One is a streaming all-in-one and the other is an amplifier. Judge them on how many boxes you want and what you already own, not on the spec sheet alone.
| Area | Better | Why |
|---|
| Power | evenly matched | Effectively the same output - 130W against 150W into 8 ohms is under 1dB, which is not an audible difference in loudness. |
| Grip on hard loads | B | Buchardt I150 holds up better into a 4-ohm load: its output nearly doubles to 300W, where the other barely increases. That matters with demanding speakers far more than the 8-ohm figure does. |
| Noise floor | B | Buchardt I150 is the quieter design on paper - 121dB against 95dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | B | Both decode on board. Buchardt I150 goes higher - 394kHz against 384kHz. Very few recordings exist above 192kHz, so treat this as headroom, not as sound quality. |
| Streaming | A | Only NAD C 389 BluOS-D has AirPlay 2, Roon and BluOS. |
| Phono stage | depends | NAD C 389 BluOS-D has a built-in phono stage and Buchardt I150 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 | Buchardt I150 takes up about 37% less shelf area (1147cm² against 1809cm²), and it is 106mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | evenly matched | Priced within a few per cent of each other. |
A NAD C 389 BluOS-D B Buchardt I150
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?
Buchardt I150 has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is. If your speakers are a difficult load - 4 ohms nominal, big woofers, or a sensitivity in the low 80s - Buchardt I150 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 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.