Different price classes - Audioengine N22 G2 costs roughly 1.8x what Fosi Audio ZA3 does. Expect it to lead on paper; the question is whether you will hear the difference through the speakers you own.
| Area | Better | Why |
|---|
| Speaker load rating | A | Fosi Audio ZA3 is rated down to 2 ohms against 4, so it is the safer partner for a low-impedance speaker. |
| Noise floor | A | Fosi Audio ZA3 is the quieter design on paper - 106dB against 90dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | B | Audioengine N22 G2 has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Analogue inputs | evenly matched | The same number of line-level inputs (2). |
| Room to grow | A | Only Fosi Audio ZA3 offers a subwoofer output - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Headphones | depends | Only Audioengine N22 G2 has a headphone output. Worth something if you listen late, nothing if you never do. |
| Amplifier class | depends | Fosi Audio ZA3 is Class D and Audioengine N22 G2 is Class A/B. Class D runs cool and draws almost nothing at idle; Class A/B runs warm and is the long-established mainstream choice. Modern examples of both measure well - judge by the rest of the page. |
| Shelf space | depends | Audioengine N22 G2 takes up about 23% less shelf area (218cm² against 285cm²), and it is 26mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | Fosi Audio ZA3 costs less - $150 against $269 at list. |
A Fosi Audio ZA3 B Audioengine N22 G2
depends neither is better in the abstract - it turns on your room, your system or how you will use them. Only specs published for both amplifiers are judged; anything missing on either side is left out rather than guessed.
Which should you choose?
Fosi Audio ZA3 is the easier recommendation: it leads on most of the measured areas and costs less. Take Audioengine N22 G2 if one of the "depends" rows above describes your system. If you already own a DAC or a streamer, the built-in one is money you are paying twice for, and Fosi Audio ZA3 becomes the more rational buy. Think about the whole system: the roughly $119 saved by taking the cheaper one would buy better speakers or a subwoofer, which does more for the sound than the difference between two competent amplifiers.
What a spec sheet cannot show: how either sounds with your speakers, how the controls feel day to day, and what the app is like to live with - which is where most all-in-one amplifiers are actually won or lost. Power figures are the manufacturers' own and are not measured to a common standard, so treat small differences as noise. If you can hear both, that will tell you more than any row above.