A valve amplifier against a solid-state one. They are not really rivals: they differ in character, in what they will drive and in what owning them involves, so start there rather than with the watts.
| Area | Better | Why |
|---|
| Power | A | PS Audio Stellar M1200 has more power - 600W against 140W into 8 ohms. That is about 6.3dB - a different class of amplifier rather than a bigger version of the same one, and far more than most rooms will ever ask for. |
| Room size | depends | We rate PS Audio Stellar M1200 the better fit for a very large room, and PS Audio Stellar S300 for desk or near-field listening, a small room and a mid-size room. Match the amplifier to the room you actually have, not the one you want. |
| Grip on hard loads | evenly matched | Both behave much the same into 4 ohms - output nearly doubles (1200W and 300W). |
| Noise floor | A | PS Audio Stellar M1200 is the quieter design on paper - 112dB against 100dB. Audible mainly with sensitive speakers in a quiet room. |
| Analogue inputs | evenly matched | The same number of line-level inputs (1). |
| Amplifier type | depends | PS Audio Stellar M1200 is Hybrid and PS Audio Stellar S300 is Solid State. Valve designs are usually warmer and softer at the limits and need their tubes replaced eventually; solid state is the lower-maintenance choice. This is a taste and ownership decision, not a quality one. |
| Price | B | PS Audio Stellar S300 costs less - $1,999 against $3,499 at list. |
| Watts per dollar | A | PS Audio Stellar M1200 is the cheaper watt - about $6 per watt against $14. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A PS Audio Stellar M1200 B PS Audio Stellar S300
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?
The usual trade-off: PS Audio Stellar M1200 measures better, PS Audio Stellar S300 costs about 43% less. With most speakers in most rooms that gap is smaller in practice than it looks here. 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 M1200 has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 140 watts is already more than most people ever use, and the extra 460 watts would be headroom you pay for and never hear - we rate PS Audio Stellar M1200 poorly for near-field use for exactly that reason. Think about the whole system: the roughly $1,500 saved by taking the cheaper one would buy better speakers or a subwoofer, which does more for the sound than the difference between two competent amplifiers.
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.