Fosi Audio MC331 Tube Integrated Amplifier with DAC
- 105W x2 at 4 ohms
- Bluetooth, USB, coaxial, optical, RCA inputs
- Built-in DAC, preamp and headphone amp
- 5725W or 6J1 tubes, replaceable
- VU meter
- Pre-out and 3.5mm headphone output
- Remote with bass and treble
- 24-month warranty
Last refreshed Jun 20, 2026 · Based on the Amazon listing and published specifications, not hands-on testing.
A versatile desktop tube amp and DAC for powering bookshelf speakers from almost any source. Turntables need their own phono preamp, and the tube type shipped cannot be chosen.
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ASIN: B0DM1VLXHNModel: MC331Category: Stereo Amplifiers
Overview
Switching between a phone, computer, CD player and turntable from the couch is what the Fosi tube amplifier is built for, combining a DAC, preamp, power amp and headphone amp in one desktop box. Vacuum tubes and an analog VU meter give it a vintage look and a warmer tone.
One compact box replaces a DAC, a headphone amp and a stereo amplifier, with swappable tubes for those who like to tweak tone. There is no phono stage, so most turntables need a separate preamp.
Who it's for
Desktop audio fans and small-room listeners get a feature-packed amp with retro tube character. Vinyl lovers without a phono preamp will need to add one.
Pros and cons
- DAC, preamp and headphone amp in one
- Wide range of digital inputs
- Strong output for bookshelf speakers
- Swappable tubes to tune sound
- No built-in phono stage
- Tube type shipped at random
- Dimensions not listed
Performance notes
The built-in DAC converts digital sources to analog, and the tubes color the signal toward a warmer tone before the power stage drives the speakers. Output is rated into low impedance loads, so efficient bookshelf speakers are the natural match. Bass and treble controls fine-tune the balance from the remote.
Specifications
| Brand | Fosi Audio |
|---|---|
| Model | MC331 |
| Dimensions & fit | |
| Item weight | 4.2 pounds |
| Capacity & performance | |
| Output Power | 105W x2 at 4 ohms |
| Outputs | Pre-out, 3.5mm headphone |
| Power & efficiency | |
| Power Source | 24V 4.5A power adapter |
| Included components | |
| Included Components | Amplifier, Bluetooth antenna, 2 vacuum tubes, 2 tube covers, 24V 4.5A power adapter, remote |
| Warranty & support | |
| Warranty Description | 24 months manufacturer |
| Other details | |
| Control Type | Remote, bass and treble |
| Number of Channels | 2 |
| Dac | Built-in |
| Inputs | Bluetooth, USB, coaxial, optical, RCA |
| Tubes | 5725W or 6J1 (shipped randomly), replaceable |
| Meter | VU meter |
Frequently asked questions
Can I connect a turntable to the Fosi MC331?
Only turntables with a built-in phono preamp, through the RCA input.
Which tubes come with the Fosi MC331?
Two tubes, either 5725W or 6J1, shipped randomly. The type cannot be specified.
Can the Fosi MC331 feed another amplifier or subwoofer?
It has a pre-out for connecting other equipment.