Musical Power Of MonoBlock Delivery – Fosi Audio ZA3 Balanced Stereo Amplifier
Fosi Audio ZA3 is a $175 USD Balanced Stereo Power Amplifier based on the TPA3255 Chip, designed to run either in stereo mode, and act as an integrated amplifier for your stereo setup, or be used in Mono mode, with two ZA3 working together to power up your speakers. Today we will review the ZA3 Balanced Speaker Amplifier and see how they sound and briefly compare them to the market.
Introduction
Fosi Audio has been a real champ when it comes to producing high-quality amplifiers that simply work and sound wonderful for the price paid, having produced countless high-quality units. Right now, Fosi Audio is slowly reaching a level of popularity that starts to look like what FiiO had going a couple of years ago, so it is possible that in the near future we will see Fosi becoming available at the shops of local dealers, right now their products being available on the fosiaudio website, Aliexpress and Amazon.
As an Amazon Influencer, I earn from qualifying purchases, and using the purchase links in my reviews helps me maintain this website and Youtube Channel. Huge thanks to Fosi Audio for providing us with the sample for this review.
Product Link
Amazon – https://amzn.to/42RxwQf
Build Quality/Aesthetics
Fosi Audio ZA3 is a really beautiful-looking amplifier that comes with either an orange or a black volume wheel, and you can purcahse it either with a 48V 5A Power Supply (The variant we are reviewing), or with a 32V 5A power supply, or without a power supply entirely. The inner design has a balanced dual-mode Class D power amplification at the core. To create the best stereo amplifier possible, Fosi Audio based the design of ZA3 on feedback received from customers and fans after the launch of the mighty Fosi Audio V3 that we reviewed in the past.
As ZA3 is based on V3, it improves on every aspect that we liked in the V3, including offering both RCA and XLR inputs, with both Mono and Stereo outputs. We also have a better technical performance for ZA3, including a SNR of 106 dB, THD lower than 0.006%, and a rater power output of 180W x 2 or 235W in Mono mode, for an impedance of 4 OHMs.
To create the sound it has, Fosi Audio ZA3 uses a TI TPA3255 Amplifier Class D Chip, the same that we’ve seen implemented in Fosi Audio MC351, AIYIMA A70, Fosi Audio v3, and a couple of other entry-level amplifiers, at this point Fosi Audio being a great candidate for the best implementer of this chip. As audiophiles all around the globe asked for this, ZA3 comes with much better heat dissipation than V3, having cooling and ventilation on the sides, with dust covers, and you can easily swap the op-amps of the ZA3 for a different sonic signature. Fosi also separate the Analog and Digital parts of the circuit for a better sonic performance.
Including a 12V Trigger interface, I mainly ran ZA3 in Mono mode to get things going, and it also has a Logarithmic Potentiometer to increase the volume quicker towards the end of the volume wheel’s movement, to give you a more precise control for most of the movement. The input list includes both XLR and RCA inputs, and if you don’t purchase it with a power supply, the DC input voltage can vary between 24V and 48V. You can use the ZA3 to power an active subwoofer too, via a banana plug or bare wire, and even an active subwoofer output via the RCA output. The channel used for Mono mode is the right channel.
As the OP-AMP swap is an easy and intended purpose for the ZA3, the company sells a selection of OP-AMPs themselves, including SparkoS SS3602, Burson V7 Classic, Burson V7V or V7 Vivid, MUSES02, and OPA 2134PA.
Subjective Usage
Getting the ZA3 to work is fairly simple, and you can go multiple ways about it too. Used in Stereo Mode it is a brilliant amplifier, but it can run a bit hot, and the channel crosstalk is a bit higher, while used in Mono mode, the channel crosstalk improves considerably, and ZA3 sounds considerably more detailed and cleaner, so for most of my time with them, I used two Fosi Audio ZA3 in mono mode to power my speakers. I also have used the high-power 48V 5A Power Bricks that Fosi Audio created for ZA3, and this combo does not heat up at all for me, both amplifiers and the power bricks being cool to the touch for most of their operation.
To my ears, as long as the DAC has a good quality and low noise, there is no considerable difference between the XLR and RCA input of the ZA3, it sounds brilliant with both inputs, although I did notice that most DACs will sound a bit better over the XLR balanced output. This being said, because I wanted to match the size and shape of the ZA3 with that of the DAC, I have mostly used them via the RCA input, in a combo together with Shanling EH2, Dethonray Listening M1, Fosi Audio ZD3, HIFIMAN EF500. There is no audible background noise with any of those DACs, and you can run ZA3 in either mono mode or stereo mode easily, and if you want to set the volume at maximum you can, but I found that using the volume and setting it at about half gives me more and better control of the volume, so I mostly have used the ZA3 this way.
Fosi made sure that the cables of the power bricks are long enough for a comfortable usage, which I like a lot, and the power bricks themselves have a much higher quality than those of Topping B100, which has power bricks of a lower power and which feel more hollow inside. I noticed no disadvantage for ZA3, everything works really well, and my time with them has been excellent. If anything, you should consider that while in my photos they are always stacked on top of each other, this can overheat both units, if you live in a hot environment, and if you run them loud, but in my situation, even after having the amplifiers turned on and playing for almost an entire week, with the two stacked on top of each other, I detected no overheating, and at most they are warm to the touch.
Sound Quality
Pairings – Testing the ZA3 is easy as we now have both floorstanding and bookshelf speakers, and I have combined the amplifiers with Audience ClairAudient 1+1 V5, Pylon Audio Diamond 30 mkii, KLH Model Five, and NHT C3 for speakers. The power is plenty for all the speakers tested, the sound is excellent with all speakers, control is very good. The Class D typical signature is far less audible with ZA3 than with other AMPs I tested in the past that have a Class D Amplification and which use the same OP-AMP Chip.
