Thanks for the clarification. I have seen multiple anecdotes floating around the internet about how you need a balanced DAC, connected to the balanced inputs of the AMP, to get the best results (I think one of them was from Zeos, this is why I consider that chap unreliable, he hardly understands electrical and electronics logic).
To me, by basic common sense, since a DAC converts digital to analog, being transparent is the most relevant quality it should have, post which the analog signal is passed on to the AMP. Does the concept of common vs isolated ground have anything of relevance to do here?