The STA-2A is a dual-channel, line-level audio preamplifier. Each channel is identical. The audio inputs are bridged at 20 k ohm and accept either an unbalanced or a balanced audio signal. Gain is adjustable from unity to +24 dB using a 25-turn precision audio taper trimming potentiometer. The output line driver circuits are designed to drive long balanced audio lines into 600 ohm loads. The STA-2A features wideband circuitry for excellent phase response, low noise, low distortion and exceptional audio clarity. RDL's SupplyFlex power input configuration is included in the STA-2A. The power supply input may be fed from a floating (not ground-referenced) 24 Vdc power source, from a bipolar power supply (+/- 12 Vdc or +/-15 Vdc) or from a ground-referenced 24 Vdc power supply. Many audio products provide optimum performance when feeding into a bridging input, but may not provide the output needed to directly drive low-impedance lines terminated with 600 ohm transformers. The STA-2A is specifically designed for such installations, and is also ideal in installations requiring high gain in line-level audio transmission.