Siblings in Yamaha's A-S range, so they share a design and a house sound. It comes down to power, features and price.
| Area | Better | Why |
|---|
| Power | evenly matched | Effectively the same output - 90W against 90W into 8 ohms is under 1dB, which is not an audible difference in loudness. |
| Grip on hard loads | evenly matched | Both behave much the same into 4 ohms - output increases strongly (150W and 150W). |
| Noise floor | evenly matched | Much the same signal-to-noise ratio (110dB vs 110dB). |
| Analogue inputs | A | Yamaha A-S1200 takes more analogue sources - 6 against 5. |
| Room to grow | evenly matched | The same expansion options on both. |
| Price | A | Yamaha A-S1200 costs less - $3,000 against $4,500 at list. |
| Watts per dollar | A | Yamaha A-S1200 is the cheaper watt - about $33 per watt against $50. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Yamaha A-S1200 B Yamaha A-S2200
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 A-S1200 is the easier recommendation: it leads on most of the measured areas and costs less. Take Yamaha A-S2200 if one of the "depends" rows above describes your system. Think about the whole system: the roughly $1,500 saved by taking the cheaper one would buy better speakers or a subwoofer, and either 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 interface feels 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.