I tried browsing through the different threads to see who is repairing these subs. It sounds like the Carver shop isn't doing the repairs right now?? I'm in San Diego and my sub has been out for about a year.
It turns and and typically plays from 5 min to an hour before the audio signal gets VERY muted and a loud hum sound takes over. Unplugging the sub and plugging it back in will occasionally reset it for another 5-60 min again... obviously not the best way to watch a movie.
The hum isn't related to ground loop issues, there's definitely something wrong with the sub.