Fosi Audio V3 Mono – Are Two Amps Better Than One?

Fosi Audio V3 stereo amplifier was a wild success for the brand. But if one V3 was that good, can you imagine what two mono-blocks can do for you and your sound? Let’s find out.

Build and features

V3 mono is a small device that can fit in the palm of your hand, yet it’s a very well-made one. Aluminium is used all around and it feels sturdy enough. Gone is the volume knob from the front and mono now looks like a proper power amplifier. The switch on the left is for powering the unit ON or OFF or leaving it in an auto mode that will automatically detect the incoming signal. This is my favorite mode in any power amplifier. The switch on the right is to select single-ended RCA or balanced XLR input.

In the back, we find the analog inputs mentioned above, speaker binding posts, gain selector, and power inlet. Gain selection is a bit weird since it offers two quite similar values of 25 and 31 dB. Ideally, those should be spaced a bit further. The power inlet is 32V to 48V DC, meaning that there’s a big power brick lying behind those units.

In the heart of the device, there is a Texas Instrument TPA3255 chip amplifier and Fosi Audio claims they made it output up to 240 W at 4 Ohm load and 48 V / 10 A power supply. Fosi Audio also applied PFFB (Post-Filter Feedback) technology to the V3 Mono for the first time. This effectively overcomes the common load dependency issues of Class-D amplifiers, improving distortion and enhancing frequency response. Anyways, all those numbers and features aside, let’s find out how this amplifier performs in real-life use.

Sound

Fosi Audio V3 mono is once again a typical representative of the uncolored sound. Everything from the bassline to the highs is well-judged and you simply can’t pick a part of the sound spectrum that is asking for your attention more. This is a really good start given that affordable class D amplifiers used to sound lean and detailed but often dry or outright harsh. That’s certainly not the case with V3 mono. This amplifier manages to produce music that sounds as a coherent whole and not just some of its parts. Male vocals sound full and believable, vocals in general don’t exhibit signs of sibilance or any other nasty characteristic. I moved to some jazz instrumentals just to notice that all instruments sounded natural too – trumpets are open but not harsh, string plucks are clean but not too edgy, and cymbals are crisp but also fluid enough. Go ten years into the past and even much more expensive class D amps would struggle to sound this natural.

Almost perfect tonality aside, what about other aspects you may ask? For one, the soundstage is more than decent and an obvious improvement over stereo models like V3 and ZA3. The V3 mono offers better channel separation and a wider soundstage. It layers really well and separates instruments skilfully. This made for a well-organized soundstage with precisely pinpointed instruments and vocals.

Finally, microdynamics is decent and this is one lively sounding amplifier. Big dynamic swings are once again not done with the scale and authority that one might expect from this power rating. In fact, there are less powerful amplifiers that will sound bigger and present a bigger dynamic scale with more ease. Fosi Audio V3 mono is simply a clean and lively-sounding amplifier that is not meant to rock your house or impress you during Hans Zimmer’s movie compositions. For this to happen, the amplifier needs to have a much beefier power supply with greater current output and greater drive into impedance dips – which are often located in the bass region of a speaker and consume an unproportionate amount of energy. This fact will not take even a notch on my impression of Fosi V3 Mono, nor decrease its score. In fact I wouldn’t even mention it at this price point if some people are not reading into numbers too literally, believing that every Watt is the same no matter how it came to be.

Comparison

Fosi Audio V3 and ZA3 are more affordable stereo models. All of these share the same clean and neutral tonal character. The difference is that V3 mono creates better channel separation and a wider soundstage. Inside of it, tones are presented in a slightly cleaner way and placed more precisely. A big soundstage with great layering is one of my favorite things and I put a lot of weight on this – so in my mind, V3 Mono easily justifies its existence and asking price. But given the same tonality and similar dynamics, each of you will have to decide for yourselves if this advantage is important enough to pay double the price.

Topping PA7 Plus is almost twice the price and offers the same kind of functionality, meaning no remote, and no extra features to talk about. These two amps also share similar tonality and similar dynamics. That said, PA7 Plus does sound a bit cleaner and a touch more smooth and radiant in the highest frequencies. This last part about the highest frequencies is probably the biggest difference that one can notice. Is that worth twice the price? I’ll let you decide that for yourself.

Conclusion

Fosi Audio V3 mono is another well-made and really good-sounding amplifier of a familiar brand. It’s not some huge upgrade over V3 stereo and ZA3 but if you like spacious and precise soundstage it might be worth it. The price hike was inevitable but the value proposition is still great.