Both are NAD, from different ranges - the engineering approach is shared and the differences are mostly in power, connectivity and price.
| Area | Better | Why |
|---|
| Power | A | NAD C 388 BluOS-2i has more power - 150W against 100W into 8 ohms. That is about 1.8dB, which is a small step in loudness but real headroom on peaks. |
| Room size | depends | We rate NAD C 388 BluOS-2i the better fit for a very large room, and NAD Masters Series M10 V2 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 barely increases (150W and 100W). |
| Noise floor | A | NAD C 388 BluOS-2i is the quieter design on paper - 95dB against 90dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | B | Both decode on board, but only NAD Masters Series M10 V2 handles MQA. |
| Streaming | evenly matched | The same streaming platforms and services on both. |
| Analogue inputs | evenly matched | The same number of line-level inputs (2). |
| Phono stage | depends | NAD C 388 BluOS-2i 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 388 BluOS-2i 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 67% less shelf area (606cm² against 1840cm²), and it is 145mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | NAD C 388 BluOS-2i costs less - $2,249 against $2,999 at list. |
| Watts per dollar | A | NAD C 388 BluOS-2i 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 388 BluOS-2i 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 388 BluOS-2i 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 388 BluOS-2i saves you buying a phono stage; if you do not, ignore that row entirely. Think about the whole system: the roughly $750 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.