·【2.1 CH Subwoofer Audio Amplifier Board】 This AS-21 power amplifier is 2.1channel, allows you to connect 2 passive speakers and drive a subwoofer, comes with Treble and Bass buttons, independent subwoofer volume adjustment buttons and 20-200Hz subwoofer frequency adjustment buttons, which is very friendly for audiophiles, you can adjust the Treble and Bass buttons, make the bass more shocking and the treble clearer, make the sound more layered

·【220W*2 + 350W High Power Output】 This AS-21 audio amplifier has 220W*2 output power for left and right channel and 350W output power for subwoofer, it can drive two high-power speakers (30-220W, 3-8 ohms) and one subwoofer (30-350W, 2-8 ohms), and the adapted power supply is DC16-38V/10A or above. Note: The higher the power supply voltage/current, the higher the output power, the lower the speaker resistance, the higher the output power, the adapted power supply should higher than the actual working power of the amplifier

·【HIFI Audio Power Amplifier】 The ZK-AS21 power amplifier board built-in two TPA3255 power amplifier chips c, TPA3255 is a high-performance class D power amplifier chip, can make thedevice maintain ultra-low distortion in the whole audio frequency band and show high-definition sound quality at the same time. The wiring around the chip is an window tin spraying design to increase the output power. 6 x Low noise preamplifiers 5532 group can improve the sound quality and volume, increase the gain

·【Multiple Audio Input Modes】 This Mini amplifier receiver built-in Bluetooth 5.1, USB flash disk, USB sound card and 3.5mm AUX Input. Bluetooth 5.1 mode, faster transmission speed, lossless decoding, lower distortion rate, connection distance to audio equipment is 15m/49ft. Note: When using AUX mode, please confirm that the Bluetooth connection of this module has been disconnected

·【With Protective Function】 This Bluetooth Amp module is designed with multiple protection mechanisms, include over-voltage protection, under-voltage protection, over-heat protection, short-circuit protection, with case to protective it. Besides, There is a Long-life Ultra Silent Fan(locked rotor, no burning,no noise) above audio chips, for heat dissipation and protection of Bluetooth amplifier board

·"Note: The ZK-AS21 does NOT come with a power adapter. If yours arrives without one, it’s not missing—it’s just not included! Please keep this in mind before ordering."