Servo 550 is a three-space rack-mount power amplifier capable of stereo operation or bridged mono. It delivers 275 watts per channel into 4 ohms, or 550 watts when bridged into 8 ohms, suitable for subwoofers, monitors, and distributed installations. The unit features fully balanced 1/4-inch inputs, balanced 1/4-inch and binding post outputs, independent left/right input level controls, relay‑controlled power-on to prevent thumps, and convection cooling for quiet operation.