All-in-One DAC Amp/Headphone Amps have been gaining popularity lately and today, I review the new Fosi Audio MC331 Tube Integrated Bluetooth Amplifier with DAC and VU Meter. It’s priced at 126 USD.
Disclaimer: This sample was provided by Fosi Audio for an honest review. All observations and opinions here are my own, based on my experience with the product.
Fosi Audio MC331
Specifications
- MAX Power Output:
105W×2@4Ω - Input Mode: Bluetooth +RCA +USB +COA+OPT
- Output Mode: Passive Speakers Output, Pre-Out, 3.5mm Headphone Output
- THD: ≤0.03%
- SNR: ≥100dB
- Device Dimension: 10 x 2 x 2.7 inches
- Terminating Impedance: 4-8 Ohm
- Power Supply: 24V/4.5A
Design
The Fosi Audio MC331 is sure to garner attention with its striking VU meter, adding a retro touch to the modern, rounded aluminium chassis and bronze-coloured volume knob, along with the dual Jan 5654W vacuum tubes positioned on top of the unit.
With one analog (RCA) and four digital input modes (USB, Bluetooth, optical, coaxial), the MC331 is compatible with a comprehensive range of audio sources. Its included pre-out port makes it easy to add a sub-woofer for a 2.1 system and the 3.5mm headphone jack on the front panel makes it versatile as a desktop system too.
The MC331 comes with tone controls too, so you can tweak the bass and treble to suit your personal preference or depending on the music genre. Bluetooth connectivity enables you to connect to the MC331 wirelessly. The documentation doesn’t specify which Bluetooth chip it uses but there is neither aptX or LDAC support, so it’s restricted to SBC or AAC.
If you like to do some tube rolling, the MC331 is compatible with 6AK5, 6AK5W, 6Zh1P, 6J1, WE-403A, 403B, EF95 and various other 7-pin vacuum tubes. As you can tell, this device offers a lot in regards to versatility.
The Fosi Audio MC331 is equipped with a proprietary FS-2348B-2F DAC chip developed by Fosi Audio. It’s paired with the TPA3221 amplifier chipset, providing robust power output and efficient performance for a wide range of speakers and headphones. The MC331 is rated for 105W per channel at 4 ohms.
Sound
For testing, I connected the Fosi Audio MC331 to my computer via the USB-C port and then hooked it up to my NHT C3 Carbon speakers. I also tested the headphone output with various IEMs and headphones.
Right out of the box, the MC331 impresses with its clarity and energy. It sounds mostly neutral but with the added dimensionality and analog characteristics that tubes deliver. Despite its crispness and linearity, the sound is presented smoothly without any signs of coarseness or graininess.
The built-in tone controls, accessible either directly on the device or through the included remote, let you fine-tune the sound to match your preferences and music style. The lows offer impressive weight and extension, pushing the limits of my bookshelf speakers. For the best experience, I connected my subwoofer using the 3.5mm pre-out, which delivered more than enough bass to shake the room.
The MC331 expands the soundstage, creating a greater sense of openness and depth while enriching both male and female vocals. This added character enhances the overall presentation, making instruments and voices more engaging and organic.
Pairing & Compatibility
The MC331 was an ideal match for my detailed and precise speakers. The added fullness and dimensionality from the tube amp enhanced the speakers’ innate characteristics. However, my experience with IEMs (in-ear Monitors) wasn’t as positive. When using sensitive IEMs, the background noise from the headphone output is immediately apparent and frankly loud enough to be distracting. Higher-impedance headphones, however, like my Sennheiser HD650, sounded great.
Verdict
The Fosi Audio MC331 is a compelling addition to the brand’s diverse product lineup. Its attractive design, solid build quality, and affordable price make it an appealing option. Visually, the MC331 blends modern and retro elements: the compact, clean chassis and copper-coloured volume knob are juxtaposed beautifully with the glowing vacuum tubes and prominent VU meter.
Sound customization is offered through bass and treble tone controls, and the potential for tube rolling further expands its sonic possibilities.
The downsides include basic Bluetooth audio quality and the noticeable background noise from the headphone output. However, given its low price, these compromises are somewhat understandable, even if they are hard to ignore. But for those just starting out and wanting to experience tube sound in a stylish package, the MC331 is worth considering.