Sorry I find the opposite.
That dacs make a bigger difference than what transports do, when reading CD's and using spdif proper 75ohm BNC connected coax, as RCA are not 75ohm.
But using AT&T GLASS optical link (especially with indexing fluid) receiver and transmission as Wadia used to do as an very expensive extra, is better than proper 75ohm spidf coax with proper 75ohm BNC connections, as RCA "are not" 75ohm.
Cheers George