1. Introduction
Thank you for purchasing the Douk Audio 120W Mini Bluetooth 5.0 Power Amplifier. This compact and versatile audio amplifier is designed to deliver high-fidelity stereo sound for your home speaker system. Featuring multiple input options including Bluetooth 5.0, AUX, USB, and TF card, it offers flexible connectivity for various audio sources. This manual provides detailed instructions for setup, operation, and maintenance to ensure optimal performance and longevity of your device.
Figure 1.1: Front view of the Douk Audio 120W Mini Bluetooth 5.0 Power Amplifier.
2. Safety Information
- Read all instructions carefully before operating the device.
- Keep the device away from water, moisture, and direct sunlight.
- Do not block ventilation openings. Ensure adequate airflow around the unit.
- Use only the provided power adapter. Using an incorrect power supply may damage the device and void the warranty.
- Do not attempt to disassemble or repair the unit yourself. Refer all servicing to qualified personnel.
- Avoid exposing the device to extreme temperatures or high humidity.
- Disconnect the power adapter from the wall outlet if the unit is not going to be used for a long period.
3. Package Contents
Please check the package carefully to ensure all items are present and in good condition.
- 1x Douk Audio 120W Mini Bluetooth Power Amplifier
- 1x 19V Power Adapter
- 1x 3.5mm AUX Cable
- 1x 1:2 RCA Cable
- 1x 2:2 RCA Cable
- 1x USB Cable
Figure 3.1: Included accessories and amplifier unit.
4. Product Overview
4.1 Front Panel
Figure 4.1: Front Panel Layout.
- Previous Song Button: Short press to go to the previous track (U-disk/TF card mode).
- Play/Pause Button: Short press to play or pause (U-disk/TF card mode).
- Next Song Button: Short press to go to the next track (U-disk/TF card mode).
- Input Selection Button (M): Short press to cycle through input modes (Bluetooth, AUX, TF, USB).
- Digital Display Screen: Shows current input mode and playback information.
- TF IN: Slot for TF (Micro SD) card.
- USB IN: USB-A port for U-disk (USB flash drive).
- AUX IN: 3.5mm audio input jack.
- Volume/Power Knob: Rotate to adjust volume. Long press to power on/off.
- LED Indicator: Indicates power status and mode.
4.2 Rear Panel
Figure 4.2: Rear Panel Layout.
- Speaker Outputs (Left & Right): Connect passive speakers (4-16Ω impedance). Supports banana plugs or bare wire.
- RCA IN (Line): Stereo RCA input for external audio devices.
- DC IN (9-24V): Power input jack.
5. Setup
Follow these steps to set up your Douk Audio amplifier:
- Connect Speakers: Connect your passive speakers to the speaker output terminals on the rear panel. Ensure correct polarity (+ to + and - to -) for each speaker. The amplifier supports speakers with 4-16Ω impedance. You can use banana plugs or bare speaker wire.
Figure 5.1: Speaker and RCA connections.
- Connect Audio Source:
- For RCA Input: Connect your audio source (e.g., CD player, TV, turntable with pre-amp) to the RCA IN ports on the rear panel using an RCA cable.
- For AUX Input: Connect your audio source (e.g., smartphone, tablet, computer) to the AUX IN port on the front panel using a 3.5mm audio cable.
- For USB Input: Insert a U-disk (USB flash drive) containing audio files into the USB IN port on the front panel.
- For TF Card Input: Insert a TF (Micro SD) card containing audio files into the TF IN slot on the front panel.
- For Bluetooth Input: No physical connection needed. You will pair your device later during operation.
- Connect Power: Insert the DC plug of the provided 19V power adapter into the DC IN port on the rear panel of the amplifier. Then, plug the power adapter into a wall outlet.
- Power On: Long press the Volume/Power knob on the front panel to turn on the amplifier. The digital display will light up.
6. Operating Instructions
6.1 Input Mode Selection
Short press the M (Mode) button on the front panel to cycle through the available input modes: Bluetooth (BT), AUX, TF Card (TF), and USB. The digital display will indicate the currently selected mode.
Figure 6.1: Multiple input options for versatile connectivity.
6.2 Bluetooth Operation
- Switch the amplifier to Bluetooth mode using the M button. The display will show "BT" and the Bluetooth indicator will flash, indicating it's in pairing mode.
- On your mobile device (smartphone, tablet, etc.), enable Bluetooth and search for available devices.
- Select "Douk Audio" or "Nobsound" (device name may vary slightly) from the list of found devices to pair.
- Once successfully paired, the Bluetooth indicator on the amplifier will stop flashing and remain solid. You can now play audio from your device wirelessly.
6.3 USB/TF Card Playback
When a U-disk or TF card is inserted and the corresponding input mode is selected, the amplifier will automatically begin playing supported audio files.
- Supported Formats: WAV, APE, FLAC, MP3.
- Use the Previous Song, Play/Pause, and Next Song buttons on the front panel to control playback.
Figure 6.2: TF card and USB input options.
6.4 Volume Control
Rotate the large Volume/Power knob on the front panel clockwise to increase volume and counter-clockwise to decrease volume.
7. Maintenance
- Cleaning: Use a soft, dry cloth to clean the exterior of the amplifier. Do not use liquid cleaners or aerosols.
- Storage: If not in use for an extended period, disconnect the power and store the amplifier in a cool, dry place.
- Ventilation: Ensure the ventilation holes are not obstructed to prevent overheating.
8. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| No sound output. |
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| Bluetooth pairing failed. |
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| USB/TF card not playing. |
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| Unit powers off unexpectedly. |
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9. Specifications
| Model | GFJ782_US |
| Output Power | 120W (Max, likely peak power) |
| Channels | 2.0 Channel (Stereo) |
| Bluetooth Version | 5.0 |
| Input Interfaces | Bluetooth, AUX (3.5mm), USB (U-disk), TF Card |
| Output Interface | Speaker Outputs (Banana plug / Bare wire) |
| Speaker Impedance | 4-16Ω |
| Power Supply | DC 9-24V (19V recommended) |
| Supported Audio Formats (USB/TF) | WAV, APE, FLAC, MP3 |
| Dimensions (L x W x H) | Approx. 110mm x 90mm x 50mm (4.33 x 3.54 x 1.97 inches) |
| Item Weight | Approx. 0.76 kg (1.67 pounds) |
10. Warranty and Support
This product comes with a standard manufacturer's warranty. For specific warranty terms and conditions, please refer to the documentation included with your purchase or contact the seller directly.
For technical support, troubleshooting assistance, or any inquiries regarding your Douk Audio amplifier, please contact the customer support team of Nobsound (the manufacturer) or your retailer.
You may also find additional resources and FAQs on the official Nobsound website: Nobsound Official Store.
