One time I thought the Ashdown 15'' combo at the rehearsal space was done for when I found it with everything dimed. Turning it all back down and playing it was sounding very broken. Then I noticed the 'Subharmonic' button was engaged, disengaged and all was well. That thing must have cost a heap of sales over the years.
Assuming it actually stood up to everything at 11 then it's one tough little bugger.