Different price classes - NAD M32 costs roughly 2.2x what NAD C 388 does. Expect it to lead on paper; the question is whether you will hear the difference through the speakers you own.
| Area | Better | Why |
|---|
| Power | evenly matched | Effectively the same output - 150W against 150W into 8 ohms is under 1dB, which is not an audible difference in loudness. |
| Room size | depends | We rate NAD M32 the better fit for desk or near-field listening, a small room and a mid-size room, and NAD C 388 for a very large 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 150W). |
| Noise floor | A | NAD M32 is the quieter design on paper - 124dB 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. |
| Analogue inputs | A | NAD M32 takes more analogue sources - 4 against 2. |
| Price | B | NAD C 388 costs less - $1,499 against $3,299 at list. |
| Watts per dollar | B | NAD C 388 is the cheaper watt - about $10 per watt against $22. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A NAD M32 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?
NAD M32 is ahead, but on only 1 of the measured areas, and it costs about 120% more. That is a lot of money for a narrow margin - NAD C 388 is the sensible buy unless a specific feature above decides it for you. Think about the whole system: the roughly $1,800 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.