creating a (relatively) clear, expansive mix on a tight budget and time constraint.
JPJ is pictured holding an EB1 on the rotating disk thingy for LZ III but it doesn't mean he played it on that, or any, album.