SMAKN&reg; TDA8950 digital amplifier board / high-power amplifier board, support for Bluetooth 4.0 Dimensions: 112 (W) x110 (depth) x40 (H) (excluding potentiometer protrusions) Maximum output: 150Wx2,300Wx1 Operating Voltage: AC double 18V-28V, 26V AC recommend double. This board comes with a filter and rectifier circuit, does not require additional filtering rectifier, easy to use. Rectifier uses four high-capacity British brand original authentic NOVER (Novartis) capacitors. When the choice of single-ended or differential (balanced) audio input port, a differential (balanced) input source must also be differential (balanced) signals.