• 3-In 3-Out XLR Switching: Keep up to three balanced XLR sources and three output devices connected, so you can switch setups without repeatedly swapping cables. Select one A/B/C input and route it to Output 1, 2, or 3—or run three outputs simultaneously for a more flexible HiFi system.
• Read the Signal Behind the Swing: Calibrated dual VU meters with purpose-built driver circuitry support precise response. For actual readings, use 0 or -10 dB gain; at 0 dB gain, 0 dB corresponds to 0.775 Vrms. Gain adjusts continuously from -10 to 0 dB for different signal levels, while 35 colors and five brightness levels to shape the look from a warm vintage glow to a cool modern vibe.
• Preserve Your System Sound: Relay-based mechanical switching routes the balanced XLR signal without added amplification, attenuation, or processing. A 47 kΩ VU branch keeps loading low, while gold-plated XLR contacts support stable, clean signal transfer with minimal impact on your system sound.
• Easy A/B Comparisons: Switch between connected DACs, preamps, headphone amps, or power amps without stopping to swap XLR cables. The remote handles power, input/output selection, and VU brightness from your listening seat, keeping comparisons quick and uninterrupted.
• Built for Everyday HiFi Use: Connect your main source to Input A and primary system to Output 1; when MC303 is off, power-off bypass keeps the signal passing straight through without powering the switcher. Power-loss memory adds everyday convenience, while a CNC-machined aluminum front panel and steel chassis bring a solid, durable build for long-term HiFi use.

• Brand: Douk Audio
• Model: MC303
• Audio I/O Interface: 3 × Female XLR / 3 × Male XLR
• Working Mode: 3-in-3-out
• Frequency Response: 20 Hz–20 kHz
• SNR: ≥96 dB
• Input Impedance: 47 kΩ
• VU Meter Gain: 0 dB ~ -10 dB (Linear Gain)
• Meter Scale: -50 dB ~ +10 dB
•  dB Calibration Reference: 0.775 Vrms
• Max. Input Voltage: 0 dB: 2.45 Vrms; -10 dB: 7.75 Vrms
• Indication Accuracy: ±2 dB at the 0 dB reference point
• Meter Response Mode: PEAK
• Backlight Brightness: 5-level (Including Off)
• Backlight Color: 35 colors
• Power-loss Memory: Supported
• Remote Control: Supported
• Power Input: USB-C, DC 5V / ≥1A
• VU Meter Size: 60 × 35 mm
• Dimensions (W × D × H): 275 × 155 × 74 mm / 10.83 × 6.10 × 2.99 in
• Package Dimensions (W × D × H): 315 × 180 × 150 mm / 12.40 × 7.09 × 5.91 in 
• Net Weight: 1.47 kg / 3.24 lb
• Package Weight: 1.90 kg / 4.19 lb

User Manual of Douk Audio-MC303

FAQs

Q: Can multiple channels operate at the same time?
A: Yes. Outputs 1, 2, and 3 can operate simultaneously. A/B/C sources can all stay connected, but select only one input at a time to avoid signal mixing or distortion.

Q: What is the maximum input voltage at 0 dB and -10 dB gain?
A: The maximum input is 2.45 Vrms at 0 dB gain and 7.75 Vrms at -10 dB gain. Start at -10 dB, then increase toward 0 dB if needle movement is too small. Do not exceed the selected range, as excessive input may damage the VU meters.

Q: Does the VU meter gain affect the audio output?
A: No. The gain control adjusts only the signal sent to the VU meter and its measurement range; it does not change the routed audio level.

Q: Can MC303 pass audio when powered off?
A: Yes. When powered off, Input A bypasses directly to Output 1, so audio can continue to pass through normally. VU metering and channel switching require power.

Q: What type of power supply should I use?
A: It's recommended to use the included DC 5V / ≥1A USB power supply. Most fast-charging adapters will work, although some may not be recognized correctly.

Q: Which functions are available only from the front panel?
A: VU meter gain, backlight color settings, and simultaneous multi-output activation require the front-panel controls. Power, input/output switching, and VU brightness can also be controlled by remote.

Q: Why doesn’t the remote control include batteries?
A: For safer and faster shipping, batteries are not included with the remote control. Please prepare 2 × AAA batteries separately.