The FiiO KA13 is a USB dongle at $79. It delivers 50 mW into 32Ω and 5.0 mW into 300Ω, which ranks it 251 of 280 for raw power among the sources in this database.
Measured at 100 dB SPL it has comfortable headroom on 451 of the 567 dynamic and planar headphones catalogued here, enough but not generous on 93, only marginal on 11 and not enough power for 12. Desktop mode raises output at the cost of your phone's battery. Balanced 4.4 mm.
The manufacturer publishes 70 mW into 16Ω, 50 mW into 32Ω, 5.0 mW into 300Ω. Everything else in the table above is worked out from those figures, and this table says which is which.
The balanced output is rated separately: 260 mW into 32Ω through the 4.4mm jack.
Derivation holds output voltage steady between and beyond the published loads rather than output power, because that is what an amplifier actually does. The full method is written up here.
Source: fiio.com.
| Load | Power | Status | How it was arrived at |
|---|---|---|---|
| 16 Ω | 70 mW | Published | the manufacturer publishes this figure at this exact load |
| 32 Ω | 50 mW | Published | the manufacturer publishes this figure at this exact load |
| 150 Ω | 10 mW | Derived | worked out between two published loads, holding output voltage linear between them |
| 300 Ω | 5.0 mW | Published | the manufacturer publishes this figure at this exact load |
| 600 Ω | 2.5 mW | Derived | beyond the published loads, holding output voltage constant — which understates rather than flatters |
Ordered from easiest to hardest to drive. Headroom is measured at 100 dB SPL, which is louder than almost anyone listens — a small negative number means the source still plays loud, just without reserve for peaks.
These figures come from each manufacturer's own sensitivity rating. A handful of planars — the HiFiMAN Susvara and the Abyss AB-1266 in particular — are widely reported to need far more than their published sensitivity implies, so treat a bare pass on those as optimistic rather than settled.
| Headphone | Impedance | Sensitivity | Needs | Headroom | Verdict |
|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 114.0 dB/mW | 0.04 mW | +30 dB | Comfortable audible hiss, damping |
| 64 Audio U12t | 12.6 Ω | 108.0 dB/mW | 0.16 mW | +25 dB | Comfortable audible hiss, damping |
| Shure SE215 | 17 Ω | 107.0 dB/mW | 0.20 mW | +25 dB | Comfortable audible hiss |
| Moondrop Aria | 32 Ω | 107.1 dB/mW | 0.19 mW | +24 dB | Comfortable audible hiss |
| Audeze LCD-X 2021 | 20 Ω | 103.0 dB/mW | 0.50 mW | +21 dB | Comfortable faint hiss |
| Truthear Hexa | 20.5 Ω | 103.1 dB/mW | 0.49 mW | +21 dB | Comfortable faint hiss |
| Sennheiser IE 200 | 18 Ω | 101.6 dB/mW | 0.69 mW | +20 dB | Comfortable faint hiss |
| Sony MDR-7506 | 63 Ω | 106.0 dB/mW | 0.25 mW | +20 dB | Comfortable faint hiss |
| Meze 99 Classics | 32 Ω | 103.0 dB/mW | 0.50 mW | +20 dB | Comfortable faint hiss |
| Focal Clear MG | 55 Ω | 104.0 dB/mW | 0.40 mW | +19 dB | Comfortable faint hiss |
| Philips SHP9500 | 32 Ω | 101.0 dB | 0.79 mW | +18 dB | Comfortable faint hiss |
| Focal Utopia | 80 Ω | 104.0 dB/mW | 0.40 mW | +17 dB | Comfortable faint hiss |
| Meze Empyrean | 32 Ω | 100.0 dB | 1.0 mW | +17 dB | Comfortable faint hiss |
| Campfire Audio Andromeda 2020 | 9 Ω | 94.0 dB | 4.0 mW | +10 dB | Enough faint hiss, damping |
| Etymotic ER2SE | 15 Ω | 96.0 dB/mW | 2.5 mW | +14 dB | Comfortable faint hiss |
| AKG K371 | 32 Ω | 99.1 dB/mW | 1.2 mW | +16 dB | Comfortable faint hiss |
| Audio-Technica ATH-M50X | 38 Ω | 99.0 dB/mW | 1.3 mW | +15 dB | Comfortable faint hiss |
| Beyerdynamic DT 900 Pro X | 48 Ω | 100.0 dB/mW | 1.0 mW | +15 dB | Comfortable faint hiss |
| Audeze LCD-2 Classic | 70 Ω | 101.0 dB/mW | 0.79 mW | +15 dB | Comfortable faint hiss |
| Grado SR80x | 38 Ω | 98.0 dB/mW | 1.6 mW | +14 dB | Comfortable faint hiss |
| Sennheiser HD 560S | 120 Ω | 100.8 dB/mW | 0.83 mW | +12 dB | Comfortable |
