Both are dongles, $99 against $109. 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 ddHiFi TC44 Pro E2 on 565.
| Specification | ddHiFi TC44 Pro E2 | FiiO KA15 |
|---|---|---|
| Power into 32Ω | 250 mW | 180 mW |
| Power into 150Ω | 53 mW | 38 mW |
| Power into 300Ω | 27 mW | 19 mW |
| Power into 600Ω | 13 mW | 9.5 mW |
| Output impedance | not published | 0.8 Ω |
| Output noise | not published | 1.7 µV |
| Price | $99 | $109 |
| 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 KA15 but not on the ddHiFi TC44 Pro E2 — Moondrop PARA.
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: ddHiFi TC44 Pro E2 and FiiO KA15. Or put either against your own headphones in the source comparison tool.