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

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.

Excellent product.

FIRST REVIEW [28 DEC 2024] [2 stars]: I’ve set this up at home on my desk, for casual music playback. I’ve connected a pair of Philips bookshelf speakers for two-channel playback. I primarily use the USB-C port on my MacBook Pro M1 Pro (Model Number: MKGP3HN/A) to connect the MC331. And occasionally use my iPhone 15 to play music via Bluetooth.When I connect the MC331 via the headphone jack, I can choose between several options up to 24-bit 96kHz formats for playback in the Midi setup app. But when I connect it via a USB-C cable, the options are limited to 48kHz and 16-bit. (See attached screenshot)Despite this discrepancy, the user manual states that the device can support up to 24-bit/96kHz playback over USB. (See attached screenshot)I purchased this device specifically for its advertised audio capabilities, and the fact that the amplifier is not functioning as advertised is unacceptable. Reached out to the OEM and they washed off hands saying the manual is incorrect.UPDATED REVIEW [15 JAN 2025] [4 Stars]: After using the amp for a month, here is my updated review. I have tried all other inputs and tested the features of the device and they perform on par with the claims.The 3.5mm and Optical inputs works very well and the sound quality is pretty good. Bluetooth range is also reasonable. Apart fromt the above mentioned shortcoming, I didn't find any other issues. And comparing to other features, I can overlook the limited sampling rate for USB input. And I think the feedback can be changed to 4 stars.

The media could not be loaded. Writing this review after extensive testing for 10 days. I was on the hunt for a stereo receiver as my marantz sr3001 broke down. Came across the fosi audio mc331 on Amazon. Initially I was a bit disappointed by the lack of bass when testing music from streaming apps on my phone. Then connected my xbox via optical input and gaming sounds were impressive. Also tested some remastered songs from YouTube, they sound great as well with good bass. No heating issues or bluetooth connectivity drops till now. Overall a good package at this price point.

This is an absolute beast of a product.Comes with GE Jan Tubes (though they were unmatched, so I bought some riverstone matched GE tubes)But this thing is an absolute beast.Comes packed with a 110 watt adapter which truly brought my old Philips Deck Speakers (DH415) to life!Good punchy bass, clean mids and sparkling trebles (though I will have to get better speakers because the Phillips have aged)

A well made product - build and construction. Audio output is sufficient for me - using it in as monitor setup for close proximity hearing. No issues with of auto switch off. The Tube mellowness is there to hear. Bluetooth connection is smooth and without glitches. However I feel cheated as the product is rated for 24 x 96 kHz - even the manual says so but the product is able to play only 16 x 44 kHz. Writing to Fosi about the issue got me an apology saying they will update their specifications !! Not acceptable at all and such casualness will not get them customers.If i were to buy again i would go for Ayima T9 Pro..

Cannot use additional sub woofer with this setup, it has no output for passive Sub woofer, and if I use active sub woofer with the co axial pre amp output, there will be a crossover of the frequencies of speakers and the sub woofers.