1. Introduction
The Douk Audio VFD253 is a versatile device integrating an audio spectrum analyzer, a Bluetooth 5.0 receiver, and a 3.5mm AUX selector. It features a high-resolution VFD display and offers multiple audio input options, including microphone pickup. This manual provides detailed instructions for setting up and operating your VFD253 to ensure optimal performance and enjoyment.
2. Product Features
- VFD Audio Spectrum Analyzer: Utilizes a dedicated green VFD display screen with 25 × 15 high resolution for accurate frequency band visualization.
- Bluetooth Receiver & Audio Switcher: Supports Bluetooth 5.0 and two 3.5mm AUX inputs, alongside microphone pickup. Compatible with phones, PCs, game players, amplifiers, and speakers.
- High-Precision Clock: Features an RX8025T built-in crystal oscillator for high clock accuracy (within ±3ppm year error).
- Wide Frequency Range & AGC Display: Supports an 80Hz-16KHz frequency range with high-precision display. The special AGC algorithm and customized output curve ensure ideal visual effects across varying input signal levels.
- Adjustable Display Settings: Allows adjustment of main light column falling speed, peak holding time, peak falling speed, brightness (5 levels + auto), and gain (5 levels).
- Multiple Display Modes: Offers 5 music spectrum display modes and 2 clock display modes.
- Power-Off Memory: All settings are saved automatically and retained after power-off.
- Remote Control: Provides convenient adjustment of all settings and real-time monitoring of music level status.
- Durable Design: Constructed with CNC machined aluminum and transparent acrylic case for both durability and aesthetic appeal.
3. Package Contents
- 1 × VFD253 Audio Spectrum Analyzer
- 1 × USB Cable (Type-C)
- 1 × Remote Control
- 2 × Anti-slip Pads (for bottom placement)
- 1 × User Manual
4. Product Overview
The VFD253 unit features a clear VFD display on the front and various input/output ports on the rear for versatile connectivity.
The device integrates multiple functions, serving as an audio spectrum analyzer, a Bluetooth receiver, an audio switcher, and a high-precision clock. The display dynamically visualizes audio signals or shows the current time.
5. Setup Instructions
- Power Connection: Connect the provided USB Type-C cable to the DC 5V input port on the rear of the VFD253 and plug the other end into a suitable 5V power adapter (not included).
- Audio Input (Wired):
- For external audio sources (e.g., phone, PC, amplifier), use a 3.5mm audio cable to connect your source to either the IN1 or IN2 3.5mm AUX input ports on the rear panel.
- Note: 3.5mm AUX1 and 3.5mm AUX2 cannot be used simultaneously. Select one audio source at a time.
- For ambient sound visualization, the built-in microphone pickup can be used.
- Audio Input (Bluetooth):
- Ensure the VFD253 is powered on.
- Select Bluetooth mode using the audio source selection button on the front panel or the remote control.
- On your device (e.g., smartphone, tablet), search for Bluetooth devices and select "VFD253" to pair.
- Audio Output: If you wish to pass the audio signal through the VFD253 to another device (e.g., headphones, amplifier), connect a 3.5mm audio cable from the 3.5mm AUX output port on the rear panel to your desired output device.
- Placement: Attach the two anti-slip pads to the bottom of the unit for stability. Place the VFD253 on a stable, flat surface.
6. Operating Instructions
6.1. Basic Operation
- Power On/Off: Press and hold the "Audio source selection / Power switch" button on the front panel or use the power button on the remote control.
- Audio Source Selection: Briefly press the "Audio source selection / Power switch" button on the front panel or the dedicated input selection buttons on the remote (MIC / Bluetooth / IN1 / IN2) to cycle through available audio inputs.
- Mode Switching: Use the "Mode -" and "Mode +" buttons on the front panel or the remote control to switch between music spectrum display modes and clock display modes.
6.2. Display Modes
The VFD253 offers two main display categories: music spectrum and clock.
- Music Spectrum Display: Features 5 distinct visual modes to represent audio frequencies.
- Clock Display: Offers 2 different clock display styles.
- Auto Mode: The device can automatically switch between music spectrum display (when music is detected) and clock display (when no music input is present).
6.3. Adjusting Settings (Using Remote Control)
The remote control provides comprehensive access to all adjustable settings.
- Brightness: Adjust the display brightness through 5 levels or enable auto-adjustment.
- Gain: Modify the input gain across 5 levels to optimize display sensitivity for different audio sources.
- Spectrum Parameters: Independently adjust the falling speed of the main light column, the peak holding time, and the peak falling speed to customize the visual response.
- Clock Settings: Set the time and date as needed. Refer to the remote control's specific buttons for time adjustment.
7. Specifications
| Parameter | Value |
|---|---|
| Display Screen | VFD (Vacuum Fluorescent Display) |
| Resolution | 25 × 15 |
| Frequency Range Supported | 80Hz-16KHz |
| Display Item | Music Spectrum / Clock |
| Audio Signal Input | MIC / Bluetooth 5.0 / 2 groups of 3.5mm AUX |
| Audio Signal Output | 1 group of 3.5mm AUX |
| Work Mode | Auto mode (spectrum with music, clock without music) / Clock display mode (always) |
| Clock Display Modes | 2 kinds |
| Music Spectrum Display Modes | 5 kinds |
| Music Display Mode | AGC + customized output curve (Real output / Smooth output) |
| Adjustable Items | Main light column falling speed / Peak holding time / Peak falling speed |
| Brightness Adjustment | 5 levels + auto adjustment |
| Gain Adjustment | 5 levels |
| Power-off Memory Function | Supported |
| Remote Control | Supported |
| Working Voltage | DC 5V |
| Dimensions (W*D*H) | 184*75*66mm / 7.24*2.95*2.60in |
| Net Weight | 322g / 0.71lb |
| Package Weight | 500g / 1.10lb |
8. Troubleshooting
- No Power: Ensure the USB Type-C cable is securely connected to both the VFD253 and a working 5V power source. Try a different USB cable or power adapter.
- No Audio Spectrum Display:
- Check if an audio source is playing and connected correctly (wired AUX or Bluetooth).
- Verify the correct input source is selected on the VFD253.
- Adjust the gain setting using the remote control to increase sensitivity.
- If using the microphone, ensure there is ambient sound for pickup.
- Bluetooth Connection Issues:
- Ensure the VFD253 is in Bluetooth pairing mode.
- Disable and re-enable Bluetooth on your source device.
- Move your source device closer to the VFD253 to improve signal strength.
- Forget the device on your source and attempt to re-pair.
- Incorrect Time Display: Use the remote control to set the correct time. Refer to the remote control's specific buttons for time adjustment.
- Remote Control Not Responding:
- Check and replace the batteries in the remote control.
- Ensure there are no obstructions between the remote and the VFD253's IR receiver.
9. Maintenance
- Cleaning: Use a soft, dry cloth to clean the unit. Avoid using harsh chemicals or abrasive materials that could damage the display or casing.
- Storage: When not in use for extended periods, store the device in a cool, dry place away from direct sunlight and extreme temperatures.
- Handling: Handle the unit with care to prevent physical damage, especially to the VFD display.
10. Warranty and Support
For warranty information and technical support, please refer to the documentation included with your purchase or visit the official Douk Audio website. Keep your purchase receipt as proof of purchase for warranty claims.
