The California Jam was in 1974, EB-3Ls had been around since 1969 already, the maple neck, neck pup farther back ones since 1972. In fact, with the introduction of the Ripper and Grabber as Gibson's new mainstay model, EB-3Ls were a dying breed by then - the ugly relative in the cellar with zero promotion though still in albeit limited production.
I have to disagree re the sound: Comsidering that this was 1974, a huge open-air (largest one in the world until then) and Black Oak basically the opening act of the whole thing, the sound is nothing short of excellent. And the EB-3L - not Gibson's greatest bass by a stretch - plainly audible with a full sound of its own. No complaints there.
The whole California Jam went like clockwork which astounded even the musicians playing there. ABC, which were filming the whole thing, made sure that organisation was perfect. Deep Purple had the choice to be top of the bill with ELP playing before them, but decided to reverse things believing that the festival would inevitably run late so that they would not be playing at the then scheduled time (still in daylight), but at dark bringing their light show to full effect, wheras being the last band to play might risk a very short set due to the curfew. But as a matter of fact the festival ran so smoothly it ran half an hour early and DP were asked to commence their set in broad daylight. Blackmore refused to leave his trailer though until the sun set and ABC directors as well as ELP managment were frothing at the mouth ("You will never play the US again!") and threatening damages and, in the end, saying that DP would not be allowed to play at all then. DP road manager Ossy Hoppe then made an impromptu stage announcement to the audience: "Do you want to hear Deep Purple?" to thunderous approval (
Dave Westheimer's solitary no was unceremoniously drowned out) and it was clear that taking DP off the bill at that point would have been asking for a riot. Finally, Blackmore left his trailer, hating all things ABC (hence the camera smashing when an ABC camera man got too close to him during Space Trucking) and Deep Purple came, saw and conquered. Their largest gig ever and the one that put the Mk 3 line-up and their new Burn album squarely and fairly on the map of endless US tours.
ELP never got to play due to the curfew of the festival and the considerable damage Blackmore's staged Marshall backline explosion had done. Their management threatened to sue, but it was all settled quietly when they found a cheque in the mail from the DP management. As did the ABC camera man who according to lore retired from his job after that particular show (I doubt that, in the vid he doesn't act scared, but follows Blackmore after the first few hits, maybe he became a theater of war reporter later on!
). Who knows, maybe he was even part of the ploy and that part was staged too, Blackmore had a penchant for the severest of practical jokes, but always tried to make sure no one got hurt.
Of course we need scientific evidence for all this: Watch Blackmore ruining not one, but three Strats in a row, smashing an ABC camera with the second one and cueing in the Marshall explosion at 3.15 which proved to be a bit hefty, blowing Blackmore almost off the stage and lightly burning both Paice and Hughes in the process.
http://www.youtube.com/watch?v=1aQ9P4qi8uo&playnext=1&list=PL4BF48801251154F9