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 | evenly matched | Effectively the same output - 80W against 75W into 8 ohms is under 1dB, which is not an audible difference in loudness. |
| Grip on hard loads | B | Cambridge Audio Evo 75 holds up better into a 4-ohm load: its output nearly doubles to 150W, where the other increases strongly. That matters with demanding speakers far more than the 8-ohm figure does. |
| Built-in DAC | evenly matched | Both have a DAC on board with much the same capability. |
| Streaming | B | Only Cambridge Audio Evo 75 has AirPlay 2 and Chromecast. |
| Analogue inputs | A | Cambridge CXA81 II takes more analogue sources - 5 against 1. |
| Use with a TV | depends | Only Cambridge Audio Evo 75 has HDMI ARC, so the television can drive it directly and one remote controls the volume. If the system is for music only, this changes nothing. |
| Room to grow | evenly matched | The same expansion options on both. |
| Amplifier class | depends | Cambridge CXA81 II is Class A/B and Cambridge Audio Evo 75 is Class D. Class A/B runs warm and is the long-established mainstream choice; 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 75 takes up about 25% less shelf area (1190cm² against 1595cm²). |
| Price | A | Cambridge CXA81 II costs less - $1,199 against $2,499 at list. |
| Watts per dollar | A | Cambridge CXA81 II is the cheaper watt - about $15 per watt against $33. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Cambridge CXA81 II B Cambridge Audio Evo 75
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?
Neither runs away with it - they trade advantages. Let the "depends" rows and the speakers you already own settle it. If your speakers are a difficult load - 4 ohms nominal, big woofers, or a sensitivity in the low 80s - Cambridge Audio Evo 75 is the safer partner, because how an amplifier behaves when the impedance drops matters more than its 8-ohm rating. If this sits under a television, Cambridge Audio Evo 75 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.