These are not the same size of amplifier: NAD Masters Series M33 has roughly 2x the power of Cambridge Audio Edge A. 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 | NAD Masters Series M33 has more power - 200W against 100W into 8 ohms. That is about 3dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Room size | depends | We rate NAD Masters Series M33 the better fit for a very large room, and Cambridge Audio Edge A for desk or near-field listening, a small room and a mid-size 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 (380W and 200W). |
| Noise floor | A | NAD Masters Series M33 is the quieter design on paper - 120dB against 103dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | B | Both decode on board. Cambridge Audio Edge A goes higher - 384kHz against 192kHz. Very few recordings exist above 192kHz, so treat this as headroom, not as sound quality. |
| Streaming | A | Only NAD Masters Series M33 has AirPlay 2, Roon and BluOS. |
| Analogue inputs | B | Cambridge Audio Edge A takes more analogue sources - 3 against 2. |
| Phono stage | depends | NAD Masters Series M33 has a built-in phono stage (MM,MC) and Cambridge Audio Edge A 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 | NAD Masters Series M33 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. |
| Price | evenly matched | Priced within a few per cent of each other. |
| Watts per dollar | A | NAD Masters Series M33 is the cheaper watt - about $32 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 NAD Masters Series M33 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?
NAD Masters Series M33 has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is. 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 - NAD Masters Series M33 has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 100 watts is already more than most people ever use, and the extra 100 watts would be headroom you pay for and never hear - we rate NAD Masters Series M33 poorly for near-field use for exactly that reason. If you play records, NAD Masters Series M33 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.