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 | Arcam A15+ 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 Arcam A15+ the better fit for a mid-size room, a large room and a very large room, and Marantz PM7000N for desk or near-field listening and a small room. Match the amplifier to the room you actually have, not the one you want. |
| Grip on hard loads | A | Arcam A15+ holds up better into a 4-ohm load: its output increases strongly to 120W, where the other increases modestly. That matters with demanding speakers far more than the 8-ohm figure does. |
| Noise floor | B | Marantz PM7000N is the quieter design on paper - 115dB against 106dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | evenly matched | Both have a DAC on board with much the same capability. |
| Streaming | B | Only Marantz PM7000N has AirPlay 2, Roon and HEOS. |
| Analogue inputs | evenly matched | The same number of line-level inputs (3). |
| Room to grow | B | Only Marantz PM7000N offers a subwoofer output - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Price | B | Marantz PM7000N costs less - $1,299 against $1,500 at list. |
A Arcam A15+ B Marantz PM7000N
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?
Marantz PM7000N has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is. If your speakers are a difficult load - 4 ohms nominal, big woofers, or a sensitivity in the low 80s - Arcam A15+ is the safer partner, because how an amplifier behaves when the impedance drops matters more than its 8-ohm rating.
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.