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

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.

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!

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.

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?

Been using these for about 6 months and love them. They sound as good as my $4000 Yamaha A-S2100 even though they are Class D. Love these little amps

These little amp pack a punch for their size. I needed an amp in my living room theater setup and decided to go Mono Blocks (just because). I have them connected to a Gustard R26 dac and they’re driving a set of Klipsch Heresy II’s. For giggle I brought them into my listening room to give them a listen. I connected them to my Parasound P6 preamp via XLR and wires them to my Dynaudio Evoke 50 floor standers - wow. They were clean and spot on, and like I said, pack a hell of a punch for their size. I have since lent them to a friend who had a channel in his power amp go out. He’s Driving Magnepans with them, and now seems IN NO RUSH to replace his power amp. Go figure! 😂 I’d definitely recommend them.

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.

I purchased a set of two monoblock amplifiers for a typical 2 channel stereo system. However, as others have pointed out, I also received two different types of power supplies. The specs look the same, 48v at 5A, but different styles, one larger than the other and different power-on indicator lamps, and probably from different vendors. I would expect a matched pair both aesthetically and electronically. Second problem was that one of these two amps doesn’t go into sleep mode when the audio signal isn’t present after time. Third problem is that one amp has a very dim power on LED that’s somewhat difficult to see except in darkness, especially when viewed from an angle. All that said, the audio quality of both amps has been excellent. Yes, as others mentioned they do run quite warm if you push them beyond about 10 watts input. I don’t drive them very hard so heat should not be an issue in my case. But, for a 240 watt capable amplifier, even running in class-D, I think they should have a better, more beefy, finned heat sinks. Nobody wants to listen to fans if we can avoid it. But we don’t want to see our amplifiers burn up and fail either. Again sound quality is excellent. I ended up buying a third amplifier in hopes that it would match one of the two amps I originally bought. It matches the amplifier with the dimmer LED, so I will return the one that had a brighter LED and wasn’t appearing to go into sleep mode. After buying three of these monoblock amplifiers, I concluded that these have either undergone parts revisions or are being manufactured by more than one vendor. Looking closely, I can see the indicator LEDs are of slightly different models, one being noticeably brighter than the other. Same thing with the power supply bricks being physically different sizes but of similar specs electrically. The manufacturer could prevent these inconsistencies by putting a revision number on the box label or changing the model number slightly. Otherwise, you can expect to possibly not receive matching parts. All that aside, they sound great and don’t seem to run too hot as others had mentioned. They get quite warm though, and cooling can be made better simply by putting taller feet on the bottoms for better air circulation. Fosi has a good product, but needs to place more attention to consistency details. I’d gladly take it to 5 stars if quality control was better.