Ahhh... I was under the impression that you WERE in some random warehouse... but if there's a bunch of bands there... Either way, old buildings have funky power to start with. Add several decades of rats chewing on wires & random repairs/additions done by random people & things get even more random!
Chances are good that the building manager has an electrician on call... I'd tell him about the high voltage & dead amps... Maybe tag up with the other band & get more info from them before approaching the manager. Maybe they'll just move you to another room...
Several years ago my studio was in an old warehouse right around the corner from Giants Stadium... my space was formally the home of General Mopeds & was then a pre-pro space for Dream Theater & the Misfits among others... and there were maybe 30 other bands in the building... and the power was always stable but always funky!
I took over the space when my friend moved his studio to Brooklyn, but he had a really random power problem that drove him nuts for a long time. Had 2-3 different electricians out & none of 'em could trace it down. Even with a 50 amp, $5k Equitech power conditioner he had buzzes & stuff...
It was eventually traced to the freight elevator on the other side of the building... which was on its own panel & feed, but somehow had tied to another circuit, which was tied to another circuit in another part of the building... etc. etc.
Funky old buildings.
You should still get the amps checked out by a tech...
