I purchased a 6300 series 4k TV from Costco and the set only has an optical out for audio. I have a Bose (2009) Cinemate digital system with RCA inputs. I purchased a optical to RCA converter and the TV audio sounds great. When I switch to Netflix or YouTube the volume cuts off and it is loud static. Any advice? Thank you.
Sounds like the audio on Netflix and Youtube are not compatible with the converter you bought. Don't know if you can change the audio type that on Netflix or YouTube directly. You can try to change the audio output type in the TV menu.
I am not recording the audio, just trying to watch a movie with surround sound.
But you could connect a recording device this way. That's why all the audio and video interfaces typically need the HDCP handshake to play copy protected material and that only works on the digital interfaces.