No single best amplifier here. What decides it is what you have to drive, what you need to plug in, and how much of the system you want in one box.
| Area | Better | Why |
|---|
| Power | B | Musical Fidelity M2si has more power - 76W against 60W into 8 ohms. That is about 1dB, which is a small step in loudness but real headroom on peaks. |
| Room size | depends | We rate Marantz PM7000N the better fit for desk or near-field listening and a small room, and Musical Fidelity M2si 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 | B | Musical Fidelity M2si holds up better into a 4-ohm load: its output nearly doubles to 137W, where the other increases modestly. That matters with demanding speakers far more than the 8-ohm figure does. |
| Noise floor | A | Marantz PM7000N is the quieter design on paper - 115dB against 96dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | A | Marantz PM7000N has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Analogue inputs | B | Musical Fidelity M2si takes more analogue sources - 5 against 3. |
| Headphones | depends | Only Marantz PM7000N has a headphone output. Worth something if you listen late, nothing if you never do. |
| Price | evenly matched | Priced within a few per cent of each other. |
| Watts per dollar | B | Musical Fidelity M2si is the cheaper watt - about $17 per watt against $22. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Marantz PM7000N B Musical Fidelity M2si
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?
Musical Fidelity M2si 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 - Musical Fidelity M2si is the safer partner, because how an amplifier behaves when the impedance drops matters more than its 8-ohm rating. If you already own a DAC or a streamer, the built-in one is money you are paying twice for, and Musical Fidelity M2si 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.