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 D 3045 has more power - 60W against 40W 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 D 3045 the better fit for a very large room, and NAD C 328 for desk or near-field listening. Match the amplifier to the room you actually have, not the one you want. |
| Noise floor | evenly matched | Much the same signal-to-noise ratio (98dB vs 100dB). |
| Built-in DAC | A | Both decode on board. NAD D 3045 goes higher - 384kHz against 192kHz. Very few recordings exist above 192kHz, so treat this as headroom, not as sound quality. |
| Analogue inputs | evenly matched | The same number of line-level inputs (2). |
| Room to grow | evenly matched | The same expansion options on both. |
| Shelf space | depends | NAD D 3045 takes up about 85% less shelf area (208cm² against 1349cm²), and it is 21mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | B | NAD C 328 costs less - $699 against $899 at list. |
A NAD D 3045 B NAD C 328
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 D 3045 measures better, NAD C 328 costs about 22% less. With most speakers in most rooms that gap is smaller in practice than it looks here.
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.