In my case, I've tried various ICs to no avail. Problem arrived with the preamp (CJ Prem 17LS2), but nobody else seems to have experienced it, and nothing CJ did was any help. They even brought over a duplicate preamp and it muted here just like mine does. Too bad I love the thing, otherwise.
It usually mutes quietly and I've never blown a fuse, but the muting is occasionally accompanied by pretty loud pops.