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 359S has more power - 70W against 50W into 8 ohms. That is about 1.5dB, which is a small step in loudness but real headroom on peaks. |
| Room size | depends | We rate NAD C 359S the better fit for a mid-size room, a large room and a very large room, and NAD C 338 for desk or near-field listening and a small room. Match the amplifier to the room you actually have, not the one you want. |
| Grip on hard loads | A | NAD C 359S holds up better into a 4-ohm load: its output increases strongly to 120W, where the other barely increases. That matters with demanding speakers far more than the 8-ohm figure does. |
| Bass control | evenly matched | Similar damping factor (210 vs 300). |
| Noise floor | B | NAD C 338 is the quieter design on paper - 98dB against 90dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | A | Both decode on board, but only NAD C 359S handles MQA. |
| Streaming | A | Only NAD C 359S has Roon and BluOS. |
| Analogue inputs | A | NAD C 359S takes more analogue sources - 3 against 2. |
| Room to grow | B | Only NAD C 338 offers preamp outputs - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Amplifier class | depends | NAD C 359S is Class A/B and NAD C 338 is Class D. Class A/B runs warm and is the long-established mainstream choice; Class D runs cool and draws almost nothing at idle. Modern examples of both measure well - judge by the rest of the page. |
| Shelf space | depends | NAD C 338 takes up about 23% less shelf area (1349cm² against 1740cm²), and it is 90mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | B | NAD C 338 costs less - $799 against $1,299 at list. |
A NAD C 359S B NAD C 338
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 C 359S measures better, NAD C 338 costs about 38% 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 C 359S is the safer partner, because how an amplifier behaves when the impedance drops matters more than its 8-ohm rating. Think about the whole system: the roughly $500 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.