So I had a gig 2 nights ago and about a half hour into the set, I noticed that my tone seemed to lose a little low end and get a warm, snarly sound to it--like if I had cranked my preamp on my DB 680. I've heard of similar things happening with the SWR IOD. Anyway, the extra gain I seemed to have was causing my speakers so sound a little stressed out (farty)... Any ideas guys? I don't think my speakers are damaged, sounds like my tubes just got hotter or something. I dunno though, so that's why I'm apostin'. Thanks!