what the heck am I looking at?

Look like 2x15 bandmaster cabs to me.

 

I've seen that video before. The music you hear is NOT from that concert. Somebody placed music from another concert over that video footage. It's not even the same song, IIRC.

 

The video portion is from a festival held at Devonshire Downs horsetrack in Northridge, CA, in 1969(here's info:
http://en.wikipedia.org/wiki/Newport_Pop_Festival ). Jimi was sitting in with the Buddy Miles Express. Those are Fender Showman 2x15" cabs with JBL's stacked on their sides, one of many odd 60's gear set-ups I've seen on film and in photos( here's some pix: https://www.pinterest.com/Schatzvik/newport-hendrix/ ) As always, Jimi still sounds like Jimi going through the Fenders, as opposed to the usual Marshall stacks.

 

Speaking of weird amp set-ups, check out Sly and company at their peek; aside from Larry and Freddie, I still can't figure it out. Where's the PA speakers?

 

The guitar amps are acoustic, bass are dual showmen, keyboards are sunn, organ used 3 122s and a 147. My guess is the pa cabs are behind the scrim and way up high on towers, most likely A7s, a whole poopieload of them.

Just imagine the stage volume, and no monitors, just what you can hear from the mains.

Sly developed terrible stage fright and missed many shows, too scared to even get in the car to go to the gig. I read something about him living in a converted van working odd jobs in the 90s.

 

Just think how hard Jimi would have to push those Showman heads to get the same tone he got out of his Marshall rig.

 

A lot of his tone was from his fuzz pedal and various other effects, not really from the amps.

Oh, and his playing technique, perhaps.

 

Yes, totally correct on both accounts. I had one of those dual showman, which I occasionally ran with two 215 D140F cabs. Disappointing for bass, but I guess we all know that.

 

I believe that is still the case. I remember seeing some "Where Are They Now" bit a year or so ago, and Sly was living in an RV. Really sad stuff what drugs can do to the greats.