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 | Anthem MRX 740 8K has more power - 140W against 110W into 8 ohms. That is about 1dB, which is a small step in loudness but real headroom on peaks. |
| Analogue inputs | evenly matched | The same number of line-level inputs (5). |
| Phono stage | depends | Marantz Cinema 50 has a built-in phono stage and Anthem MRX 740 8K 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. |
| Built-in sources | depends | Marantz Cinema 50 has a radio tuner built in. That is one less box if you still play discs or listen to radio, and dead weight if you do not. |
| Amplifier class | depends | Marantz Cinema 50 is AB and Anthem MRX 740 8K is AB+D. 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 | A | Marantz Cinema 50 costs less - $2,800 against $3,100 at list. |
A Marantz Cinema 50 B Anthem MRX 740 8K
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: Anthem MRX 740 8K measures better, Marantz Cinema 50 costs about 10% less. With most speakers in most rooms that gap is smaller in practice than it looks here. If you play records, Marantz Cinema 50 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.