The Rolls RA163 is an eight channel mono, or four channel stereo distribution amplifier designed for the contractor / install market. The outputs are designed to drive high-level balanced lines in a sound distribution system. The XLR jacks on the rear panel are for input and output, and each output may power more than one line. Mono or Stereo Operation – mono input to eight outputs, or stereo inputs to four stereo outputs +20 dB Gain switch XLR jack inputs and outputs Input Impedance: 100 K Ohms balanced Max Input Level: +24 dBV I/O Connectors: XLR Output Impedance: 50 Ohms balanced Max Output Level: +24 dB Max Gain: 20 dB S/N Ratio: >90 dB Frequency Response: 10 Hz – 40 kHz, +/- 1 dB THD: <.008% Power: 120 VAC 50-60 Hz, 15VA Size: 19" x 1.75" x 6.5" (48 x 4.5 x 17 cm) Weight: 7 lbs. (3 kg)