The first tech that looked in to my 360 backin the day said
that it was way over built compared to all the amps he had seen up to that point. Everything was speced to exceed what others were using as standard wiring an parts. In short built like a tank. I guess Jaco, Larry Graham, and JPJ didn't have a clue to what a good bass amp sounded like? I think I smell a troll.
No, hardly. I am 54 years old, and went to concerts all the time during that period. I am also a bass player, like all of you. I live in NYC, and saw Hendrix, Santana, the Airplane, Hot Tuna, The Allman Bros, etc., at the Filmore East, which I went to a lot. And then there was the Schaffer Music Festival in Central Park, which had four concerts a week all summer long. For $2. a pop, you could go just to see how bad someone was

In short, I saw a ton of concerts in the day. And EVERY time the rig was a 360, the tone sucked. NO low end. And the midrange always sounded "honky". And there was never an exception. But it was LOUD. Which is why a lot of bands used it. If there were multiple bands on the bill. and one of them had a 360, that guy had the worst bass sound of the night. You can say what you want, but I was there, and I heard it. Over and over again. I am not a troll.
Not that this is a proper way to just a loud bass amp, but the local Sam Ash sold them, and they sounded terrible in the store too.
Regarding the names you mentioned:
Jaco - He was obsessed with being the loudest thing on the stage. I knew him when he lived in NYC, so I know this first hand. One night he sat in with a friend's band, and turned every knob on the house B15 to the top. He blew the speaker on the very first note, and left the band's bass player scrambling to find an amp. If xyz bass amp was louder than a 360, he would have used it. For what it's worth, I never saw him use a 360 in NY. He used whatever was at hand, and he either blew it up or he didn't. He used my amp one night at my gig, but it was at a club owned by Gordon Edwards, so maybe he thought he should behave himself, lol.
Larry Graham - double what I just said. I currently play bass with several of the P-Funk guys, and LG's obsession with volume is legion. We were driving back from a gig three weeks ago, and saw a trackor-trailer in front of us. On of them says, "That's for Larry's bass amp". Another one retorts, "Yeah, but just for the E and A strings". LG used to bring an entire PA for his bass. Not even the 360 cut it after a while, but it was a start.
JPJ - It was the loudest bass amp of the day, and he was up against several Marshall stacks, and John Bonham. I'd probably have done the same.
I stick by my original point, it was used because it was loud, but the tone was crap. When I saw Hendrix, Billy Cox used two Sunn 2000s heads with four cabinets, a total of 8 JBL D140 speakers. Now that was tone! Or Jack Casidy using an Alembic preamp into a McIntosh 2300 power amp. Or Rocco with an SVT. Or even Howard Johnson playing into a B15. All sounded infinity better than a 360, which out in the room sounded like a huge transistor radio. I am not a troll. I was there, and the tone sucked. Every single time. If there is a new one coming, and it sounds good, it will be because it is NOT a faithful recreation of the original, which would sound even worse now, now that we actually have bass amps that sound both loud, AND good!