1. TPA3118D2 high power amplifier board 2*30W 8 ohm +60W 4 ohm output, this board uses official standard circuit to open enough power and low heat, 32dB gain test 2. When the volume is not plugged in, the volume is turned up to the maximum and the low noise is not heard.As long as the power supply does not interfere with the power amplifier board itself, there is no interference, as long as you connect the audio cable. If there is no interference, then it is perfect. 3. This circuit design uses the test application circuit of TPA311X chip instead of the official standard circuit, so please do not make any changes to the circuit of the component on the power amplifier board, so as to avoid unnecessary loss caused by overheating of the chip! Maximum Power Per Channel: 60W Channels: 3 (2.1) Product parameters: Power amplifier chip: TPA3118DD2 Power supply: DC15-25V Current: 4A or more Output power: 30W+30W+60W Output channel: 2.1 three channels Frequency response range: 20-18.5KHz Harmonic distortion: -1% The power supply requirement is 15-25V 4A or above, 2 x 30W 8 ohm + 60W 4 ohm can work normally. If only the power supply below 3A is used, the perfect one is 2 x 25W 8 ohm + 50W 8 ohm. colour:Green+black Material:PCB size:80 x 68mm Package Contents: 1 x Subwoofer amplifier board Only the above package content, other products are not included. Note: Light 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.