Dedicated single-channel amplifier delivers 250W of power into 70.7V soundmasking speaker system. It is designed for reliable service in permanent installations demanding continuous use and comes complete with short-circuit and thermal protection with an automatic reset. Input sensitivity selectors, gain controls, and high-pass filter selectors are located on rear panel to deter tampering. Power amplifier shall provide single channel, reliable continuous power of 250W via an internal transformer, at 8 ohm, 70V, 25V outputs. Balanced or unbalanced input shall be selectable via rear panel switch. Input sensitivity, of either 775mV or 300mV, shall be selectable via rear panel switch, and screw-driver adjustable level control shall be included. High-pass filter of 12dB/octave at 125Hz shall be selectable via rear panel switch. Short-circuit and thermal protection circuitry shall be provided.