Welcome to our store. Our products have affordable prices and good quality. We support and . If you want to work with us for a long time, please contact us and we will give you a very favorable price.Best Regards! This is pure power amplifier board, the sensitivity of the input signal of 1.5V rms, if your input signal voltage can't reach this value,recommend add preamp. Mono channel,for 2.0 channel need bid two. The rated output power: 500W (+/- 65V power supply, 4 ohm load, distortion 10%) Efficiency: 90% SNR: 90dB color: blue The total harmonic distortion: 380W (+/- 65 power 4 ohm speaker, distortion Less than 0.1%) 280W (+/- 65 power 8 ohm speaker, distortion Less than 0.1%) Frequency range: 20Hz-20KHz Speaker: 4-8ohm Voltage Magnification: 36 times Input sensitivity 1.5V (RMS) 0. Output short circuit protection: Yes That output DC bias protection speaker protection: Yes Over-temperature protection: Yes, radiator FET temperature higher than 100 Celsius, turn off the output! Amplifier board size: length x width x height = 98x43x30mm Weight: 190 g use precautions: Rated supply voltage is +/-65V, +/-58---+/-70V range, do not over 70V! positive and negative do not pick wrong Recommended power supply +/-65V Recommended 4-8ohm / 10-18inch speaker Carefully check before electricity, ensure the wiring is correct. Material:CCL Package Contents 2PC Digital Amplifier Module Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.