1. Introduction
This manual provides detailed instructions for the proper setup, operation, and maintenance of your Douk Audio Mini Bluetooth Amplifier G3. Please read this manual thoroughly before using the device to ensure safe and optimal performance. This amplifier is designed to deliver high-fidelity audio for home stereo speakers with versatile connectivity options.

Image 1.1: The Douk Audio Mini Bluetooth Amplifier G3, showcasing its compact design and front panel controls.
2. Product Overview
2.1. Front Panel Controls

Image 2.1: Detailed view of the amplifier's front panel, indicating the power indicator, bass control, treble control, and multi-function volume knob.
- Power Indicator: Illuminates when the amplifier is powered on.
- Bass Control: Adjusts the low-frequency output. Rotate clockwise to increase bass, counter-clockwise to decrease.
- Treble Control: Adjusts the high-frequency output. Rotate clockwise to increase treble, counter-clockwise to decrease.
- Multi-function Knob (Volume / Power):
- Rotate clockwise to increase volume, counter-clockwise to decrease.
- Rotate fully counter-clockwise until a click is heard to power off the unit. Rotate clockwise from the off position to power on.
2.2. Rear Panel Connections

Image 2.2: Detailed view of the amplifier's rear panel, showing the Bluetooth antenna, AUX input, speaker outputs, and DC power input.
- Bluetooth Antenna: Connect the provided antenna for stable Bluetooth signal reception.
- AUX Input (3.5mm): Connect audio sources such as smartphones, tablets, PCs, or CD players using a 3.5mm audio cable.
- Speaker Output (Banana Plugs/Binding Posts): Connect passive stereo speakers. Ensure correct polarity (+ to + and - to -).
- DC 15V-24V Input: Connect the provided power adapter to this port.
3. Setup Instructions
Follow these steps to set up your Douk Audio Mini Bluetooth Amplifier G3:
- Connect Speakers: Using speaker wire, connect your passive stereo speakers to the speaker output terminals on the rear panel. Ensure the positive (+) terminal on the amplifier connects to the positive (+) terminal on your speaker, and the negative (-) terminal connects to the negative (-).
- Attach Bluetooth Antenna: Screw the provided Bluetooth antenna into the designated port on the rear panel.
- Connect Power: Plug the DC output of the provided power adapter into the DC 15V-24V input port on the amplifier's rear panel. Then, plug the power adapter into a wall outlet.
- Power On: Rotate the multi-function knob (volume/power) clockwise until you hear a click and the power indicator light on the front panel illuminates.

Image 3.1: The amplifier and its included 19V power adapter, as part of the packing list.
4. Operating Instructions
4.1. Bluetooth Connection
The Douk Audio G3 features Bluetooth 5.0 for wireless audio streaming.
- Ensure the amplifier is powered on.
- On your Bluetooth-enabled device (smartphone, tablet, computer), go to the Bluetooth settings.
- Search for available devices. The amplifier will appear as "Douk Audio G3" or a similar name.
- Select the amplifier to pair. Once paired, your device will confirm the connection.
- You can now play audio from your device, and it will be transmitted wirelessly to the amplifier.

Image 4.1: Illustration of the amplifier's Bluetooth 5.0 capability, enabling wireless connection to mobile devices.
4.2. AUX Input Connection
For wired audio sources, use the 3.5mm AUX input.
- Connect one end of a 3.5mm audio cable to the AUX input port on the amplifier's rear panel.
- Connect the other end of the 3.5mm audio cable to the headphone jack or audio output of your source device (e.g., PC, CD player).
- The amplifier will automatically switch to AUX input when a cable is detected.
4.3. Adjusting Audio
- Volume: Use the large multi-function knob on the front panel to adjust the overall volume.
- Bass/Treble: Use the dedicated Bass and Treble knobs to fine-tune the low and high frequencies according to your preference.

Image 4.2: The Douk Audio G3 amplifier integrated into a home audio setup, demonstrating its wide application.
5. Specifications
| Feature | Specification |
|---|---|
| Brand | Douk Audio |
| Model Number | JP-ZJX-31 (G3) |
| Item Dimensions (L x W x H) | 4.2 x 3.4 x 1.2 inches (10.7 x 8.7 x 3.0 cm) |
| Item Weight | 10 ounces (286 grams) |
| Output Power | Up to 100 Watts (TPA3116 chip) |
| Number of Channels | 2 (Stereo) |
| Bluetooth Version | 5.0 |
| Input Interface | Bluetooth, 3.5mm AUX |
| Supply Voltage Range | DC 15V - 24V |
| Manufacturer | Nobsound |
6. Troubleshooting
If you encounter issues with your Douk Audio G3 amplifier, refer to the following common problems and solutions:
- No Sound:
- Ensure the amplifier is powered on and the power indicator light is illuminated.
- Check all cable connections (power, speakers, audio source) for secure fit.
- Verify the volume knob is not set to minimum.
- If using Bluetooth, ensure the device is properly paired and connected. Try unpairing and re-pairing.
- If using AUX, ensure the cable is fully inserted and the source device is playing audio.
- Test with a different audio source or speakers to isolate the problem.
- Distorted Sound:
- Reduce the volume on both the amplifier and the audio source.
- Check speaker wire connections for any loose strands or short circuits.
- Ensure the impedance of your speakers is compatible (3-8 ohms recommended).
- Adjust Bass and Treble controls to a neutral position or slightly lower.
- Bluetooth Disconnection/Unstable Connection:
- Ensure the Bluetooth antenna is securely attached.
- Move the audio source closer to the amplifier to reduce interference.
- Avoid placing the amplifier near other wireless devices that may cause interference (e.g., Wi-Fi routers, microwaves).
- Try restarting both the amplifier and the Bluetooth source device.
- Unit Not Powering On:
- Verify the power adapter is securely connected to both the amplifier and the wall outlet.
- Ensure the wall outlet is functional by testing it with another device.
- Confirm the multi-function knob is rotated clockwise past the 'off' click.
7. Maintenance
To ensure the longevity and optimal performance of your Douk Audio G3 amplifier, follow these maintenance guidelines:
- Cleaning: Use a soft, dry cloth to wipe the exterior of the amplifier. Do not use liquid cleaners, aerosols, or abrasive materials, as they may damage the finish or internal components.
- Placement: Place the amplifier on a stable, flat surface with adequate ventilation. Avoid placing it in direct sunlight, near heat sources, or in areas with high humidity or dust.
- Handling: Handle the unit with care. Avoid dropping or subjecting it to strong impacts.
- Power Off When Not in Use: If the amplifier will not be used for an extended period, it is recommended to power it off and unplug it from the wall outlet.
8. Warranty and Support
For warranty information and technical support, please refer to the official Douk Audio website or contact their customer service directly. Keep your purchase receipt as proof of purchase for any warranty claims.
You may also find additional resources and a PDF user manual at the following link: Douk Audio G3 User Manual (PDF)





