US 16X08 and US2x2 Interference

[catscurlyear]

hi there i am having trouble with both the US 16X08 and US2x2 when using either one of them, i get a sound like a bad earth loop or unscreened lead interference .i am using phono cables(RCA)with 1/4 inch jack adapters from the outputs which then go into the amp ,i haven`t tried using 2 normal screened leads with 1/4 inch jacks with 2 phono adapters on yet .will this cure the interference thanks