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.
Arrives
Wednesday, Apr 22
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: 5.71 x 4.24 x 1.57 inches
Voltage: 230 Volts
Manufacturer: Fosi Audio
Maximum Supply Voltage: 48 Volts (DC)
Minimum Supply Voltage: 48 Volts (DC)
Voltage: 230 Volts
Maximum Supply Voltage: 48 Volts (DC)
Minimum Supply Voltage: 48 Volts (DC)
Mounting Type: Surface Mount
Number of Channels: 1
Output Power: 240 Watts
Supply Current: 1.04 Amps
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
Included Components: Fosi Audio V3 MONO Power Amplifier; 48V/5A Power Supply Unit; User Manual
Item Weight: 750 Grams
Warranty Description: 24-month manufacturer
Frequently asked questions
If you place your order now, the estimated arrival date for this product is:
Wednesday, Apr 22
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.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
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Top Amazon Reviews
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.
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Reviewed in the United States on September 15, 2024 by Ross
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!
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Reviewed in the United States on July 18, 2025 by goodtimesroll
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.
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Reviewed in the United States on October 13, 2025 by Phil
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?
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Reviewed in the United States on August 7, 2024 by Mavesard
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
Pros: Sound ok stock. But put some Sparkos SS2602 op amps in it and it sounds very good! So the fact that you can "tune" it with op amps is a huge plus for me. Customer support is ridiculously good!! I had a faulty unit and a few emails and pics etc later they are sending me a new board. Nice bunch of guys also. Very honest about everything! (RARE!) Cons: Power supplies are as large as amp. Speaker outputs are too small for 12 gauge wire, so you have to use banana plugs. (But at least there is that option!) All in all a great (however expensive) upgrade to my 7 speaker porch "Listening room"!!
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Reviewed in the United States on October 31, 2024 by Paxton
I have had this for two weeks and I will update if I find any discrepancies in my review. I am using this on a homemade 10'' floor facing subwoofer that I did not make and I really do not know what speaker is in it but the cabinet and speaker weigh about 70 LBS. My system that I am using is an Onkyo TX-NR727 that has 110 watts per channel. This amplifier works fine and keeps up the volume with the reciever. There is no cutoff/tone or volume adjustment as it just uses what is sent from your receiver or preamp via RCA or balanced XLR jack (I am using an RCA). It took me forty-five minutes to an hour to find the sweet spot that would be good for a variety of music. After a short while, at high volumes, it gets somewhat hot and this is challenging to what I know 'run cool' about Class D amplifiers but since it is small they probably use the case as a heat sink. Since the Sub is floor firing, I do not notice any distortion. The Auto on and off sensing works.
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Reviewed in the United States on January 23, 2026 by SeaCheese