Different price classes - Yamaha R-S202 costs roughly 2.3x what Fosi Audio V3 Mono does. Expect it to lead on paper; the question is whether you will hear the difference through the speakers you own.
| Area | Better | Why |
|---|
| Analogue inputs | B | Yamaha R-S202 takes more analogue sources - 4 against 2. |
| Amplifier class | depends | Fosi Audio V3 Mono is Class D and Yamaha R-S202 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. |
| Price | A | Fosi Audio V3 Mono costs less - $110 against $250 at list. |
A Fosi Audio V3 Mono B Yamaha R-S202
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?
Yamaha R-S202 is ahead, but on only 1 of the measured areas, and it costs about 127% more. That is a lot of money for a narrow margin - Fosi Audio V3 Mono is the sensible buy unless a specific feature above decides it for you. Think about the whole system: the roughly $140 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.