Different price classes - Naim Uniti Star costs roughly 2.5x what Naim Nait 5si does. Expect it to lead on paper; the question is whether you will hear the difference through the speakers you own.
| Area | Better | Why |
|---|
| Power | evenly matched | Effectively the same output - 60W against 70W into 8 ohms is under 1dB, which is not an audible difference in loudness. |
| Room size | depends | We rate Naim Nait 5si the better fit for desk or near-field listening and a small room, and Naim Uniti Star for a mid-size room, a large room and a very large room. Match the amplifier to the room you actually have, not the one you want. |
| 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. |
| Analogue inputs | A | Naim Nait 5si takes more analogue sources - 4 against 1. |
| Use with a TV | depends | Only Naim Uniti Star has HDMI ARC, so the television can drive it directly and one remote controls the volume. If the system is for music only, this changes nothing. |
| 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. |
| Price | A | Naim Nait 5si costs less - $2,299 against $5,699 at list. |
| Watts per dollar | A | Naim Nait 5si is the cheaper watt - about $38 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 Naim Nait 5si 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?
Naim Nait 5si has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is. If this sits under a television, Naim Uniti Star is the one to buy - HDMI ARC means the TV remote controls the volume and there is no second box in the way. If you already own a DAC or a streamer, the built-in one is money you are paying twice for, and Naim Nait 5si 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.