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 | A | Marantz Model 30 has more power - 100W against 70W into 8 ohms. That is about 1.5dB, which is a small step in loudness but real headroom on peaks. |
| Room size | depends | We rate Marantz Model 30 the better fit for a large room and a very large room, and Denon PMA-1700NE for a small room. Match the amplifier to the room you actually have, not the one you want. |
| Grip on hard loads | evenly matched | Both behave much the same into 4 ohms - output nearly doubles (200W and 140W). |
| Noise floor | B | Denon PMA-1700NE is the quieter design on paper - 107dB against 88dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | B | Denon PMA-1700NE has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Analogue inputs | A | Marantz Model 30 takes more analogue sources - 6 against 3. |
| Room to grow | A | Only Marantz Model 30 offers preamp outputs - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Amplifier class | depends | Marantz Model 30 is Class D and Denon PMA-1700NE 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 | Denon PMA-1700NE costs less - $2,099 against $2,999 at list. |
A Marantz Model 30 B Denon PMA-1700NE
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 Model 30 is ahead, but on only 1 of the measured areas, and it costs about 43% more. That is a lot of money for a narrow margin - Denon PMA-1700NE is the sensible buy unless a specific feature above decides it for you. If you already own a DAC or a streamer, the built-in one is money you are paying twice for, and Marantz Model 30 becomes the more rational buy. Think about the whole system: the roughly $900 saved by taking the cheaper one would buy better speakers or a subwoofer, which does more for the sound than the difference between two competent amplifiers.
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.