Different price classes - WiiM Amp costs roughly 2x 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 98dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | B | WiiM Amp has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Use with a TV | depends | Only WiiM Amp has HDMI ARC, so the television can drive it directly and one remote controls the volume. If the system is for music only, this changes nothing. |
| Room to grow | evenly matched | The same expansion options on both. |
| Shelf space | depends | Fosi Audio ZA3 takes up about 32% less shelf area (285cm² against 420cm²), and it is 36mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | Fosi Audio ZA3 costs less - $150 against $299 at list. |
A Fosi Audio ZA3 B WiiM Amp
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 has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is. If this sits under a television, WiiM Amp is the one to buy - HDMI ARC means the TV remote controls the volume and there is no second box in the way. 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.
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.