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-S801 has more power - 100W against 55W into 8 ohms. That is about 2.6dB, 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-S801 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. |
| Built-in DAC | evenly matched | Both have a DAC on board with much the same capability. |
| Streaming | A | Only Yamaha WXA-70A has AirPlay 2, Chromecast and Roon. |
| Analogue inputs | B | Yamaha A-S801 takes more analogue sources - 6 against 1. |
| Phono stage | depends | Yamaha A-S801 has a built-in phono stage (MM) 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-S801 has a headphone output. Worth something if you listen late, nothing if you never do. |
| Shelf space | depends | Yamaha WXA-70A takes up about 67% less shelf area (587cm² against 1792cm²), and it is 145mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | B | Yamaha A-S801 costs less - $900 against $1,300 at list. |
| Watts per dollar | B | Yamaha A-S801 is the cheaper watt - about $9 per watt against $24. 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-S801
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-S801 is the easier recommendation: it leads on most of the measured areas and costs less. Take Yamaha WXA-70A if one of the "depends" rows above describes your system. 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-S801 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 45 watts would be headroom you pay for and never hear - we rate Yamaha A-S801 poorly for near-field use for exactly that reason. If you play records, Yamaha A-S801 saves you buying a phono stage; if you do not, ignore that row entirely.
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.