Douk Audio SUC-U2-PRO-AU

DoukAudio U2PRO USB Digital Interface User Manual

Model: SUC-U2-PRO-AU

1. Product Overview

The DoukAudio U2PRO is a high-performance USB digital interface designed to convert USB audio signals into various digital outputs, including Optical, Coaxial, and I2S. It is equipped with the advanced XMOS XU316 chip, ensuring stable, low-latency, and high-resolution audio transmission. This device is ideal for connecting PCs, Macs, phones, or gaming consoles like PS5 and Switch to DACs, amplifiers, and AV receivers that lack USB input, providing a significant upgrade to audio quality.

DoukAudio U2PRO USB Digital Interface front view

Image: Front view of the DoukAudio U2PRO USB Digital Interface, showcasing its compact black chassis and indicator lights.

2. Key Features

3. What's in the Box

Upon opening the package, please verify that all the following items are included:

Contents of the DoukAudio U2PRO package

Image: Visual representation of the DoukAudio U2PRO package contents, including the device, optical cable, USB-C cable, and user manual.

4. Setup Guide

Follow these steps to set up your DoukAudio U2PRO digital interface:

  1. Connect to Source Device: Use the provided USB-C to USB-A/C cable to connect the U2PRO's "PC-USB IN" port to your source device (PC, Mac, phone, PS5, Switch). The U2PRO is USB-powered, so no external power adapter is needed.
  2. Select UAC Mode: On the bottom of the U2PRO, locate the UAC mode switch.
    • For gaming consoles (PS4, PS5, Switch), set the switch to UAC 1.0 for plug-and-play functionality.
    • For high-resolution audio with PCs, tablets, or network music players, set the switch to UAC 2.0.

    Note: The selected UAC mode will take effect only after a restart (disconnect and reconnect USB power).

  3. Connect to Audio Receiver (DAC/Amplifier/AV Receiver):
    • Optical Output: Use the provided optical cable to connect the U2PRO's "OPT OUT" port to the optical input of your audio receiver.
    • Coaxial Output: Use a coaxial cable (not included) to connect the U2PRO's "COAX OUT" port to the coaxial input of your audio receiver.
    • I2S Output: Use an HDMI cable (not included) to connect the U2PRO's "HDMI-IIS OUT" port to the I2S input of your audio receiver. Refer to the pinout definition on the bottom of the device for compatibility.
    Rear panel with input/output ports and UAC switch

    Image: Detailed view of the U2PRO's rear panel, showing the USB-C input, HDMI-IIS output, Optical output, Coaxial output, and the UAC mode switch on the bottom.

  4. Power On: Once all connections are secure, power on your source device and audio receiver. The U2PRO will power on automatically via the USB connection.

5. Operating Instructions

The DoukAudio U2PRO is designed for simple operation. Once connected, it functions as a plug-and-play device.

5.1. Indicator Lights

The front panel of the U2PRO features indicator lights that display the current audio format and sample rate:

Front panel with PCM and DSD indicator lights

Image: Close-up of the U2PRO's front panel, showing the blue lights for PCM sample rates and red lights for DSD rates, indicating the active audio format.

5.2. UAC Mode Switching

As mentioned in the setup, the UAC mode switch on the bottom of the device allows you to optimize compatibility. Remember to disconnect and reconnect the USB cable after changing the switch position for the new setting to take effect.

6. Maintenance

To ensure the longevity and optimal performance of your DoukAudio U2PRO, please follow these maintenance guidelines:

7. Troubleshooting

If you encounter issues with your DoukAudio U2PRO, please refer to the following common problems and solutions:

ProblemPossible CauseSolution
No audio output.Incorrect UAC mode selected.
Incorrect input selected on DAC/amplifier.
Loose cable connections.
Source device audio settings.
  • Verify the UAC mode switch is set correctly for your source device (1.0 for consoles, 2.0 for PC/tablet). Disconnect/reconnect USB after changing.
  • Ensure your DAC/amplifier is set to the correct input (Optical, Coaxial, or I2S) corresponding to the U2PRO's output.
  • Check all cable connections are secure.
  • Verify audio output settings on your source device (e.g., Windows Sound settings, macOS Audio MIDI Setup).
No indicator lights on U2PRO.No power from USB source.
Faulty USB cable.
  • Ensure the USB source device is powered on and providing power. Try a different USB port.
  • Try a different USB-C to USB-A/C cable.
Audio distortion or dropouts.High jitter (less common with XU316).
Cable interference.
Driver issues (UAC 2.0).
  • Ensure cables are not near strong electromagnetic interference sources.
  • For UAC 2.0, ensure proper drivers are installed on your PC if required by your operating system (though often plug-and-play).
  • Try a different cable.
UAC mode switch not working.Not restarted after switching.
  • After changing the UAC mode switch, disconnect the USB cable from the U2PRO and reconnect it to restart the device.

If the problem persists after trying these solutions, please contact Douk Audio customer support for further assistance.

8. Specifications

FeatureDetail
Product Dimensions3.35 x 3.11 x 0.1 inches
Item Model NumberSUC-U2-PRO-AU
Weight14.08 ounces
ManufacturerDouk Audio
ASINB0FF4KKZ1F
Supply Voltage5 Volts (DC)
Interface TypeCoaxial, HDMI (I2S), Optical, USB
Number of Channels2
Max. Sampling Rate (PCM)32bit/768kHz
Max. Sampling Rate (DSD)DSD512
ChipsetXMOS XU316

9. Warranty and Support

Douk Audio products are designed for reliability and performance. For specific warranty details, please refer to the warranty card included in your product packaging or visit the official Douk Audio website.

If you require technical assistance, have questions about your product, or need to report an issue, please contact Douk Audio customer support through their official channels. You can typically find contact information on the manufacturer's website or through the retailer where you purchased the product.

For more information, visit the Douk Audio Store on Amazon.

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