This power amplifier is a compact, extremely high-power amplifier designed to meet the most stringent needs of professional use in concert touring, high quality sound reinforcement, and professional fixed installations. It uses forced-air to cool channel heat sinks mounted in a back-to-back tunnel configuration. Stereo, parallel, and bridged mono operating modes can be chosen with a rear-panel Mode Select switch. Actively balanced female XLR input connections and 5-way output binding post connectors are provided for each channel. Fully compatible with the other Professional Series amplifiers, Octal Socket Accessories and the NexSys® computercontrolled audio system. Design and Construction. Only high-grade components are used for the modular sub-assemblies in this ultra-strong, single piece steel chassis.