V1.0G

AN UPDATE: I liked this tiny amplifier so much that I bought a second one for my office computer. Previously, my main computer used a Lepai LP-2020A+ driving a set of decent bookshelf speakers, and my office computer used a set of cheap USB active speakers. Later I bought the first Fosi to replace the Lepai on my main computer system, and it worked out beautifully (see the ORIGINAL REVIEW below). I decided I would use the Lepai on my office computer, and for that, I bought a set of Polk Audio T15, which are probably the cheapest slightly "serious" bookshelf speakers but should be far better than those cheap USB speakers. But within minutes of setting up the system, I felt terrible. It's not that the Lepai LP-2020A+ with the Polk Audio sounded worse than the cheap USB speakers. On the contrary, they were noticeably better. The trouble was that I started to compare the office sound with my main computer system sound, and I just couldn't help it. This is what happens when you get into a better system. It spoils you. On the office system with Lepai, everything sounded so hollow and distorted, especially the vocals and human voice recordings (not singing), which was so bad that I couldn't stand. It was painful. At first I thought it might be the Polk Audio T15s, but then I suspected it was something else, including the built-in line output, etc. Speculating all kinds of diagnostic possibilities was driving me crazy. Finally, I just gave in and bought a second Fosi, with a good DAC, planning to return the Polk Audio T15s for something better as well. Well, the Fosi and DAC came in, and I connected them to the computer and the Polk Audio T15s. What an improvement! Clearly, the Polk Audio T15s are fine (although not great). The culprit was the Lepai LP-2020A+ amplifier, as the Fosi made a huge difference. The following is the original review I wrote after about the first Fosi: ORIGINAL REVIEW: Unbelievable value for a small desktop setup or computer sound system. Everything is perfect. The sound, the functions, the build quality, and the appearance. This replaced my seven-year-old Lepai LP-2020A+, which actually had quite good sound on my computer sound system as well, but left me wanting a bit more. One of the obvious issues with Lepai was the highly noticeable noise floor when the volume is turned past 50%. Although I seldom turn the volume past 50%, the limitation is bothersome. After seeing some reviews on the TI TPA3116D2 chip, I decided to upgrade, to just give me a bit more peace of mind. And I am very satisfied. The Fosi sounds great. To be honest, I did not do a side-by-side comparison with the Lepai, but I am pretty sure Fosi delivers cleaner and fuller sound. The noise floor is much lower. It is quite low even if you turn the volume all the way up to the maximum. On my desktop speakers, I can hear no noise when the volume is below 30%. Once it passes the 30% level, the noise floor steps up abruptly, but strangely enough, it stays quite flat after that and does not further increase too much even if you turn the volume all the way to 100%. Even at the maximum level, the noise is only slightly noticeable when I sit about five feet away from the speakers. This is a near-field environment, and I'm fairly picky about the noise, but still, this is completely manageable. A day-and-night difference compared to Lepai LP-2020A+. Fosi comes with a rather large power supply, which may seem unnecessarily large, but is necessary for its 50W x2 power rating. When it comes to power, you simply don't have any way to cheat. For example, having a 30 W power supply for 50 W x2 = 100 W amplifier will inevitably lead to insufficient amplification and distortion at higher volumes. Also, the fact that Fosi has five-way binder posts for speaker connectors is a plus, much better than Lepai's primitive clippers. I did hesitate in choosing between the Fosi (this unit) and Micca OriGain A250 or OriGain AD250. OriGain A250 is $20 more expensive, not a lot in the dollar amount, but one-third (33%) more in relative terms, which becomes a matter of principle, if not affordability. Still, I almost got OriGain A250 instead of Fosi V1.0 because the A250 has slightly better user review ranking, and I desired peace of mind. But then I saw reviews that mentioned OriGain A250's having heavy bias on the left channel at low volume level. That bothered me as I usually listen to background music at quite low volume levels. OriGain AD250 had its own attractions because it had a built-in ADC and USB sound input. However, in the end, I decided not to go that route because integrating ADC may appear convenient now but could be an invitation for trouble further down the road. What if the built-in ADC develops problems? (I did see one reviewer mentioning OriGain AD250's built-in ADC has a signal synchronization problem). Or what if you want to upgrade ADC? Etc. Anyway, I'm glad I settled on the Fosi. It leaves me wanting nothing more for my computer-based desktop system.

