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 120W into 8 ohms. That is about 1dB, which is a small step in loudness but real headroom on peaks. |
| Grip on hard loads | evenly matched | Both behave much the same into 4 ohms - output nearly doubles (240W and 300W). |
| Bass control | B | Devialet Astra has the higher damping factor (2000 vs 500), which usually means a tighter grip on a woofer. Above about 100 the returns flatten out, so read this as a tendency rather than a ranking. |
| 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 | A | Esoteric F-02 takes more analogue sources - 7 against 2. |
| Headphones | depends | Only Esoteric F-02 has a headphone output. Worth something if you listen late, nothing if you never do. |
| Amplifier class | depends | Esoteric F-02 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. |
| Shelf space | depends | Devialet Astra takes up about 29% less shelf area (1490cm² against 2096cm²), and it is 85mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | evenly matched | Priced within a few per cent of each other. |
| Watts per dollar | B | Devialet Astra is the cheaper watt - about $133 per watt against $175. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Esoteric F-02 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?
Devialet Astra has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is. If you already own a DAC or a streamer, the built-in one is money you are paying twice for, and Esoteric F-02 becomes the more rational buy.
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.