Hiss, hum bad for speakers?

I have two Rel Stentors. One older model and one newer. When I hooked up the second one recently I had a bad hum problem that I didnt have in the other one. It turned out to be a ground loop problem. I recommend eliminating the chance of it being a ground loop.

I dont know what makes the newer models more seceptable to the hum but the high current cable is a little different in the newer models.

Dont forget to check your cable tv for the ground loop also.