The Fosi Audio V1.0G is a fantastic little Class D amplifier. I was genuinely impressed with how well it performs for its size and price. I paired it with some very efficient speakers and a separate phono stage for my daughter’s record player, and it turned out to be exactly what we needed. The sound quality is clean and surprisingly full. It delivers more than enough power for a small to medium room when paired with efficient speakers, and it does so without distortion or harshness. The simplicity of the 2-channel design is a big plus here — no unnecessary features, just volume control and solid amplification. For a compact amp, it feels well put together and runs cool. This is a great option for turntables (with a phono preamp), desktop audio, or any simple stereo setup where you want good sound without spending a lot of money or taking up much space. For the price, it punches well above its weight. TL;DR: Excellent small Class D amp with clean sound and plenty of power for efficient speakers. Simple, affordable, and perfect for a basic 2-channel or turntable setup.

So, I bought this little unit in 2020… 4 whole years ago… and finally found the time and the need to use it. Boy am I pleasantly surprised. Paired with my various Klipsch speakers (mostly using my giant corner horns at the moment), this amp sounds amazing. It really does. And I'm quite nitpicky when it comes to sound quality. I'm used to various amps, including vintage Sansui, Marantz, Kenwood receivers and vintage and newer Mcintosh, which all sound different. I'm using an (too expensive) ADI 2 Pro DAC converter that has phenomenal sound reproduction characteristics, so if the end result is anything less than great, it's this little amps fault. I'm glad to say that it sounds very crisp and clean, very much like the Sansui AU-919, which was designed to provide very faithful reproduction of the original music. In fact, it sounds just as good as my AU-919. It is the exact opposite of the "warm tube amp" sound, similar to the sound that Marantz and Macintosh amps are known for. If that's the sound you're looking for, this isn't the amp. You could use a preamp to tweak the sound, if you wanted to, I suppose. The most important thing to remember is that this amp is "only" 50 W, so the more efficient your speakers, the better the sound is going to be. Klipsch speakers can get very loud with just a couple of watts of power. I have a 17 W tube amp and I can't turn the volume more than 50% or the sound will be so loud it's unbearable. So 50 W for my speakers is more than enough. If you have speakers that NEED 50 W, you probably will need something more powerful… and there are different models of this amp that will work better for you. This amp would be perfect with a surround sound system… One amp for each channel. Now that I know how well this unit works, I will definitely be buying a couple of more of them to add additional speaker pairs. I've seen some others say that their unit gets really hot. Mine doesn't… not at all. Probably because I'm not using all 50 W. This goes back to pairing it with the right speakers. I set the volume on the amp to 50% and then adjust the input to get additional volume. If you are having to run the volume on the amp at 100% all the time, you definitely need an amp with more power… 100 W or more.

Works ok. No hiss or buzzing. But a very annoying POP when it powers on.

Took a gamble on a brand not well known in audio and for $50 my gamble was well worth it! I use it as an amplifier from my vinyl record player to my two bookshelf speakers, and i couldn’t have been more impressed with the ease of use and sound quality i got from it. As I’m relatively new to vinyl listening, I needed something small that went from rca to speaker wire, and I didn’t really care for all the bass treble stuff. As cool as it would be in the future, more moving parts leads to more ways to failure. So i fell on this little guy. Very solid and not cheap feeling, and nice rubber feet on the bottom to keep it from sliding around. Volume knob and the on and off switch feel nice. The speaker wire outputs support banana plugs, which is a nice to have. Theres not a lot to say about it besides that it works wonderfully at the moment, hopefully time proves to be fruitful.

