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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

  • Based on 244 reviews
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Availability: In Stock.
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Arrives Friday, Jan 9
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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.

Item dimensions L x W x H: 5.59 x 4.2 x 1.61 inches


Voltage: 230 Volts


Manufacturer: Fosi Audio


Maximum Supply Voltage: 48 Volts (DC)


Minimum Supply Voltage: 48 Volts (DC)


Item dimensions L x W x H: 5.59 x 4.2 x 1.61 inches


Voltage: 230 Volts


Manufacturer: Fosi Audio


Maximum Supply Voltage: 48 Volts (DC)


Minimum Supply Voltage: 48 Volts (DC)


Mounting Type: Surface Mount


Brand: Fosi Audio


Number of Channels: 1


Output Power: 240 Watts


Specification Met: CE


Supply Current: 1.04 Amps


Material: Metal


Product Dimensions: 5.59 x 4.2 x 1.61 inches


Item Weight: 1.65 pounds


Item model number: V3 Mono


Date First Available: July 10, 2024


Language: English


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Friday, Jan 9

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Top Amazon Reviews


  • great class d amp for the money
great class d amp for the money. Able to power magnepan .7 without issues. quiet, accurate. This is a monoblock amp, if you run L+R you need two. only has XLR or RCA inputs, no volume control, so you need a preamp that can control volume to line out. Can get a bit warm to the touch (40 oC)
Reviewed in the United States on August 18, 2025 by Whatevs

  • Great Monoblock Power and A Nice Way to Upgrade Your Home Theater
I first encountered the Fosi monoblock V3 for use in a music-only system and was blown away by its transparent sound and high power for such a tiny box at such a low price. I began to think about deploying more of them as a possible upgrade for an older (but top of the line) Onkyo Dolby Atmos AVR in a 5.1.2 Atmos layout, using the Onkyo's preamp outputs rather than the internal amps. So far I have installed 3 of them, powering the from L & R and the Center Channel. As I expected. everything sounds better. The sound is more detailed and accurate, imaging is more precise, dialog emerges more clearly from other soundtrack elements. I look forward to soon adding more V3's to complete the surround channels and the height speakers, but the listening experience is already so impressively improved. The way these amps power on and off based on detection of signal has functioned perfectly with no delays, popping sounds or any other negative aspect. They just work. I was always pleased and proud of the high fidelity of my AVR, but this has been an extremely high value upgrade that has put it into a whole other category. HIGHLY recommended! ... show more
Reviewed in the United States on July 18, 2025 by goodtimesroll

  • 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

  • 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

  • Great personal stage monitor amp
Great stage monitor amp originating from mic level output
Reviewed in the United States on October 26, 2025 by Clee22

  • Ordered 3, one was defective
1 out of 3 was defective , it powers on but no sound. The remaining two work great, they do seem a bit too hot. As long as it doesn’t break in next some years, nor interfere with the sound heat doesn’t bother me. One thing to note there is much louder sound when I use RCA input vs XLR I had to add +9 db on my receiver for same volume. Also there is a some noise when using RCA to RCA, XLR has almost no noise. My receiver unfortunately doesn’t have XLR output, I just use RCA to XLR cable. Works great, no interference noise, only downside is I have to +9db on a receiver. I hear lots of people adding Sparkos OP amps. Is it worth it I wonder? ... show more
Reviewed in the United States on August 7, 2024 by Mavesard

  • It was supossed to be new and got one in a really horrible shape, not only used but abused
Got two these working as L, R, with a denon avr, feeding a pair of kef r3 and they are amazing, really clean and effortless sound, they get a little on the warmer side but my x3800h is even hotter to the touch than the v3 mono, the standby wake up option works every time. 10/10
Reviewed in the United States on July 24, 2025 by Jose

  • Excelente, pero...
Pedirle mas sería totalmente injusto por este precio, es muy transparente, la zona alta la reproduce muy, pero muy bien... y la zona de graves es seca, da golpes secos y claros... totalmente satisfecho con el rendimiento.! Pero hay un detalle que acabo de confirmar, la polaridad esta invertida, al usarlo con el denon 4800H y calibrarlo me envio el mensaje de polaridad invertida, intercambie los cables y se soluciono... pero esto no esta bien, y ya compre 2 y los dos estan invertidos, tengo un tercero en camino y nose si vendra invertido tambien. Fosi por favor enviame con la polaridad correcta, no invertida! Necesito cambiar los dos que ya llegaron con esa falla de polaridad..! Y llego el tercer Fosi...y que creen? Sí, tambien llego con la polaridad invertida y con otro color...que ahora es negro intenso, los anteriores eran negros tambien pero tirando hacia el grisaceo. ... show more
Reviewed in the United States on August 27, 2024 by eddy manosalva villavicencio

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