Introduction to the Fosi Audio ZA3 Review
Fosi Audio made a splash with their extremely affordable products. The ZA3 especially caught my attention, as I adore both my headphones and my stereo. Papa loves you equally, stop fighting. It’s been some time since I reviewed anything stereo, so it would be a shame to waste an opportunity like that.
The ZA3 is currently the top integrated amp from Fosi, bettered only by the freshest V3 Mono, which is a single-channel power amplifier. Both use one of the best class-D chips from Texas Instruments, although in different implementations. Back to the ZA3, why it’s so popular? It’s a set of features and final sound quality. A set of features focused on sound quality to be exact. More power than you’ll need. No problems with driving low impedance. Great specs. Looks nice. Sub out. But it doesn’t matter if the sound doesn’t deliver…
Packaging
Everything comes in a blue box. That’s it. It’s a solid box, with hard foam inserts, the same thing as with Topping or SMSL. A proven and budget-friendly solution. Inside, you’ll find the amplifier, power supply, and mains cable. It is as barebones as can be to keep the price low.
The attached manual explains how to connect everything and has a small paragraph about swapping opamps. It is very short and lacks info about recommended types. It shows a picture of a stock NE5532 and a picture of Sparkos SS3602 and explains how to identify pin 1 of an opamp. Nice tip, if you don’t know.
Design and Build Quality
The chassis is all aluminum. The main part is a piece of an extruded sleeve, capped by front and rear panels. The color scheme is dark grey and orange accents: the volume knob and ventilation nets. There is also a variant with a dark grey knob, but I heard it doesn’t sell as well. Guess we all need a bit of color pop in our lives. In the back you’ll find small 2-way binding posts, accepting banana plugs and bare wire. They are really tiny, so I recommend using banana plugs for convenience. All in all the build quality is really good for the price and my biggest complaint for inconvenient speaker connectors is due to size constraints.
Inside, we’ll find a lot of high-quality parts from the biggest brands like Wima, Nippon Chemicon, or Elna. There is absolutely nothing to complain about. Stock opamps are the ol’ reliable NE5532 from Texas Instruments. But that is up to you… For the design portion, I really wish the front stereo/mono switch was moved to the back and replaced by a gain switch. When using the ZA3 in a close field, the gain was sometimes too much. With no remote, it is a primary setting for it.
But then we have to take a look at the whole lineup of Fosi Audio products. And there is a problem. Why in the hell does every single one of them look different and have a different size..? Reviewed Fosi Audio ZA3 looks different than DAC/pre ZD3 which looks different than V3 monos. There is also an LC30 speaker selector that is a useful thing for people like me swapping stuff all the time, which looks different than the rest and has a different form factor than all of the rest. I really wish they had a more unified design, especially devices that are supposed to go together.
Tech
The heart of the Fosi Audio ZA3 is TPA3255, a class D amplifier made by Texas Instruments. For some time it’s been regarded as one of the best amplifiers in its category. It provides a ton of clean power, giving the Fosi Audio ZA3 up to 155W @ 4Ohm per channel with the 48V power supply. With a 32V supply, it goes down to 95W @ 4Ohm per channel. The amp can work in mono mode delivering 235W @ 4Ohm and 110W @ 4Ohm respectively. Impressive numbers for such a small unit, but remember that the power supply is separate and is actually bigger than the amp itself. My version is the 48V one.
The TPA3255 here is used without Post Filter FeedBack (PFFB) technology, which is used in the V3 Mono. This technology offers even lower distortion and lower output impedance, but even without it, we are looking at impressive specs. The ZA3 cites THD < 0,006%, but no information about how it was measured. Inside the amp, you’ll find a rather complex preamplifier with XLR/RCA inputs, sub out and a line stage. Each of those has swappable opamps in DIP8 sockets allowing you to tune the sound to your liking. It is encouraged by Fosi, so go ahead and have fun. I’ll be reviewing the stock configuration with NE5532s, but had some fun with discrete opamps and can tell you it’s fun.
The amplifier has one XLR and one RCA input. The internals aren’t fully balanced and the XLR inputs are handled by a dedicated opamp. Sub out is a very pleasant addition, I have supplemented my KEF LS50 with Audiovector Mi Sub Signature to great effect. Reviewed Fosi AudioZA3 is designed as a barebones amplifier with two inputs. The only option for remote control is the trigger input in the back. It has its ups and downs. On one hand, all of your money goes directly towards performance. On the other, you need to get your ass off the couch to change the volume or source. Which can be tough after a 3rdhot toddy. I really wish Fosi would release a full-sized integrated amp with multiple inputs, phono, DAC, and amp sections like this one. That would be a painful kick in the nuts for fat cats of audio who only annually change the price of their products.
