I would respectfully disagree about any Ayre product sounding better using RCA connections and would suggest sticking with your XLR cables to the QB9. Having used both the QB9 and now the Ayre Codex, both pieces sound dramatically better running balanced. I have no experience with Parasound products and I won’t speak to the effect on them. But if the Parasound gear is truly a balanced design I would stick with your XLR’s.
Good Luck!
Good Luck!