Introduction
The Nobsound Douk Audio X1 is a versatile vacuum tube amplifier designed to enhance your audio experience. It features Bluetooth 5.0 connectivity, multiple input options including MM Phono, and a powerful TDA7498E amplifier IC for driving a wide range of passive speakers. The GE5752W vacuum tubes provide a warm and natural sound signature. This manual provides detailed instructions for setting up, operating, and maintaining your amplifier.
Package Contents
- Douk Audio X1 Amplifier Unit
- GE5752W Vacuum Tubes (pre-installed or to be installed)
- 32V / 5A Power Adapter
- Bluetooth Antenna
- User Manual (this document)
Please check all contents upon unboxing. If any items are missing or damaged, contact customer support.
Product Overview
Front Panel Controls
Image: Front view of the Douk Audio X1 amplifier, highlighting the Power Switch, Input Switch (BT, Phono, RCA), Bass Boost Switch, Tone Switch (Off, On), Tube LED Switch (Blue, Off, Orange), Bass Knob, Main Volume Knob, and Treble Knob.
- Power Switch: Turns the amplifier on or off.
- Input Switch: Selects the audio input source (Bluetooth, MM Phono, RCA).
- Bass Boost Switch: Engages or disengages bass enhancement.
- Tone Switch: Activates or deactivates the Bass and Treble tone controls.
- Tube LED Switch: Controls the illumination color of the vacuum tubes (Blue, Off, Orange).
- Bass Knob: Adjusts the low-frequency output when Tone is 'On'.
- Main Volume Knob: Controls the overall output volume.
- Treble Knob: Adjusts the high-frequency output when Tone is 'On'.
Rear Panel Connections
Image: Rear view of the Douk Audio X1 amplifier, showing the MM Phono input with ground terminal, RCA Audio In, Bluetooth antenna port, Subwoofer Output, Speaker Outputs (Left and Right), and DC Power Input.
- MM PHONO Input: Connects to a turntable with an MM cartridge. Includes a GND (ground) terminal.
- RCA/AUDIO IN: Connects to external audio sources via RCA cables (e.g., CD player, DAC, TV).
- BT (Bluetooth) Antenna Port: Connects the included Bluetooth antenna for wireless audio reception.
- SUB OUT: Connects to an active subwoofer for a 2.1 channel audio setup.
- SPEAKER OUTPUT: Connects to passive speakers (Left and Right channels).
- DC IN (19V-35V): Connects the provided power adapter.
Setup
1. Vacuum Tube Installation (if not pre-installed)
Carefully insert the GE5752W vacuum tubes into their respective sockets on the amplifier. Ensure they are seated firmly but do not force them. The tubes are fragile, handle with care.
2. Connecting Speakers
Connect your passive speakers to the SPEAKER OUTPUT terminals on the rear panel. Ensure correct polarity (+ to + and - to -) for both left and right channels. For optimal sound, use high-quality speaker cables.
Important Safety Note: When connecting speaker cables without banana plugs, ensure that the bare wire ends do not touch the amplifier case or each other to prevent short circuits and potential damage to the amplifier.
3. Connecting Audio Sources
- MM Phono Input: Connect your turntable's RCA output to the MM PHONO input. Connect the turntable's ground wire to the GND terminal on the amplifier to reduce hum.
- RCA Input: Connect other audio devices (e.g., CD player, DAC, TV) to the RCA/AUDIO IN ports using RCA cables.
- Bluetooth Input: Screw the provided Bluetooth antenna onto the BT antenna port.
4. Connecting an Active Subwoofer (Optional)
If you wish to use an active subwoofer, connect its input to the SUB OUT port on the amplifier's rear panel.
5. Power Connection
Connect the provided 32V / 5A power adapter to the DC IN port on the amplifier, then plug the adapter into a suitable wall outlet.
Image: The Douk Audio X1 amplifier set up with a turntable and bookshelf speakers, demonstrating a typical MM Phono input connection.
Operating Instructions
1. Power On/Off
Press the Power Switch on the front panel to turn the amplifier on. The vacuum tubes will light up, and the Bluetooth indicator will flash if Bluetooth is selected. Press again to turn off.
2. Input Selection
Use the Input Switch to select your desired audio source: BT for Bluetooth, PHONO for MM turntable, or RCA for other wired devices.
