Engineered for Audiophiles - Optimal Choice for Home Audio Systems

In 2023, following the launch of the V3 stereo amplifier, we received numerous valuable suggestions and feedback from our global audio lovers. We listen intently, record diligently, and develop with dedication, ultimately striving to transform your suggestions and ideas into reality—the V3 mono.

  • Input: RCA, XLR, ¼" TRS; Output: Passive Speaker (supports banana plug or bare wire connection)
  • SINAD: XLR--101dB; RCA--93dB; SNR: ≥123dB
  • Rated Power Output: 48V/5A 240W@4Ω; 32V/5A 100W@4Ω

NICHICON Caps, Japanese

Ensure superior sound clarity, longevity, and stable electrical performance, enhancing the fidelity of audio reproduction.

WIMA Caps, German

Provide exceptional sound quality and signal stability, greatly enhancing the audio experience.

Sumida Inductor, Japanese

Offers superior signal purity and noise reduction, elevating the amplifier's sound performance.

ELNA Caps, Japan

Ensure enhanced audio clarity and stability, contributing to a richer sound experience.

Product details

Description
  • Mini Monoblock Amplifier: Crafted for HiFi audiophiles, the V3 Mono allows you to drive a single passive speaker with one amp, delivering up to 240W @4Ω of rated power. It offers the flexibility to build your home audio 2/3/4/5-channel system effortlessly. The V3 Mono can serve as a power amplifier for multi-channel AVRs, complementing the output power to easily drive high-power speakers in home theater systems.

  • Innovative Cutting-Edge Technology: Fosi Audio has achieved a technological breakthrough through independent research and development by applying 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, thereby significantly enhancing sound quality and performance.

  • Audiophile-Grade Components: The V3 Mono incorporates the high-end TPA3255 Class-D amp chip, paired with well-known components such as Japanese Nichicon filter capacitors, ELNA capacitors, German WIMA capacitors, and Japanese Sumida inductors, etc. Additionally, it features an upgraded four-layer PCB. This combination not only ensures high power output but also achieves a THD as low as 0.006%, a SINAD of 101dB, and an SNR of 123dB. As a result, the fidelity and quality of the audio are assured.

  • Advanced Cooling: Utilizing Fosi Audio's pioneering full-body heat dissipation design, the TPA3255 amplifier chip is placed at the bottom and tightly integrated with the chassis, allowing heat to be effectively dissipated through the casing. Coupled with dual side ventilation holes that enhance internal airflow, this ensures the V3 Mono can deliver stable, high-power output over extended periods.

  • User-Friendly Design: Supports both XLR/¼" TRS balanced and RCA single-ended(with gain selection) inputs, with an easy toggle switch for selection. Additionally, it features an auto power/signal sensing mode to enhance energy efficiency. You can also customize your preferred sound signature by replacing the stock NE5532 op-amps, supporting DIP8 dual discrete op-amps such as Sparkos SS3602, MUSES02, OPA2604, Burson V5i, V6, V7, and more.

  • V3 mono stereo audio component mini power monoblock amplifier 2 channel amplifier single channel 2/2.1/3/4/5 channel class d amp tpa3255 for home theater desktop outdoor bookshelf Tower floorstanding passive speakers ZA3.
Specifications
  • Channel : 1.0
  • Amplifier Chip : Texas Instruments TPA3255 
  • Input : RCA, XLR, ¼" TRS
  • Output : Speaker Output (supports banana plug or bare wire connection) 
  • SINAD : XLR: 101dB ; RCA: 93dB 
  • SNR : ≥123dB 
  • Dynamic Range : ≥123dB 
  • THD : <0.006% 
  • Gain : XLR/¼” TRS: 20dB ; RCA: 19dB, 25dB;  
  • Terminal Impedance : 2-8Ω 
  • Rated Power Output : 48V/5A--240W@4Ω ; 32V/5A --100W@4Ω 
  • Frequency Response : 10Hz-30kHz(±0.06dB)  
  • Input Voltage Range : DC 32-48V  
  • Standard PSU : 48V/5A 
What‘s in the box?

Which Product is right for you?

Compare products to find the best one for your needs.

