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 | Marantz Stereo 70s has more power - 75W against 45W into 8 ohms. That is about 2.2dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Room size | depends | We rate Marantz Stereo 70s 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 | Marantz Stereo 70s holds up better into a 4-ohm load: its output nearly doubles to 150W, where the other increases modestly. That matters with demanding speakers far more than the 8-ohm figure does. |
| Noise floor | B | Marantz PM6007 is the quieter design on paper - 102dB against 74dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | A | Both decode on board, but only Marantz Stereo 70s handles DSD. |
| Streaming | A | Only Marantz Stereo 70s has AirPlay 2, Roon and HEOS. |
| Analogue inputs | B | Marantz PM6007 takes more analogue sources - 4 against 3. |
| Room to grow | evenly matched | The same expansion options on both. |
| Price | B | Marantz PM6007 costs less - $899 against $1,000 at list. |
| Watts per dollar | A | Marantz Stereo 70s is the cheaper watt - about $13 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 Marantz Stereo 70s 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?
Marantz Stereo 70s leads across most of the measured areas for a fairly modest premium, so it is the easier pick if the budget stretches. Marantz PM6007 is the one to take if it does not. If your speakers are a difficult load - 4 ohms nominal, big woofers, or a sensitivity in the low 80s - Marantz Stereo 70s 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 - Marantz Stereo 70s 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 30 watts would be headroom you pay for and never hear - we rate Marantz Stereo 70s 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.