Product Description Bluetooth 5.0 TPA3116D2 Digital 2.1 Subwoofer Audio Amplifier Board DC12-24V Features: High-Quality Materials: Built with top-grade materials to ensure durability and reliability. Compact Design: Exquisite and compact appearance with a neat arrangement of components. Bluetooth & External Audio Input: Supports Bluetooth audio reception and external audio input with preamplification, bass crossover processing, and multiple control options including bass volume, bass frequency, left and right channel volume, treble, and master volume. High Efficiency: Easy to use with a wide operating voltage and power-saving design, delivering over 90% efficiency. Versatile Applications: Compatible with various power supplies, including good quality switching power supplies, laptop power adapters, rechargeable batteries, or car power supplies. Specifications: Operating Voltage Range: DC12-24V (Current: 3-4A, or 19-24V/4-5A; for higher power requirements: 20-24V/8-9A or more). When using an AC transformer power supply, it must be converted to DC power through a rectifier filter. Ensure the DC no-load voltage does not exceed 25.5V. Bluetooth Reception Distance: Greater than 8 meters (version 5.0), with no obstacles blocking the signal. Reception distance may vary depending on your phone's Bluetooth performance. Audio Input Sensitivity: 600-800mV Frequency Response Range: 20Hz-20kHz Speaker Impedance: Left and right channels: 4-8 ohms; bass channel: 2-8 ohms Package Includes: 1 x Digital Amplifier Board 5 x Knob Caps 1 x Cable 1 x Kit Frequently Asked Questions: Current Sound or Noise: Power Supply Issues: Ensure the power supply is well-filtered; poor power supply or audio source input can cause noise. Input Signal Quality: Poor-quality input signals or defective input devices can lead to noise. Connection Issues: Check the input connection line for damage or poor contact. No Sound or Channel Issues: Speaker Connection: Ensure the speaker connection is secure. Input Connection: Check the input connection for damage or poor contact. Distortion or Breakup: Wiring and Power Supply: Confirm the wiring is correct and that the power supply current is sufficient. Speaker Issues: Poor performance or damage to the speaker, or mismatched speaker power, can cause distortion. Amplifier Burnout: Power Supply: Ensure correct polarity and voltage levels; exceeding limits can cause burnout. Wiring: Correct wiring before connecting to power to avoid short circuits.