Recently I have been playing about with XLR and RCA IC’s. There are several Youtubers advocating for trying both with any given component. I have always been a proponent of XLR’s just based on the seeming logic, but then I tried swapping out XLR for RCA to see what might happen, so the Holo May is now feeding the Serene with a pair of RCA Black Dragons from Moon Audio. It a pleasant surprise to find that with the May and the Serene the RCA’s were superior. There was a faintly warmer and more tube-like sound with no loss of detail or dynamics. or sound stage. The Serene then feeds the two Audion Mk3’s with a pair of Moon Audio XLR’s.
Technically, all these components are "balanced," but there are interactions going on that I don't quite understand.