The sound of the reviewed Fosi Audio ZA3
In short, the reviewed amp keeps the sound neutral. It follows the “wire with gain” route. What stands out to me is the amount of detail and control it holds over speakers, even those hard to drive. You might say that the KEF LS50 Meta is not a suitable desktop speaker, but… It was a fantastic-sounding setup. They take a ton of space, yes. They have low sensitivity, yes. Yet they worked beautifully with the ZA3. A really good coaxial driver in close field does wonders both in games and movies.
It replaced the SMSL AO200 MKII in that role. I did some opamp swapping and can confirm that it is absolutely worth it. Sparkos SS3602 and Muzg Audio dual were clear standouts. I would say they helped tested Fosi ZA3 reach the next level of performance. For the review, I’ll stick to stock opamps, to give you the most out of a box impressions. With that much power comes a lot of control.
ZA3 handled a wide variety of speakers with zero issues. Bookshelf, floor standers. Even some ceiling speakers on one occasion. It is noteworthy how well the Fosi Audio ZA3 works with much more expensive equipment. In my experience, it absolutely handles speakers a couple of times more expensive than it is. Thanks to its resolution and cleanliness it can really deliver with really good accompanying equipment.
Bass
Reviewed Fosi Audio ZA3 is clean and powerful. It delivers what is recorded, and adds nothing. I loved how easily it handled every speaker in that regard. Multi-driver Pylon Pearl 27, low impedance and sensitivity KEF LS50 Meta made no difference for this little amp. It has complete control over the drivers. The lows are tight and have really good detail. Listening to Bob Marley’s Buffalo Soldier is a great example of how it handles bass notes: great textures and great extension. Extra power really helps to extract as many low frequencies as possible, even from small speakers.
On the other hand, Pylon Audio Pearl 27 has a lot of bass with a bottom-heavy tuning. I was curious how it will handle contemporary pop with a big, synth bass. So I listened to The Weeknd’s Save Your Tears and I’m happy to report that ZA3 hasn’t allowed the bass to be unnecessarily boomy or loose. It had ample weight and punch, characteristics I look for in this type of music. The dynamics even in larger rooms were unparalleled by the competition. The amount is spot on and it doesn’t bleed on the midrange. Speaking of which…
Midrange
It excels at dynamics and detail. Guitars in Southbound Again by Dire Straits are snappy and engaging. They draw you in instantly. The attack is fast and precise. Mark Knopfler’s vocals are presented a little behind the guitar. This also connects with how the sound staging is built, later on that. If you prefer warmness and richness, then ZA3 is not for you. Here you have a direct, uncoloured sound. You’ll get what you give, both in terms of source material and connected equipment.
Another song I played was No Light No Light by Florence + the Machine Unplugged. It further highlighted the technical and dynamic prowess of this surprising amp. It effortlessly goes from quiet to loud parts, with no loss of fidelity or tonality. The accompanying piano was completely separated and wasn’t influencing the vocals – something that often happens at this price range.
Treble
Is crisp and detailed. Long gone are times when class D had terrible top range. Even without PFFB, the ZA3 delivers excellent results. The cymbals in Bishop School by Yusef Lateef flow freely, nicely and smoothly. I like how clear-cut and separated they are. The precision and control of Fosi ZA3 come back again.
Then I tried something really tough: Bamboche by Jean-Louis Beaumadier. It shows that while in its price range, ZA3 performs really well and often above expectations, it shows its limitation in treble first. While it nimbly tackled the task at hand, it didn’t have the class and detail presented by a more expensive class AB amp. On the other hand, in this price range, it’s mostly class D amps anyway.
Soundstaging
The Fosi ZA3 builds the space in between the speakers, with a surprising reach to both sides. It does struggle a bit with depth. It shows in Take Five from the album Jazz At The Pawnshop by Arne Domnerus.
Precision is on point, with clear sound sources. As mentioned before, it performs really well with width, but due to shallow presentation, it builds a soundstage which is far (between the speakers) and relatively flat as it doesn’t come too close to the listener. On the other hand, its direct competitor does the opposite. It’s narrow but deeper, so pick your poison.
Pairings
Pylon Audio Pearl 27
In my, sadly, short time with those speakers, I found an excellent combo for large rooms. The neutral sound of the Fosi ZA3 compliments this speaker very well. It had more than enough power to fill 40 sqm with full, musical sound. It is one of the nicest combinations I have tried over the months I had the pleasure of using the ZA3. One of the reasons I like to review affordable products is to find gold like that. Why would you buy a 30-year-old amp and speakers on the second-hand market, when you can get this sound for 900 bucks in Europe.
