grounding issue

i am having some major hum with my jolida 302 b. when i have my phono hooked up there is no hum, but when i try to hook up my DVD/SACD/CD player i get terrible hum. however if i plug my ipod into the same connection via RCAs i get no hum. i am wondering if i am not grounding the DVD player properly. actually its not grounded at all i dont think. my system is a MMF 2.1 into a bellari 129 into the jolardi 302b. the dvd player is plugged directly into the jolardi with relatively high end cables. like i said the ipod plugged into the same input with terribly cheap RCAs makes no hum. thoughts?