Both are dongles, $149 against $140. 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 Tanchjim LUNA reaches 100 dB on 565 of the 567 models here, the FiiO KA17 on 564.
| Specification | FiiO KA17 | Tanchjim LUNA |
|---|---|---|
| Power into 32Ω | 140 mW | 285 mW |
| Power into 150Ω | 34 mW | 80 mW |
| Power into 300Ω | 20 mW | 54 mW |
| Power into 600Ω | 10.0 mW | 27 mW |
| Output impedance | 1.0 Ω | not published |
| Output noise | 2.0 µV | 1.3 µV |
| Price | $149 | $140 |
| Headphones it reaches 100 dB on out of 567 | 564 | 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 Tanchjim LUNA but not on the FiiO KA17 — Symphonium Crimson.
5 headphones stay below the audible-hiss threshold on the Tanchjim LUNA but cross it on the FiiO KA17 (64 Audio Fourte, Campfire Audio Clara, Shure SE846, 2 more).
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: FiiO KA17 and Tanchjim LUNA. Or put either against your own headphones in the source comparison tool.