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Fosi Audio

Fosi Audio V3 Mono Power Amplifier for Home Audio Speakers, Mini Monoblock Class D Amp with TPA3255, 240W for HiFi Home Theater AVR Receiver Component, RCA/XLR Balanced Inputs 48V/5A Power

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Availability: In Stock.
Fulfilled by Amazon
Arrives Tuesday, Oct 20
Order within 4 hours and 52 minutes
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Features

  • Mini Monoblock Amplifier: Crafted for HiFi audiophiles, the amplifier home audio allows you to drive a single passive speaker with one amp, delivering up to 240W @4 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 audio component amplifiers 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.
  • User-Friendly Design: Supports both XLR/14" 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. For example, it will work with Sparkos SS3602, MUSES02, OPA2604, Burson V5i, V6, V7, and more. Note: Please ensure that the device is powered off when connecting the speaker cable.

Description

We listen intently, record diligently, and develop with dedication, ultimately striving to transform your suggestions and ideas into reality—the V3 mono. Significantly reduces distortion, enhances linearity and frequency response to get superior sound. Crafts an immersive sound experience, satisfying your craving for superior musical quality. Enhances stereo depth and soundstage accuracy for a purer audio experience. Meeting your pursuit of a personalized audio experience Effortlessly switched by a toggle switch, easily adapted for both home and professional scenarios. Long-term efficient operation of the amp, prevents overheating. Effortlessly integrates into various settings like home theater, study room, desktop, and studios. Enters standby after 10 minutes of no signal input, effectively reducing power consumption. Ensure superior sound clarity, longevity, and stable electrical performance, enhancing the fidelity of audio reproduction. Provide exceptional sound quality and signal stability, greatly enhancing the audio experience. Ensure enhanced audio clarity and stability, contributing to a richer sound experience. Offers superior signal purity and noise reduction, elevating the amplifier's sound performance. No sound change after switching the gain switch? The gain switch on the V3 MONO only works with the RCA input. When using RCA mode, switching the gain setting will noticeably change the volume. (If it's already set to RCA mode, the output level from the preamp is usually sufficient.) Would the noise still occur if no audio input cables are connected? Try replacing the audio source, using well-shielded audio cables, and switching to a different speaker. Doesn't work in standby mode? Use a separate power supply and power strip for each V3 MONO to avoid ground-loop noise affecting the standby function; if the light dims but the unit doesn't automatically shut down, please try replacing high-quality RCA cables. V3 MONO don't have volume control or knobs? Yes. V3 MONO is a pure power amplifier, it is recommended to use it with a DAC, preamplifier, or player with volume control. What's the V3 MONO? V3 MONO is a mono channel amplifier. To achieve 2 channel amplifier effect, two V3 MONO are needed to connect two speakers. Guided by our mission of "Redefining HiFi with Unmatched Value", Fosi Audio continues to fuel its passion for the Hifi industry, ramp up R&D efforts, and co-create new HiFi equipment with users. We pledge to bring more amazing Hifi gear with high value for the price, innovative design, cutting-edge technology, and premium quality, to audiophiles worldwide.

Item dimensions L x W x H: 5.71 x 4.24 x 1.57 inches


Voltage: 230 volts


Manufacturer: Fosi Audio


Maximum Supply Voltage: 48 volts_of_direct_current


Minimum Supply Voltage: 48 volts_of_direct_current


Voltage: 230 volts


Maximum Supply Voltage: 48 volts_of_direct_current


Minimum Supply Voltage: 48 volts_of_direct_current


Mounting Type: Surface Mount


Number of Channels: 1


Supply Current: 1.04 A


Maximum Output Power: 240 watts


Item Dimensions: 5.71 x 4.24 x 1.57 inches


Material Type: Metal


Specification Met: CE


Manufacturer: Fosi Audio


Model: V3 Mono


Brand Name: Fosi Audio


Number of Items: 1


Warranty Description: 24-month manufacturer


Included Components: Fosi Audio V3 MONO Power Amplifier; 48V/5A Power Supply Unit; User Manual