With some repurposed used home theater speakers, this thing provides a FANTASTIC solution for home office desktop sound! It has more than enough power to drive efficient home theater speakers LOUDLY with volume knob barely cracked. Which is, actually, my only minor complaint-- this knob almost seems linear, rather than logarithmic. I only wind up turning it through about 15 degrees to go from off to blasting-- but it does so smoothly and cleanly. I am not willing to see "how loud" it will go-- both these speakers and this amplifier are game for more than I am. I have two old BIC Venturi surround-sound speakers that I use for near-field monitoring. These are findable on eBay and thrift stores from time to time-- and they are EXCELLENT. I had been driving four of them with a big ELAC center channel... as... a videoconferencing setup. The idea was that I could be anywhere in my office and still get good audio. Anyway, long story short, it was total overkill, took up a ton of room, and was a wiring nightmare. Now I have the Venturis hooked up to this amp, running off a Focusrite Scarlett USB audio interface, itself on a USB switch connected to multiple machines. Whatever I'm on now has amazing sound, and I have a ton of room back and far less cable management. The amplifier itself is TINY, fits under my monitor, and doesn't even get warm. This new generation of power amplifiers is really something else-- >90dB SnR, etc. Phenomenally clean sound with a good audio source. Literally so transparent there is no point in turning it off when you're not playing something. I can't believe this thing is $50. Sometimes I really love living in the future!

Works like a charm, just what I needed. It was a replacement for the old one.

WOW, One song into testing it in my studio; "Yulunga (Sprit Dance)", Wake - "Dead Can Dance" album. I am blown away. I have a pair of old Cambridge Soundworks, Ensemble III, speakers that I use as studio monitors that ran through an old amp that gave out last week after some 50 years. They sounded great on the old amp and sound even better through this mini power amplifier. The sound coming out of this tiny amp through these tiny speakers compares nicely to the HiFi sound coming from the bi-amped Clayton Shaw speakers in my living room. Very impressive, at the price I'd say unbeatable. And, I've been listening to, reviewing and recording music for decades, this amp is very accurate and very quiet. You hear what is there, nothing more, nothing less. It makes me wonder what their more costly amps sound like.

Compact, simple, faceile à installer, de bonne qualité, cet ampli fait le job : bonne qualité audio, assez puissant pour un living, fonctionnement durable dans le temps. Il est branché sur mon ordi avec des enceintes 3 voies depuis 2 ans sans souci et fonctionne tous les jours de longues heures !

Great little amp for. Good price too. Looks nice. Quality is good. Easy enough to carry around as part of a kit, but also good for installs. Audio sounded fine, no distortions

Prima

Lo usé para mejorar el audio de una pantalla

Die Endstufe meines Magnat MC 200 hat nach 5 Jahren den Geist aufgegeben und die Reparatur (Einsenden, Reparieren etc.) war mir zu teuer. Daher habe ich an die Kopfhörerausgangplatine einen Chinch-Anschluss gelötet und gehe mit dem Ausgangssignal an den Line in Port des Fosi Mini-Verstärkers. Aufgrund des gelöteten Anschlusses wird die Bass-Box nicht ausgeschaltet, d.h. der Sound bleibt rund. Die Bedienbarkeit wie Lautstärke, Bass, Treble und Balance des Magnat-Verstärkers bleiben hierdurch erhalten. Die Lautstärke des Fosi wird fest eingestellt und alles andere regelt der Magnat-Verstärker. Der Fosi ist an Canton Mini-Boxen angeschlossen und hat einen zufriedenstellenden Klang. Wenn der Fosi über Cut-Off -Leiste angeschaltet wird, produziert er ein unangenehmes Knacken. Daher sollte man den Fosi über seinen On-Off Schalter bedienen.