Both are dongles, $109 against $79. 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 KA15 reaches 100 dB on 566 of the 567 models here, the FiiO KA3 on 565.
| Specification | FiiO KA15 | FiiO KA3 |
|---|---|---|
| Power into 32Ω | 180 mW | 130 mW |
| Power into 150Ω | 38 mW | 28 mW |
| Power into 300Ω | 19 mW | 14 mW |
| Power into 600Ω | 9.5 mW | 7.0 mW |
| Output impedance | 0.8 Ω | 0.5 Ω |
| Output noise | 1.7 µV | 1.7 µV |
| Price | $109 | $79 |
| Headphones it reaches 100 dB on out of 567 | 566 | 565 |
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 KA15 but not on the FiiO KA3 — Moondrop PARA.
11 headphones are left alone by the FiiO KA3 under the one-eighth rule but coloured by the FiiO KA15 (64 Audio Nio, 64 Audio Volur, Campfire Audio Andromeda 2023, 8 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: FiiO KA15 and FiiO KA3. Or put either against your own headphones in the source comparison tool.