CA-MT21 Bluetooth Amplifier – Powerful 2.1 Channel Audio Module

The CA-MT21 Bluetooth Amplifier is a versatile 2.1 channel audio amplifier module designed for DIY speaker systems, home audio projects and custom subwoofer setups. It combines Bluetooth 5.0 wireless connectivity with AUX audio input, allowing you to connect compatible devices and enjoy flexible audio playback. With separate left, right and subwoofer outputs, this amplifier board provides an integrated solution for building a 2.1 channel sound system.

Featuring an advertised output of 2 × 50W for stereo speakers and 100W for the subwoofer, the CA-MT21 Bluetooth Amplifier is designed for audio projects that require separate stereo and low-frequency sound channels. It supports compatible 4–8Ω speakers and operates from a 12–24V DC power supply.

Key Features of the CA-MT21 Bluetooth Amplifier

1. 2.1 Channel Stereo and Subwoofer Output

This amplifier module provides three separate audio output channels:

• Left channel: Advertised 50W output
• Right channel: Advertised 50W output
• Subwoofer channel: Advertised 100W output

The dedicated subwoofer channel makes this board suitable for DIY 2.1 channel speaker systems where separate low-frequency output is required.

2. Bluetooth 5.0 Wireless Connectivity

The built-in Bluetooth 5.0 audio input allows wireless connection with compatible smartphones, tablets, laptops and other Bluetooth-enabled audio sources. This makes it convenient to build a wireless audio system without requiring a separate Bluetooth receiver module.

3. AUX Audio Input

In addition to Bluetooth, the CA-MT21 Bluetooth Amplifier supports a 3.5mm AUX audio input. You can use a compatible wired audio source when Bluetooth connectivity is not required.

Having both input options provides greater flexibility for different audio applications.

4. Independent Bass, Treble and Subwoofer Controls

The module features five rotary adjustment controls on its front panel:

• Subwoofer Frequency: Adjusts the subwoofer frequency range, marked 20–200Hz.
• Subwoofer Volume: Controls the subwoofer output level.
• Treble: Adjusts high-frequency response for the stereo channels.
• Bass: Adjusts low-frequency response for the stereo channels.
• Master Volume: Controls the overall audio volume and incorporates the power switch.

These adjustment options allow users to balance the stereo and subwoofer sound according to their speaker configuration.

5. 12–24V DC Power Supply

The amplifier board operates with a DC supply voltage of 12–24V. It features a 5.5 × 2.1mm DC power input connection for convenient power supply installation.

For reliable operation, use a suitable regulated DC power supply with adequate current capacity. The product information indicates a current requirement above 9A; the actual supply requirement depends on the output level and connected speakers.

6. Screw-Terminal Speaker Connections

The board provides separate screw-terminal connections for the left speaker, right speaker and subwoofer. These terminals make it easier to connect compatible speakers during DIY audio assembly.

7. Integrated Heatsink and External Antenna Support

An integrated heatsink is fitted to the amplifier board to assist with heat dissipation. The PCB also provides a soldering point for an external Bluetooth antenna or antenna base, as shown in the product images.

Applications of the CA-MT21 Audio Amplifier Board

The CA-MT21 Bluetooth Amplifier can be used in several DIY and custom audio applications, including:

• DIY 2.1 channel speaker systems
• Home audio amplifier projects
• Bluetooth-enabled stereo speakers
• Subwoofer amplifier projects
• Multimedia speaker systems
• Custom speaker enclosures
• Electronics and audio experimentation
• Audio system upgrades

Technical Specifications

Installation and Usage Guidelines

Before connecting the CA-MT21 Bluetooth Amplifier, make sure the DC power supply voltage is within the specified 12–24V range. Check the polarity of the power connection before switching on the module.

Connect the left and right speakers to their respective output terminals and connect the compatible subwoofer to the dedicated subwoofer output. Ensure that the connected speakers have a compatible 4–8Ω impedance.

For Bluetooth operation, pair the amplifier with a compatible Bluetooth audio device. Alternatively, connect an audio source through the 3.5mm AUX input.

Adjust the master volume, bass, treble and subwoofer controls gradually to achieve the desired sound balance. Ensure adequate ventilation around the amplifier during operation.

Important: The advertised 2 × 50W + 100W output is a product rating and should not be interpreted as guaranteed continuous output under all conditions. Actual power depends on supply voltage, current capacity, speaker impedance, cooling and operating conditions. Use an appropriate power supply and compatible speakers.

Why Choose Electrica?

At Electrica, we provide electronic components, amplifier modules, development boards, sensors, tools and accessories for DIY projects, technicians, students and electronics professionals.

The CA-MT21 Bluetooth Amplifier is a practical option for users looking to build a compact 2.1 channel audio system with Bluetooth connectivity, AUX input and separate audio adjustment controls.

Explore more electronic components and project modules at:

https://www.electrica.com.pk

For product information and orders, contact Electrica through the WhatsApp option available on our website.

Please check all product images for the board layout, dimensions, connection terminals, adjustment controls and accessories before placing your order.