I have a Sony DAV-DX155/DX255/DX315 home theater system. I just purchased a Samsung 55" 4KUHD QLED LCD TV. The home theater system is at least 15 years old and only has RCA cables for hook up to audio. We are due to receive the TV tomorrow but as I understand it it only has HDMI and optical audio connections. We'd like to use our current home theater system but people on the Samsung blog have not had much luck with a converter (digital to analog). Any suggestions?