I like to use RCA to my dynaco sca-35 tube amp and optical to the dac that feeds my NAD receiver. Doesn't seem to work for me. Even when switching outputs in the app. Not using both at the same time, just 2 separate systems in the same cabinet for different types of music. If it's not possible it seems I will return this to Amazon until it matures. It should be simple, as my Sonos connect has been doing this for 10 years.