It does this from time to time and scares the cat or me. I have a pioneer VSX-915 connected to 2 Jamo C407s and a Jamo SUB 200 via 4.0(mm I assume) silver/copper wire (no bananas) and separate sub cable. Its connected to my PC with an RCA to AUX cable to my rear jack. Volume does not matter, it just needs to be turned on. Issue is intermittent, I can run them for a whole week/month before it does the switch. I got the amp from a close friend in the summer, he says it's almost never used since its purchase. Any ideas?