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 | B | NAD C 700 has more power - 80W against 50W into 8 ohms. That is about 2dB, 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 (50W and 80W). |
| Noise floor | A | NAD C3030S is the quieter design on paper - 90dB against 84dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | A | Both decode on board. NAD C3030S 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 C3030S 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 | B | Only NAD C 700 offers preamp outputs - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Headphones | depends | Only NAD C3030S has a headphone output. Worth something if you listen late, nothing if you never do. |
| Shelf space | depends | NAD C 700 takes up about 46% less shelf area (651cm² against 1208cm²), and it is 42mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | NAD C3030S costs less - $1,499 against $1,599 at list. |
| Watts per dollar | B | NAD C 700 is the cheaper watt - about $20 per watt against $30. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A NAD C3030S 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 700 measures better, NAD C3030S costs about 6% 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 700 has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 50 watts is already more than most people ever use, and the extra 30 watts would be headroom you pay for and never hear - we rate NAD C 700 poorly for near-field use for exactly that reason. If you play records, NAD C3030S 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.