1. Introduction
The Douk Audio M3 is a versatile 2.1 channel stereo audio amplifier designed for home and desktop audio systems. It features multiple input options including Bluetooth 5.0, RCA stereo, and USB U-disk playback. Equipped with two TPA3116D2 amplifier chips, it delivers 50W x 2 for stereo channels and 100W for subwoofer output, allowing for flexible 2.0, 2.1, or 2.2 channel audio configurations. The M3 amplifier also includes independent bass, treble, subwoofer volume, and subwoofer cut-off frequency controls for precise sound adjustment.
2. Safety Instructions
- Power Supply: Use only the provided 24V/4.5A power adapter or a compatible DC 12-24V power supply. Using an incorrect power supply may damage the device and void the warranty.
- Ventilation: Ensure adequate ventilation around the amplifier. Do not block ventilation openings or place the unit in an enclosed space.
- Moisture: Keep the amplifier away from water, moisture, and high humidity environments. Do not operate with wet hands.
- Heat: Avoid placing the unit near heat sources such as radiators, heat registers, stoves, or other heat-producing appliances.
- Cleaning: Disconnect power before cleaning. Use a dry, soft cloth. Do not use liquid cleaners or aerosol sprays.
- Servicing: Do not attempt to service this product yourself. Refer all servicing to qualified service personnel.
3. Package Contents
Verify that all items are present in the package:
The image above shows the complete packing list for the Douk Audio M3 amplifier.
- 1x Douk Audio M3 Amplifier
- 1x 24V 4.5A Power Supply
- 1x Bluetooth Antenna
- 1x Remote Control
- 1x Instruction Manual
4. Product Overview
Detailed diagram of the Douk Audio M3 amplifier's front and rear panels with labeled components and connection examples.
4.1 Front Panel Controls
- AUX Indicator: Lights up when AUX (RCA) input is selected.
- BT Indicator: Lights up when Bluetooth input is selected.
- USB Indicator: Lights up when USB U-disk input is selected.
- U-disk Input (USB Port): For connecting a USB flash drive for music playback.
- Infrared (IR) Receiver: For receiving signals from the remote control.
- SUB FREQ Knob: Adjusts the subwoofer cut-off frequency.
- SUB VOL Knob: Adjusts the subwoofer output volume.
- BASS Knob: Adjusts the bass level for the main stereo channels.
- TREBLE Knob: Adjusts the treble level for the main stereo channels.
- MODE / Power Switch / Input Channel Switch / Volume Knob: This multi-function knob controls power (press and hold), input selection (short press), and master volume (rotate).
4.2 Rear Panel Connections
- BT (Bluetooth Antenna Interface): Connect the included Bluetooth antenna here.
- AUDIO IN (RCA L/R): For connecting external audio sources via RCA cables (e.g., CD player, TV, MP3 player).
- SUB OUT (RCA): For connecting an active subwoofer.
- SPEAKER OUT (L/R): For connecting passive stereo speakers.
- SPEAKER OUT (SUB): For connecting a passive subwoofer.
- DC 12-24V: Power input jack. Connect the provided power adapter here.
5. Setup
5.1 Connecting Speakers and Subwoofer
The rear panel of the amplifier illustrating how to connect speakers and subwoofers for various audio system configurations.
- Passive Stereo Speakers (2.0 Channel): Connect your passive left and right speakers to the "SPEAKER OUT (L/R)" terminals. Ensure correct polarity (+ to + and - to -).
- Active Subwoofer (2.1 Channel): Connect an active subwoofer to the "SUB OUT (RCA)" port using an RCA cable.
- Passive Subwoofer (2.1 or 2.2 Channel): Connect a passive subwoofer to the "SPEAKER OUT (SUB)" terminals. This allows for a 2.1 or 2.2 channel setup where the amplifier powers both passive stereo speakers and a passive subwoofer.
5.2 Connecting Audio Sources
The Douk Audio M3 amplifier showcasing its Bluetooth 5.0 and USB U-disk input options.
- RCA Input: Connect your audio source (e.g., CD player, TV, MP3 player) to the "AUDIO IN (RCA L/R)" ports using an RCA cable.
- Bluetooth Input: Ensure the Bluetooth antenna is attached to the BT interface on the rear panel.
- USB U-disk Input: Insert a USB flash drive containing music files into the "U-disk Input" port on the front panel.
5.3 Power Connection
- Connect the provided 24V 4.5A power adapter to the "DC 12-24V" input jack on the rear panel.
- Plug the power adapter into a suitable wall outlet.
6. Operating Instructions
6.1 Power On/Off and Input Selection
- Power On/Off: Press and hold the multi-function knob on the front panel for approximately 3 seconds to turn the amplifier on or off.
- Input Selection: Short press the multi-function knob to cycle through the available input modes: AUX, Bluetooth (BT), and USB. The corresponding indicator light (AUX, BT, USB) on the front panel will illuminate.
