Fosi Audio MC331 Tube Integrated Amplifier with DAC, 2 Channel Home Audio Stereo Power Amp for HiFi Bookshelf Speakers/3.5mm Headphones, Vintage VU Meter Preamp with Bluetooth and USB/Opt/Coax/RCA

Price: $131.99
(as of Sep 01, 2026 18:06:23 UTC – Details)

Product description

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All-in-One DAC Amp/Headphone Amp

The MC331 supports one analog and four digital input modes, ensuring compatibility with a broad range of audio sources. It also boasts a pre-out port, facilitating easy setup of a 2.1 system. The VU meter and vacuum tubes add a touch of retro flair, delighting audio enthusiasts with both visual and auditory pleasure.

Input: RCA, Bluetooth, USB, Optical, CoaxialOutput: Passive Speakers Output, Pre-Out, 3.5mm Headphone OutputSNR≥100dB; THD≤0.03%; Bluetooth Codecs: SBC, AACPower Supply: 24V 4.5A

Catering to Most Audio Sources

Connect multiple audio sources simultaneously and switch inputs seamlessly.

Maximize Space Efficiency

Fits into your audio system effortlessly, offering high-quality audio with minimal space.

Hybrid Tube Integrated Amplifier

With a built-in DAC and versatile connectivity, MC331 offers rich, immersive sound.

Pointer Dances to the Music

Displays audio signal strength in real time to adjust volume and prevent overload.

JAN 5725W or 6J1 Vacuum Tubes

Compatible tubes: 5654W, 6AK5, 6AK5W, 6Zh1P, 6J1, 6J1P, WE-403A, 403B, EF95, and other 7-pin tubes.

1 Analog/Digital Input

2 Compact Design

3 Multifunctional

4 Visual Dial

5 DIY Tubes

Bass and Treble Control

Customize Your Unique Sound

With central detents to easily restore the natural sound.

Easy to Set up and Intuitive to Operate

Allows for adjusting bass and treble from the comfort of your listening chair.

Memory Function

Setting automatically restore to previous upon restart, eliminating repetitive adjustments.

CNC Integrated Design

All-metal casing, finely sandblasted, featuring a minimalist and durable design.

1 Tone Tuning

2 Remote Control

3 One-Click Switching

4 Aluminum Alloy Chassis

1 Vinyl Experience

2 Desktop Audio

3 Wireless Streaming

4 Home Theater

Friendly Solutions Guide

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: 16bit/48kHz; OPT/COA: 24bit/192kHz

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.

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 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