These are not the same size of amplifier: Rotel Diamond RA-6000 has roughly 2.2x the power of Yamaha A-S2200. That is about 3.5dB, 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 | Rotel Diamond RA-6000 has more power - 200W against 90W into 8 ohms. That is about 3.5dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Room size | depends | We rate Yamaha A-S2200 the better fit for desk or near-field listening, a small room and a mid-size room, and Rotel Diamond RA-6000 for a large room and a very large 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 increases strongly (150W and 350W). |
| Noise floor | A | Yamaha A-S2200 is the quieter design on paper - 110dB 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. |
| Streaming | evenly matched | Only Rotel Diamond RA-6000 has Roon. Neither list is longer in a way that matters - check the one service you actually pay for. |
| Analogue inputs | A | Yamaha A-S2200 takes more analogue sources - 5 against 4. |
| Room to grow | evenly matched | The same expansion options on both. |
| Price | evenly matched | Priced within a few per cent of each other. |
| Watts per dollar | B | Rotel Diamond RA-6000 is the cheaper watt - about $23 per watt against $50. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Yamaha A-S2200 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?
Rotel Diamond RA-6000 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 - Rotel Diamond RA-6000 has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 90 watts is already more than most people ever use, and the extra 110 watts would be headroom you pay for and never hear - we rate Rotel Diamond RA-6000 poorly for near-field use for exactly that reason. If you already own a DAC or a streamer, the built-in one is money you are paying twice for, and Yamaha A-S2200 becomes the more rational buy.
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.