As most reviews state, V3 is a good bang for the buck amp. So, how does it compare to other TPA3255 amps? Well, I have the TI evaluation module and a JLE amp board to compare to. The V3 and TI board have about the same gain level. You need a 1V nominal input at a minimum. The TI is mellower on top but your highs will be dependent on the speaker load with these designs. The bass slam is about the same. The V3 has more punch than the JLE. In short, this amp fares very well and deserves a good power supply. A stout Meanwell 48V unit turned down to 46V will work great.
How does it compare to traditional class AB amps like an Onkyo, Adcom, Rotel, etc. You ask? AB amps with good power supplies like an Onkyo 504 or Adcom 5400 sound more muscular, no doubt about it. However, the Rotels and Adcoms don't sound as clean as the TPA3255 ones I have, perhaps due to matching of 4 to 8 transistors per side in parallel? Not sure but this is readily apparent listening to massed strings and cymbals.
Lastly, I swapped out the stock opamps with opa2134. The sound lost a bit of drive and liveliness. Might be ok for bright speakers but I put the 5532 back. You will go a lot further with a stout power supply than with exotic opamps.

This thing is incredible. I was looking for a compact integrated amp to connect to my Sonos system and drive the speakers in my kitchen ceiling. I wanted something small that would fit in the cabinet above the refrigerator. A friend recommended a "Class D" amp, and after some research, I found the Fosi V3. When it arrived, I was impressed by the weight of the box. This little amp is built like a tank. A very nicely finished, anodized aluminum box and the parts inside must be top-notch because it sounds great. I didn't think I would notice much difference in sound between this and the Audiosource Amp 100 it replaced, but it actually sounds better. There is no noise, the bass is deep and clean, and there's way more volume than I'll ever need in the kitchen. And it's a steal!

I wanted to go small in my sound dept. I bought the Audio Techica AT-LP3XBT, FOSI box3, P3, and V3 and went large with 48v a PS. , All I had were my Bose 301 series ii reflective speakers. They hummed with joy . While the mid was still lost or flat, I was able to bring mid to the front than ever before, almost tolerable.
The bass thumped, tweets were great .I heard stuff in LP's I never could hear before. As you turn up the volume, that is what you get, volume, not blurred noise . My old turntable was MSC 6203 :>( terrible . The Bose are 75 watts @ 8oHms. This little amp did them justice.
I was happy. The only problem I had was the volume knob itself would jump up while increase the sound. but for the price, great return policy and refund I have no complaints. I only wish I could have kept it

Use this to power my Sonny Sscs5 speakers which are 6ohm. I also use a Fosi Audio Box x4 Phono preamp. The X4 preamp has a 3.5mm aux input on the back, to which I use a old LG ThinQ phone that has the QuadDAC inside it and use the phones 3.5 earphone jack to plug into the X4 preamp. Adjust the gain in the X4 to full and Running the Fosi v3 amp at 12 o'clock position results in a nice listening level IMO. Turn the V3 all the way up and stand back!!! The Sony Sscs5 get so super loud and yet still so clear with no apparent distortion, well other than speaker vibrating on the desk they are on as I have yet to get speaker stands and isolation pads. With volume at full power I definitely had to stand back at least 12 feet so I didnt get hearing damage lol. Turning the volume down to 3/4 and it is plenty loud for being in my living room.

Only problem I encountered was the 32v power supply that came with it quit working after one day of use. No problem as Fosi has great customer care. I Emailed them and told them my problem, gave them my Amazon order number and they offered me a replacement supply right away. They also offered me the 48v power supply and asked that I paid the $30 price difference, which isn't too bad of a deal.

If you want clean amp with ample power for your 6 or 8 ohm speakers then go with Fosi. I'm now waiting until their new Za3 amp comes out so I can have a amp with sub out.

I've been listening on this for over a month paired with a behringer UMC404HD (connected to PC via USB) and Klipsch RP-500M II in a small room (10ft by 12ft). I'm playing music directly, not over Bluetooth, from Spotify on very high streaming quality (320kbit/s).

To me it sounds as good or better than the SMSL AO200 I tried for a while (although the v3 doesn't have Bluetooth, EQ, remote, LCD screen, balanced outputs etc... I think most of the extra cost in the pricier class D amps is going to the extra features rather than improving the sound quality, but maybe I'm wrong about that). When I saw Fosi (which seems to be near the top, if not the top, of class D amp brands for quality and reliability) put out a new amp with all newly sourced parts, I couldn't pass up the chance to go minimal and give it a go.

Then I swapped out the two TI NE5532p op amps for the Sparkos SS3602 discrete dual op amps, which was a breeze to do (see attached pictures, I suggest taking off the volume knob, face plate, and using a long allen wrench or skinny screwdriver to lever the IC chips up from below, and the dip socket riser and Sparkos pop right in with hardly any pressure and there is room to spare).

I'd describe the difference as listening to a recording of a concert with the TI NE5532p vs. being at the concert with the Sparkos SS3602 (perhaps that's a bit drastic). How about with the Sparkos SS3602 it sounds like you're at the concert on the stage floor, not sitting in the upper level like the TI NE5532p. Or maybe you're waiting to get into the club and the music sounds really good (TI NE5532p) vs. you're on the club floor being hugged by sound (Sparkos SS3602). That's also probably too drastic. OK, my point is that I noticed a big difference, and I'm very satisfied with the upgrade!

I love the nonlinear volume so I can get just the right volume sitting in near field. RP-500M II have sensitivity of [email protected]/1m, 75W/300W cont/peak at 8 Ohms. I'm usually listening at a distance between 4 to 8ft. I usually set the volume at 33% at 4ft and hit a max of 70dB, which is perfect. With the volume at 66% at 6ft/2m away, max dB is in the low 80s (which is just beyond comfortable for me). At 100% volume, it was maxing out at 88 dB with noticeable distortion (so there's room to spare above 66%, but I will never listen at these volumes). So I feel the v3 for my space and setup is perfect!