No single best amplifier here. What decides it is what you have to drive, what you need to plug in, and how much of the system you want in one box.
| Area | Better | Why |
|---|
| Power | B | Arcam SA30 has more power - 130W against 100W into 8 ohms. That is about 1.1dB, which is a small step in loudness but real headroom on peaks. |
| Room size | depends | We rate PS Audio Stellar Strata MK2 the better fit for a small room, and Arcam SA30 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 200W). |
| Built-in DAC | B | Both decode on board, but only Arcam SA30 handles MQA. |
| Analogue inputs | B | Arcam SA30 takes more analogue sources - 4 against 1. |
| Use with a TV | depends | Only Arcam SA30 has HDMI eARC, so the television can drive it directly and one remote controls the volume. If the system is for music only, this changes nothing. |
| Amplifier class | depends | PS Audio Stellar Strata MK2 is Class D and Arcam SA30 is Class G. Class D runs cool and draws almost nothing at idle; Class G/H switches its supply rails to cut the heat a Class A/B design wastes. Modern examples of both measure well - judge by the rest of the page. |
| Price | B | Arcam SA30 costs less - $3,300 against $3,499 at list. |
| Watts per dollar | B | Arcam SA30 is the cheaper watt - about $25 per watt against $35. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A PS Audio Stellar Strata MK2 B Arcam SA30
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?
Arcam SA30 has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is. If this sits under a television, Arcam SA30 is the one to buy - HDMI ARC means the TV remote controls the volume and there is no second box in the way.
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.