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 | B | Yamaha A-S1200 has more power - 90W against 55W into 8 ohms. That is about 2.1dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Room size | depends | We rate Yamaha WXA-70A the better fit for desk or near-field listening and a small room, and Yamaha A-S1200 for a mid-size room, a large room and a very large room. Match the amplifier to the room you actually have, not the one you want. |
| Grip on hard loads | A | Yamaha WXA-70A holds up better into a 4-ohm load: its output nearly doubles to 105W, where the other increases strongly. That matters with demanding speakers far more than the 8-ohm figure does. |
| Built-in DAC | A | Yamaha WXA-70A has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Streaming | A | Only Yamaha WXA-70A has AirPlay 2, Chromecast and Roon. |
| Analogue inputs | B | Yamaha A-S1200 takes more analogue sources - 6 against 1. |
| Phono stage | depends | Yamaha A-S1200 has a built-in phono stage (MM,MC) and Yamaha WXA-70A does not. Decisive if you own a turntable, completely irrelevant if you do not - and an outboard phono stage is easy to add later either way. |
| 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. |
| Shelf space | depends | Yamaha WXA-70A takes up about 72% less shelf area (587cm² against 2123cm²), and it is 221mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | Yamaha WXA-70A costs less - $1,300 against $3,000 at list. |
| Watts per dollar | A | Yamaha WXA-70A is the cheaper watt - about $24 per watt against $33. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Yamaha WXA-70A 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?
Yamaha WXA-70A is the easier recommendation: it leads on most of the measured areas and costs less. Take Yamaha A-S1200 if one of the "depends" rows above describes your system. If your speakers are a difficult load - 4 ohms nominal, big woofers, or a sensitivity in the low 80s - Yamaha WXA-70A is the safer partner, because how an amplifier behaves when the impedance drops matters more than its 8-ohm rating. Start with the room. In a large or open-plan room, or with speakers that are hard to drive - low sensitivity, or an impedance that dips - Yamaha A-S1200 has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 55 watts is already more than most people ever use, and the extra 35 watts would be headroom you pay for and never hear - we rate Yamaha A-S1200 poorly for near-field use for exactly that reason.
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.