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 | B | Marantz Model 40n has more power - 70W against 45W into 8 ohms. That is about 1.9dB, which is a small step in loudness but real headroom on peaks. |
| Room size | depends | We rate Marantz PM6007 the better fit for desk or near-field listening and a small room, and Marantz Model 40n 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. |
| Grip on hard loads | evenly matched | Both behave much the same into 4 ohms - output increases modestly (60W and 100W). |
| Noise floor | B | Marantz Model 40n is the quieter design on paper - 106dB against 102dB. 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 Model 40n has AirPlay 2, Roon and HEOS. |
| Analogue inputs | A | Marantz PM6007 takes more analogue sources - 4 against 3. |
| Room to grow | evenly matched | The same expansion options on both. |
| Shelf space | depends | Marantz PM6007 takes up about 17% less shelf area (1764cm² against 2126cm²), and it is 82mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | Marantz PM6007 costs less - $899 against $2,499 at list. |
| Watts per dollar | A | Marantz PM6007 is the cheaper watt - about $20 per watt against $36. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Marantz PM6007 B Marantz Model 40n
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 Model 40n is ahead, but on only 1 of the measured areas, and it costs about 2.8x the price. That is a lot of money for a narrow margin - Marantz PM6007 is the sensible buy unless a specific feature above decides it for you. Think about the whole system: the roughly $1,600 saved by taking the cheaper one would buy better speakers or a subwoofer, and either does more for the sound than the difference between two competent amplifiers.
What a spec sheet cannot show: how either sounds with your speakers, how the interface feels 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.