2.1CH Subwoofer Audio Amplifier Board The -AS21P amplifier board features a 2.1-channel design, allowing you to connect two passive speakers and a subwoofer. Equipped with treble/bass adjustment knobs, an subwoofer volume control, and a 20-200Hz frequency adjustment knob, it delivers optimized audio performance for audiophiles. Fine-tune the sound to experience bass, crisper highs, and a more immersive, layered soundstage. HIFI-Grade Audio Amplifier Powered by dual TPA3255 amplifier chips-high-performance Class D modules that ultra-low distortion across the entire frequency range while delivering crystal-clear HD audio. The PCB utilizes advanced windowed tin-sprayed traces to enhance power output, while six low-noise NE5532 preamplifiers refine sound quality, boost volume, and improve gain. Massive 300Wx2 + 600W Output Packs 300W per channel (left/right) and a staggering 600W subwoofer output, effortlessly driving high-power speakers and subwoofers. Requires an 18-50V DC/10A+ power supply ( voltage input: 18-50V DC). Note: Higher voltage/current and lower speaker impedance increase output power-always use a PSU rated above the amplifier's operational demand. Versatile Audio Inputs Supports Bluetooth 5.1 (faster transmission, lossless decoding, andlt;15m range), USB flash drives, USB sound card mode, and 3.5mm AUX input. Pro tip: Disconnect Bluetooth when using AUX for uninterrupted playback. Cooling Built-in safeguards: over/under-voltage, overheating, and short-circuit protection. A whisper-quiet, long-life cooling fan (stall-proof, noiseless) sits atop the amp chips, ensuring optimal heat dissipation and reliability. (External potentiometer) Color: As Shown Material: Metal Package Contents: 1 pcs * Only the above package content, other products are not included. Note: Light reflection 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.