These are not the same size of amplifier: Sonos Amp has roughly 2.8x the power of Marantz PM6007. That is about 4.4dB, so it is a question of room size and how hard your speakers are to drive, not of one being the better amplifier.
| Area | Better | Why |
|---|
| Power | A | Sonos Amp has more power - 125W against 45W into 8 ohms. That is about 4.4dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Room size | depends | We rate Sonos Amp the better fit for a mid-size room, a large room and a very large room, and Marantz PM6007 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 | Sonos Amp holds up better into a 4-ohm load: its output nearly doubles to 250W, where the other increases modestly. That matters with demanding speakers far more than the 8-ohm figure does. |
| Noise floor | A | Sonos Amp is the quieter design on paper - 116dB 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 | evenly matched | Only Sonos Amp has AirPlay 2. Neither list is longer in a way that matters - check the one service you actually pay for. |
| Analogue inputs | B | Marantz PM6007 takes more analogue sources - 4 against 1. |
| Phono stage | depends | Marantz PM6007 has a built-in phono stage (MM) and Sonos Amp 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. |
| Headphones | depends | Only Marantz PM6007 has a headphone output. Worth something if you listen late, nothing if you never do. |
| Amplifier class | depends | Sonos Amp is Class D and Marantz PM6007 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 | Sonos Amp takes up about 71% less shelf area (518cm² against 1764cm²), and it is 161mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | Sonos Amp costs less - $699 against $899 at list. |
| Watts per dollar | A | Sonos Amp is the cheaper watt - about $6 per watt against $20. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Sonos Amp B Marantz PM6007
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?
Sonos Amp is the easier recommendation: it leads on most of the measured areas and costs less. Take Marantz PM6007 if one of the "depends" rows above describes your system. If your speakers are a difficult load - 4 ohms nominal, big woofers, or a sensitivity in the low 80s - Sonos Amp is the safer partner, because how an amplifier behaves when the impedance drops matters more than its 8-ohm rating. Start with the room. In a large or open-plan room, or with speakers that are hard to drive - low sensitivity, or an impedance that dips - Sonos Amp has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 45 watts is already more than most people ever use, and the extra 80 watts would be headroom you pay for and never hear - we rate Sonos Amp poorly for near-field use for exactly that reason.
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.