No single best amplifier here. What decides it is what you have to drive, what you need to plug in, and how much of the system you want in one box.
| Area | Better | Why |
|---|
| Power | B | AudioControl Bijou 600 has more power - 100W against 80W into 8 ohms. That is about 1dB, which is a small step in loudness but real headroom on peaks. |
| Grip on hard loads | B | AudioControl Bijou 600 holds up better into a 4-ohm load: its output nearly doubles to 200W, where the other barely increases. That matters with demanding speakers far more than the 8-ohm figure does. |
| Noise floor | evenly matched | Much the same signal-to-noise ratio (95dB vs 95dB). |
| Built-in DAC | A | Both decode on board. NAD C 379 goes higher - 384kHz against 192kHz. Very few recordings exist above 192kHz, so treat this as headroom, not as sound quality. |
| Phono stage | depends | NAD C 379 has a built-in phono stage and AudioControl Bijou 600 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. |
| Shelf space | depends | AudioControl Bijou 600 takes up about 70% less shelf area (534cm² against 1810cm²), and it is 171mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | B | AudioControl Bijou 600 costs less - $899 against $1,099 at list. |
| Watts per dollar | B | AudioControl Bijou 600 is the cheaper watt - about $9 per watt against $14. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A NAD C 379 B AudioControl Bijou 600
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?
AudioControl Bijou 600 is the easier recommendation: it leads on most of the measured areas and costs less. Take NAD C 379 if one of the "depends" rows above describes your system. If your speakers are a difficult load - 4 ohms nominal, big woofers, or a sensitivity in the low 80s - AudioControl Bijou 600 is the safer partner, because how an amplifier behaves when the impedance drops matters more than its 8-ohm rating. If you play records, NAD C 379 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.