I wish to explain some things over the RCA output. The common on coaxial is 75Ohm , unfortunatly RCA connectors and RCA cables will not be capable of 75Ohm due to geometry/physics . We spoke to a few companies of DACs and some of them by now carried out 50Ohm https://localtailor.net/California/Displays-&-Holders-Charters-6075216