Alpine R-A75M R-Series Mono Digital Amplifier - 750 Watts x 1 at 2-Ohms, 500 Watts x 1 at 4-Ohms The new R-Series amplifiers produce accurate imaging and dependable power. Use them with the R-Series speakers and amplifiers for a loud and fun experience. The R-Series Amplifiers have a diagnostic LED located behind the blue Alpine Jewell on the top of the amplifier. A Blue light means the amplifier is operating normally. A red blinking light means the amplifier is currently too hot for operation and needs to cool down. A solid red light can mean three things; 1. Amplifier circuit is abnormal. 2. Temperature is too high. 3. Power supply voltage is too high. The R-Series amplifiers utilize Alpine's advanced amplifier platform that takes the classic Class-D amplifier circuit and adds dual post-filter feedback loops for unmatched accuracy and control. This technology., originally launched in the premium X-Series amplifiers, produces efficient power with enhanced dynamic range, qualifying the R-Series amplifiers to be Hi-Resolution Audio compliant. Specifications: Power output 2-Ohm @ 14.4 Volts: 750 W RMS X 1 Power output 4-Ohm @ 14.4 Volts: 500 W RMS X 1 THD 10 W into 4 Ohms: Less Than 0.02% THD 10 W into 2 Ohms: Less Than 0.03% THD Rated Power 4 Ohms: Less Than 0.3% THD Rated Power 2 Ohms: Less Than 1.0% S/N Ratio: 1 W into 4 Ohms: >85dB Frequency Response:+0/-3 dB 10Hz - 400Hz Frequency Response:+0/-1 dB 15Hz - 325Hz Input Sensitivity: Hi (0.5 - 10V), Low (0.2 - 4.0V) Crossover: Variable HPF/LPF, (50Hz - 400 Hz) Dimensions: Width - 10-3/4", Height - 2", Depth - 7-7/8" Weight: 7lb In the box: R-A75M Mono Amplifier 4 x M4x20 Self Tapping Screws 8 x Mounting Bracket Screws 4 x Mounting Brackets 1 x Hexagon Wrench