Fjn04, there is no difference between RCA and XLR with APL products because of transformer coupled output of the tube stage (no capacitors). If you enjoy the resolution of balanced designs, you may want to consider the new NWO-M1 which, unlike the older single ended APL3910 (no longer offered), is employing fully differential configuration.
Please email us if you have more questions.
Thanks!
Alex
Please email us if you have more questions.
Thanks!
Alex