Now, with a warranty, the speakers are made in Poland. Of course, you can go cheaper with second-hand stuff, but still, the value here is insane. The Pearl 27 is neutral in sound and an overall jack of all trades. I know it sounds biased but I can’t find any flaws in this speaker in relation to its price. Solid sound staging, incredible bass capability, musical midrange and pleasant, extended treble. Dynamics? Don’t get me started. Perhaps the enclosure looks a little crude, but don’t let the pictures fool you. It is a solid and aesthetic build through and through. Have the space and budget? It’s a no-brainer.
KEF LS50 Meta + Audiovector Mi Sub Signature
It is a star of my stereo system. I absolutely adore those speakers, especially since I use them both in close fields and normally. Together with the ZA3, they created an exceptional package. Sound completely separated from the speakers, sometimes I would forget they stand in front of me. That worked beautifully in music, games and movies. It also is proof of how capable the ZA3 truly is. It was paired with speakers known for how picky they are about amps.
Low impedance and even lower sensitivity were no problem for Fosi at all. With LS50 Meta, the sound went towards cleanliness and refinement. Sound staging, detail, and resolution all were miles ahead of the Pearl 27, but obviously at the cost of dynamics and bass extension. The latter was fixed with a subwoofer mentioned earlier. This set is perfect for those who value precision, dynamics and open, spacious sound. Yes, with a better amp, it does better, but with ZA3 you get 85-90% off the price of a fancy dinner. If you aim for the stars but don’t have the budget, the ZA3 is a great point of start.
Vienna Acoustic Haydn Grand
Another example of reviewed Fosi Audio ZA3 punching above its weight. It drives them with no effort and it doesn’t feel like “cheap sound” at all. This combo brings a similar amount of detail compared to the previous setup but in a much more pleasant package. Sometimes LS50s can sound strained or sharp. That never happens with Haydn Grand. Sound staging and resolution are still really good. Is it the right pick? Not necessarily.
But if you’re in a situation where you can buy some really good speakers and cannot afford an amp to go with them the ZA3 will come to the rescue. Can those speakers sound better? No question about it, but ZA3 still brought me joy and it allowed me to judge the character of those speakers correctly. Would I like to hear it with something bigger and meaner? Damn right.
Comparisons
SMSL AO200 MKII
This was my go-to desktop amp for quite some time. It served with my KEF LS50 Meta but it was replaced by the Fosi ZA3 due to cleaner and more spacious presentation. It also takes less space on my desk. Still, SMSL is no slouch. It is capable, still powerful, and integrated with more features than Fosi’s ZA3. Depending on your use case it can tilt the scale towards it. A built-in, crappy DAC and a BT receiver can make the deal for some people. EQ and tone control are expected by many customers too. For not-so-critical listening they do fine.
Sound-wise wise they differ a lot. AO200 MKII is the warmer sounding of the two, and noticeably so. It has a bigger, bolder bass, but it doesn’t have the extension of the ZA3. In direct comparison, it also loses some of the detail I got used to with Fosi. The midrange of the SMSL can be a winner for some: more coloured it feels more lush and natural. But then again it lacks the sheer dynamics and resolution of the ZA3. Lastly treble, follows the other two ranges: SMSL has less extension, and less crispness, but is smoother. Depending on your speakers it will, or will not be a pro. Sound staging of the SMSL is more natural as width and depth are relatively the same, while Fosi has a bigger difference between them. SMSL also plays closer to the listener and I know many of you prefer that.
To sum it up, SMSL AO200 MKII has more features and a more pleasant, more forgiving sound. On the other hand, Fosi ZA3 can go much further in overall sound quality but is also more picky. Both are easily recommended but for different reasons. The best type of competition.
Fosi Audio ZA3 Review – Summary
Well, what Fosi ZA3 actually is? It’s an incredibly capable, yet extremely barebones integrated amplifier that has an extremely affordable price. If you’re looking for an amp that won’t add anything and drive everything, you’re golden. This is exactly what it is.
“Wire with gain” sound signature, meaning you get what you give. It handles basically any reasonable speaker in any reasonable room. Even if it isn’t on the performance level of accompanying equipment, it still sounds just good, not cheap or bad. Fantastic way of getting into stereo, or a temporary amp for the future.
For many: first and last amp they’ll buy. If that sounds up your alley, then there isn’t much else on the market that matches the value of this little amp. Kudos to Fosi Audio for bringing this gem. It’s an instant classic.
Highly Recommended!
Big thanks to Fosi Audio and Audeos.pl for providing us with the ZA3 for this review. I wasn’t paid or asked to say anything good or bad about this product, all of the above is just my personal, unbiased opinion.
I can really say “been there, done that” in regard to audio. Designing, building, fixing, reviewing, selling. All of that for big boy stereo. Headphones are something new and fresh for me. We all need something exciting now and then, so join me in my quest of discovering this cool world. We will listen to, drink and WE WILL bring the balance to the force. Oh, I like beer.
