A guy I play with has an old big box Switchblade (passive AB switcher) and amp output 1 is doing nothing. Tested for continuity, everything seems to be working fine (except grounds? everything is grounded through the chassis but my meter won't make a noise when testing between sleeve connections and chassis)
the other thing is that, as a passive switcher, it sounds pretty bad! would it help to put a buffer (eg klon-style buffer) on each output or is there no point in doing anything that doesn't have phase reversal/ground lift/fancy ABY options?