Own a Paradigm PDR-10 sub. It started humming perhaps 6 months ago, intermittently at first, now all the time and seemingly louder as time goes by. Pretty much unbearable now except when playing music loudly. I've tried: -Ground loop isolator (didn't work, prevented reception of HDTV channels) -Isolation transformer (didn't work) -Unplugging cable input into set-top box (didn't work) -Unplugging each component one by one (didn't work) The only things I *haven't* done are unplug ICs from the amp one by one (although I don't see how that would be the problem) and running power to the sub from another circuit (which would be an unpractical solution for everyday living). I'm wondering if the sub amp itself has gone bad ... in which case it would provide me with the perfect excuse to upgrade to a better, tighter yet inexpensive sub such as the Dayton/Partsexpress kit or the Adire Rava. Thoughts? Any further suggestions? Thanks in advance.