I didn't follow too closely, but I think there were some changes made at least in the EP500 that the newest amps don't fit in the old cabinet.

As for the RCA in XLR. The center connect is electrically separate from the balanced XLR pins. The change was made because one of the most common repairs was for people who broke their RCA jacks off because of how the cable went straight into the amp. Now with the right-angle adapter, the coax cable will point down, and there's nothing to snap off the amp.


Pioneer PDP-5020FD, Marantz SR6011
Axiom M5HP, VP160HP, QS8
Sony PS4, surround backs
-Chris