No single best amplifier here. What decides it is what you have to drive, what you need to plug in, and how much of the system you want in one box.
| Area | Better | Why |
|---|
| Power | B | Roksan Attessa Integrated Amp has more power - 80W against 60W into 8 ohms. That is about 1.2dB, which is a small step in loudness but real headroom on peaks. |
| Room size | depends | We rate Naim Nait 5si the better fit for desk or near-field listening and a small room, and Roksan Attessa Integrated Amp 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 | Roksan Attessa Integrated Amp 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 2. |
| Phono stage | depends | Roksan Attessa Integrated Amp has a built-in phono stage (MM) and Naim Nait 5si 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. |
| Shelf space | depends | Naim Nait 5si takes up about 27% less shelf area (1300cm² against 1779cm²), and it is 109mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | B | Roksan Attessa Integrated Amp costs less - $2,099 against $2,299 at list. |
| Watts per dollar | B | Roksan Attessa Integrated Amp is the cheaper watt - about $26 per watt against $38. 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 Roksan Attessa Integrated Amp
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?
Roksan Attessa Integrated Amp 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, Roksan Attessa Integrated Amp 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 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.