Usage Tips:Power supply: dual DC power supply ± 58 --- ± 70V The rated output power: 500W (± 65V power supply, 4 ohm load, distortion 10%) Efficiency:≥ 90% SNR: 90dB 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: 4-8Ω Voltage Magnification: 36 times Input sensitivity 1.5V (RMS) Output short circuit protection: Yes That output DC bias protection speaker protection: Yes Over-temperature protection: Yes, radiator FET temperature higher than 100 ° C, turn off the output! Use precautions: Rated supply voltage is ±65V, ±58---±70V range, do not exceed 70V! positive and negative do not pick wrong Recommended power supply ±65V Recommended 4-8Ω / 10-18inch speaker Carefully check before electricity, ensure the wiring is correct. Material: ABS colour: As shown Package Contents: 1 x Audio Power Amplifier Board Only the above package content, other products are not included. Note: Light reflection 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.