The ST-PH1 is a stereophonic phono preamplifier. Each of the two channel circuits is identical. The ST-PH1 has standard 47 kΩ impedance unbalanced phono cartridge inputs. Equalization follows the RIAA curve. Each output is capable of driving balanced or unbalanced, high or low impedance loads. RDL's SupplyFlex power input configuration is included in the ST-PH1. 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. Although phono inputs are provided on some equipment, optimum system performance is obtained when phonographs are preamplified as close to the turntable as possible, and then the line-level signals are fed to the next equipment in the chain. The convenience of the ST-PH1 is ideal for all such applications.