Astell&Kern HC3 vs FiiO KA17

Both are dongles, $179 against $149. 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 KA17 reaches 100 dB on 564 of the 567 models here, the Astell&Kern HC3 on 561.

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.

These two columns are not the same kind of number, and that matters more than the gap between them. FiiO KA17 publishes a power rating (at 32 Ω and at 300 Ω); Astell&Kern HC3 publishes no power figure at any load, only a maximum output voltage, so every milliwatt in its column is a ceiling worked out from that voltage.

A ceiling assumes the amplifier holds that voltage into the load, and nothing on Astell&Kern HC3’s own sheet says it does. It is the most flattering reading available, and it is used here only because the alternative is a blank. Where the Astell&Kern HC3 column looks the stronger of the two, treat the difference as unproven rather than measured. 24 of the 280 sources here are in that position, with no published power rating at any load.

What each of these labels means, and why a derived figure is still worth printing, is set out in how this data was built.

3 headphones reach 100 dB on the FiiO KA17 but not on the Astell&Kern HC3 — Moondrop COSMO, Symphonium Helios, Symphonium Zenith.

74 headphones are left alone by the FiiO KA17 under the one-eighth rule but coloured by the Astell&Kern HC3 (64 Audio Aspire 1, 64 Audio Fourte, 64 Audio Ocean, 71 more).

561 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.

The counts above say how many models the two treat differently. This says by how much. The same 8 headphones appear on every page of this kind, ordered from the easiest to drive to the hardest, so a row can be read across pages as well as across columns. Headroom is at a 100 dB SPL peak.

The widest gap on the list is the Shure SE846: FiiO KA17 has +32 dB of headroom there against +29 dB. 2 dB is about 1.8 times the power, which matters for peaks rather than for how loud the music sits.

The hiss columns are empty for Astell&Kern HC3 because that maker publishes no output noise figure. That is a gap in the specification, not a quiet amplifier, and it is left blank here rather than filled with a plausible number.

The Astell&Kern HC3 costs $30 more than the FiiO KA17, and on these three axes the money buys nothing: among the 567 models here there is not one that the Astell&Kern HC3 handles and the FiiO KA17 does not — not on power, not on the one-eighth rule, not on hiss. The traffic runs the other way: the cheaper FiiO KA17 drives 3 models to 100 dB and leaves 74 alone under the one-eighth rule that the Astell&Kern HC3 does not.

Everything in this paragraph counts only figures the two makers published. An advantage on an axis one of them leaves blank cannot be counted, and is not counted — how often that happens is its own page.

Each has a page of its own with every power figure traced to what the maker published and a full headphone list: Astell&Kern HC3 and FiiO KA17. Or put either against your own headphones in the source comparison tool.