I got to encounter this beast in a different setting. I worked on a TV show called "Big" where we built, well, big things. We built a giant guitar on the show and were lucky enough to have Ampeg bring down an appropriate rig for the guitar. Best part of it was having Peter Frampton play the guitar with a 2ft. long slide. The pickups were custom made by Seymore Duncan himself. As to the Ampeg, I'm not sure of the exact number, but I am certain the low E on the guitar was well below 30hz (the strings were something like 12' long). The Ampeg handled it just fine. This amp is WAY loud!
Me and my boys (and I am 6'4")
Here's a good shot of the guitar with the Ampeg in the background.