The STA-1 is a dual-channel line-level preamplifier with bridging inputs, adjustable gain or loss, and low-impedance outputs. Each of the two identical circuits is both an electronic line transformer and a line amplifier. Hook up the STA-1 just like a pair of audio transformers with gain. True dc amplifiers produce unsurpassed audio clarity, high common-mode rejection, ultra-low distortion and low noise. The STA-1 is perfect for most line amplification, impedance or balanced/unbalanced conversion. The STA-1 operates from floating or bipolar dc power. For installations where ground-referenced power is preferred, use the STA-2A Dual High Gain Line Amplifiers. Up to 20 dB Gain in an Audio Line; Conversion from Balanced to Unbalanced; Conversion from Unbalanced to Balanced; Conversion from High to Low Impedance; Conversion from Low to High Impedance; To Bridge an Audio Line Feed; To Precisely Match Audio Levels.