Thanks for your response. If you really get into the dCS frame of mind my ( reasonably well informed) guess is that if the there was a need to compromise the RCA output board they would either have not done it at all or would have changed the box to suit. After all this circuitry is more or less what they have been using for a long time with earlier models so when designing the third generation ( Vivaldi etc) they already knew what was going to be required.
Why do I think that compromise ( or, more accurately, too much compromise ) is not acceptable at dCS? Did you ever read the reason that they decided not to add a USB output on Network Bridge even though it was highly desired by their customers? This really indicates their mindset: