300W 2.1 Channel Subwoofer Power Amplifier Board – 2×100W + 120W DIY Audio Amp

Product Overview

This high-power 2.1 channel audio amplifier board is designed for DIY stereo and subwoofer systems. It provides separate left and right stereo channels together with a dedicated BTL subwoofer channel, making it suitable for DIY speaker systems, powered subwoofers, home audio projects, and custom amplifier builds.

The circuit uses six power amplifier transistors: four for the left and right stereo channels and two connected in a BTL configuration for the subwoofer channel. The board incorporates 1% metal-film resistors, large filter capacitors, an aluminum heatsink, and an active cooling fan for reliable operation.

Key Features

• 2.1-channel stereo + subwoofer amplifier design
• Maximum rated output: 100W × 2 stereo + 120W × 1 subwoofer
• Six power amplifier transistors
• Dedicated BTL subwoofer channel
• Four independent adjustment controls
• Treble, bass, subwoofer volume, and master volume adjustment
• Large aluminum heatsink
• Integrated cooling fan
• 1% metal-film resistors
• Large filter capacitors
• Suitable for 4–16Ω speaker loads
• Designed for DIY audio, speaker, and subwoofer projects

Technical Specifications

Amplifier Type: 2.1 Channel Stereo + Subwoofer Power Amplifier Board

Maximum Rated Output:
Left Channel: 100W
Right Channel: 100W
Subwoofer Channel: 120W

Output Impedance: 4–16Ω

Power Input: Dual AC 18–22V

Recommended Power Input: Dual AC 22V

Number of Power Amplifier Transistors: 6

Controls: Treble, Bass, Subwoofer Volume, Master Volume

Dimensions: Approx. 14.3 × 13.2 × 5.9 cm

Cooling: Aluminum heatsink with cooling fan

Control Functions

The four front potentiometers, from left to right, control:

1. Treble
2. Bass
3. Subwoofer Volume
4. Master Volume

This allows convenient adjustment of both the stereo channels and subwoofer output for different speaker configurations and listening preferences.

Connections

The amplifier board provides connections for:

• Left-channel speaker
• Right-channel speaker
• Subwoofer
• Stereo audio input
• Dual AC power input

The rear speaker terminals are separated for the left speaker, right speaker, and subwoofer, while the RCA connectors provide the audio signal input.

Applications

Suitable for a variety of DIY and replacement audio applications, including:

• DIY 2.1 speaker systems
• DIY subwoofer systems
• Home audio projects
• Custom stereo amplifiers
• Powered speaker projects
• Speaker repair and modification
• Electronics and audio hobby projects

Important Notes

• A power transformer, speakers, enclosure, and other external accessories are not included unless otherwise specified.
• This board requires a dual AC power supply. Do not connect it directly to household mains power.
• Please verify the power supply voltage, speaker impedance, and wiring before powering on the amplifier.
• Maximum output figures are rated specifications. Actual output power depends on the power supply, speaker impedance, load, cooling, input signal, and operating conditions.