Fosi Audio ZA3 - my perspective (review)

Brad’s Audio Review (3/16 through 3/23/2025)

 

Fosi Audio ZA3 review

 

A review of the Fosi Audio ZA3  Balanced Dual-Mode Class-D amplifier.  The review is an unbiased and no influence overview of my experience and what I heard during my time with the ZA3.  All of the equipment used, except for the ZA3, has been purchased by me.  They were all purchased for my own use with no plans to ever be used in a review.

 

What is the Fosi Audio ZA3 amp?

 

The ZA3 from Fosi Audio is an amplifier that can be used as a Stereo amp or setup as mono, with a price tag around $149.  This amount can vary, depending on the power supply selected.  The ZA3 amp is a high performing unit, aimed at the budget or price conscience consumer.  The ZA3 includes both Balanced XLR and unbalanced RCA inputs, stereo speaker binding posts, a 12v trigger in, and even a true sub-out.  Plus you can roll the OP-AMPS, which I didn’t do.

 

Review preparations

 

For this review I used more of a near field approach, the space in-between my bar and counter area behind my theater room to setup the equipment and review the ZA3.  The PSB Synchrony Two B speakers were set up 4’ 6” wide, 19.5” from the front wall, and 3.5” from the counter tops.  The listening chair was placed 4’ 6” from the speakers, making an equilateral triangle.  Everything was measured and nothing was moved until after the review was completed.  All of the same cables were used and output via RCA.  No room correction or EQ was used on any of the products.

 

Listening to the ZA3

 

In preparing for this review.  I once again listened to the ZA3 with various kinds of music, DACs, and speakers.  The music  consisted of great recordings and some that were not.  Along with known recordings that envelope you in sound and even Quadraphonic recordings, the ZA3 was able to handle and reproduce all of it with no issue across the frequency spectrum.  It was a very pleasant experience.  As with the previous review, I can say that I prefer XLR to RCA when listening.  It just had a wider soundstage and openness to it.  Nothing was wrong with the RCAs, I just took a liking to the XLR sound.  For the review I had to use RCA the whole time  as the Fosi Audio V3 Stereo doesn’t have XLR.  In doing so, it kept everything simple and as even as I could get during the review and comparisons.

 

 

I used the same songs (however I removed the Alter Bridge song.  Some how I lost my lossless rip from the CD.), from the previous review of the Fosi Audio ZD3 DAC.  The songs that I selected were ones that I like very much and listen to often and have throughout the years.  They aren’t the best recordings or any typical audiophile type names or recordings.  I like music and enjoy what I hear, I want to listen and be entertained.

 

• All songs were balanced to 80db with my Radio Shark SPL meter.  I used the same time span of each song to set the volume to 80db for each amp.  This is the best that I could do, since I don’t have measuring equipment.  No room correction or EQ was used, everything is was set to Flat.
• All music was from my personal purchased files that were streamed from my NAS drive, via my Wiim Pro Plus, line-out (RCAs) to the amps.

 

 

 

 

Finally, onto the music and review!

 

 

Fuel “Sunburn” from “Sunburn”

 

Fosi Audio V3 Mono amps - Great separation.  Drums and guitar are so clear in the beginning and build up.  Holds true throughout the song.

 

Fosi Audio V3 Stereo amp - Good separation, balanced presentation.

 

Fosi Audio ZA3 Stereo amp - Clean and clear throughout the song.

_____

 

The Smashing Pumpkins “Mayonaise” from “Siamese Dream [remastered]”

 

Fosi Audio V3 Mono amps - Great separation.  Music just compliments the vocals so well.  EDIT: I went back and listened to this song again.  The drums weren’t as defined as the V3 Stereo was.

 

Fosi Audio V3 Stereo amp - Never heard the different drums as defined and clear as this, after the whole band plays together.  This occurs at 0:54.  Top to bottom, great sound.  I guess this is some of the benefits of near field listening.

 

Fosi Audio ZA3 Stereo amp - Great sounding throughout the song.  Drums are defined, but not on the scale of how the V3 Stereo did it.

