SVT 4 pro running mono, cables are correct for bridged mono Plays great for >1 hour and then starts to cut out sound intermittently...comes back and seems fine after 6 or 8 mutes. I Haven't pushed it much after that as it's usually toward the end of rehearsals and it freaks me out a bit. No lights change, no tonal changes. I am hoping it'll be a pre tube or something simple...maybe one side is going and I'll test the stereo amps to see if I can re-create it on a side. Anybody have an idea of what may be going on?