The RB-UL4 is a 1U rack-mount quad stereo unit for interfacing domestic or semi-professional unbalanced equipment to professional balanced line levels.
 
All connections are on the rear panel. The eight RCA unbalanced inputs have an impedance of 10kΩ and are routed to eight balanced XLR-3 outputs with an output impedance of <50Ω.The output gain can be individually adjusted for left and right channels by using pre-set potentiometers accessible through the rear panel.