TheYamaha P8500S is a rack-mountable power amplifier for sound reinforcement applications offering and a moderate weight for its size. The 8500w has been optimized for use with Club Series speakers and is equipped with a engagement switch, which activates proprietary circuitry that matches the output of the amplifier to the capability of the speakers; that being said, speakers from all other manufacturers are supported as well Another exclusive feature of the Mosfet 8500w is the energy conservation design, which obtains the same full output that conventional amplifier designs offer, This attribute, in conjunction with a full complement of thermal and limiting overload protection, allows for cooler, quieter operation and improved frequency response with minimized distortion.