1. Introduction
Thank you for choosing the Douk Audio X1 HiFi Stereo Bluetooth 5.0 Vacuum Tube Amplifier. This amplifier is designed to provide a high-fidelity audio experience with its versatile input options and powerful output. Featuring genuine JAN5654 vacuum tubes, it delivers a warm, rich, and transparent sound, enhancing your listening pleasure. This manual will guide you through the setup, operation, and maintenance of your new amplifier.
Figure 1: Front view of the Douk Audio X1 Vacuum Tube Amplifier.
2. Safety Information
- Power Supply: Use only the provided power adapter. Ensure the voltage matches your local power supply.
- Ventilation: Do not block ventilation openings. Ensure adequate airflow around the amplifier to prevent overheating.
- Moisture: Keep the amplifier away from water, moisture, and high humidity. Do not operate with wet hands.
- Heat Sources: Avoid placing the amplifier near heat sources such as radiators, heat registers, stoves, or other heat-producing apparatus.
- Cleaning: Disconnect power before cleaning. Use a soft, dry cloth. Do not use liquid cleaners or aerosol cleaners.
- Servicing: Do not attempt to service this product yourself. Refer all servicing to qualified service personnel.
- Tube Handling: Vacuum tubes can become hot during operation. Avoid touching them directly. Allow them to cool before handling or replacing.
3. What's in the Box
Upon opening the package, please verify that all items listed below are present and in good condition:
- 1x Douk Audio X1 Amplifier
- 2x JAN5725 Vacuum Tubes (Note: Product description mentions JAN5654, but packing list image shows JAN5725. Both are compatible small signal pentodes.)
- 1x 32V/5A Power Supply
- 1x Bluetooth Antenna
- 1x User Manual (this document)
Figure 2: Included components in the product packaging.
4. Product Features
- Versatile Inputs: Features Bluetooth 5.0, Stereo RCA, and MM Phono inputs. The MM phono input converts phono signals to line level, ensuring clear and clean sound for turntables. The 3.5mm AUX input amplifies low-level audio signals from various devices.
- JAN5654 Vacuum Tubes: Default with JAN5654 tubes (or JAN5725 as per packing list), which enhance detail, transparency, richness, and dynamic range. The pluggable tube socket allows for easy tube rolling to customize sound.
- High Output Power: Utilizes a TDA7498E amplifier IC, delivering a maximum output power of 160W + 160W (4Ω). The included 32V/5A power supply efficiently drives most home passive speakers.
- Low Frequency Output: Includes a dedicated subwoofer output, enabling easy connection to an active subwoofer for a powerful 2.1 stereo audio system.
- Tone Control & Bass Boost: Adjustable treble and bass knobs allow for sound customization. A bypass function is available for original sound playback. The bass boost switch significantly enhances bass effects for a more impactful audio experience.
- Exquisite Design: Features a durable metal black case and illuminated vacuum tubes (blue or orange light options), providing a fashionable and attractive aesthetic suitable for various home and desktop audio setups.
Figure 3: High output power and dedicated subwoofer output.
Figure 4: Imported JAN5725 tubes for vintage warm sound.
Figure 5: Tone control and bass boost features.
Figure 6: Customizable blue and orange LED tube lighting.
5. Setup
5.1 Tube Installation
Carefully insert the two JAN5725 vacuum tubes into their respective sockets on the top of the amplifier. Ensure they are firmly seated but do not force them. The tubes are fragile, so handle them with care.
5.2 Connecting Audio Sources
The Douk Audio X1 offers multiple input options:
- MM Phono Input: Connect your turntable to the MM PHONO input using RCA cables. Ensure your turntable has an MM (Moving Magnet) cartridge. Connect the turntable's ground wire to the GND terminal on the amplifier.
- RCA Input: Connect CD players, DACs, or other audio devices with RCA outputs to the AUDIO IN (RCA) jacks.
- Bluetooth Input: For wireless connection, ensure the Bluetooth antenna is securely screwed into the BT port.
5.3 Connecting Speakers
Connect your passive speakers to the SPEAKER OUTPUT terminals. Ensure correct polarity (red to red, black to black). For a 2.1 stereo system, connect an active subwoofer to the SUB OUT port.
5.4 Power Connection
Connect the provided 32V/5A power supply to the DC IN port on the rear panel of the amplifier, then plug the power supply into a wall outlet.
