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 | A | PS Audio PMG S200 has more power - 100W against 70W into 8 ohms. That is about 1.5dB, which is a small step in loudness but real headroom on peaks. |
| Analogue inputs | evenly matched | The same number of line-level inputs (1). |
| Amplifier type | depends | PS Audio PMG S200 is Solid State and PrimaLuna EVO 400 Power is Tube. 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. |
| Shelf space | depends | PrimaLuna EVO 400 Power takes up about 14% less shelf area (1559cm² against 1806cm²). |
| Price | B | PrimaLuna EVO 400 Power costs less - $5,995 against $7,999 at list. |
A PS Audio PMG S200 B PrimaLuna EVO 400 Power
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?
PS Audio PMG S200 is ahead, but on only 1 of the measured areas, and it costs about 33% more. That is a lot of money for a narrow margin - PrimaLuna EVO 400 Power is the sensible buy unless a specific feature above decides it for you. Think about the whole system: the roughly $2,004 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.