A valve amplifier against a solid-state one. They are not really rivals: they differ in character, in what they will drive and in what owning them involves, so start there rather than with the watts.
| Area | Better | Why |
|---|
| Power | B | Devialet Expert 140 Pro has more power - 105W against 70W into 8 ohms. That is about 1.8dB, which is a small step in loudness but real headroom on peaks. |
| Built-in DAC | B | Devialet Expert 140 Pro has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Analogue inputs | A | PrimaLuna EVO 400 Integrated takes more analogue sources - 5 against 1. |
| Phono stage | depends | Devialet Expert 140 Pro has a built-in phono stage (MM,MC) and PrimaLuna EVO 400 Integrated 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 type | depends | PrimaLuna EVO 400 Integrated is Tube and Devialet Expert 140 Pro is Solid State. Valve designs are usually warmer and softer at the limits and need their tubes replaced eventually; solid state is the lower-maintenance choice. This is a taste and ownership decision, not a quality one. |
| Price | evenly matched | Priced within a few per cent of each other. |
| Watts per dollar | B | Devialet Expert 140 Pro is the cheaper watt - about $62 per watt against $93. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A PrimaLuna EVO 400 Integrated B Devialet Expert 140 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 Expert 140 Pro 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 play records, Devialet Expert 140 Pro saves you buying a phono stage; if you do not, ignore that row entirely. If you already own a DAC or a streamer, the built-in one is money you are paying twice for, and PrimaLuna EVO 400 Integrated 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.