Interested in reviews of Fosi Audio MC331 Tube? It got 3.4 out of 5 stars from our customers. Find specific customer reviews of Fosi Audio MC331 Tube below. We will appreciate if you also share your experiences with Fosi Audio MC331 Tube after purchasing.
I'm quite a demanding user and I returned the product for two main reasons. The aggressive noise gate makes listening at lower volumes (though not all that low) impossible. It starts to cut off and chop up the sound. This is most noticeable over Bluetooth with spoken word. It cuts off the beginnings and ends of words, making speech unintelligible. It's also noticeable with music. The second issue is the significant latency. I needed the amplifier for monitors when mixing music, and for that, it's completely unusable. However, the delay is also apparent when watching films. There is a model from Fosi, the BT20A Pro, which doesn't have a noise gate or latency, but it's just a boring grey box, and it doesn't have the same power anyway (class D), so for half the price I bought an older Pioneer amplifier (class AB) with absolutely uncompromising sound. I can't think of any sensible use for this piece of kit, even though it looks very nice.
Lovely design
Quality design, not cheap plastic.
aggressive "noise gate"
latency approx 100ms
The performance is actually lower than the parameters state.
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Zdeněk, Praha 8 - Dolní Chabry
Rated 07/07/2026, variant Fosi Audio MC331 Tube
Verified purchase
I’ve been using it for about half a year as a stopgap replacement for the AIWA NSX-S90, so I can’t exactly say I have a top-quality speaker, but the sound is still very decent.
The valves really do make a difference; they come fitted with American GE 5654W valves as standard. For a few crowns, I swapped them for Soviet 6Ž1P-EVs, and there was a noticeable change in the sound, so everyone can tweak the sound to their own taste.
Very decent sound
Given the price, it’s ideal as a home multimedia hub
the option to replace the valves
It’s well-made and, design-wise, it’s simply a lovely product
It really won’t work if you want to listen in complete silence
Given the power supply’s specifications, the stated power output is nothing short of a pipe dream
I find the sound quality from the headphone output isn’t great at higher volumes.
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Lukáš, Plzeň
Rated 12/03/2026, variant Fosi Audio MC331 Tube
Verified purchase
In its price range, it is a nifty little amp, but, see cons.
design
Inputs
sound
Bluetooth and USB DAC
At low volume, the noise gate cuts off the weaker signal. Pretty awful.
The DAC could be better, it's only 16b.
volume knob is pretty crappy (rotary encoder)
it could use a balance
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