One is a streaming all-in-one and the other is an amplifier. Judge them on how many boxes you want and what you already own, not on the spec sheet alone.
| Area | Better | Why |
|---|
| Power | B | Rotel RA-1592 MKII has more power - 200W against 120W into 8 ohms. That is about 2.2dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Grip on hard loads | evenly matched | Both behave much the same into 4 ohms - output increases strongly (200W and 350W). |
| Noise floor | A | Arcam SA35 is the quieter design on paper - 110dB against 103dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | B | Both decode on board, but only Rotel RA-1592 MKII handles MQA. |
| Streaming | A | Only Arcam SA35 has AirPlay 2 and Chromecast. |
| Room to grow | evenly matched | The same expansion options on both. |
| Headphones | depends | Only Rotel RA-1592 MKII has a headphone output. Worth something if you listen late, nothing if you never do. |
| Amplifier class | depends | Arcam SA35 is Class G and Rotel RA-1592 MKII is Class A/B. Class G/H switches its supply rails to cut the heat a Class A/B design wastes; Class A/B runs warm and is the long-established mainstream choice. Modern examples of both measure well - judge by the rest of the page. |
| Shelf space | depends | Arcam SA35 takes up about 17% less shelf area (1575cm² against 1888cm²), and it is 72mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | evenly matched | Priced within a few per cent of each other. |
| Watts per dollar | B | Rotel RA-1592 MKII is the cheaper watt - about $16 per watt against $28. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Arcam SA35 B Rotel RA-1592 MKII
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 RA-1592 MKII 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 RA-1592 MKII has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 120 watts is already more than most people ever use, and the extra 80 watts would be headroom you pay for and never hear - we rate Rotel RA-1592 MKII 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.