This is the upgraded version Bluetooth power amplifier board with small standby heat emitting. The stereo sound quality is great, suitable for small Bluetooth speakers. <br><br><strong>​Features:</strong><br>Sound quality is very good by using this module.<br>Mini size, convenient and easy operation.<br>Power By DC 5V or 3.7V lithium battery with power charging function.<br>Micro USB interface with ON/OFF switch for charging or DC power supply.<br>Applicable speaker impedance: 6ohm, 8ohm.<br><br><strong>Specifications:</strong><br>Brand Name: SANWU<br>Model: HF69B<br>Color: Green<br>Material: Epoxy Board<br>Power Interface: Micro USB Interface<br>Output Power: 6W+6W<br>Stereo: Dual Channel Stereo<br>Bluetooth Speaker Interface Model: PH2.0 2P  <br>Battery Interface Model: 2.54 2P<br>Audio Input: Bluetooth Audio Receiving<br>Impedance Range: 6ohm, 8ohm (If the speaker impedance is too small, there will be sound staccato phenomenon when amplify volume.)<br>Supply Voltage: USB DC 5V, 3.7V Lithium Battery(Also Can Be Rechargeable) (During using, if the connector cable is too long or the battery is without voltage or the voltage is too low, the volume will be slightly up then staccato.)<br>Supply current: &gt;1A (If the current is too low, there will be sound staccato phenomenon when amplify volume.)<br>Charging Interface: When charging interface is powered by the lithium battery, the supply voltage is 5V and mobile phone charger can charge a single lithium battery (the maximum limitation voltage for battery is 4.2VDC by the charging management circuit).<br>PCB Board Size: Approx. 70 * 40 * 8mm / 2.75 * 1.57 * 0.31in<br>Item Weight: Approx. 15g / 0.52oz<br>Package Size: Approx. 8 * 6 * 1cm / 3.15 * 2.36 * 0.39in<br>Package Weight: Approx. 16g / 0.58oz<br><br><strong>Note:</strong><br>1. When the slide switch is ON, the Micro USB port is the charging port and it can work only powered by the lithium battery. When the slide switch is OFF, the Micro USB port is the power supply port, it can work without connecting lithium battery.<br>2. If turn up the volume during using and the speaker appears staccato phenomenon, please check the power supply. If the output current of power supply is insufficient, the sound staccato will occur.<br><br><strong>Package List:</strong><br>1 * Bluetooth Audio Receiver Amplifier Board