Fosi AudioV3 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 (1)

Wasn't sure if these were going to be a 4 or 5 star review. As other commentators have said, they do run hot; burning hot, over 60C. They sit at 40C in standby. I worry about the heat affecting electrolytic capacitor lifespan.I bought four for my bi-amping project, (I was replacing my 4 channel 3886 hybrid 'scraplifier') and the quiescent current draw must have been enormous.So, on advice, I replaced the 48v psu (x4) with a 32v psu (x4).It added an extra hundred quid to the project, but I was eight hundred in to it by now, so it seemed rude not to.And, WOW, I'm still producing 100w (x4) into 8 ohms. And with a usb dac, everything reaches FSD (full volume) at the same point.And now they run 'cool' at about 40C in-use and just above room temp in standby.Sound? Acoustically invisible.Confidence? Much better.Value for money?...Well, it works for me. You'll have to decide for yourself. Four and a half stars.

I bought 4 of these Fosi v3 monoblocks with 2 x 48volt/10amp power supply units. They are being used to drive Tannoy XT8F revolution tower speakers in a vertical mono/bi-amp mode ( i.e. each speaker is connected to 2 monoblocks with a shared PSU ).After an initial 24 hour burn in, they opened up to produce a wonderfully transparent, dynamic and powerful sound. The treble is clean without edge or grain, the midrange is very clear with excellent low level detail resolution and the bass is well controlled, defined, extended and surprisingly hard hitting. The overall tonal balance is quite neutral with just a hint of treble forwardness.The Fosi v3 small form factor, belies its capability when producing a very large soundstage with terrific focus on, and the space between, the musical elements within it. Plus the stereo imagery is precise with good centre focus, coherence and decent depth.I was originally sceptical about the V3 mnbks when I heard, read and saw ( on You tube ) the rave reviews about them. Now I have confirmed for myself, their exceptional performance for the money.Compared to my 2 other, much more expensive power amps, from Marantz and Emotiva, they more than hold their own.Highly recommended.Additional information:- Everything said about the v3 monoblocks remains the same, ( if anything they're even better sounding than when they were first reviewed, due to slightly less treble forwardness ). However they do become hot during use.Therefore I recommend using a low noise fan ( if you can't put them on/in a well ventilated shelf/cabinet ). DON'T stack them on top of each other without adding feet to separate them.

Amazing power from tiny monobloc amplifiers.Paired with DZ3 sounds great.They do run hot though. I have them sat on a AC Infinity aircom S7.

These amps sound fantastic, loads of presence and power at lower volume, exactly what I wanted.However, presumably to keep costs down, they require external power supplies and suffer from a serious design flaw - overheating. Putting aside the PSU issue which I could live with, the cases are just not adequate for dissipating heat, I've never come across class D amps which run so hot. This is surely going to limit the life of the units and means that they need to be very well ventilated, this is just not practical.A real shame as they are sonically the absolute shiznit for the money. If a redesign cures the heat issues, I'll certainly reconsider.

Brilliant performance at budget prices.

I replaced my old Rotel power amps for these monos, and they are absolutely fantastic. Running a pair of Monitor Audio Gold Signatures, I had high expectations and they exceeded them.Immense imaging, clarity and a big full bodied sound. Bigger brands should be very worried...Bravo Fosi Audio.

Brings a whole new dimension to the word hifi,

I bought a pair of these micro Mono powerblock amps on the recommendation of numerous online reviews.They do sound great but get worryingly hot after a couple of hours of fairly quiet listening on my KEF R300 speakers.I decided to return them as I was concerned about the heat generated by the amps.