These are not the same size of amplifier: Marantz Model 10 has roughly 3.6x the power of Marantz Model 50. That is about 5.5dB, 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 | Marantz Model 10 has more power - 250W against 70W into 8 ohms. That is about 5.5dB - a different class of amplifier rather than a bigger version of the same one, and far more than most rooms will ever ask for. |
| Room size | depends | We rate Marantz Model 10 the better fit for a large room and a very large room, and Marantz Model 50 for desk or near-field listening, a small room and a mid-size room. Match the amplifier to the room you actually have, not the one you want. |
| Grip on hard loads | A | Marantz Model 10 holds up better into a 4-ohm load: its output nearly doubles to 500W, where the other increases modestly. That matters with demanding speakers far more than the 8-ohm figure does. |
| Noise floor | A | Marantz Model 10 is the quieter design on paper - 122dB against 113dB. Audible mainly with sensitive speakers in a quiet room. |
| Analogue inputs | A | Marantz Model 10 takes more analogue sources - 6 against 5. |
| Room to grow | A | Only Marantz Model 10 offers a pre-out/main-in loop - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Amplifier class | depends | Marantz Model 10 is Class D and Marantz Model 50 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. |
| Price | B | Marantz Model 50 costs less - $1,800 against $15,000 at list. |
| Watts per dollar | B | Marantz Model 50 is the cheaper watt - about $26 per watt against $60. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Marantz Model 10 B Marantz Model 50
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?
The usual trade-off: Marantz Model 10 measures better, Marantz Model 50 costs about 88% less. With most speakers in most rooms that gap is smaller in practice than it looks here. If your speakers are a difficult load - 4 ohms nominal, big woofers, or a sensitivity in the low 80s - Marantz Model 10 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 Model 10 has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 70 watts is already more than most people ever use, and the extra 180 watts would be headroom you pay for and never hear - we rate Marantz Model 10 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.