The Sonifex CM-ULR1 Unbalanced to Balanced Audio Converter allows the connection of a stereo unbalanced line input on RCA connectors to a balanced line output via 2 male XLRs. It is transformer balanced, with a 1:2 ratio, so 6 dB of gain is added to the input to help interface with the higher signal levels associated with professional outputs.
This unit is a passive version of the RB-UL1 and provides you with an alternative to wiring an unbalanced output directly into a balanced input. By placing this box close to the unbalanced output, before the cable runs to the balanced input, the connection will benefit from the input device's common mode rejection capabilities, reducing noise and interference.