_____

 

Tremonti “Proof” from “All I Was”

 

Fosi Audio V3 Mono amps - Monos seems to bring out more bass emphasis.  Still clean and defined throughout all frequencies of the song.

 

Fosi Audio V3 Stereo amp - Vocals and music sounds great.  Great presentation.

 

Fosi Audio ZA3 Stereo amp - Smooth, ZA3 produced heftier bass than the V3 Stereo.

_____

 

Alainis Morissette “Head over Feet” from “Jagged Little Pill”

 

Fosi Audio V3 Mono amps - Clean and clear.  Vocals and instruments are well defined.

 

Fosi Audio V3 Stereo amp - Clear and defined, no complaints.

 

Fosi Audio ZA3 Stereo amp - Clear and balanced.  Great, missing nothing.

_____

 

Hooverphonic “Anger Never Dies” from “With Orchestra Live (Koningin Elisabethzaal 2012)”

 

Fosi Audio V3 Mono amps - Monos seem to have a little more authority and hold with this live song.  All good marks.

 

Fosi Audio V3 Stereo amp - Great presentation.  I still can’t believe this isn’t a James Bond theme song.

 

Fosi Audio ZA3 Stereo amp - Great live performance.  Balanced through and through.

_____

 

Summary

 

It was a pleasure to use the Fosi Audio ZA3.  This is a standout product at any price and can easily fit into any 2 channel audio setup, regardless of price.  The offerings that the ZA3 has and the detailed presentation that it provides at this ridiculously low price is just amazing.  As I mentioned before, these songs were not the best recordings and I knew that going in, nor do they have all kinds of hidden or barely audible sounds within or have hard hitting bass.  I have played songs on the ZA3 (outside of this review) that do have those characteristics and the ZA3 allowed all of it to happen, and in the correct presentation.  Well done Fosi Audio.

 

I am fortunate to have 3 Fosi Audio amps to compare and use.  Even though they all share the same Texas Instrument TPA3255 amp chip.  They still produce some differences in the songs.  I am happy with all of them.  They all have a place in my house, the V3 Monos will be tasked with running my outdoor speakers.  The ZA3 and matching ZD3 will be anchoring my computer desk.  As for the V3 Stereo, it will probably go back to the desk with the work computer or garage setup.  These areas that I speak of are all 2 channel, but will probably incorporate a sub with my home computer setup.

 

PROS:

• Sound quality, what is on the recording, the ZA3 allows it to pass through without any adjustment.
• Build quality and presentation are well done.
• Smallish form factor is a big plus, especially for the purpose of it being a desktop amp.
• Even better, a perfect fit and function with the ZD3 DAC.
• Price

 

(hardly) CONS:

• When paired/stacked with the ZD3, there are two volume knobs.  I know the ZD3 can be defeated, but then I think you lose the display screen.
• Maybe some high pass filtering, just in case some folks don’t want the full range sounds going to smaller speakers.

 

Final thoughts, the ZA3 is a well designed, attractive desktop amp.  Whatever front end you plan to use with and connect to the ZA3, it will surely give you everything it has.  At the lowly price of around $149, it should be an easy choice to add to a list of potential purchases.  Highly recommended and stacked with the ZD3, it is even more attractive and functional!

 

TEST EQUIPMENT

 

Source:

Wiim Pro Plus, Wiim App

• Self contained when testing Wiim DAC, RCA out to the AMPs.

 

Amplifiers (used the same Fosi Audio 48v/5a Power Supply that came with the ZA3):

• Fosi Audio V3 Monos (used with above PS and Fosi DC power splitter)
• Fosi Audio Stereo V3
• Fosi Audio ZA3 Stereo

 

Speakers:

PSB Synchrony Two B

on Pangea LS300 28” stands

 

Cables:

Speaker - Micca 14g 12ft, banana clips on both ends.

RCAs - none branded

Power Conditioner - cheap GE 6 outlet power strip