Short answer
Both are audio interfaces, $3499 against $2799.
The Lynx Aurora(n) reaches 100 dB on 567 of the 567 models here, the RME Fireface UFX II on 564.
| Specification | Lynx Aurora(n) | RME Fireface UFX II |
|---|---|---|
| Power into 32Ω | 1.3 W | 200 mW |
| Power into 150Ω | 277 mW | 43 mW |
| Power into 300Ω | 138 mW | 21 mW |
| Power into 600Ω | 69 mW | 11 mW |
| Output impedance | not published | 2 Ω |
| Output noise | not published | not published |
| Price | $3499 | $2799 |
| Headphones it reaches 100 dB on out of 567 | 567 | 564 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Load | Lynx Aurora(n) | RME Fireface UFX II |
|---|---|---|
| 32 Ω | Upper bound | Published |
| 150 Ω | Upper bound | Derived |
| 300 Ω | Upper bound | Derived |
| 600 Ω | Upper bound | Derived |
These two columns are not the same kind of number, and that matters more than the gap between them. RME Fireface UFX II publishes a power rating (at 32 Ω); Lynx Aurora(n) publishes no power figure at any load, only a maximum output voltage, so every milliwatt in its column is a ceiling worked out from that voltage.
A ceiling assumes the amplifier holds that voltage into the load, and nothing on Lynx Aurora(n)’s own sheet says it does. It is the most flattering reading available, and it is used here only because the alternative is a blank. Where the Lynx Aurora(n) column looks the stronger of the two, treat the difference as unproven rather than measured. 24 of the 280 sources here are in that position, with no published power rating at any load.
3 headphones reach 100 dB on the Lynx Aurora(n) but not on the RME Fireface UFX II — Moondrop PARA, Symphonium Crimson, Symphonium Titan.
564 of the 567 models here reach 100 dB on both.
Headroom is at a 100 dB SPL peak.
The widest gap on the list is the Sennheiser HD 600: Lynx Aurora(n) has +13 dB of headroom there against +5 dB. 8 dB is about 6.5 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Lynx Aurora(n) and RME Fireface UFX II because neither maker publishes no output noise figure.
| Headphone | Impedance | Needs | Lynx Aurora(n) headroom | RME Fireface UFX II headroom | Lynx Aurora(n) hiss | RME Fireface UFX II hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +40 dB | +32 dB damping | not published | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +20 dB | +12 dB damping | not published | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +29 dB | +21 dB | not published | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +24 dB | +16 dB | not published | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +21 dB | +13 dB | not published | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +17 dB | +9 dB | not published | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +13 dB | +5 dB | not published | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | +11 dB | +3 dB | not published | not published |
The Lynx Aurora(n) costs $700 more than the RME Fireface UFX II. Out of the 567 models here, that difference buys 3 more models driven to 100 dB.
Nothing runs the other way: there is no axis here on which the cheaper of the two does better.
Only published figures count here; blank axes are counted separately.
Each in full: Lynx Aurora(n) and RME Fireface UFX II.