These are not the same size of amplifier: Cambridge Audio Evo 300 has roughly 2x the power of Cambridge Audio Evo 150 SE. That is about 3dB, 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 | A | Cambridge Audio Evo 300 has more power - 300W against 150W into 8 ohms. That is about 3dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Grip on hard loads | A | Cambridge Audio Evo 300 holds up better into a 4-ohm load: its output nearly doubles to 550W, where the other increases strongly. That matters with demanding speakers far more than the 8-ohm figure does. |
| Built-in DAC | A | Both decode on board. Cambridge Audio Evo 300 goes higher - 768kHz against 384kHz. Very few recordings exist above 192kHz, so treat this as headroom, not as sound quality. |
| Streaming | evenly matched | The same streaming platforms and services on both. |
| Room to grow | evenly matched | The same expansion options on both. |
| Shelf space | depends | Cambridge Audio Evo 150 SE takes up about 19% less shelf area (1185cm² against 1463cm²). |
| Price | B | Cambridge Audio Evo 150 SE costs less - $3,299 against $3,999 at list. |
| Watts per dollar | A | Cambridge Audio Evo 300 is the cheaper watt - about $13 per watt against $22. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Cambridge Audio Evo 300 B Cambridge Audio Evo 150 SE
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 300 leads across most of the measured areas for a fairly modest premium, so it is the easier pick if the budget stretches. Cambridge Audio Evo 150 SE is the one to take if it does not. If your speakers are a difficult load - 4 ohms nominal, big woofers, or a sensitivity in the low 80s - Cambridge Audio Evo 300 is the safer partner, because how an amplifier behaves when the impedance drops matters more than its 8-ohm rating. 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 300 has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 150 watts is already more than most people ever use, and the extra 150 watts would be headroom you pay for and never hear.
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.