These are not the same size of amplifier: NAD C 368 BluOS-2i has roughly 2.7x the power of NAD D 3020 V2. That is about 4.3dB, so it is a question of room size and how hard your speakers are to drive, not of one being the better amplifier.
| Area | Better | Why |
|---|
| Power | B | NAD C 368 BluOS-2i has more power - 80W against 30W into 8 ohms. That is about 4.3dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Room size | depends | We rate NAD D 3020 V2 the better fit for desk or near-field listening and a small room, and NAD C 368 BluOS-2i for a mid-size room, a large room and a very large room. 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 98dB). |
| Built-in DAC | evenly matched | Both have a DAC on board with much the same capability. |
| Streaming | B | Only NAD C 368 BluOS-2i has AirPlay 2, Roon and BluOS. |
| Analogue inputs | B | NAD C 368 BluOS-2i takes more analogue sources - 2 against 1. |
| Room to grow | evenly matched | The same expansion options on both. |
| Shelf space | depends | NAD D 3020 V2 takes up about 92% less shelf area (146cm² against 1840cm²), and it is 175mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | NAD D 3020 V2 costs less - $499 against $1,749 at list. |
| Watts per dollar | A | NAD D 3020 V2 is the cheaper watt - about $17 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 D 3020 V2 B NAD C 368 BluOS-2i
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 368 BluOS-2i measures better, NAD D 3020 V2 costs about 71% less. With most speakers in most rooms that gap is smaller in practice than it looks here. Start with the room. In a large or open-plan room, or with speakers that are hard to drive - low sensitivity, or an impedance that dips - NAD C 368 BluOS-2i has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 30 watts is already more than most people ever use, and the extra 50 watts would be headroom you pay for and never hear - we rate NAD C 368 BluOS-2i poorly for near-field use for exactly that reason. Think about the whole system: the roughly $1,250 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.