Features Upgraded Performance: The ungraded version of the board possesses circuit optimization, increased horn relay protection, startup delay, shutdown instant break, effectively solved the impact of switching. Multi Protection: This board features multi protection function, including output short circuit protection, output DC bias protection horn protection, over temperature protection. When the temperature of heat sink FET is higher than 100℃, the output will Working Details: Efficiency of this board is greater than or equal to 90%. The frequency response range is from 20Hz to 20KHz, 50 times voltage magnification. And it possesses Output DC bias protection speaker protection. PCB Board: Made of premium PCB board, this high power amplifier is safe and reliable for long term use, you can take it with confidence! Easy Carrying: Comes with a small size and lightweight as well, you can easily carry this board for convenient using. Specification: Item Type: High Power Amplifier Board Mode: IRS2092S Material: PCB Power Supply Voltage: Dual DC power supply ± 45-± 70V (+- 65V power supply is recommended) Rated Output Power: 500W (± 65V power supply 4 Ω load, distortion 1%) Efficiency: Greater than or equal to90% Signal to Noise Ratio: 90dB Total Harmonic Distortion:  380W (± 70 power supply 4 ohm horn, distortion less than 0.1%) 280W (± 70 power supply 8 ohm horn, distortion less than 0.1%) Frequency Response Range: 20Hz to 20KHz Horn: 4 to 8 Ω Voltage Magnification: 50 times Input Sensitivity: 1V (RMS) Output DC Bias Protection, Horn Protection: Yes Power Amplifier Board Size: Approx. 105 x 43 x 28mm / 4.13 x 1.69 x 1.1in(L x W x H) Package List: 1 x High Power Amplifier Board Note: 1. The rated power supply of the power supply is dual power supply ± 65V, and the voltage is 45 ‑ ± 70, which can work normally (if it exceeds 70V, it will burn out) 2. The recommended power supply is ± 65V filtered DC dual power supply. 3. Recommended 10‑18" 4‑8" speakers. 4. Although the output is short circuit protected, please try not to short circuit. 5. Please check carefully before power on to ensure that the wiring is correct before power on. 6. The voltage magnification of this board is fixed at 50 times. If the output power is not enough, the front stage amplification can be increased according to the specific situation. Package List 1 x High Power Amplifier Board