These are not the same size of amplifier: PS Audio Stellar M700 has roughly 2.7x the power of Onkyo Icon M-80. That is about 4.3dB, 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 | B | PS Audio Stellar M700 has more power - 350W against 130W into 8 ohms. That is about 4.3dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Analogue inputs | A | Onkyo Icon M-80 takes more analogue sources - 2 against 1. |
| Amplifier class | depends | Onkyo Icon M-80 is Class A/B and PS Audio Stellar M700 is Class D. Class A/B runs warm and is the long-established mainstream choice; Class D runs cool and draws almost nothing at idle. Modern examples of both measure well - judge by the rest of the page. |
| Price | B | PS Audio Stellar M700 costs less - $1,749 against $2,000 at list. |
| Watts per dollar | B | PS Audio Stellar M700 is the cheaper watt - about $5 per watt against $15. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Onkyo Icon M-80 B PS Audio Stellar M700
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?
PS Audio Stellar M700 has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is. 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, 130 watts is already more than most people ever use, and the extra 220 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.