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 | McIntosh MA252 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. |
| Built-in DAC | B | Naim Uniti Star has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Streaming | B | Only Naim Uniti Star has AirPlay 2, Chromecast and Roon. |
| Phono stage | depends | McIntosh MA252 has a built-in phono stage and Naim Uniti Star 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. |
| Room to grow | B | Only Naim Uniti Star offers preamp outputs - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Built-in sources | depends | Naim Uniti Star has a CD player built in. That is one less box if you still play discs or listen to radio, and dead weight if you do not. |
| Amplifier type | depends | McIntosh MA252 is Hybrid and Naim Uniti Star 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 | A | McIntosh MA252 costs less - $5,000 against $5,699 at list. |
| Watts per dollar | A | McIntosh MA252 is the cheaper watt - about $50 per watt against $81. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A McIntosh MA252 B Naim Uniti Star
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: Naim Uniti Star measures better, McIntosh MA252 costs about 12% less. With most speakers in most rooms that gap is smaller in practice than it looks here. If you play records, McIntosh MA252 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 McIntosh MA252 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.