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 235W into 8 ohms. That is about 4.1dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Grip on hard loads | A | PS Audio Stellar M1200 holds up better into a 4-ohm load: its output nearly doubles to 1200W, where the other increases modestly. That matters with demanding speakers far more than the 8-ohm figure does. |
| Noise floor | A | PS Audio Stellar M1200 is the quieter design on paper - 112dB against 103dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | B | Rotel Diamond RA-6000 has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Analogue inputs | B | Rotel Diamond RA-6000 takes more analogue sources - 4 against 1. |
| Phono stage | depends | Rotel Diamond RA-6000 has a built-in phono stage (MM) and PS Audio Stellar M1200 does not. Decisive if you own a turntable, completely irrelevant if you do not - and an outboard phono stage is easy to add later either way. |
| Headphones | depends | Only Rotel Diamond RA-6000 has a headphone output. Worth something if you listen late, nothing if you never do. |
| Amplifier type | depends | PS Audio Stellar M1200 is Hybrid and Rotel Diamond RA-6000 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. |
| Shelf space | depends | PS Audio Stellar M1200 takes up about 33% less shelf area (1316cm² against 1979cm²), and it is 151mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | PS Audio Stellar M1200 costs less - $3,499 against $4,499 at list. |
| Watts per dollar | A | PS Audio Stellar M1200 is the cheaper watt - about $6 per watt against $19. 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 Rotel Diamond RA-6000
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 M1200 is the easier recommendation: it leads on most of the measured areas and costs less. Take Rotel Diamond RA-6000 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 M1200 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 M1200 has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 235 watts is already more than most people ever use, and the extra 365 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.
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.