The Aphex Model 124A Audio Level Interface is designed to allow use of -10dBV consumer hi-fi equipment with +4 or +8dBm professional / industrial / broadcast audio systems. It provides an extremely clean, reliable two-way buffer so both systems can operate at maximum performance levels, matching impedances and operating levels. INPUT Servo-balancing means that high common mode voltages, such as induced hum from a nearby AC line, are compensated for, preserving headroom. The input impedance of 100K Ohms allows bridging over a 600 Ohm balanced or unbalanced line with negligible loading effects. Front panel switchable 600 Ohm load allows for input line termination when required. OUTPUTS Servo-balancing allows the outputs may be used balanced or unbalanced (single-ended) at any time by simply grounding either unused pin. The servo compensates for the voltage loss on one side so there is no 6dB loss of level. The outputs are also protected against short-circuits, so nothing is damaged if the wrong pins are grounded. A front panel indicator will flash red when the balanced output level is 5dB below clipping.