Both are dongles, $269 against $229. 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 Qudelix T71 reaches 100 dB on 566 of the 567 models here, the Cayin RU7 on 563.
| Specification | Cayin RU7 | Qudelix T71 |
|---|---|---|
| Power into 32Ω | 160 mW | 500 mW |
| Power into 150Ω | 34 mW | 107 mW |
| Power into 300Ω | 17 mW | 53 mW |
| Power into 600Ω | 8.5 mW | 27 mW |
| Output impedance | not published | 0.3 Ω unverified |
| Output noise | not published | 2.5 µV unverified |
| Price | $269 | $229 |
| Headphones it reaches 100 dB on out of 567 | 563 | 566 |
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.
3 headphones reach 100 dB on the Qudelix T71 but not on the Cayin RU7 — Moondrop PARA, Symphonium Crimson, Symphonium Helios.
563 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: Cayin RU7 and Qudelix T71. Or put either against your own headphones in the source comparison tool.