No single best amplifier here. What decides it is what you have to drive, what you need to plug in, and how much of the system you want in one box.
| Area | Better | Why |
|---|
| Power | B | Emotiva BasX A1 has more power - 200W against 125W into 8 ohms. That is about 2dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Room size | depends | We rate Sonos Amp the better fit for desk or near-field listening, a small room and a mid-size room, and Emotiva BasX A1 for a very large room. Match the amplifier to the room you actually have, not the one you want. |
| Grip on hard loads | A | Sonos Amp holds up better into a 4-ohm load: its output nearly doubles to 250W, where the other increases strongly. That matters with demanding speakers far more than the 8-ohm figure does. |
| Noise floor | A | Sonos Amp is the quieter design on paper - 116dB against 112dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | A | Sonos Amp has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Analogue inputs | B | Emotiva BasX A1 takes more analogue sources - 2 against 1. |
| Use with a TV | depends | Only Sonos Amp has HDMI ARC, so the television can drive it directly and one remote controls the volume. If the system is for music only, this changes nothing. |
| Amplifier class | depends | Sonos Amp is Class D and Emotiva BasX A1 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 | Sonos Amp takes up about 70% less shelf area (518cm² against 1700cm²), and it is 156mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | B | Emotiva BasX A1 costs less - $569 against $699 at list. |
| Watts per dollar | B | Emotiva BasX A1 is the cheaper watt - about $3 per watt against $6. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Sonos Amp B Emotiva BasX A1
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 - Sonos Amp 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 - Emotiva BasX A1 has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 125 watts is already more than most people ever use, and the extra 75 watts would be headroom you pay for and never hear - we rate Emotiva BasX A1 poorly for near-field use for exactly that reason.
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.