Mid-Solo
That would be rough, glad you got it sorted quickly though! I've had a tube amp do that except there was smoke, a blown fuse and a cooked tube lol. Couldn't reboot that one hahaha!
Yeah it was pretty bad...the show stopped for about 5 mins as I scrambled around to find the issue. You go into panic mode a bit! We were playing a new festival so a few hundred people hanging around waiting for me....the singer ran out of jokes 
I never had a tube amp go down so I was lucky, although to re-iterate, it was nothing to do with the KPA, the power lead had worked loose from the power conditioner!