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 | evenly matched | Effectively the same output - 50W against 50W into 8 ohms is under 1dB, which is not an audible difference in loudness. |
| Noise floor | evenly matched | Much the same signal-to-noise ratio (98dB vs 100dB). |
| Built-in DAC | A | NAD C 338 has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Streaming | evenly matched | Only NAD C 338 has Chromecast. Neither list is longer in a way that matters - check the one service you actually pay for. |
| Analogue inputs | B | Rotel A11 Tribute takes more analogue sources - 4 against 2. |
| Room to grow | evenly matched | The same expansion options on both. |
| Amplifier class | depends | NAD C 338 is Class D and Rotel A11 Tribute is Class A/B. Class D runs cool and draws almost nothing at idle; Class A/B runs warm and is the long-established mainstream choice. Modern examples of both measure well - judge by the rest of the page. |
| Shelf space | depends | NAD C 338 takes up about 17% less shelf area (1349cm² against 1629cm²), and it is 67mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | evenly matched | Priced within a few per cent of each other. |
A NAD C 338 B Rotel A11 Tribute
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?
Neither runs away with it - they trade advantages. Let the "depends" rows and the speakers you already own settle it. If you already own a DAC or a streamer, the built-in one is money you are paying twice for, and Rotel A11 Tribute becomes the more rational buy.
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.