To be fair, I only played for a minute or two, and I was in a very large room- I'd say 20x40 feet, with 15 foot ceilings, which probably helped a bit. It was
very loud, enough to drown out a drummer entirely; it certainly wasn't pleasant or anything I'd want to do again... just that an old-school Marshall and a Mesa Mark series are even louder.
The last time I ever forgot my earplugs was the time I mentioned in my previous post with the Mark IV... never again. I need earplugs no matter what as my drummer's snare is uncomfortably loud without them. Thankfully my hearing tests out normal!