The AS21-II is a 2.1 channel Bluetooth power amplifier module built on two original TPA3255 chips. It delivers up to 220W per left and right channel plus a dedicated 350W subwoofer channel, and combines Bluetooth 5.1, AUX, USB drive playback, FM radio and infrared remote control in one compact board. Independent bass and treble knobs, adjustable subwoofer frequency and an on-board 12V silent cooling fan make it a ready solution for home theater, powered subwoofer cabinets, DIY speaker builds and OEM audio systems.

• Dual TPA3255 architecture: two original TPA3255 class D chips provide 220W + 220W stereo plus 350W subwoofer output, about 790W total.
• Full input set: Bluetooth 5.1 (BT-APP, up to 10m), AUX line input, USB drive playback, FM radio and infrared remote control.
• Dial wheel control: one dial button for power, mode switching (USB / Bluetooth / AUX / FM), play and pause, previous and next track, and short press twice for TWS pairing.
• Independent tuning: separate bass, treble, main volume and subwoofer frequency knobs (subwoofer 20–200Hz adjustable).
• Active cooling: large orange aluminium heat sink with 12V silent fan keeps the module cool for long running sessions.
• TWS true wireless stereo: pair two AS21-II boards to build a left and right channel wireless stereo system.
• APP control: connect through the BT-APP / BT-APP-BLE app for EQ curves, local media, USB and SD playback, FM and alarm functions.
• Protection: reverse connection, undervoltage, overheat, overcurrent and short circuit protection.

Output rises with supply voltage. The table below is the factory reference measurement for the AS21-II; make sure the adapter rated power is higher than the actual working power of the amplifier.

A large-area orange heat sink plus a 12V silent cooling fan keeps module temperature down under continuous high-power playback. High-capacity gold electrolytic capacitors and premium inductors provide ultra-clean power filtering, and the low-noise front stage op amp design keeps the background quiet.

The board provides a subwoofer small signal output for an external pure post-stage amplifier, a PBTL bridging option, and two microphone front board expansion ports (reverb input and output).

Two AS21-II boards can be paired by double clicking the middle of the dial button twice within 10 seconds, forming a wireless left and right stereo pair over Bluetooth. The BT-APP / BT-APP-BLE app adds EQ adjustment, local media and USB or SD playback, FM radio, light effects and alarm settings. The infrared remote control covers power, mode, mute, play and pause, previous and next track, EQ, volume, repeat mode and direct song selection by number.

Before installing the knobs, turn the potentiometer fully to the left first. The horizontal line on the knob should follow the direction shown in the installation diagram.

Factory direct OEM and ODM support: custom logo printing on the PCB, heat sink, fan sticker or packaging, PCB colour options (black, blue, red, green), customised packaging, function tuning and 7-day fast sampling. MOQ for customised orders is 50 pieces, and standard models can be supplied in smaller trial quantities.

Shenzhen Creatall Electronics Co., Ltd. is a professional audio amplifier board manufacturer with 20 years of experience, ISO 9001 certified, 3 million pieces monthly capacity, and CE / RoHS certified products. Every unit passes incoming quality control, high precision SMT, precision through-hole soldering, in-process inspection, 100 percent functional testing and outgoing quality control before packing.

Contact us now for wholesale price, OEM customization and samples.