Both are desktop DAC/amps, $199 against $199. 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 K7 reaches 100 dB on 567 of the 567 models here, the Fosi Audio K7 on 566.
| Specification | FiiO K7 | Fosi Audio K7 |
|---|---|---|
| Power into 32Ω | 1.2 W | 600 mW |
| Power into 150Ω | 269 mW | 128 mW |
| Power into 300Ω | 140 mW | 64 mW |
| Power into 600Ω | 70 mW | 32 mW |
| Output impedance | 1.0 Ω | not published |
| Output noise | 3.1 µV | 2.5 µV |
| Price | $199 | $199 |
| Headphones it reaches 100 dB on out of 567 | 567 | 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 K7 but not on the Fosi Audio K7 — Symphonium Titan.
10 headphones stay below the audible-hiss threshold on the Fosi Audio K7 but cross it on the FiiO K7 (AFUL Performer 8, Campfire Audio Chimera, Dunu SA6 MKII, 7 more).
566 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 K7 and Fosi Audio K7. Or put either against your own headphones in the source comparison tool.