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 | Marantz PM-10 has more power - 200W against 150W into 8 ohms. That is about 1.2dB, which is a small step in loudness but real headroom on peaks. |
| Grip on hard loads | evenly matched | Both behave much the same into 4 ohms - output nearly doubles (400W and 300W). |
| Noise floor | A | Marantz PM-10 is the quieter design on paper - 111dB against 100dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | B | Primare I35 Prisma has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Streaming | B | Only Primare I35 Prisma has AirPlay 2, Chromecast and Roon. |
| Analogue inputs | evenly matched | The same number of line-level inputs (5). |
| Phono stage | depends | Marantz PM-10 has a built-in phono stage (MM,MC) 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 | B | Only Primare I35 Prisma offers preamp outputs - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Headphones | depends | Only Marantz PM-10 has a headphone output. Worth something if you listen late, nothing if you never do. |
| Price | B | Primare I35 Prisma costs less - $5,795 against $8,999 at list. |
A Marantz PM-10 B Primare I35 Prisma
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?
Primare I35 Prisma 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, Marantz PM-10 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 Marantz PM-10 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.