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 | B | Denon PMA-900HNE has more power - 50W against 30W into 8 ohms. That is about 2.2dB, so it plays usefully louder before it runs out and has more in hand on peaks. |
| Room size | depends | We rate Schiit Aegir 2F 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. |
| Grip on hard loads | evenly matched | Both behave much the same into 4 ohms - output increases strongly (50W and 85W). |
| Noise floor | A | Schiit Aegir 2F is the quieter design on paper - 122dB against 105dB. 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. |
| 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 Schiit Aegir 2F 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. |
| Headphones | depends | Only Denon PMA-900HNE has a headphone output. Worth something if you listen late, nothing if you never do. |
| Amplifier class | depends | Schiit Aegir 2F is Class A and Denon PMA-900HNE is Class A/B. Class A runs hot and is inefficient by design, in exchange for the simplest signal path; 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. |
| Shelf space | depends | Schiit Aegir 2F takes up about 56% less shelf area (755cm² against 1710cm²), and it is 63mm shallower, which is the measurement that decides whether a rack door shuts. |
| Price | evenly matched | Priced within a few per cent of each other. |
| Watts per dollar | B | Denon PMA-900HNE is the cheaper watt - about $19 per watt against $32. A blunt measure, and it says nothing about how either sounds, but it is the honest one for raw output. |
A Schiit Aegir 2F 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?
Denon PMA-900HNE has the edge on paper, though not by much. The rows marked "depends" are more likely to decide this than the score is. 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, 30 watts is already more than most people ever use, and the extra 20 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.