Both are audio interfaces, $1495 against $1749. This page puts them side by side on the only three things a maker can be held to — power, output impedance and noise — and then asks the question that actually matters: which headphones do they treat differently?
The Apogee Symphony Desktop reaches 100 dB on 566 of the 567 models here, the RME Fireface UCX II on 564.
| Specification | Apogee Symphony Desktop | RME Fireface UCX II |
|---|---|---|
| Power into 32Ω | 490 mW | 210 mW |
| Power into 150Ω | 145 mW | 45 mW |
| Power into 300Ω | 103 mW | 22 mW |
| Power into 600Ω | 90 mW | 11 mW |
| Output impedance | not published | 1 Ω |
| Output noise | not published | not published |
| Price | $1495 | $1749 |
| Headphones it reaches 100 dB on out of 567 | 566 | 564 |
A figure marked not published is missing from the maker’s own material, which is not the same as being good or bad. Where one of these two publishes a number and the other does not, the comparison on that axis cannot be made at all — and saying so is more useful than guessing.
2 headphones reach 100 dB on the Apogee Symphony Desktop but not on the RME Fireface UCX II — Moondrop PARA, Symphonium Crimson.
564 of the 567 models here reach 100 dB on both. That is a power count and nothing more; whether either source suits a given headphone also depends on the two lines above.
Each has a page of its own with every power figure traced to what the maker published and a full headphone list: Apogee Symphony Desktop and RME Fireface UCX II. Or put either against your own headphones in the source comparison tool.