Good morning. I purchased a PSW10 for my home theater in 2007. I have a periodic issue that creeps up every so often and unfortunately it has started up again. It hasn't done this in months and just started back up. The issue is the sub seems to randomly decide to just emit a constant bass hum. I don't mean some quiet, low level hum. It's like a constant bass note. I have the power switch set for auto. Again, it just randomly emits this constant bass note whether we are watching TV or not. I woke up in the middle of the night the other night to the sound of bass. Everything was turned off. Later that day, my wife and I were watching TV and it started to do it. It's plugged directly into the wall by itself on the other side of my room as the rest of my AV equipment. I have a single RCA cable running from the receiver to the sub. Turning the power off and then back on doesn't help. If I leave the power off on the sub for a longer period of time, say an hour, the sound goes away. If I disconnect the RCA cable, the sound goes away. I'd say it's possibly the receiver, but even when the receiver is turned off this happens. I'm thinking of swapping the RCA cable, but that's quite a bit of work running it down through the basement to the other side of the room.