All-in-One DAC Amp: A DAC. amplifier. preamplifier. and headphone amplifier are all integrated into the Fosi Audio MC331. You can easily switch between audio sources with the help of the remote control. ensuring a seamless and enriched listening experience
Amazing Combination: As an integrated tube DAC amp with a VU meter. the visual aesthetics of the 5725W vacuum tubes and VU meter add a nice warm and soft effect to not only the appearance but the sound as well. giving the modern look a retro feel
Setup Flexibility: It supports Bluetooth. USB. coaxial. optical. and RCA inputs. making it compatible with a variety of sources such as computers. phones. CD players. turntables with built-in phono preamps. etc.. allowing you to build various systems
Compact Yet Powerful: The MC331 only takes up minimal desktop space but boasts a maximum power output of 105W x2@4Ω. effectively driving your bookshelf speakers. Additionally. it has a pre-out and a 3.5mm headphone output. making it versatile enough
User-Friendly Design: The MC331 comes with a remote control. allowing you to adjust bass and treble from the comfort of your listening chair. Its replaceable tube design lets you customize the sound signature to suit your personal preferences

Output: Passive Speakers Output. Pre-Out. 3.5mm Headphone Output

SNR≥100dB; THD≤0.03%; Bluetooth Codecs: SBC. AAC

Power Supply: 24V 4.5A

1Analog/Digital Input2Compact Design3Multifunctional4Visual Dial5DIY Tubes1Tone Tuning2Remote Control3One-Click Switching4Aluminum Alloy Chassis1Vinyl Experience2Desktop Audio3Wireless Streaming4Home Theater

1. Check Connections & Device Compatibility: --Ensure all audio cables are fully inserted and undamaged. Replace any frayed cables with high-quality shielded ones (recommended: cables with metal connectors).-- Confirm your speakers' power rating (e.g.. 50W/100W) and impedance (e.g.. 4Ω/8Ω) match the amplifier's requirements (see product manual). If your speakers have an impedance outside the 4-8Ω range. they may not work optimally with the MC331. -- Avoid raising the volume beyond your speakers' labeled maximum (e.g.. “Max 80%") to prevent distortion.

2. Optimize Setup & Audio Sources: -- Speaker Placement: Use high-resolution speakers placed at least 30cm away from walls or corners. Add rugs or curtains to reduce echoes. -- Audio Quality: Play lossless music formats (e.g.. FLAC. WAV) on dedicated devices (e.g.. music players or updated phones/computers). -- Bluetooth Compatibility: Ensure your device supports SBC and AAC Bluetooth formats. Keep the Bluetooth device within 10 meters of the amplifier and minimize obstacles.

3. Reduce Environmental Interference: -- Anti-Interference Cables: Use shielded RCA cables with grounding (metal-shell connectors) to minimize buzzing. -- Distance from Interference: Keep audio/Bluetooth cables ≥30cm away from routers. power outlets. or microwaves. -- Troubleshoot Sources: Test the same song on another phone/computer. If the noise persists. contact support for assistance.

Quick Tips:

- Using a Turntable? Ensure it has a built-in phono preamp or connect an external one (required for proper volume).

- Bluetooth Stability: Check if the antenna is securely installed and keep it away from other wireless devices (e.g.. Wi-Fi routers).

- Power Supply: Ensure you are using the correct power supply (24V 4.5A for 69W output; 24V 8.5A for maximum 105W output).

- Warm-Up Time: Allow the vacuum tubes to warm up for 10-15 minutes after powering on to ensure stable performance.

PS: Sampling Rate--USB: 24bit/96kHz; OPT/COA: 24bit/96kHz

The volume is very low when connecting the turntable to the MC331. Do I need a turntable preamp?

If your turntable does not have a built-in preamp. you will need to add a separate phono preamp (such as the BOX series). If your turntable has a built-in preamp. make sure it's set to LINE mode to output the signal properly.

Q: What is the purpose of the pre-out port on the MC331?

The MC331 has a pre-out port that can be connected to a powered subwoofer. speaker. or another amplifier with passive speakers for better sound quality.

Can headphones and passive speakers play simultaneously?

The MC331 defaults to headphone output priority. To use speaker output. you need to disconnect the headphones first.

What tube models are compatible for replacement?

The following tube models are compatible: EF95. 6AK5. 6AK5W. 403A/403B. 6J1. 6J1P. 6J2. 6J3. 6J4. 6J5. among others. You can test and choose based on your personal preference.

Tube Integrated Amplifier

All-in-One DAC Amp/Headphone Amp

Catering to Most Audio Sources

Maximize Space Efficiency

Hybrid Tube Integrated Amplifier

Pointer Dances to the Music

JAN 5725W Vacuum Tubes

Customize Your Unique Sound

Easy to Set up and Intuitive to Operate

Memory Function

CNC Integrated Design

Friendly Solutions Guide

The volume is very low when connecting the turntable to the MC331. Do I need a turntable preamp?

Q: What is the purpose of the pre-out port on the MC331?

Can headphones and passive speakers play simultaneously?

What tube models are compatible for replacement?