One is a streaming all-in-one and the other is an amplifier. Judge them on how many boxes you want and what you already own, not on the spec sheet alone.
| Area | Better | Why |
|---|
| Power | A | Primare I35 Prisma has more power - 150W against 80W into 8 ohms. That is about 2.7dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Room size | depends | We rate Primare I35 Prisma the better fit for a large room and a very large room, and NAD C 368 for desk or near-field listening, a small room and a mid-size room. Match the amplifier to the room you actually have, not the one you want. |
| Grip on hard loads | A | Primare I35 Prisma holds up better into a 4-ohm load: its output nearly doubles to 300W, where the other barely increases. That matters with demanding speakers far more than the 8-ohm figure does. |
| Noise floor | evenly matched | Much the same signal-to-noise ratio (100dB vs 98dB). |
| Built-in DAC | A | Both decode on board, but only Primare I35 Prisma handles DSD. |
| Streaming | A | Only Primare I35 Prisma has AirPlay 2, Chromecast and Roon. |
| Analogue inputs | A | Primare I35 Prisma takes more analogue sources - 5 against 2. |
| Phono stage | depends | NAD C 368 has a built-in phono stage (MM) and Primare I35 Prisma 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 | evenly matched | The same expansion options on both. |
| Headphones | depends | Only NAD C 368 has a headphone output. Worth something if you listen late, nothing if you never do. |
| Price | B | NAD C 368 costs less - $1,199 against $5,795 at list. |
| Watts per dollar | B | NAD C 368 is the cheaper watt - about $15 per watt against $39. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Primare I35 Prisma B NAD C 368
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: Primare I35 Prisma measures better, NAD C 368 costs about 79% less. With most speakers in most rooms that gap is smaller in practice than it looks here. If your speakers are a difficult load - 4 ohms nominal, big woofers, or a sensitivity in the low 80s - Primare I35 Prisma is the safer partner, because how an amplifier behaves when the impedance drops matters more than its 8-ohm rating. Start with the room. In a large or open-plan room, or with speakers that are hard to drive - low sensitivity, or an impedance that dips - Primare I35 Prisma has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 80 watts is already more than most people ever use, and the extra 70 watts would be headroom you pay for and never hear - we rate Primare I35 Prisma poorly for near-field use for exactly that reason.
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.