One is a streaming all-in-one and the other is an amplifier. Judge them on how many boxes you want and what you already own, not on the spec sheet alone.
| Area | Better | Why |
|---|
| Power | evenly matched | Effectively the same output - 100W against 90W into 8 ohms is under 1dB, which is not an audible difference in loudness. |
| Grip on hard loads | B | Yamaha A-S1200 holds up better into a 4-ohm load: its output increases strongly to 150W, where the other barely increases. That matters with demanding speakers far more than the 8-ohm figure does. |
| Noise floor | B | Yamaha A-S1200 is the quieter design on paper - 110dB against 90dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | A | NAD M10 V3 has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Streaming | A | Only NAD M10 V3 has AirPlay 2, Roon and BluOS. |
| Room to grow | evenly matched | The same expansion options on both. |
| Headphones | depends | Only Yamaha A-S1200 has a headphone output. Worth something if you listen late, nothing if you never do. |
| Amplifier class | depends | NAD M10 V3 is Class D and Yamaha A-S1200 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 | NAD M10 V3 takes up about 71% less shelf area (606cm² against 2123cm²), and it is 210mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | B | Yamaha A-S1200 costs less - $3,000 against $3,199 at list. |
A NAD M10 V3 B Yamaha A-S1200
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?
Neither runs away with it - they trade advantages. Let the "depends" rows and the speakers you already own settle it. If your speakers are a difficult load - 4 ohms nominal, big woofers, or a sensitivity in the low 80s - Yamaha A-S1200 is the safer partner, because how an amplifier behaves when the impedance drops matters more than its 8-ohm rating. If you already own a DAC or a streamer, the built-in one is money you are paying twice for, and Yamaha A-S1200 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.