3. Volume Control
Rotate the Main Volume Knob to adjust the overall sound level. Start with a low volume and gradually increase it to a comfortable listening level.
4. Tone Control
The amplifier features Bass and Treble controls. Flip the Tone Switch to 'On' to activate them. Then, use the Bass Knob and Treble Knob to fine-tune the low and high frequencies according to your preference. Set the Tone Switch to 'Off' for a flat frequency response.
5. Bass Boost Function
Engage the Bass Boost Switch to enhance the low-frequency output for a more impactful bass sound.
6. Bluetooth Pairing
- Select BT input using the Input Switch. The Bluetooth indicator will flash.
- On your smartphone, computer, or other Bluetooth device, search for available Bluetooth devices.
- Select "Douk Audio X1" (or similar name) from the list to pair.
- Once paired, the Bluetooth indicator will remain solid, and you can play audio wirelessly.
Note: When connecting via Bluetooth from a PC, ensure that the audio output method is correctly configured on your computer's sound settings.
7. Tube LED Control
Use the Tube LED Switch to change the illumination color of the vacuum tubes to Blue, Orange, or turn the LED off.
Image: The Douk Audio X1 amplifier receiving audio wirelessly from a smartphone via Bluetooth, with speakers connected.
Specifications
| Feature | Specification |
|---|---|
| Model | X1 |
| Vacuum Tube Model | GE5752W |
| Amplifier IC | TDA7498E |
| Op-Amp | NE5532 |
| Max Output Power | 160W + 160W (4Ω) |
| Bluetooth Version | 5.0 |
| Audio Inputs | Bluetooth, Stereo RCA, MM Phono |
| Audio Outputs | 2.0 Channel Speaker Output, Active Subwoofer Output |
| Power Supply | DC 32V / 5A (included) |
| Dimensions (approx.) | 31.8 x 28 x 8 cm |
| Weight (approx.) | 1.46 kg |
| Other Functions | Tone Control (Bass/Treble), Bass Boost, Tube LED Illumination, Short Circuit Protection |
Troubleshooting
- No Sound:
- Ensure the amplifier is powered on and the volume is turned up.
- Verify that the correct input source is selected (BT, PHONO, RCA).
- Check all cable connections (power, speakers, audio sources) for secure fit and correct polarity.
- If using Bluetooth, ensure the device is paired and the PC/phone output is set to the amplifier.
- Distorted Sound:
- Reduce the volume level from both the amplifier and the source device.
- Check speaker impedance compatibility.
- Ensure vacuum tubes are properly seated.
- Humming/Noise:
- If using MM Phono, ensure the turntable's ground wire is connected to the amplifier's GND terminal.
- Check for interference from other electronic devices.
- Ensure all cables are properly shielded and connected.
- Bluetooth Disconnection/Failure to Pair:
- Ensure the Bluetooth antenna is securely attached.
- Move the source device closer to the amplifier.
- Forget the device on your source's Bluetooth settings and try pairing again.
- Restart both the amplifier and the source device.
Maintenance
- Cleaning: Use a soft, dry cloth to clean the amplifier's exterior. Do not use liquid cleaners or solvents.
- Vacuum Tubes: The GE5752W vacuum tubes have a finite lifespan. If sound quality degrades or tubes fail to light up, they may need replacement. Contact customer support for compatible replacement tubes.
- Ventilation: Ensure the amplifier has adequate ventilation to prevent overheating. Do not block ventilation holes.
- Storage: When not in use for extended periods, disconnect the power adapter and store the amplifier in a cool, dry place.
Safety Information
- Do not expose the amplifier to water, moisture, or extreme temperatures.
- Do not open the amplifier casing. There are no user-serviceable parts inside, and doing so voids the warranty and poses a risk of electric shock.
- Use only the provided power adapter or a compatible replacement specified by the manufacturer.
- Keep the amplifier away from children and pets.
- Disconnect power during lightning storms or when unused for long periods.
Warranty and Support
Nobsound products are designed for reliability and performance. For warranty information, technical support, or service inquiries, please refer to the warranty card included with your product or visit the official Nobsound website. Please have your model number (X1) and purchase details ready when contacting support.
