These are not the same size of amplifier: Cambridge Audio Evo 150 has roughly 3.8x the power of Naim Uniti Atom. That is about 5.7dB, so it is a question of room size and how hard your speakers are to drive, not of one being the better amplifier.
| Area | Better | Why |
|---|
| Power | B | Cambridge Audio Evo 150 has more power - 150W against 40W into 8 ohms. That is about 5.7dB - a different class of amplifier rather than a bigger version of the same one, and far more than most rooms will ever ask for. |
| Room size | depends | We rate Naim Uniti Atom the better fit for desk or near-field listening, a small room and a mid-size room, and Cambridge Audio Evo 150 for a large room and a very large room. Match the amplifier to the room you actually have, not the one you want. |
| Built-in DAC | evenly matched | Both have a DAC on board with much the same capability. |
| Streaming | evenly matched | Only Cambridge Audio Evo 150 has AirPlay 2. Neither list is longer in a way that matters - check the one service you actually pay for. |
| Analogue inputs | B | Cambridge Audio Evo 150 takes more analogue sources - 2 against 1. |
| Phono stage | depends | Cambridge Audio Evo 150 has a built-in phono stage (MM) and Naim Uniti Atom does not. Decisive if you own a turntable, completely irrelevant if you do not - and an outboard phono stage is easy to add later either way. |
| Room to grow | evenly matched | The same expansion options on both. |
| Amplifier class | depends | Naim Uniti Atom is Class A/B and Cambridge Audio Evo 150 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 | Naim Uniti Atom takes up about 34% less shelf area (781cm² against 1190cm²), and it is 56mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | B | Cambridge Audio Evo 150 costs less - $3,249 against $3,799 at list. |
| Watts per dollar | B | Cambridge Audio Evo 150 is the cheaper watt - about $22 per watt against $95. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Naim Uniti Atom 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 is the easier recommendation: it leads on most of the measured areas and costs less. Take Naim Uniti Atom if one of the "depends" rows above describes your system. 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 - Cambridge Audio Evo 150 has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 40 watts is already more than most people ever use, and the extra 110 watts would be headroom you pay for and never hear - we rate Cambridge Audio Evo 150 poorly for near-field use for exactly that reason. If you play records, Cambridge Audio Evo 150 saves you buying a phono stage; if you do not, ignore that row entirely.
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.