AUDIO INTERFACES Redbox - Stereo To Mono Converters RB-SM2 Dual Stereo To Mono Converter All connections are on the rear panel. The XLR-3 inputs are electronically balanced with an impedance of 20kΩ bridging. These can be wired unbalanced to accept an output from domestic equipment. The XLR-3 line outputs are electronically balanced with an output impedance of <50Ω. The outputs can be wired unbalanced by grounding the non-phase signal, allowing you to feed both balanced and unbalanced equipment.