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. |
| Grip on hard loads | B | 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. |
| 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 is the easier recommendation: it leads on most of the measured areas and costs less. Take Onkyo Icon M-80 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 - 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, 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.