Review: Fosi Audio V3 Mono Amplifiers
When Fosi Audio tapped me to review their V3 Mono
Amplifiers, I was ready to put them through the wringer. The goal? See if these
little powerhouses lived up to the hype—not just by their specs, but by
real-world testing with 48V10A and 48V5A power supplies. I also wanted to see
if Fosi had sent me pristine, cherry-picked units or if they were consistent
with what’s on the market. Spoiler alert: they held up, and then some.
First Impressions:
Right out of the box, these amps feel solid—like they mean
business. I received 2 monoblocks with the 48 Volt/10
Amp power supplies. I also (with my own funds) purchased 2 monoblocks from
Amazon with the 48 Volt/5 Amp power supplies to compare quality and noticeable
differences in the different power supplies. But as much as I was impressed with the build
quality, I immediately noticed something annoying: the power port is
uncomfortably close to the speaker terminals. While you won’t be pulling cables
in and out every day, I could see this tight squeeze becoming a pain point for
those who swap out equipment often. Additionally, I’ve always gone by the rule
of at least attempting to keep my power and audio signals separated when
possible. Something I picked up in radio fundamentals during my military
training. And yes, I understand shielding and space limitations on the panel,
but this just seems too close. They are damn near right on top of each other. This
next bit may be getting nit picky, but this is for you perfectionists out
there; here few other notable differences that could be related to Quality
Control:
1.
The feet depth on the 2 amps were noticeable
different. When placed next to each other, one amp sits higher than the other.
2.
There were differences in the paint for the
markings.
3.
Different amounts of thermal paste used.
Probably a non-issue but it was observed.
4.
Different date version on the front panel power
component.
Here are a few pics of the unit’s next to each other. The unit with the red and white “Tips” sticker is the unit sent from Fosi Audio.
Weight between the 2 amplifiers came down to an exact match down to the gram.
In the photos above, you can see the difference in the
thickness of the feet mentioned above.
Here, if you look closely, you can see the differences in
the paint for the markings. Specifically, the areas around “Gain, 31 db and
25db”. Somewhat hard to capture it in photos, but it was obvious in person.
Again, minor issue.
Side by side of amplifier internals.
Amp I purchased above.
Amp Fosi Audio sent to me.
Here you can observe the different version dates on the front panel power component mentioned above.
The V3 amps run hot, too—like, really hot. Fosi clearly
prioritized performance over passive cooling here, so expect these amps to get
toasty after long listening sessions. Mine measured in at 118 degrees on the
external casing. I purchased some $10 cooling fans from Amazon to set under
each and they dropped the same measured temperatures by about 15 degrees and
give me a little more peace of mind. And while we’re on the subject of design
choices, Fosi, please stop publishing “peak” or “max” wattage ratings. These
amps shine when it comes to real-world performance, so why inflate the numbers?
Just give us the straight RMS figures at 8 and 4 ohms! Or better yet, go one
step above and show some real-world dyno tests results before other testers and
youtubers get ahold of your products. Being upfront and NOT overinflating your
numbers goes along way within this community.
Williston Audio Labs V3 Mono Dyno Bench Test - https://www.youtube.com/watch?v=2x5v00XYJ6k
Power and Performance:
Now, onto the good stuff. Let’s talk power—because these V3
monos deliver. Paired with the 48 Volt/10 Amp power supply, they provide
serious headroom, enough to push my speakers to their limits without breaking a
sweat. A bit about my speakers: I recently acquired a set of mint Paradigm
Studio Reference 100V2’s. These monsters come in at 100lbs each and stand 45.5
inches tall. The are rated at 8 ohms (talk more about that in a bit and have a
recommended amplifier power of 15-350 watts. These paradigms sound fine with a
good 50-75 watts. But they really sing if you can push them with 150 or more. I
normally have them paired with my Denon AVR-5805 that pushes 240 wpc @8 ohms
and 390 wpc @4 ohms in 2-channel operation. Cehck out the chart below that
shows how the Paradigms dip down into the 4-ohm range and even 2-ohm range
quire often depending on frequency range. The V3 monos did an excellent job
pushing my Paradigms. I could tell they did not have the authority that my
Denon has, but that’s to be expected. The channel separation was better from
the V3 monos (expected) and I could tell a slight difference at higher volumes
between the 5A vs the 10A power supplies. The 10A didn’t seem to struggle as
much to deliver during certain gitar rifts and bass notes, but these were very
subtle and many may not even notice. Overall, the 10 Amp power supplies are NOT
worth the extra money. There was very little significant difference.
https://www.stereophile.com/content/paradigm-reference-studio100-v2-loudspeaker-measurements
I ran tests using
tracks like:
• “Mudshovel” by Staind: This was a great test for guitars
and midbass. The Fosi amps kept everything tight and punchy. The distortion was
minimal, even at high volumes.
• “Lose Control” by Teddy Swims: Vocals and low bass? No
problem. These amps handled Teddy’s smooth voice like a charm while keeping the
bass well-grounded and not muddy.
• “Imagine the Fire” by Hans Zimmer: Zimmer’s epic
orchestral arrangement pushed the V3s through a gauntlet of dynamic shifts. The
amps maintained clarity and separation, even during the most complex passages.
• “Hook” by Blue’s Traveler: The amps nailed the harmonica
solo, delivering the distinct timbre without bleeding into the other
instruments. Vocals were clear and bright, and the amp provided solid
instrument separation.
Channel separation was particularly impressive with these
amps. They give each speaker the breathing room it needs, so you’re not getting
any overlap in stereo imaging, making the listening experience feel spacious
and accurate.
A Look at the Specs:
I’m a sucker for a good set of measurements, and that’s
where the Fosi V3s really shine. Over on the Audio Science Review (ASR) forums,
these amps tested exceptionally well for SINAD (Signal to Noise and
Distortion), meaning you’re getting clean, low-distortion sound at a very
budget-friendly price. In fact, it’s shocking just how clean these amps sound
considering the price point. They’re punching well above their weight class.
https://audiosciencereview.com/forum/index.php?threads/fosi-audio-v3-mono-amplifier-review.53474/
Since I purchased a set of these amplifiers on my own to
compare them against the units sent by Fosi, and I can confidently say there
was no discernible difference in build or sound quality. Both pairs performed
nearly identically, which tells me Fosi isn’t just cherry-picking units for
reviewers—what you get is genuinely representative of the product.
The Verdict:
At the end of the day, Fosi Audio’s V3 Mono Amplifiers offer
stellar performance at an unbeatable price point. They deliver enough power to
satisfy all but the most power-hungry systems, and they do so with minimal
distortion and excellent channel separation.
Yes, the power port placement is inconvenient, and yes,
these amps run hot. But for the price, these are minor trade-offs. What you’re
really paying for is performance, and in that respect, the V3s overdeliver. For
budget-conscious audiophiles or anyone looking to dip their toes into
high-quality mono-block amplification, the V3 is an excellent choice.
Final Thoughts: Fosi Audio, keep those RMS ratings accurate,
and you’ll have even more fans.
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