ZK-ST21 TPA3221 Bluetooth 5.1 2.1 Channel Digital Amplifier Board

The ZK-ST21 Bluetooth 5.1 Digital Power Amplifier Board is a premium 2.1-channel Class-D Hi-Fi amplifier powered by dual original Texas Instruments TPA3221 amplifier chips, delivering powerful stereo output along with a dedicated high-power subwoofer channel. Designed for DIY audio enthusiasts, home theatre systems, Bluetooth speakers, multimedia sound systems, and custom Hi-Fi projects, it combines exceptional audio quality with high efficiency and low heat generation. The board supports Bluetooth 5.1, AUX, USB flash drive, and USB sound card inputs, making it a versatile solution for modern audio applications. It also features independent controls for master volume, bass, treble, subwoofer volume, and subwoofer frequency, allowing users to fine-tune their listening experience.

Key Features:

• Dual Original Texas Instruments TPA3221 Class-D amplifier ICs
• Powerful 2.1 Channel Audio Output (100W × 2 + 200W Peak)
• Bluetooth 5.1 wireless audio streaming
• Supports Bluetooth, AUX, USB Drive & USB Sound Card inputs
• Independent Bass, Treble, Subwoofer Frequency & Volume Controls
• High-efficiency Class-D design with low distortion
• Wide operating voltage of 12V–30V DC
• Premium Hi-Fi sound quality
• Large aluminium heat sink for efficient cooling
• Built-in protection against reverse polarity, undervoltage, overcurrent, overheating, and short circuits
• Ideal for DIY speaker systems, home theatres, and active subwoofer projects

Applications:

• DIY Bluetooth Speaker Systems
• Home Theatre Systems
• Active Subwoofer Projects
• Bookshelf Speakers
• Multimedia Audio Systems
• Hi-Fi Stereo Amplifiers
• Desktop Audio Systems
• Portable PA Systems
• Educational Electronics Projects
• Custom Audio Installations
• Workshop Sound Systems
• Audio Amplifier Development

Prototyping and Engineering Tips from Robogears:

• For maximum performance, use a 24V–28V DC SMPS rated at 10A or higher.
• Pair the amplifier with 4Ω speakers and a compatible passive subwoofer for optimal power output.
• Install the board inside a well-ventilated enclosure to ensure efficient cooling during continuous high-volume operation.
• Use high-quality shielded audio cables to minimize noise and interference.
• Ensure speaker impedance matches the recommended specifications for reliable long-term performance.

Package Includes:

• 1 × ZK-ST21 TPA3221 Bluetooth 5.1 2.1 Channel Digital Power Amplifier Board

Disclaimer:

Output power depends on the input voltage, speaker impedance, power supply capability, and audio source quality. Peak output ratings are achieved under recommended operating conditions. Power supply, speakers, cables, enclosure, and other accessories are not included. Product appearance, PCB layout, Bluetooth module revision, and heat sink design may vary slightly between manufacturing batches while maintaining identical electrical performance and functionality.