Fosi Audio ZA3 Balanced Stereo Amplifier Home Audio Component Mini 2 Channel Mono Amp TPA3255 for Subwoofer Desktop Home Theater Bookshelf Tower Floorstanding Passive Speakers with 48V Power Supply

I bought a pair of these as an experiment to see what a "class D" amp sounds like. I had always assumed they would be shrill and sterile sounding. After listening to the 2, paired with a WiiM Ultra Preamp/Streamer, my opinion has changed. The sound is fantastic with good sound stage, decent low and high end. Kind of cool that you can turn these on via a 12 volt trigger cable and thats exactly what I do. I'm extremely happy with them and for the price, they can't be beat.

As the headline says: I love it!I have this hooked up for my computer in my office. It is attached to a couple of older JBL Studio monitors and it sounds fantastic! I've ran these particular speakers with amplifiers in the past and have found them difficult to properly power, but this little amplifier makes them sound clear, clean, and powerful. I had forgotten how good these speakers really were until attaching this amplifier to them.Currently, I'm just using this amplifier in stereo (no LFE out used) and signal is via RCA connector. So, the fact that it sounds this clean with the RCA's is really a boon to the setup.I'm very happy with this little amplifier and plan to purchase more of them in the future!

This small amplifier is well designed and good value for the money with connectivity for many options.It is ideal for anyone needing a small desktop or bedroom amp especially.For music sound quality you would be better served by buying the entry level receiver from Yamaha.These small amps just can’t compete with the much larger integrated or power amps with transformers and larger capacitors for music listening .That said,I am keeping this as it works well and think the Fosi people did a good job and may use it with my TelevisionThe ZA3 has a very clear sound with defined left and right separation, and a very shallow depth soundstage that is noticeableBass is lean but there, just not much authority.The ZA3 may work best in conjunction with a preamp as at low volumes the potentiometer is touchy

After a brief hiccup with only one channel playing in mono mode, thanks to Crystal on the chat line, both amps are working beautifully (use only the red input on each amp when in mono mode).At around three hundred dollars for two amps and two 48 volt power supplies, this is hard to beat. Some reviewers question the advertised power ratings but my Maggie LRS and Emotiva B2 do not give a crap. They play clean, open and loud with audible improvement in channel separation with these amps.Cheers to Fosi Audio for hearing their customers and making this hobby fun and affordable.

I bought a pair and I am very happy. I used them in my work shop to power some Paradigm bookshelf speakers. I previously had a Fosi Audio V3. The new amps excel in every area and have lots of power reserve. The detail and soundstage is greatly improved along with more heft and body to the presentation. I have been running them 24/7 for a week o burn them in. The sound has improved. I have not tried XLR connections yet. The no run very cool in my application. The speaker binding posts are a joke. I run banana plugs so it is tolerable when running as a monoblock. I am looking forward to trying them on other systems in the house.

I ordered a Fosi ZA3 from Amazon this past Wednesday and it arrived yesterday morning. Upon unboxing the nicely packed amp and 48V-5A power supply, both pieces were ice cold, so I had to allow for everything to warm up to room temperature before powering anything on.I connected the ZA3 amp to my Audio Research LS7 tube line stage, and played back tracks through my Raspberry Pi 4 running Volumio 3 connected to an SMSL SU-9 V. 2 DAC. Over a period of 2-3 hours, I could hear the sound signature changing from a bright, etched sound with narrow image and small soundstage to a warmer, full-bodied sound whose soundstage expanded beyond the outer boundaries of my modified Klipsch Forte 2 speakers. The image projected slightly in front of the speakers to behind them and grew in height. I could feel the bass lines coming through the floor and felt the impact of some deep notes through the air. With the Klipsch speaker efficiency rated at 98dB, I found myself dialing the volume down a couple steps as the amp burned in.A friend recommended leaving the ZA3 powered on, so I left it on all night with the volume turned all the way down. When I spun some vinyl the next day, I was really impressed with the scale of the soundstage compared to what I heard the previous day. The music has a really solid foundation in terms of imaging and separation. The musicians all have their place in the soundstage, and the tonality is very rich. This amp digs more deeply in the lower bass compared to my Pass DIY Sony VFET Class A amp and the McIntosh MC-240. It’s very dynamic with nice, sustained notes. It’s crazy how great this amp sounds for the $130 I spent on it.In the last photo, the Fosi ZA3 is sitting on top of a Pass DIY Sony VFET push-pull single-ended Class A amp I built several years ago. Next to that is a McIntosh MC-240 tube amp I had rebuilt with new power supply and coupling caps. Over the next several days while I have time off from work, I will compare these amps using my analog set-up, and the above-mentioned digital source:- Technics SL-1200GR- Audio Technica AT33/PTG II LOMC cartridge- Audio Research PH5 tube phono stage - single-ended connectionI split my time between two homes for my work. At my other home--an apartment--I plan to take this amp and try it out in the system there:- Bill Neumann (Fix My Dual) rebuilt Dual 1229 idler wheel-drive turntable- Shure V15 Type III MM cartridge- Schiit Mani 2 phono stage preamp - single-ended connection- Raspberry Pi4 running Volumio 3 USB-based streaming source- Denafrips Pontus 2 R2R DAC - balanced connection- Schiit Freya Tube/SS line stage with OS GE 6SN7's with side-getters (gain stage) and Tung Sol 6SN7's (driver stage) - balanced connection- Pass DIY Aleph J Single-Ended Class A power amp - balanced connection- KEF LS50 speakersIt's with this system that I am most interested in trying the Fosi ZA3 with balanced connections driving the less efficient KEF LS50 speakers. The Copper accents on the Fosi ought to coordinate well with the Copper-colored drivers on my KEF's.I've ordered some op amps from Fosi Audio to try out as well:- Texas Instruments OPA2134- Nisshinbo MUSES02