As documented by this October 24, 1991 photo taken by Ed Sirrs, Cobain used a Studio .22 for a show that day at Off the Record in San Diego, California. On LiveNIRVANA.com, Caio Leme notes that it was “[p]ossibly a rental”.

"Me 8 years ago playing my 70's Fender tele and a Mesa Boogie Studio .22 combo" - Rob Chapman.

In this photo from an interview on stage during the Joshua Tree Tour, the Mesa Boogie Studio 22 amp used by Bono can be seen between Bono and Larry underneath the drum riser.

And what do you use live?

I have a Dual Rectifier and a VHT Pitbull. That’s in my rack, and when I’m travelling with my rack I do a left and right split on stage and in the PA, so it’s true stereo. A lot of guitar players never get that. I always tell them, first piece of advice, get two heads and a splitter. And I’ve even used a delay between the two in the past, and it really opens up the whole of the middle for the vocals and the kick and snare and bass. If you sit out front and listen to a true stereo guitar with two stereo heads, it’s huge. It’s way bigger than one mic. But a lot of the times when I’m on the road I’ll just use two Dual Rectifiers split, two full stacks. And it’s a lot of work to lug that stuff around, but either way, the Dual Rectifier, I would say, is my signature sound. I’ve been playing Boogies since our first recording on Epitaph, and that’s just the old school Dual Rectifier, one of the best amps I’ve ever heard in my life. It’s a very versatile amp, and durable. Y’know, it’s funny. I saved up and thought “I want to sound like Metallica,” so I went out and got a Mesa Boogie Studio 22 preamp and the Strategy 400 watt all tube stereo power amp, which was just insane. It cost me a lot of money. It cost $3500 bucks or something. I saved up all summer. And not to say that I’m that guy, but I’m pretty sure I turned the whole punk scene onto those Boogies. NOFX used it on their album, Bad Religion used it on their album, Down By Law used it on their album. After I recorded with it, Brett [Gurewitz, Bad Religion guitarist & Epitaph founder] was like, “Can I borrow it?” Then Eric Melvin from NOFX came down and he was really into it and he would up buying a Mark III. In the meantime I was trying to get sponsored by Boogie. I was like, “Hey look, you’ve got to hook up some punk bands.” And they were like, “Punk bands can’t afford our stuff. It’s too high end.” And I was like, “No, I’ve already got three bands that have bought it from you. Why don’t you give us some free stuff?” And they don’t give anybody free stuff. Maybe Metallica, I don’t know. But they’re one of those amp companies that really keeps it tight. And it’s hilarious because I look back on it and there was an article in a magazine entitled Boogie Man, and I just want to call them up and tell the old guy, “You know how many punk guys are using Rectifiers now? You owe me steak dinners for life!”

Seth is pictured with a Mesa Boogie Studio .22

Alan Murphy used the Mesa/Boogie Studio .22 amplifier but later switched to Fender Super Champs to achieve his desired sound, as noted on his official equipment page.