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 | B | FiiO AIR AMP has more power - 90W against 50W into 8 ohms. That is about 2.6dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Room size | depends | We rate Audioengine N22 G2 the better fit for desk or near-field listening and a small room, and FiiO AIR AMP for a mid-size room, a large room and a very large room. Match the amplifier to the room you actually have, not the one you want. |
| Grip on hard loads | B | FiiO AIR AMP holds up better into a 4-ohm load: its output increases modestly to 120W, where the other barely increases. That matters with demanding speakers far more than the 8-ohm figure does. |
| Built-in DAC | B | Both decode on board, but only FiiO AIR AMP handles DSD. |
| Streaming | evenly matched | Only FiiO AIR AMP has Roon. Neither list is longer in a way that matters - check the one service you actually pay for. |
| Analogue inputs | A | Audioengine N22 G2 takes more analogue sources - 2 against 1. |
| Room to grow | B | Only FiiO AIR AMP offers a subwoofer output - which decides whether you can add a subwoofer or a power amplifier later without replacing the box. |
| Headphones | depends | Only Audioengine N22 G2 has a headphone output. Worth something if you listen late, nothing if you never do. |
| Amplifier class | depends | Audioengine N22 G2 is Class A/B and FiiO AIR AMP is Class D. Class A/B runs warm and is the long-established mainstream choice; Class D runs cool and draws almost nothing at idle. Modern examples of both measure well - judge by the rest of the page. |
| Price | A | Audioengine N22 G2 costs less - $269 against $300 at list. |
| Watts per dollar | B | FiiO AIR AMP is the cheaper watt - about $3 per watt against $5. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Audioengine N22 G2 B FiiO AIR AMP
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?
FiiO AIR AMP leads across most of the measured areas for a fairly modest premium, so it is the easier pick if the budget stretches. Audioengine N22 G2 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 - FiiO AIR AMP is the safer partner, because how an amplifier behaves when the impedance drops matters more than its 8-ohm rating. 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 - FiiO AIR AMP has the headroom, and headroom is what stops an amplifier hardening up on peaks. At desk distance or in a small room, 50 watts is already more than most people ever use, and the extra 40 watts would be headroom you pay for and never hear - we rate FiiO AIR AMP poorly for near-field use for exactly that reason.
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.