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 | Cambridge Audio Evo 150 has more power - 150W against 120W into 8 ohms. That is about 1dB, which is a small step in loudness but real headroom on peaks. |
| Grip on hard loads | evenly matched | Both behave much the same into 4 ohms - output increases strongly (200W and 250W). |
| Built-in DAC | B | Both decode on board, but only Cambridge Audio Evo 150 handles DSD. |
| Streaming | evenly matched | The same streaming platforms and services on both. |
| Room to grow | evenly matched | The same expansion options on both. |
| Headphones | depends | Only Cambridge Audio Evo 150 has a headphone output. Worth something if you listen late, nothing if you never do. |
| Amplifier class | depends | Arcam SA35 is Class G and Cambridge Audio Evo 150 is Class D. Class G/H switches its supply rails to cut the heat a Class A/B design wastes; Class D runs cool and draws almost nothing at idle. Modern examples of both measure well - judge by the rest of the page. |
| Shelf space | depends | Cambridge Audio Evo 150 takes up about 24% less shelf area (1190cm² against 1575cm²). |
| Price | evenly matched | Priced within a few per cent of each other. |
| Watts per dollar | B | Cambridge Audio Evo 150 is the cheaper watt - about $22 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 Cambridge Audio Evo 150
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?
Cambridge Audio Evo 150 has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is.
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.