Siblings in NAD's Classic range, so they share a design and a house sound. It comes down to power, features and price.
| Area | Better | Why |
|---|
| Power | A | NAD C 389 BluOS-D has more power - 130W against 80W into 8 ohms. That is about 2.1dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Grip on hard loads | evenly matched | Both behave much the same into 4 ohms - output barely increases (130W and 80W). |
| Noise floor | A | NAD C 389 BluOS-D is the quieter design on paper - 95dB against 84dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | A | Both decode on board. NAD C 389 BluOS-D goes higher - 384kHz against 192kHz. Very few recordings exist above 192kHz, so treat this as headroom, not as sound quality. |
| Streaming | evenly matched | The same streaming platforms and services on both. |
| Phono stage | depends | NAD C 389 BluOS-D has a built-in phono stage and NAD C 700 does not. Decisive if you own a turntable, completely irrelevant if you do not - and an outboard phono stage is easy to add later either way. |
| Room to grow | evenly matched | The same expansion options on both. |
| Headphones | depends | Only NAD C 389 BluOS-D has a headphone output. Worth something if you listen late, nothing if you never do. |
| Shelf space | depends | NAD C 700 takes up about 64% less shelf area (651cm² against 1809cm²), and it is 120mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | B | NAD C 700 costs less - $1,599 against $2,549 at list. |
A NAD C 389 BluOS-D B NAD C 700
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 389 BluOS-D measures better, NAD C 700 costs about 37% 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 389 BluOS-D has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 80 watts is already more than most people ever use, and the extra 50 watts would be headroom you pay for and never hear. If you play records, NAD C 389 BluOS-D saves you buying a phono stage; if you do not, ignore that row entirely.
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.