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 | evenly matched | Effectively the same output - 70W against 60W into 8 ohms is under 1dB, which is not an audible difference in loudness. |
| Room size | depends | We rate Marantz PM8006 the better fit for a mid-size room, a large room and a very large room, and Rotel A12 MKII for desk or near-field listening and a small room. Match the amplifier to the room you actually have, not the one you want. |
| Noise floor | A | Marantz PM8006 is the quieter design on paper - 106dB against 100dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | B | Rotel A12 MKII 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 PM8006 takes more analogue sources - 5 against 4. |
| Room to grow | evenly matched | The same expansion options on both. |
| Price | B | Rotel A12 MKII costs less - $1,100 against $1,499 at list. |
A Marantz PM8006 B Rotel A12 MKII
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 PM8006 is ahead, but on only 1 of the measured areas, and it costs about 36% more. That is a lot of money for a narrow margin - Rotel A12 MKII 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 PM8006 becomes the more rational buy. Think about the whole system: the roughly $399 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.