These are not the same size of amplifier: PS Audio Stellar M700 has roughly 2.2x the power of Emotiva BasX A2+. That is about 3.4dB, so it is a question of room size and how hard your speakers are to drive, not of one being the better amplifier.
| Area | Better | Why |
|---|
| Power | A | PS Audio Stellar M700 has more power - 350W against 160W into 8 ohms. That is about 3.4dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Grip on hard loads | A | PS Audio Stellar M700 holds up better into a 4-ohm load: its output nearly doubles to 700W, where the other increases strongly. That matters with demanding speakers far more than the 8-ohm figure does. |
| Noise floor | B | Emotiva BasX A2+ is the quieter design on paper - 112dB against 105dB. Audible mainly with sensitive speakers in a quiet room. |
| Analogue inputs | B | Emotiva BasX A2+ takes more analogue sources - 2 against 1. |
| Amplifier class | depends | PS Audio Stellar M700 is Class D and Emotiva BasX A2+ 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 | PS Audio Stellar M700 takes up about 23% less shelf area (1316cm² against 1700cm²), and it is 89mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | B | Emotiva BasX A2+ costs less - $799 against $1,749 at list. |
A PS Audio Stellar M700 B Emotiva BasX A2+
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 - PS Audio Stellar M700 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 - PS Audio Stellar M700 has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 160 watts is already more than most people ever use, and the extra 190 watts would be headroom you pay for and never hear - we rate PS Audio Stellar M700 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.