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 Masters Series M33 V2 has more power - 200W against 150W into 8 ohms. That is about 1.2dB, which is a small step in loudness but real headroom on peaks. |
| Grip on hard loads | A | NAD Masters Series M33 V2 holds up better into a 4-ohm load: its output nearly doubles to 380W, where the other barely increases. That matters with demanding speakers far more than the 8-ohm figure does. |
| Noise floor | A | NAD Masters Series M33 V2 is the quieter design on paper - 120dB against 95dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | evenly matched | Both have a DAC on board with much the same capability. |
| Streaming | A | Only NAD Masters Series M33 V2 has AirPlay 2, Roon and BluOS. |
| Use with a TV | depends | Only NAD Masters Series M33 V2 has HDMI eARC, so the television can drive it directly and one remote controls the volume. If the system is for music only, this changes nothing. |
| Room to grow | evenly matched | The same expansion options on both. |
| Price | B | NAD C 388 costs less - $1,499 against $7,399 at list. |
| Watts per dollar | B | NAD C 388 is the cheaper watt - about $10 per watt against $37. 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 V2 B NAD C 388
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 M33 V2 measures better, NAD C 388 costs about 80% less. With most speakers in most rooms that gap is smaller in practice than it looks here. If your speakers are a difficult load - 4 ohms nominal, big woofers, or a sensitivity in the low 80s - NAD Masters Series M33 V2 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, NAD Masters Series M33 V2 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.