Fosi Audio V3 Mono Monoblock Power Amplifier - Fosi Audio
From $109.99

Fosi Audio V3 Mono Monoblock Power Amplifier

Type
Monoblock
Amp Chip
TPA3255
MAX Power Output
300W@4Ω
Input
RCA, XLR, ¼”TRS
Output
Speaker Output
Treble & Bass Control
No
THD+N
<0.006%
SNR
≥123dB
Terminating Impedance
2-8Ω
Power Supply
32V/5A, 48V/5A
Fosi Audio ZA3 Balanced Stereo Amplifier - Fosi Audio
From $109.99

Fosi Audio ZA3 Balanced Stereo Amplifier

Type
2.0 CH Amp
Amp Chip
TPA3255
MAX Power Output
2x 300W@4Ω
Input
RCA, XLR, ¼”TRS
Output
Speaker Output, Sub-Out
Treble & Bass Control
No
THD+N
<0.006%
SNR
≥106dB
Terminating Impedance
2-8Ω
Power Supply
32V/5A, 48V/5A
Fosi Audio V3 Mini Stereo Amplifier - Fosi Audio
From $69.99

Fosi Audio V3 Mini Stereo Amplifier

Type
2.0 CH Amp
Amp Chip
TPA3255
MAX Power Output
2x 300W@4Ω
Input
RCA
Output
Passive Speakers, Pre-Out
Treble & Bass Control
No
THD+N
<0.003%
SNR
≥110dB
Terminating Impedance
2-8Ω
Power Supply
32V/5A, 48V/5A
Fosi Audio BT20A Pro Bluetooth Stereo Power Amp - Fosi Audio
From $79.99

Fosi Audio BT20A Pro Bluetooth Stereo Power Amp

Type
Bluetooth 2.0 Ch Amp
Amp Chip
TPA3255
MAX Power Output
2x 300W@4Ω
Input
Bluetooth, RCA
Output
Speaker Output, Pre-Out
Treble & Bass Control
Yes
THD+N
≤ 0.005%
SNR
≥ 108dB
Terminating Impedance
2-8Ω
Power Supply
32V/5A, 48V/5A
Fosi Audio M03 Subwoofer Mono Amplifier - Fosi Audio
From $89.99

Fosi Audio M03 Subwoofer Mono Amplifier

Type
Subwoofer Amp/MoxAmp
Amp Chip
MAX Power Output
200W
Input
RCA
Output
Passive Speakers + Active/Passive Subwoofer
Treble & Bass Control
No
THD+N
≤0.03%
SNR
≥ 106dB
Terminating Impedance
4-8Ω
Power Supply
32V/5A

FAQs

Please read our FAQs page to find out more.

The V3 Mono has three op-amps. What does each one do? And if l want to get a better sound, which one should l change?

The three op-amps in the V3 Mono serve distinct functions: Position 1 converts the RCA unbalanced signal to a balanced signal, while positions 2 and 3 adjust the tone. lf you're considering replacing an op-amp, it's recommended to start with the one in position 2. Replacing both the op-amps in positions 2 and 3 will have a more noticeable effect. Users can try swapping different op-amps to experience changes in sound quality.

For the V3 Mono do I need any specific type of op-amp?

It supports DIP8 dual op-amps. We highly recommend the op-amp available through the following link: https://fosiaudio.com/products/op-amp-chip-muses02-opa2604ap-opa2134pa?_pos=20&_sid=71ca24042&_ss=r
Using different op-amps can result in various sound signatures. Please refer to the video via the link: https://youtu.be/jtK9oYZ_XoI

The V3 MONO's power LED does not work but it outputs sound.

Check if the LED is out of position after swapping the op-amp. Open the unit and align the LED correctly.

  • 5 stars: 157 (84%)
  • 4 stars: 25 (13%)
  • 3 stars: 5 (3%)
  • 2 stars: 0 (0%)
  • 1 star: 1 (1%)
A
A S.
Amazing product

My friend had gotten two of these for me and it works very well. My setup is similar to the picture I've attatched!

P
Paulo N.
Excelent Little Monster!

I have a pair of speakers from B&W 805S and they have some considerable variations on impedance across frequency.
I buy a pair of Fosi Mono V3 AMP mainly on expectation that PFFB could "tame" the load.
Et voilá, I used previously Fosi ZA3 (no PFFB) and, although excelent it had some small harshness on higher frequencies.
The Monos V3 done an excelent job even with the stock opamps.
So very pleased with them!

Later I changed the opamps to LME49720 and increased this smoothness even more, without loosing any detail.

Recently I swapped the opamp #2 to the Sparkos SS3602 and gained speed and transient response without loosing anything.

This is now my choice o AMP and recommend it to anyone.
- Lot's of power
- No sign of distortion
- Effective load variation independence

A
Anonymous
Love

I love the sound output

F
Flo
Preis / Leistung Top

Bin super zufrieden; Sound und Leistung sehr gut. Einzigste Manko tatsächlich die Hitzeentwicklung. Das lässt sich aber mit aktiver Abluft lösen.

P
Petter F.
Great sound quality and performance

I got this recently and it took my setup from 0 to 100 with the sound.

S
Slavisa J.
Great mono AMP V3

Using this dual mono V3 amplifiers for a more then 1 year now. Only what i can say it is really perfect for my taste. Lots of powers. I am paired them with Infinity reference 61 mk II speakers. Really great product this 2 mono. My recommendation

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J
JS
Small but Powerful

I'm using a pair of V3s to drive vintage 16 ohm Altec Lansing speakers through my Fosi P4 preamp. They provide plenty of power and deliver crystal clear audio! I love them.

