HELP!! subwoofers in my car keeps humming after installation?

i recently installed a JVC deck as well as a Pioneer prs-x220 amplifier. because my deck does not have the RCA outputs i had to buy a line output converter. before i installed the LOC i had absolutely no sound coming from the Subs. after i installed the LOC its just a continuous b hum even if my deck volume is on zero.. please help