Hi everyone, I just purchased a Klipsch R-115SW subwoofer. I also have a SVS PB-13 ultra that I've kept right next to the Klipsch for testing. I ran some tests and the Klipsch sounded louder and more punchy, to my surprise. However, after a few tests I noticed the Klipsch was emanating a hum noise. After doing some experimenting here's what I know: 1) When the Klipsch is on and not connected to anything it does not hum 2) When the Klipsch is on and ANY audio connector is connected to it, it will hum, even if the audio connector is not connected to the receiver! 3) If I take the exact same audio connector and plug it into the SVS I have no hum from the SVS. The Klipsch's power plug only has 2 prongs and no ground level. The SVS cord has a ground level. It seems to me that the Klipsch's input ports are overly sensitive or defective. The hum is very loud at max volume and does get quieter as the sub's gain drops. However, the hum only vanishes once the sub's gain is 0. Please help, I really like this sub and I don't know how to fix it! Thanks, Prem