Highly accurate 4-segment LED output metering and input gain control for easy level setting, Servo-balanced inputs and outputs with 1/4" TRS and gold-plated XLR connectors, e.g. floor rumble, Shielded toroidal power transformer for ultra-low noise performance, Ultra-low noise audio operational amplifiers offer outstanding sound performance, Additional low-cut filter removes unwanted frequencies, High-quality components and exceptionally rugged construction ensure long life, Dedicated mono subwoofer output with adjustable crossover frequency, 19" rack/1U