Siblings in Marantz's Model range, so they share a design and a house sound. It comes down to power, features and price.
| Area | Better | Why |
|---|
| Power | A | Marantz MODEL M1 has more power - 100W against 70W into 8 ohms. That is about 1.5dB, which is a small step in loudness but real headroom on peaks. |
| Room size | depends | We rate Marantz MODEL M1 the better fit for a large room and a very large room, and Marantz Model 40n for a small room. Match the amplifier to the room you actually have, not the one you want. |
| Grip on hard loads | B | Marantz Model 40n holds up better into a 4-ohm load: its output increases modestly to 100W, where the other increases modestly. That matters with demanding speakers far more than the 8-ohm figure does. |
| Built-in DAC | evenly matched | Both have a DAC on board with much the same capability. |
| Streaming | evenly matched | The same streaming platforms and services on both. |
| Analogue inputs | evenly matched | The same number of line-level inputs (3). |
| Phono stage | depends | Marantz Model 40n has a built-in phono stage (MM) and Marantz MODEL M1 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. |
| Amplifier class | depends | Marantz MODEL M1 is Class D and Marantz Model 40n is Class A/B. Class D runs cool and draws almost nothing at idle; Class A/B runs warm and is the long-established mainstream choice. Modern examples of both measure well - judge by the rest of the page. |
| Shelf space | depends | Marantz MODEL M1 takes up about 74% less shelf area (552cm² against 2126cm²), and it is 228mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | Marantz MODEL M1 costs less - $1,000 against $2,499 at list. |
| Watts per dollar | A | Marantz MODEL M1 is the cheaper watt - about $10 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 MODEL M1 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 M1 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 - Marantz Model 40n is the safer partner, because how an amplifier behaves when the impedance drops matters more than its 8-ohm rating. If you play records, Marantz Model 40n saves you buying a phono stage; if you do not, ignore that row entirely.
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.