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 | evenly matched | Effectively the same output - 150W against 150W into 8 ohms is under 1dB, which is not an audible difference in loudness. |
| Room size | depends | We rate NAD M32 the better fit for desk or near-field listening, a small room and a mid-size room, and Cambridge Audio Evo 150 for a very large room. Match the amplifier to the room you actually have, not the one you want. |
| Grip on hard loads | B | Cambridge Audio Evo 150 holds up better into a 4-ohm load: its output increases strongly to 250W, where the other barely increases. That matters with demanding speakers far more than the 8-ohm figure does. |
| Built-in DAC | B | Both decode on board. Cambridge Audio Evo 150 goes higher - 384kHz against 192kHz. Very few recordings exist above 192kHz, so treat this as headroom, not as sound quality. |
| Analogue inputs | A | NAD M32 takes more analogue sources - 4 against 2. |
| Use with a TV | depends | Only Cambridge Audio Evo 150 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. |
| Shelf space | depends | Cambridge Audio Evo 150 takes up about 29% less shelf area (1190cm² against 1688cm²). |
| Price | evenly matched | Priced within a few per cent of each other. |
A NAD M32 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. If your speakers are a difficult load - 4 ohms nominal, big woofers, or a sensitivity in the low 80s - Cambridge Audio Evo 150 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 150 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.