Is there an advantage to using shielded Cat-5 wire?
The AudioControl Active Balanced Technology products run signals as a balanced signal over standard twisted-pair wire (commonly found in Cat-5).  For this reason, a shield is not necessary.  Should you be using wire with a shield, be certain that it is only grounded at the Receiving end.  This will act as a drain. 
 
Do not connect the shield on both ends!  Doing so will cause a ground loop and hurt performance.