Definitely Fender on Irish Tour - Rory when interviewed, and then the later Donal/Gerry commentary, are slightly confused over what it is exactly. I get the feeling Gerry knew what it was, but didn't want to make Donal look too much of a nob!!
I'm not sure it's a bassman, especially not 4X10 - didn't look the right kinda size/shape. But he did like them - I think he might be playing one on at least one of the Montreux gigs or Rockpalast gigs I've got on DVD.
By the time I caught up with him (1980) it was usually 2 Marshall 50w M/V combos. I'm not sure I ever saw the Marshall/AC30 combination, but that was his stated favourite at the time. He'd wheel them out at the soundcheck, any phase problems and the AC30 was straight off and replaced with the other Marshall. And he always had some other stuff - including a Stramp over on Gerry's side. Gerry used to get sh1t for trying to turn it down so's he could see, let alone hear...
Later on he moved to Marshall heads and 4x12s - not sure this was the right move personally. He was so f***ing loud on stage, horribly loud. Last gig I saw was Worthing Assembly rooms, it was just after Fresh Evidence came out. He was good, but no longer "mystically" good - I understood everything he played, it had never been like that before.
That night he kinda fell off the pedastal I'd put him on. I was right down the front (my wife at the time retreated to the mixing desk halfway through the first song). You couldn't hear any drums, bass, or vocals, to start with. He kept getting on at the monitor engineer because he couldn't hear his vocals. At one point during the gig he even did a "tut" rolling his eyes thing at me in a "can't hear meself, can't get the staff, eh?" sort of way. I just looked up at my idol and thought "you idiot, your guitar's too bluddy loud, SERIOUSLY too bluddy loud!!"
It was a great gig, I think the fifth I saw, but I'm kind of glad I didn't go to anymore after that - I've heard the last ones were a bit sad.