Hi, Dave:
In response to your specific question, "why does my Paradigm Servo-15 sub hum", there are two possibilities:
1. because it is happy;
2. because it doesn't know the words to the song.
That's probably not the answer you want, however, so my third option is that the transformer that is part of the sub's amplifier module is humming. You might try removing the amp module from the sub enclosure and then plug it in, listening for the hum. Transformers, particularly less expensive types, sometimes hum, due to electrical eddies (this is not common with toroidal transformers, but is not unusual with the older-style, square transformers).
There is a remote possibility that there may be a grounding problem related to the amplifier module, rather than the grounding of the electric supply from the wall.
After you've done a little more analysis, please provide a follow-up post so we can help you narrow down the problem.
In response to your specific question, "why does my Paradigm Servo-15 sub hum", there are two possibilities:
1. because it is happy;
2. because it doesn't know the words to the song.
That's probably not the answer you want, however, so my third option is that the transformer that is part of the sub's amplifier module is humming. You might try removing the amp module from the sub enclosure and then plug it in, listening for the hum. Transformers, particularly less expensive types, sometimes hum, due to electrical eddies (this is not common with toroidal transformers, but is not unusual with the older-style, square transformers).
There is a remote possibility that there may be a grounding problem related to the amplifier module, rather than the grounding of the electric supply from the wall.
After you've done a little more analysis, please provide a follow-up post so we can help you narrow down the problem.