6.2 Bluetooth Pairing
- Ensure the Bluetooth antenna is securely connected.
- Select the Bluetooth input mode by pressing the multi-function knob until the "BT" indicator lights up. The amplifier will enter pairing mode.
- On your audio device (smartphone, tablet, computer), enable Bluetooth and search for available devices.
- Select "Douk Audio M3" from the list of devices to pair. Once connected, the BT indicator will remain solid.
6.3 USB U-disk Playback
- Insert a USB flash drive (formatted as FAT32) containing supported audio files (MP3, WAV, APE, FLAC, WMA) into the front USB port.
- Select the USB input mode by pressing the multi-function knob until the "USB" indicator lights up.
- The amplifier will automatically begin playing music from the USB drive. Use the remote control for playback functions (play/pause, next/previous track).
6.4 Volume and Tone Controls
The front panel of the Douk Audio M3 amplifier, highlighting the bass, treble, subwoofer volume, and subwoofer frequency adjustment knobs.
- Master Volume: Rotate the multi-function knob on the front panel or use the VOL+/- buttons on the remote control to adjust the overall volume.
- Bass/Treble: Use the "BASS" and "TREBLE" knobs on the front panel to adjust the low and high frequencies of the main stereo channels.
- Subwoofer Volume: Use the "SUB VOL" knob to adjust the output volume of the subwoofer independently.
- Subwoofer Cut-off Frequency: Use the "SUB FREQ" knob to set the low-pass filter frequency for the subwoofer output. This allows you to control the upper frequency limit of the sound reproduced by the subwoofer.
6.5 Remote Control Operation
The Douk Audio M3 amplifier with its dedicated remote control.
The included remote control provides convenient access to various functions:
- Power Button: Turns the amplifier on/off.
- SELECT Button: Cycles through input modes (AUX, BT, USB).
- Mute Button: Mutes/unmutes the audio output.
- VOL+/- Buttons: Adjusts the master volume.
- Playback Controls (Play/Pause, Previous/Next): For controlling USB U-disk playback.
- Numeric Buttons (0-9): May be used for direct track selection on USB (functionality may vary).
- MODE1/MODE2/MODE3 Buttons: May offer preset EQ modes or other functions (refer to specific remote documentation if available).
7. Maintenance
- Cleaning: Use a soft, dry cloth to wipe the exterior of the amplifier. Do not use abrasive cleaners, waxes, or solvents.
- Storage: If storing the amplifier for an extended period, disconnect it from the power supply and store it in a cool, dry place.
- Ventilation: Regularly check that the ventilation openings are free from dust and debris to ensure proper airflow.
8. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| No power | Power adapter not connected or faulty. Wall outlet not working. | Ensure power adapter is securely connected to the amplifier and a working wall outlet. Try a different outlet. |
| No sound | Incorrect input selected. Volume too low. Speakers not connected properly. Audio source issue. Mute activated. | Select the correct input mode. Increase volume. Check speaker connections and polarity. Verify audio source is playing. Deactivate mute on remote. |
| Bluetooth connection issues | Amplifier not in pairing mode. Device too far. Interference. | Ensure BT input is selected and indicator is blinking. Move device closer to amplifier. Avoid obstacles. Try re-pairing. |
| USB U-disk playback issues | USB drive not formatted correctly (FAT32). Unsupported file format. Corrupted files. | Ensure USB drive is FAT32. Check if files are MP3, WAV, APE, FLAC, or WMA. Try a different USB drive or files. |
| Distorted sound | Volume too high. Input signal too strong. Speaker impedance mismatch. | Reduce volume. Check audio source output level. Ensure speakers are compatible with amplifier output. |
9. Specifications
The Douk Audio M3 amplifier's rear panel, highlighting its power output capabilities.
- Brand: Nobsound (Douk Audio)
- Model: M3
- Amplifier Chip: 2x TPA3116D2
- Output Power: 50W x 2 (Left/Right Channel) + 100W (Subwoofer Output)
- Audio Inputs: RCA Stereo, Bluetooth 5.0, USB U-disk
- USB Supported Formats: MP3, WAV, APE, FLAC, WMA
- Audio Outputs: Speaker Out (L/R), Sub Out (RCA), Speaker Out (Passive Subwoofer)
- Power Supply: DC 12-24V (24V/4.5A recommended)
- Product Dimensions (L x W x H): Approximately 13 cm x 13 cm x 3 cm (5.12 in x 5.12 in x 1.18 in)
- Net Weight: Approximately 540 grams (1.19 lbs)
10. Warranty and Support
This product comes with a standard manufacturer's warranty. For specific warranty terms, duration, and support inquiries, please refer to the documentation included with your purchase or contact the seller/manufacturer directly. Keep your proof of purchase for warranty claims.
For technical assistance or further questions, please reach out to Nobsound customer support through their official channels or the platform where the product was purchased.
