Two years have passed since its introduction, but the Fosi Audio ZA3 remains one of the best-selling amplifiers in the sub-$200 range – and that’s for good reason. The ZA3 is a direct evolution of the already-amazing Fosi Audio V3 and it offers fantastic sound quality in a similarly small, desktop-friendly package while also adding quite a bit of flexibility through highly-requested features like a mono mode, balanced input, subwoofer output and 12 V trigger input.
Disclaimer: I got a free unit directly from Fosi Audio for the purpose of writing this review. The ZA3 retails for $139.99 with no PSU, $159.99 with a 32 V/5 A PSU, or 199.99$ with a 48 V/5 A PSU. Additional information on Fosi’s website.
TL;DR: recap
| Pros |
Cons |
| + Compact
+ Large power output + Neutral sound signature + Mono mode + Balanced input through both XLR and 6.3 mm jack + Loads of features |
– Nothing to report |
Rating: 10/10
Packaging & Accessories
Fosi Audio ships the ZA3 with no accessories, as it only comes with the power supply and a manual. As mentioned in the disclaimer section, the ZA3 is sold in three versions: entirely without a PSU, with a 32 V PSU or with a 48 V one (which is the version I received).
Design & Build
Fosi Audio’s Z line-up includes various devices, all with the same design language: a black metal chassis and an orange volume knob. This applies to the Fosi Audio ZA3, too: its chassis has the same shape as the other devices, too, which means that it has a large groove in the middle on the bottom – or, conversely, there are two protrusions to the sides which act like feet on which the device rests.
The chassis is a single piece of aluminium, with the front and back secured to it with screws. It is remarkably well manufactured, with very tight tolerances that make it look like all pieces fit perfectly together.
The front is designed to be symmetrical: the large volume knob sits perfectly in the middle, and to its side are two physical switches to select input (RCA/XLR) and operation mode (mono or stereo). The ZA3 is entirely analogue, in the sense that there are no screens nor remote controls – it is completely operated by hand. The only non-symmetrical element on the front is the power LED, which is between the input switch and the volume knob; it is orange, in keeping with the general design theme (and a real classy touch, if I may add).
On the back side we find the XLR and RCA inputs, a subwoofer output, the speaker outputs (which take both banana plugs and bare wires), the 12 V trigger input and the power connector.
The volume knob uses a logarithmic potentiometer, which is unusual but in some ways easier to manage. Contrarily to linear potentiometers, a logarithmic one makes it so that setting the knob at 50% does not actually mean that output will be at 50%, but at 10%. This means that there is more “space” at the bottom to adjust the volume, as a relatively large movement will lead to relatively little increase or decrease, so that you can have better control in the lower volume area which is also the one where you will most likely operate.
Features & Specs
The Fosi Audio ZA3 is a pure amplifier and, as such, only takes analogue input through RCA or XLR connectors. It has to be noted that the XLR connectors are combo, so they can be used with TRS 6.35 mm jacks too. The amplifier can be configured to operate in mono mode, in which case you will only need to connect one channel.
On top of supporting mono and stereo speaker outputs, the ZA3 also has a subwoofer RCA port which you can use to easily connect a subwoofer to your system.
The 12 V trigger port is extremely convenient if you have another device with 12 V trigger output, such as the Fosi Audio ZH3, as it allows you to power the amplifier on and off together with the DAC without the need to manually control the power of both.
Fosi Audio ZA3 |
| Input | RCA, XLR |
| Suitable speaker impedance | 2 – 8 Ω |
| Maximum output power | 300 W p.c. (declared, @ 4 Ω, mono mode) 150 W p.c. (declared, @ 8 Ω), mono mode 190 W p.c. (declared, @ 4 Ω, stereo mode) 100 W p.c. (declared, @ 8 Ω, stereo mode) |
| Frequency response | 20 – 20,000 Hz (±0.1 dB) |
| THD+N (@1 kHz) | < 0.006% |
| SNR | > 106 dB |
| Crosstalk | N/A |
Just like many other amplifiers launched in the past few years, the Fosi Audio ZA3 is based on the Texas Instruments TPA3255 amp chip. If you provide it with a beefy enough power supply unit, the ZA3 is able to output up to 300 W per channel; with the stock ones it can go as far up as 80 W p.c. (32 V / 5 A) or 120 W p.c. (48 W / 5A). The op-amps are user-replaceable.
It is interesting to note that, purely in terms of specifications, the ZA3 fares worse than some competitors like the LEAUDIO Cattle Pro, which costs almost half as much (but does not have balanced input). On the other hand, though, it needs to be said that the difference is below the threshold of audibility and is therefore not of any concern when it comes to sound quality; the real difference is in functionality.
Sound
I tested the Fosi Audio ZA3 with a Fosi Audio ZH3 feeding it and a pair of ELAC DBR62 speakers.
Much like most Class D amplifiers I have tested over the years, and more specifically amplifiers based on the TPA3255 chip, the ZA3 does not appear to introduce any colouration in the sound. It is perfectly neutral throughout the audible spectrum, which means you won’t hear any influence from the amplifier itself. Something I really like is how snappy the transients are with the ZA3, as they make the music really come alive.
There is no audible hiss nor hum, although the ZA3 might be sensitive to interference on the mains as I can feel a very faint something when it is powered on – not a sound, but like a pressure on my ears which goes away when I turn it off. There is also no pop when turning the unit on or off.
Final Thoughts
The Fosi Audio ZA3 has garnered a reputation for exceptional value in the audio community, thanks to a very affordable price paired with great sound quality. It is packed with lots of features that make it a very versatile amplifier: balanced input with support for both XLR and 6.3 mm jacks, subwoofer output, mono mode, 12 V trigger input… All these features make it a device which you can integrate easily in a lot of setups, as well as expand upon with time without rearchitecting everything at every passage. It is a device that gives you plenty of options and expandability, which is significant given its sub-$150 price.
I feel perfectly confident in recommending the Fosi Audio ZA3 as it is a stupendous piece of kit for the asking price. You really can’t go wrong!
