Both are portable players, $649 against $799. 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 FiiO M15S reaches 100 dB on 566 of the 567 models here, the Cayin N3 Ultra on 565.
| Specification | Cayin N3 Ultra | FiiO M15S |
|---|---|---|
| Power into 32Ω | 250 mW | 580 mW |
| Power into 150Ω | 53 mW | 150 mW |
| Power into 300Ω | 27 mW | 93 mW |
| Power into 600Ω | 13 mW | 47 mW |
| Output impedance | 0.5 Ω | 1.4 Ω |
| Output noise | not published | 3.2 µV |
| Price | $649 | $799 |
| Headphones it reaches 100 dB on out of 567 | 565 | 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.
1 headphone reaches 100 dB on the FiiO M15S but not on the Cayin N3 Ultra — Moondrop PARA.
50 headphones are left alone by the Cayin N3 Ultra under the one-eighth rule but coloured by the FiiO M15S (64 Audio Aspire 1, 64 Audio Fourte, 64 Audio Nio, 47 more).
565 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 N3 Ultra and FiiO M15S. Or put either against your own headphones in the source comparison tool.