Introduction This amplifier board with FR4 board choose a low-power high-fidelity digital amplifier chip and then with a high-frequency low-impedance capacitors TDK fully shielded inductors making this deep and powerful bass amplifier board and good flexibility. Alto honest warm clear and bright treble. The entire board with SMD machines infrared reflow soldering reliable up to 93% efficiency low power consumption heat a small less than 35W without a heat sink. Caution: 1. Power limit voltage 36V do not exceed this voltage power supply do not reverse the positive and negative; 2. Power supply recommended as 22V 2A power supply filtering better; 3. Speakers recommended 4-8 inch speaker; 4. Audio output Do not short circuit or shorted to ground each other; 5 .Please check carefully before electricity before power to ensure that the wiring is correct.