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 | Audiolab 9000A 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 Audiolab 9000A the better fit for a large room and a very large room, and Marantz Model 40n for a small room. Match the amplifier to the room you actually have, not the one you want. |
| Grip on hard loads | A | Audiolab 9000A holds up better into a 4-ohm load: its output increases strongly to 160W, where the other increases modestly. That matters with demanding speakers far more than the 8-ohm figure does. |
| Noise floor | A | Audiolab 9000A is the quieter design on paper - 110dB against 106dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | A | Both decode on board, but only Audiolab 9000A handles DSD and MQA. |
| Streaming | B | Only Marantz Model 40n has AirPlay 2, Roon and HEOS. |
| Analogue inputs | evenly matched | The same number of line-level inputs (3). |
| Room to grow | A | Only Audiolab 9000A offers a pre-out/main-in loop - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Shelf space | depends | Audiolab 9000A takes up about 29% less shelf area (1518cm² against 2126cm²), and it is 139mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | B | Marantz Model 40n costs less - $2,499 against $2,999 at list. |
A Audiolab 9000A B Marantz Model 40n
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?
Audiolab 9000A leads across most of the measured areas for a fairly modest premium, so it is the easier pick if the budget stretches. Marantz Model 40n 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 - Audiolab 9000A is the safer partner, because how an amplifier behaves when the impedance drops matters more than its 8-ohm rating.
What a spec sheet cannot show: how either sounds with your speakers, how the interface feels 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.