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 | Devialet Astra has more power - 150W against 90W into 8 ohms. That is about 2.2dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Room size | depends | We rate Naim NAP 300 DR the better fit for a small room, and Devialet Astra for a large room and a very large room. Match the amplifier to the room you actually have, not the one you want. |
| Built-in DAC | B | Devialet Astra has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Analogue inputs | B | Devialet Astra takes more analogue sources - 2 against 1. |
| Phono stage | depends | Devialet Astra has a built-in phono stage (MM/MC with 13 equalization curves and adjustable cartridge loading) and Naim NAP 300 DR 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. |
| Amplifier class | depends | Naim NAP 300 DR is Class A/B and Devialet Astra is ADH (Analog Digital Hybrid). Class A/B runs warm and is the long-established mainstream choice. Modern examples of both measure well - judge by the rest of the page. |
| Price | A | Naim NAP 300 DR costs less - $12,700 against $20,000 at list. |
A Naim NAP 300 DR B Devialet Astra
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: Devialet Astra measures better, Naim NAP 300 DR 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 - Devialet Astra has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 90 watts is already more than most people ever use, and the extra 60 watts would be headroom you pay for and never hear - we rate Devialet Astra poorly for near-field use for exactly that reason. If you play records, Devialet Astra 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.