... have world advanced levels 24dB/OCTs Lin kwitz-Riley filter for 30Hz & 180Hz low cut and high cut circuit, and offer ON ... protection circuit, let the AMP more safe, more steady, less noise.9.The AMP has the perfect protection in infrasonic, ultrasonic ... high power AMP using world advanced linear H circuit, output low distortion, low noise, high power, wide frequency response, high reliable, offer user ...