Innovation by a single power supply can share power with power amplifier board is very convenient use NE5532 op-amp welding has op-amp IC easy to change the op-amp improve playability all the CBB capacitor for Philips capacitance potentiometer is made of high quality production airtight potentiometer. With full frequency signal volume potentiometer very convenient to 2.1 power amplifier stage in front of the plate With LED lights real-time monitor the power status. Adopt double panel design makes every effort to signal transmission is concise signal-to-noise ratio is very high. Can be single/double sound channel input mono output. PCB is made of super hardness FR - 4 glass fiber board the board size: 82 x30mm excluding highlights thickness: 1.6 mm. 22Hz~300Hz frequency range the frequency range is no vocals the so-called low pass only the low frequency output after the need to add amplifier power amplifier plate can be used. Low frequency performance strength related to power amplifier board and speakers matching according to different situations please choose a different power amplifier board and bass speaker (passive subwoofer).