2x Stereo Unbalanced-to-Balanced Audio Converter - 

The Signature U2B4 is a broadcast specification double stereo unbalanced to balanced analog audio interface that is equally suitable for professional & home studio use. Its primary job is to interface domestic type audio outputs (unbalanced) to the balanced audio inputs for broadcast and professional audio equipment. The U2B4 also provides variable gain to allow the lower level audio outputs to be raised to meet the higher level broadcast and pro audio standard. The stereo audio inputs (which can work as 4x mono) is on gold plated RCA phono connectors. This input is electronically isolated with RF filters to prevent extraneous signals, and fed via multi-turn preset gain controls on the rear panel to a pair of electronically balanced and isolated outputs on Neutrik XLR.