Item Weight: 750 g


Part Number: un pezzo


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Tuesday, Oct 20

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Top Amazon Reviews

    • Amazing Amp
Review Image by Steven
Review Image by Steven
Review Image by Steven
The four channels of the TPA3255 amp chip are all utilized in a parallel arrangement in this amp. This means the dampening factor on your speakers is x2. If you have a 6ohm speaker this amp sees it as a 12ohm load. Add to this great topology the feedback filter placed at the output stage (PFFB) and you’ve got two unique features above and beyond most class D amps in this price range or higher. It makes for a great sounding powerful amp that can drive just about anything. These can get hot so I immediately replaced the pitiful squirt of thermal compound with Thermal Grizzly Duronaut (which basically performs extremely high without drying out). I then removed the rubber feet from the bottom and strapped on a 150mm aluminum heatsink with a thermal pad between. I then use the amps upside down so the heat goes straight out the top heatsink. Normally it spreads through the bottom and around the enclosure creating a cute little oven for your components. Roll op amps to improve sound, use at least a 48V 5A power supply and Bob’s your uncle ! ... show more
Reviewed in the United States on July 13, 2026 by Steven
    • Quite a Bang for the buck especially Bi Amped
Excellent sound with these mono amps running them with a wiim ultra connecting with xlr connections from rca line out. The amps a very quiet and have a decent sound stage. The speakers are Martin Logan motion 40 and I was able to achieve 92db with no distortion or clipping. Compared them to the Aiyima mono amps and they felt underpowered even with the same TI 3255 chip. Since I wrote the original review I added two more of these Mono Amps to my system . My speakers have two sets of terminals so I I set up a true bi amped system. The amps paired with my Martin Logan sound incredible. The sound is actually amazing with clear definition between high and lows And what amazing low end response, my system has never sound quite this good. Theses Mono amps are connect via xlr inputs . Highly reccomend ... show more
Reviewed in the United States on September 13, 2026 by MauriceN
    • Great sound terrible reliability.
⭐ 1 out of 5 stars Title: Great Sound, Terrible Reliability — Three Failed in 48 Hours I really wanted to like these Fosi amplifiers. In fact, when they were working, I was genuinely impressed with the sound quality. They delivered excellent clarity, strong bass, and plenty of power to drive my SVS Ultra Evolution Titan speakers. Unfortunately, that’s where the good experience ended. I went through three amplifiers, and all three failed. None lasted more than 48 hours. I had to return every single one. I’m not talking about pushing them beyond their limits or modifying anything. I was simply using them as intended in my home stereo system. It’s a real shame because I honestly enjoyed the sound while they worked. But no matter how good an amplifier sounds, it’s worthless if it won’t stay operational. Bottom line: Great sound quality means nothing without reliability. Three failures in such a short period are simply unacceptable. I can’t recommend these amplifiers based on my experience. ... show more
Reviewed in the United States on October 12, 2026 by Mark
    • Solid little amp with great features, but limited power headroom
The Fosi Audio V3 Mono Power Amplifier definitely has its place. It seems it would perform well with small to medium-sized speakers. However, the rated 240W output feels optimistic. I didn’t put it on a scope, but in practical use it seems better suited for lighter loads rather than large, power-hungry subs. I tested it on a 12" in-ground subwoofer and had to set both the amp’s gain and the Sonos sub output to their maximum just to get reasonable movement from the driver. My concern is that this likely pushes the amp’s output stage close to its limits, which could risk long-term strain or even damage. As other have mentioned, this amp gets extremely hot. That said, it’s a great value and serves a useful role as a compact, affordable mono-block amplifier, especially as an add-on to a Sonos system to drive small to medium sub. I’d love to see Fosi release a higher-power version of this amp with the same balanced input options and clean design. Solid little amp with great features, but limited power headroom. ... show more
Reviewed in the United States on October 13, 2025 by Phil
    • Enough Power for a Sub
I am using this to power one 12" subwoofer. I am using it in conjuction with the Rolls subwoofer crossover. This tiny little amp is amazing. The power supply is bigger than the amp. It drives a 12" sealed sub very cleanly to moderate to somewhat loud levels.
Reviewed in the United States on September 1, 2026 by Daniel Bal
    • Impressive performance from such a small foot print.
I wasn't expecting this much from a device like this. I have two 12 infinity subwoofers that are dual voice coiled. My thought was to give these a try in the off chance they can actually push the sub. I tried both 8 and 2 ohm configurations on one subwoofer and I am really impressed. 8 ohm, the subs were happy, I would guess they were getting around 130-140 watts as expected. The damping is impressive with 8 ohms as everything sounded amazing and tight with true accuracy of the sounds it was able to produce. When I tried 2 Ohms, that is when I laughed out loud due to my shock on how much current this thing can produce! I'm not going to say it was crazy but it was truly getting there. I'm not sure if this can double the power at 2 ohms but it did seem to be producing more then 300 Watts RMS with ease. I have a 400 Watt RMS amp and this thing is right up there with it. My plan now is to get 4 of these and pin each amp to a voice coil to provide 480 Watts RMS (240W per voice coil) to each subwoofer. While it performed well at 2 Ohm I feel a 4 Ohm load might be a slight bit better on damping. For the price these things are absolutely amazing, I am now figuring out if I need to run a dedicated 20AMP service for my audio equipment cause these alone will draw 14 Amps when they hit. I'm pretty sure I will trip the circuit breaker on a 15AMP with the rest of my gear if I don't upgrade it. ... show more
Reviewed in the United States on September 15, 2024 by Ross
    • It's worth the money
I like it it's work good with my sub
Reviewed in the United States on September 17, 2026 by Kenneth BraceKenneth Brace
    • It may die suddenly without warning.
Great sounding amp but not reliable in my experience. The first one was DOA, it didn't work at all. I returned it to amazon. The replacement was great, I bought it 4 months ago, I use it to amplify my synths in mono at home, today it's no longer working. I would buy another but being defective 2 for 2 I just don't trust it will be any better. ... show more
Reviewed in the United States on September 5, 2026 by G.Sizemore

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