One is a streaming all-in-one and the other is an amplifier. Judge them on how many boxes you want and what you already own, not on the spec sheet alone.
| Area | Better | Why |
|---|
| Power | A | NAD C 389 has more power - 130W against 100W into 8 ohms. That is about 1.1dB, which is a small step in loudness but real headroom on peaks. |
| Grip on hard loads | evenly matched | Both behave much the same into 4 ohms - output barely increases (130W and 100W). |
| Noise floor | A | NAD C 389 is the quieter design on paper - 95dB against 90dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | A | Both decode on board. NAD C 389 goes higher - 384kHz against 192kHz. Very few recordings exist above 192kHz, so treat this as headroom, not as sound quality. |
| Streaming | B | Only NAD Masters Series M10 V2 has AirPlay 2, Roon and BluOS. |
| Analogue inputs | A | NAD C 389 takes more analogue sources - 3 against 2. |
| Phono stage | depends | NAD C 389 has a built-in phono stage (MM) 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 | evenly matched | The same expansion options on both. |
| Headphones | depends | Only NAD C 389 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 64% less shelf area (606cm² against 1705cm²), and it is 114mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | NAD C 389 costs less - $1,999 against $2,999 at list. |
| Watts per dollar | A | NAD C 389 is the cheaper watt - about $15 per watt against $30. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A NAD C 389 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?
NAD C 389 is the easier recommendation: it leads on most of the measured areas and costs less. Take NAD Masters Series M10 V2 if one of the "depends" rows above describes your system. If you play records, NAD C 389 saves you buying a phono stage; if you do not, ignore that row entirely. Think about the whole system: the roughly $1,000 saved by taking the cheaper one would buy better speakers or a subwoofer, which does more for the sound than the difference between two competent amplifiers.
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.