I initially intended to conduct a thorough review of this integrated amplifier, but honestly, for just $130 and the exceptional sound quality it delivers, why write a lengthy review? I've A/B tested the Fosi MC331 on both a $3K audio system and a $15K system, and I can confidently say that for the price, the performance is great. If you're in the market for a budget-friendly option that doesn't compromise on audio performance, Just Buy It! 😎

My MC331 is better than I had anticipated (with a couple caveats). The sound is clear, and the tubes impart with slight warmth you look for with a tube (hybrid) amplifier. 100W is plenty enough for my desktop needs, and I wouldn't hesitate using it with larger (efficient) speakers. The Bass/Treble adjustments are adequate but coarse. I paired this with application based EQ for great results. I love the retro VU meter and the front panel headphone jack (3.5mm). It supports a variety of inputs and the dial to select them is easy to use. I noticed a low level noise in RCA mode that persisted after 3 different sets of tubes, but an in-line attenuator solved the problem.I recommend the Fosi MC331 for folks who want a bit better (nostalgic) sound from a small footprint amplifier. Bluetooth makes it convenient to use with phones, tablets, etc as well. One note however, it is considerably smaller than the product photography makes it appear.

Great quality and the sound comes out super, works perfectly. Better than i expected and look to be very high quality.

unit has been working fine using it with cd player and martin logan 16 bookshelf speakers

Even though the description says it is a preamp, this will not power a turntable that needs a preamp.Love the Blue Tooth feature, but will not drive the sound from a turntable that needs a preamp.

I am give this unit 5 stars. Sennheiser 660S2 a c to c usb connector from my Samsung S22 to utilize the DAC in the unit.The Sound is AMAZING!

Really enjoyed this little amp for about two hours. Heard a loud pop but it continued working and sounding great. However, after cycling power, the Bluetooth stopped connecting.

This amp sounds great when playing at moderate volumes. Worked good with my TV and streaming music.I then took it to work to use as a desktop DAC/Amp with the same speakers (Micca MB42x G2s). It failed pretty miserably in that application. With the volume low when the audio track dips to vocals only or light instrumentals it will cut out entirely. In order to mitigate this I had to turn it up to a volume level that is not appropriate for an office setting.With a different Dayton amp the speakers functioned perfectly. I found a small thread on a forum discussing this and several others are having the same experience. Supposedly Fosi is working on a solution but I believe I will be returning this unit.

Well made, nice retro appearance, very easy to set up and sounds very good straight out of the box.