Overall Signature – Fosi Audio ZA3 is a sweet, slightly mid centric, sounding amplifier, with a musical midrange, smooth textures, but excellent extension both ways. Bass is on the slower side, but large and warm, while treble is sharp, detailed and crisp, and the soundstage is on the natural side, but with an extreme amount of channel separation and instrument definition.
Bass – We start with the low-end which is warm, slow and big. This creates a nice sensation of warmth and depth. The speaker extension will be more relevant, but with Pylon Audio Diamond 30 mkii, the extension is excellent, the low-end can reach in the sub-bass nicely. This being said, most energy is in the mid bass and ZA3, at least with the default op-amps, has a warm and softer tuning.
Midrange – Vocal presentation is sweet, smooth and slightly soft, emphasizing both male and female voices equally. ZA3 is remarkably musical and full sounding, creating a warm, and pleasing signature. The sweet and gentle presentation takes away the edge in most music, so even bright and sharp sounding speakers will relax a bit, and ZA3 is simply enjoyable with all music styles, but more so with pop, cabaret, and softer sounding styles.
Treble – Although the textures are soft and gentle, ZA3 has a sharp and bright treble with a strong extension that can easily reach 20 kHz with the right speakers. In fact, with Elipson Heritage XLS 7 I have to set the treble to Ref or -2dB for rock and metal music, but I like the air and sharpness with the treble set to + 2dB when listening to pop and electronic music. Overall, the excellent treble extension combined with a softer treble makes up for a really fun listening experience.
Loudness Saturation Gradient – Now this is interesting, because there’s multiple aspects to how ZA3 handles volume, and starting with the most obvious one, the volume wheel has no impact on the sound, and you can use either ZA3 or a DAC to set the volume without any loss in sonic quality. But the more interesting aspect about the volume comes from how the volume wheel allows you to fine tune the volume at lower volumes, which is where you’re most likely to be using ZA3, as while headphones are generally to be listened loud, most people cannot pump 110dB on a pair of speakers on a daily basis. The other aspect is the actual volume control, which is perfect and ZA3 sounds as clean, crisp and clear at low volumes as it does up near max loudness, but the sound becomes more compressed dynamically as you approach extreme volumes, and the treble becomes brighter, while textures get harder if you go louder with ZA3.
Dynamics Handling – We get a dynamic, punchy and colorful sound with ZA3, as it manages to produce a really punchy and colorful sound that is far less compressed than what most Class D Amplifiers produce. I love this approach, as it brings ZA3 closer to what a class AB or B amplifier sounds like despite having the efficiency and low power consumption we see with Class D AMPs.
PRaT / Textures – As with most Fosi Audio AMPs / Devices, we get a smoother texture that’s gentle and soft. This emphasizes nicely with all music styles and creates a pleasing listening experience that takes the edge off from rock and metal, without removing the details.
Soundstage – In the soundstage is where ZA3 really excels, especially when used in 2 x Mono mode, because here it creates a really strong channel separation and layering with outstanding lateral projection. There is a clear favoritism for lateral separation over depth, but even so depth is impressive and ZA3 sounds impressive regardless of the price range.
Value and Conclusion
You can’t miss the price factor when considering a Fosi Audio product, as they always keep the lowest prices possible for their products and ZA3 is no exception, it offers a monoblock performance better than what you hear at double the price, with literally no sacrifice at any single point, but what’s even better is that you can even fine tune and customize it by replacing the default op-amps, and even use a single AMP as stereo, or buy three, one for each stereo speaker you have, and one for your passive subwoofer. The possibilities are countless, but the affordable price point makes ZA3 one of the easiest to recommend stereo amplifiers in the entry-level range for an effective way to amplify a system, both entry-level and even some better speakers being easily drivable out of ZA3.
At the end of the day, Fosi Audio ZA3 is not a cheap product by any means, and the company keeps offering better and better products for the same low prices that keep our wallets safe and allow us to enjoy more hobbies and get even better bang for the buck, and if you’re looking for a stereo power amplifier, or set of monoblocks that can drive both floorstanding and bookshelf speakers with ease, if you want a warm, musical sound that has exceptional channel separation and if you like tinkering with your devices and the idea of op-amp rolling entices you, Fosi Audio ZA3 will be the perfect amplifier for you.
PROs
- High Driving Power
- No Self Noise
- No Background Noise
- Balanced XLR and Single Ended RCA inputs
- It includes both a mono and a stereo mode
- Excellent volume control
- Does Not Get Hot
- Easy setup and configuration
- Beautiful Design
- Easy to swap OP-AMPs
- Excellent Price / Performance Ratio.
Cons
- Nothing noteworthy at this price point.
Product Link
Amazon – https://amzn.to/42RxwQf
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Full Playlist used for this review
We listened to more songs than those named in this playlist, but those are excellent for identifying a sonic signature. I recommend trying most of the songs from this playlist, especially if you’re searching for new music! The playlists are different for Spotify, Tidal and Youtube, and based on the songs I enjoy and are available on each!
https://www.youtube.com/playlist?list=PL_cjBXGmwSHSdGcwuc_bKbBDGHL4QvYBu
https://open.spotify.com/playlist/5J3oloz8Riy9LxEGenOjQ0?si=979ba4f082414be7
https://tidal.com/browse/playlist/330fd544-8e5b-4839-bd35-676b2edbb3d5
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