These are not the same size of amplifier: Denon PMA-900HNE has roughly 2.3x the power of Audioengine N22. That is about 3.6dB, 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 | B | Denon PMA-900HNE has more power - 50W against 22W into 8 ohms. That is about 3.6dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Room size | depends | We rate Audioengine N22 the better fit for desk or near-field listening, and Denon PMA-900HNE for a very large room. Match the amplifier to the room you actually have, not the one you want. |
| Noise floor | B | Denon PMA-900HNE is the quieter design on paper - 105dB against 95dB. Audible mainly with sensitive speakers in a quiet room. |
| Built-in DAC | B | Denon PMA-900HNE has a DAC on board; the other needs an external one, which is another box, another power lead and another purchase. |
| Streaming | B | Only Denon PMA-900HNE has AirPlay 2, Roon and HEOS. |
| Analogue inputs | B | Denon PMA-900HNE takes more analogue sources - 3 against 2. |
| Phono stage | depends | Denon PMA-900HNE has a built-in phono stage (MM,MC) and Audioengine N22 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. |
| Shelf space | depends | Audioengine N22 takes up about 88% less shelf area (202cm² against 1710cm²), and it is 199mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | A | Audioengine N22 costs less - $199 against $949 at list. |
| Watts per dollar | A | Audioengine N22 is the cheaper watt - about $9 per watt against $19. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Audioengine N22 B Denon PMA-900HNE
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: Denon PMA-900HNE measures better, Audioengine N22 costs about 79% less. With most speakers in most rooms that gap is smaller in practice than it looks here. 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 - Denon PMA-900HNE has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 22 watts is already more than most people ever use, and the extra 28 watts would be headroom you pay for and never hear. If you play records, Denon PMA-900HNE 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.