When I ordered this Integrated Amplifier, I guess I was the 1st person to Order as there were no reviews found. Meanwhile, when this product was shipped, I got to see a review with only 3 Star stating this Amp cannot be connected to a SubWoofer and that made me to feel skeptical, because my main requirement is to use this Amp for my Home PC with a 2.1 setup.Despite this low rating I decided to wait until the Amplifier gets delivered and hence waited patiently. And the day arrived, the first thing that I did was I connected this to my PC and tested all the inputs paired with my Pioneer Vintage Bookshelf speakers along with an Active Subwoofer wherein I connected the subwoofer to its LFE input.Initially, I was shocked to notice that my Subwoofer was silent and there was no BASS - you know I am a BASS lover, I enjoy songs and videos mostly for the deep BASS effects. However, I didn't loose my hope - I have multiple subwoofers, and most of them are custom made with Plate Amplifiers and luckily all my subwoofers are equipped with multiple inputs (RCA Line In, LFE and the Speaker In/Out).In my 2nd attempt to test the Sub I connected the Pre-out from this Amplifier to the 'Line-in' Input of my subwoofer - Oh Man it was a WoW Moment - It worked!! and what a deep bass it was really awesome.For those who says this cannot be connected to a Subwoofer, please note the 'Pre-Out' from this Amplifier is not throwing out any LFE signals, but a 'Stereo Output', which can be connected to another Stereo Amp to power Speaker-B or to an Active Subwoofer that has 'Line-In' RCA Port. At 100Hz this 'Pre-Out' works well with my Subwoofer and there are no flaws, but it might work with different Hz with other brand Subwoofers.I am not using this Integrated Amp with any Headphones, but with my Creative Sound Blaster X4, which supports multiple sampling rates.Pros:1. All inputs are working fine, especially the Bluetooth is excellent.2. It remembers the last used input and selects it when the Amp is turned on.3. Highs and Mids are very clear, but for the Low Frequencies either use a nice Pair of bookshelf speakers or connect a Subwoofer.4. It comes with a compact remote which is not the case in all the brands at this price range.5. It looks very elegant and I love the 'Volume Unit Meter', it makes to feel it Vintage.6. No distortions were observed even at high volume; thanks to the VU-Meter that helps to monitor the db level.7. The Volume control also attenuates the 'Pre-Out' level, which is not found in all the Amplifiers and I have seen few amplifiers that controls only the Stereo and the Subwoofer works even there is no output from the Speakers.Cons:1. There is no ventilation provided for the heat to dissipate like other models in this Brand.2. There is no option to dim the 'VU-Meter' light, which glows very bright.3. Would be great if the input power supply is given as 240V, instead of an external step-down Power Adaptor that limits the Wattage per Channel.4. Should have included a HDMI port with ARC (saying this because it has a wonderful DAC inside).5. Option for connecting a Passive Subwoofer isn't available, would be great if included.6. Installing the Tubes was quite hard and little risky as there is chance for breaking - they should have installed it and modified the Packaging Box so that it becomes a plug and play device without any risks while doing the initial setup.7. There are no indications on the volume level - there is no min/max level set in the Master Volume and hence I am setting the PC Volume to the minimum to avoid any damage to the connected speakers. Also there is no MUTE button included in the Amplifier.Despite having these much cons, I have rated this as 5 Stars because there is no option to mark it as 4.5Overall experience is good and it exceeded my expectations that makes me to give this rating!!!I hope the readers found my review helpful.Thank You.

I have 2 passive speakers from Somy which was placed in store room for quit a long time. As a audiophile I always wanted the Desktop DAC, this product fulfill all the needs. It’s have headphones jack which is compatible with Dolby Atmos. Sound quality is good and Flat! Kindly do not expect bass/thumb on your speakers as this is designed for bookshelf speakers which usually have mid high frequency. I’m liking this product.

The MC331 Tube Integrated Amplifier is a fantastic choice for music enthusiasts, especially those who appreciate vocal-driven tracks.This amplifier delivers a warm, textured sound signature that enhances the clarity and richness of vocals, making them feel natural and soothing. Whether you're listening to your favorite singers or enjoying acoustic sessions, the MC331 elevates the listening experience with its gentle yet detailed tonal delivery.The built-in DAC ensures crisp and accurate audio reproduction, perfectly complementing its tube amplifier's warm characteristics. Its two-channel stereo setup provides a balanced soundstage that feels immersive without overwhelming bass or treble.In terms of value for money, the MC331 stands out. Its combination of premium sound quality, solid build, and elegant design makes it a must-try for audiophiles on a budget. If you're someone who enjoys vocal-centric music or just appreciates refined audio performance, this amplifier is worth the investment.

USB-DAC(TOPPING D10s)+ハイブリッドアンプ(Dilvpoetry R50)の置き換えで買ってみました。音源はノートPCのApple Musicで、スピーカーはJBL 4312M IIです。DACはそのまま、RCA入力で聴いたところ中々音は良いです。真空管を試しに中華6K4、ロシア6J1Pに替えてみましたが、6J1P高信頼管が一番良かったですが大差ないです。シングル真空管の銃A級アンプに似た聴きやすい耳障りの無い音です。メーターは予想通り殆ど動きません。あと、USB入力にPCからダイレクトに接続した音はお粗末で、音像がお団子でモノラルかと思うほど残念な音でした。結局、USB-DACは、そのまま残すことにしました・・・追記：USB入力で20時間ぐらい鳴らし込んだら、RCA入力の音に近づきました・・・USBケーブルは緑色のオーディオ用です、このレベルならUSB-DACは不使用で我慢できそうです更に追記：だいぶ鳴らし込んで、凄く良くなってきました・・・ボーカルの人間味、温かみが良く伝わります、真空管は添付品で味が出ていいです。少し古い海外スピーカーで、BGM流したい人にはピッタリでしょうね・・・