On the inputs to the DCX, using your rca cables with an adapter (which ties pins 1 and 3 together, as most or all adapters do) is fine. The only downside is that you will not have the rejection of common mode noise that using something like a Jensen transformer would provide. See this link:
http://www.jensen-transformers.com/an/an003.pdf
Using an adapter on xlr outputs is a different story, though. Connecting pins 1 and 3 together shorts a signal (the "cold" or inverted signal on pin 3) to ground. That is USUALLY ok, but may cause damage or improper operation with some equipment. See this thread for an example of a situation where a problem was caused by connecting pins 1 and 3 together.
I would suggest checking with Behringer if you want to use an adapter at its outputs. Other alternatives are to obtain a cable that leaves pin 3 open (while connecting pin 2 to the center pin of the rca connector at the other end, and pin 1 via the cable shield to the rca ground sleeve), or to use a transformer as shown in the reference I linked to above.
Regards,
-- Al
http://www.jensen-transformers.com/an/an003.pdf
Using an adapter on xlr outputs is a different story, though. Connecting pins 1 and 3 together shorts a signal (the "cold" or inverted signal on pin 3) to ground. That is USUALLY ok, but may cause damage or improper operation with some equipment. See this thread for an example of a situation where a problem was caused by connecting pins 1 and 3 together.
I would suggest checking with Behringer if you want to use an adapter at its outputs. Other alternatives are to obtain a cable that leaves pin 3 open (while connecting pin 2 to the center pin of the rca connector at the other end, and pin 1 via the cable shield to the rca ground sleeve), or to use a transformer as shown in the reference I linked to above.
Regards,
-- Al