These are not the same size of amplifier: NAD Masters Series M10 V2 has roughly 2x the power of NAD C3030S. 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 | B | NAD Masters Series M10 V2 has more power - 100W against 50W 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 | evenly matched | Both behave much the same into 4 ohms - output barely increases (50W and 100W). |
| Noise floor | evenly matched | Much the same signal-to-noise ratio (90dB vs 90dB). |
| Built-in DAC | A | Both decode on board. NAD C3030S goes higher - 384kHz against 192kHz. 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. |
| Phono stage | depends | NAD C3030S has a built-in phono stage and NAD Masters Series M10 V2 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 | B | Only NAD Masters Series M10 V2 offers preamp outputs - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Room correction | B | NAD Masters Series M10 V2 has room correction (Dirac Live (Lite version included, can be upgraded to full for $99)). In an awkward room that does more for the sound than any other difference on this page. |
| Headphones | depends | Only NAD C3030S has a headphone output. Worth something if you listen late, nothing if you never do. |
| Shelf space | depends | NAD Masters Series M10 V2 takes up about 50% less shelf area (606cm² against 1208cm²), and it is 60mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | NAD C3030S costs less - $1,499 against $2,999 at list. |
A NAD C3030S B NAD Masters Series M10 V2
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?
The usual trade-off: NAD Masters Series M10 V2 measures better, NAD C3030S costs about 50% less. With most speakers in most rooms that gap is smaller in practice than it looks here. 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 M10 V2 has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 50 watts is already more than most people ever use, and the extra 50 watts would be headroom you pay for and never hear - we rate NAD Masters Series M10 V2 poorly for near-field use for exactly that reason. If you play records, NAD C3030S 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.