Figure 7: Rear panel showing MM Phono, RCA, Bluetooth, Speaker, Subwoofer, and DC inputs.
Figure 8: Input options for the amplifier.
6. Operating Instructions
6.1 Power On/Off
Press the POWER button on the front panel to turn the amplifier on or off. The power indicator LED will illuminate when the unit is on.
6.2 Input Selection
Use the INPUT switch to select between Bluetooth (BT), Phono, or RCA inputs. The corresponding LED indicator will light up.
6.3 Volume Control
Adjust the main VOLUME knob to control the overall output level of the amplifier.
6.4 Tone Control
Use the BASS and TREBLE knobs to adjust the low and high frequencies of the audio output. For a flat, uncolored sound, set the TONE switch to 'FLAT'. To enable tone control, set it to 'ON'.
6.5 Bass Boost
Engage the BASS BOOST switch to enhance low-frequency response. Set to 'BOOST' for enhanced bass or 'FLAT' for normal bass.
6.6 Tube LED Light Control
Use the LED switch to select the color of the tube illumination: Blue, Orange (ORG), or Off.
6.7 Bluetooth Pairing
When the INPUT switch is set to BT, the Bluetooth indicator will flash. On your device (phone, tablet, etc.), search for "Douk Audio X1" or similar and pair. Once connected, the Bluetooth indicator will remain solid.
Figure 9: Detailed view of front panel controls.
6.8 Official Product Video
Video 1: An official product video from Douk Audio showcasing the X1 Bluetooth Tube Phono Amp for MM Turntables. This video provides a visual overview of the amplifier and its features.
7. Maintenance
7.1 Cleaning
To clean the amplifier, first disconnect it from the power source. Use a soft, dry, lint-free cloth to wipe down the exterior. Avoid using abrasive cleaners, solvents, or chemical sprays, as these can damage the finish.
7.2 Tube Replacement (Tube Rolling)
The JAN5654/JAN5725 vacuum tubes are designed to be user-replaceable, allowing for 'tube rolling' to customize the sound signature. If a tube needs replacement due to wear or for sound experimentation, ensure the amplifier is powered off and unplugged. Allow the tubes to cool completely before gently pulling them straight up from their sockets. Insert new compatible tubes (e.g., 6J1 series, 6K4, 6J4, 6AK5/6*) by aligning the pins with the socket holes and gently pushing them down until seated. Refer to the product specifications or manufacturer's recommendations for compatible tube types.
8. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| No sound output | Incorrect input selected; loose connections; amplifier not powered on; volume too low. | Verify input selection; check all cable connections (RCA, speaker); ensure power is on and tubes are glowing; increase volume. |
| Buzzing or humming noise | Ground loop; loose phono ground wire; interference from other electronics; faulty tubes. | Ensure turntable ground wire is securely connected; try moving amplifier away from other electronic devices; replace tubes if suspected faulty. |
| Bluetooth not connecting | Antenna not connected; amplifier not in Bluetooth mode; device too far; interference. | Ensure Bluetooth antenna is securely attached; set INPUT switch to BT; move device closer to amplifier; restart both devices. |
| Distorted sound | Volume too high; incorrect impedance speakers; faulty tubes. | Reduce volume; ensure speakers match amplifier's impedance (4-8Ω recommended); consider replacing tubes. |
9. Specifications
- Brand: Douk Audio
- Model: SUC-X1
- Voltage: 32 Volts (DC)
- Maximum Supply Voltage: 35 Volts (DC)
- Minimum Supply Voltage: 19 Volts (DC)
- Supply Current: 5 Amps
- Number of Channels: 2
- Output Power: 160W + 160W (4Ω)
- Material: Aluminum
- Package Dimensions: 11.18 x 9.61 x 3.35 inches
- Item Weight: 3.1 pounds
- First Available Date: October 29, 2020
- Country of Origin: China
10. Warranty Information
For detailed warranty information, please refer to the warranty card included with your product or visit the official Douk Audio website. Keep your purchase receipt as proof of purchase for any warranty claims.
11. Customer Support
If you encounter any issues not covered in this manual or require further assistance, please contact Douk Audio customer support through their official website or the platform where you purchased the product. You can visit the Douk Audio Store at Amazon.com/stores/DoukAudioNobsound for more information and contact options.