S
S.G.
Still amazing

More than one year after buying a pair in the pre-launch campaing the sound of these little gemes still amazes me

M
Martin
Impressed

Been using my v3 amps for a few months now. They are clean crisp and sound great. No noise and provide plenty of power to drive my Polk towers. Whats amazing is how small they are. They do get warm but nothing alarming.i did put my amps on an acrylic stand with a few Fosi fans to cool them during long listening sessions. The auto power feature works great - less to turn on and off!

B
Bence
Amazing amplifiers.

I also ordered a p4 preamp for the v3 mono pair. I bought them for a Dali Lektor 8. When I first turned them on, I set the gain to the lowest on both amplifiers, but at first hearing this wasn't enough for the dynamics and I raised the p4 gain from 3 to 6. This proved to be good for the first few days, but after a while the bass started to get tighter (disturbingly) so I set it back to 3. I think it took a while for the set to get used to it. Since I've had the p4 on 3 again, it's as if the speakers needed a new lease of life. Those amplifiers have brought an amazing improvement compared to the previous Sony FA3ES.

E
Eric R.
Awsome

What great dound and power. Thank you fosi. Cant wait to get my luna turn table.service is outstanding.

M
Martin
Impressed

Really impressed with the performance of my v3 mono blocks. Moved from a large underpowered integrated amp to Fosi class D mini components and wasn’t sure what to think. But these two little amps really drive my hard to power speakers!

D
DocHouse
Hot Stuff

Hot stuff but very cool sound

K
Keith
Problem solved.

I bought a pair from kickstart to replace the onboard ncore amplification in my NAD M10. There is no doubt they sound better and I saved heaps by not going with another brand as I had intended before hearing about these.

A
Alex
Amazing amp at an even better price

These amps are excellent, and an amazing value. Can even be upgraded with different OPamps. great design! Currently using 7 of these for my home theater setup

D
Donnie L.
V3 monos

These mini monos easily power my KEF LS50 Metas (Wiim Ultra, Hisense Canvas monitor) to fill the workout studio with wonderful sound! Upgraded with SparkoS Labs SS3602 op-amps.

Every room deserves a Fosi! (Garage too)

W
William
Best bang for the buck amps I have found

Was looking for a desktop setup to replace my Schiit Vidar monoblocks. These sound every bit as good but are much smaller and a fraction of the price. The TPA3255 is an amazing chip and Fosi have built an incredible amp around it, at a price that is unbelievably good. I'm using them to power my LS50 Metas and they have plenty of power to push them to uncomfortably loud levels. I upgraded the opamps to Sparkos SS3602, which was definitely an improvement, but it nearly doubles the cost of the system, so I'm not sure I would recommend it. The amps do get hot because they use the chassis as a heat sink. It was a little concerning at first but I've been running them for almost a year with no issues.

P
Phil
Little footprint, Big kick!

I love these little guys. They’ve easily powered every speaker I’ve thrown at them including B&Ws.

D
Dylan M.
Would recommend, but positioning may be troublesome

Right out of the box, just holding them in my hand I could tell they were well put together little beasts. The switches in front feel really good, and the connectors in the back seemed sturdy. I was a little bit caught off guard by how small the binding posts were and I had a little bit of trouble sticking the bare wire in, and the rotation of the holes for the wire was not the same on both posts (maybe they can be rotated back, but I didn’t try that). I got the package with 1 power supply which splits into two cords, and because the amps are quite light, and the weight and stiffness of the power cords and cord splitter thing is enough to make positioning them a little bit difficult, but once they’re set they’re set. The cord from the wall to the power supply is also very short which makes positioning more strict. But I got them set up and plugged in and they’re working perfectly! They’re powering a pair of Paradigm Monitor SE 6000f speakers and compared to my Denon avr 570 that I had them powered with previously, the bass is so much more powerful and detailed. I don’t want to talk too much on the sound because I haven’t much experience to compare it to since they’re only my second amp. Something I do notice and as have other reviewers online, they can’t get quite warm to the touch when driving at louder volumes. They have never gotten to the point that they are too hot to touch, and I haven’t noticed any degradation to the sound when they heat up, so they must be engineered with the heat in mind. I am very satisfied with these monoblocks and would absolutely recommend them to someone on a lower budget looking for some kick in their system.

S
Siby K.
Great Mono Amp for audiophiles

The performance of the amp is excellent, I have two of them with two separate power supply. This when connected through XLR cable to a balanced DAC gives you impeccable performance. Highly recommended for anyone wanting to try out mono amps, rest assured there is very little compromise with these amps.

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