Static from hd54/700 audio out into wireless headpones

previous receiver had the two RCA jack audio out that I ran into work was headphones. Had to get new receiver which only has one audio out jack. I have tried 3 different splitter cables, thinking might be a bad cable, and even new headphones... all I get is static. You can hear the audio from the TV but it sounds like a bad AM radio. It’s useless. I have moved the headphone base and changed headphone “channels” to try and get better reception but nothing helps. Ami I missing something?