["brand new and high quality.\nFeatures:\nThis is pure power amplifier board, the sensitivity of the input signal of 1.5V rms.\nIf your input signal voltage can'for t reach this value, recommend add preamp.\nRated supply voltage is ±65V, ±58---±70V range, do not over 70V! positive and negative do not pick wrong\nRecommended power supply ±65V\nRecommended 4-8Ω / 10-18inch speaker\nCarefully check before electricity, ensure the wiring is correct.\n\nSpecifications:\nPower supply: dual for DC power supply ± 58 --- ± 70V\nThe rated output power: 500W (± 65V power supply, 4 ohm load, distortion 10%)\nEfficiency:> = 90%\nSNR: 90dB\nThe total harmonic distortion:\n380W (± 65 power 4 ohm speaker, distortion <0.1%)\n280W (± 65 power 8 ohm speaker, distortion <0.1%)\nFrequency range: 20Hz-20KHz\nSpeaker: 4-8Ω\nVoltage Magnification: 36 times\nInput sensitivity 1.5V (RMS)\nOutput short circuit protection: Yes\nOutput for DC bias for protection speaker protection: Yes\nOver-temperature protection: Yes, radiator FET temperature higher than 100 ° C, turn off the output.\nMaterial: Metal and Plastic\nSize: approx.100x46mm/3.94x1.81in\nColor: As pictures shown\nQuantity: 1 Pc\n\nNote:\nNo retail package.\nPlease allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid.\nDue to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you!\n\nPackage Includes:\n1 x Amplifier Board (other accessories demo in the picture is not included.)"]