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 | Cambridge Audio Edge A has more power - 100W against 75W into 8 ohms. That is about 1.2dB, which is a small step in loudness but real headroom on peaks. |
| Room size | depends | We rate Cambridge Audio Evo 75 the better fit for a small room, and Cambridge Audio Edge A 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 nearly doubles (150W and 200W). |
| Built-in DAC | evenly matched | Both have a DAC on board with much the same capability. |
| Streaming | A | Only Cambridge Audio Evo 75 has AirPlay 2, Chromecast and Roon. |
| Analogue inputs | B | Cambridge Audio Edge A takes more analogue sources - 3 against 1. |
| Room to grow | evenly matched | The same expansion options on both. |
| Amplifier class | depends | Cambridge Audio Evo 75 is Class D and Cambridge Audio Edge A is Class XA. 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 36% less shelf area (1190cm² against 1867cm²), and it is 33mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | Cambridge Audio Evo 75 costs less - $2,499 against $6,499 at list. |
| Watts per dollar | A | Cambridge Audio Evo 75 is the cheaper watt - about $33 per watt against $65. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Cambridge Audio Evo 75 B Cambridge Audio Edge A
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. Think about the whole system: the roughly $4,000 saved by taking the cheaper one would buy better speakers or a subwoofer, which does more for the sound than the difference between two competent amplifiers.
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.