Two versions of the same amplifier rather than two different designs, so the question is not which is better built but which set of features you actually need - and what the difference costs.
| Area | Better | Why |
|---|
| Power | evenly matched | Effectively the same output - 150W against 165W into 8 ohms is under 1dB, which is not an audible difference in loudness. |
| Room size | depends | We rate Devialet Astra the better fit for desk or near-field listening, a small room and a mid-size room, and Devialet Expert 220 Pro for a very large room. Match the amplifier to the room you actually have, not the one you want. |
| Built-in DAC | A | Both decode on board. Devialet Astra goes higher - 384kHz against 192kHz. Very few recordings exist above 192kHz, so treat this as headroom, not as sound quality. |
| Streaming | A | Only Devialet Astra has AirPlay 2 and Chromecast. |
| Analogue inputs | evenly matched | The same number of line-level inputs (2). |
| Room to grow | evenly matched | The same expansion options on both. |
| Price | B | Devialet Expert 220 Pro costs less - $10,000 against $20,000 at list. |
| Watts per dollar | B | Devialet Expert 220 Pro is the cheaper watt - about $61 per watt against $133. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Devialet Astra B Devialet Expert 220 Pro
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 is ahead, but on only 1 of the measured areas, and it costs about 100% more. That is a lot of money for a narrow margin - Devialet Expert 220 Pro is the sensible buy unless a specific feature above decides it for you. Think about the whole system: the roughly $10,000 saved by taking the cheaper one would buy better speakers or a subwoofer, which does more for the sound than the difference between two competent amplifiers.
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.