| HiFiMAN Edition XS | 18 Ω | 92.0 dB | 6.3 mW | +10 dB | Comfortable |
| HiFiMAN Arya Stealth | 32 Ω | 94.0 dB | 4.0 mW | +11 dB | Comfortable |
| Dan Clark Audio AEON 2 Closed | 13 Ω | 90.0 dB/mW | 10 mW | +8 dB | Enough damping |
| Audeze LCD-5 | 14 Ω | 90.0 dB/mW | 10 mW | +8 dB | Enough |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 102.0 dB/mW | 0.63 mW | +10 dB | Enough |
| HiFiMAN HE400se | 25 Ω | 91.0 dB | 7.9 mW | +8 dB | Enough |
| HiFiMAN Sundara | 32 Ω | 92.0 dB | 6.3 mW | +9 dB | Enough |
| Dan Clark Audio Stealth | 23 Ω | 90.0 dB/mW | 10 mW | +8 dB | Enough |
| Fostex T50RP MK3 | 50 Ω | 92.0 dB/mW | 6.3 mW | +7 dB | Enough |
| AKG K702 | 62 Ω | 92.9 dB/mW | 5.1 mW | +7 dB | Enough |
| ZMF Verite Closed | 300 Ω | 99.0 dB/mW | 1.3 mW | +6 dB | Enough |
| Sennheiser HD 650 | 300 Ω | 97.8 dB/mW | 1.7 mW | +5 dB | Enough |
| Sennheiser HD 800S | 300 Ω | 96.8 dB/mW | 2.1 mW | +4 dB | Enough |
| Beyerdynamic DT 770 Pro (250Ω) | 250 Ω | 96.0 dB | 2.5 mW | +4 dB | Enough |
| Audio-Technica ATH-R70X | 470 Ω | 98.0 dB/mW | 1.6 mW | +3 dB | Enough |
| ZMF Atrium | 300 Ω | 96.0 dB/mW | 2.5 mW | +3 dB | Marginal |
| Abyss AB-1266 Phi TC | 50 Ω | 88.0 dB/mW | 16 mW | +3 dB | Enough |
| Sennheiser HD 600 | 300 Ω | 91.8 dB/mW | 6.6 mW | -1 dB | Not enough |
| HiFiMAN Susvara | 60 Ω | 83.0 dB | 50 mW | -3 dB | Not enough |
At 2.5 µV of output noise, here is where that noise lands in the five most revealing in-ears in the database.
This one hisses. With the most sensitive in-ears in the database its own noise lands around 29 dB SPL, which you will hear between tracks and in quiet passages.
| In-ear | Impedance | Sensitivity | Hiss level |
|---|---|---|---|
| Simgot EA500 | 16 Ω | 141.0 dB/V | 29 dB SPL |
| Tanchjim EA FORCE | 17 Ω | 137.7 dB/V | 26 dB SPL |
| Shure SE846 | 9 Ω | 134.5 dB/V | 22 dB SPL |
| Campfire Audio Clara | 13.3 Ω | 134.1 dB/V | 22 dB SPL |
| 64 Audio Fourte | 10 Ω | 134.0 dB/V | 22 dB SPL |
At 1.7Ω output impedance, the one-eighth rule says this source suits headphones of 13.6Ω and above. 67 of the 567 models here fall below that. Most of them are multi-driver in-ears, and the mismatch tilts the frequency response audibly rather than subtly.
The rule is a rule of thumb, not physics: a source impedance below one eighth of the headphone's keeps the interaction under about 1 dB. The checker works it out for any pair.
| Source | Type | Price | Into 300 Ω | Output impedance | Output noise |
|---|---|---|---|---|---|
| FiiO KA11 | USB dongle | $29 | 22 mW | 0.7 Ω | 1.7 µV |
| FiiO BTR13 | Bluetooth receiver | $59 | 10.0 mW | 0.6 Ω | 1.0 µV |
Of the 280 sources here, 2 do everything the FiiO KA13 does as a headphone output: reach 100 dB on every headphone it reaches, stay inside the one-eighth rule wherever it does and stay under the audible-hiss threshold wherever it does. The cheapest of them is the FiiO KA11 at $29, against this one’s $79 — $50 less.
This counts a headphone output and nothing else. Inputs, converters, microphone preamps, balanced outputs, the volume control, the case and the warranty are all outside it, and any of them can be the reason to buy the dearer box. What the count does say is that the three numbers a maker can be held to do not separate them.
$79 · 130 mW into 32Ω · 0.5 Ω out
Compare →$76 · 65 mW into 32Ω · output Ω not published
Compare →$75 · 125 mW into 32Ω · 0.3 Ω out
Compare →$70 · 125 mW into 32Ω · 0.3 Ω out
Compare →$70 · 125 mW into 32Ω · output Ω not published
Compare →$70 · 65 mW into 32Ω · output Ω not published
Compare →Worked out in advance against its closest rivals: vs ddHiFi TC35Pro (Eye2) · vs EPZ TP35 Pro · vs FiiO KA11 · vs FiiO KA15 · vs FiiO KA17 · vs FiiO KA3 · vs FiiO KA5 · vs FiiO SnowSky Tiny A · vs FiiO SnowSky Tiny B · vs HiBy FC4 · vs Hidizs S9 Pro · vs Hidizs SD2 · vs iBasso DC03 Pro · vs iBasso DC04 Pro · vs iFi GO link · vs Moondrop Dawn Pro · vs Onix Alpha XI1 · vs Tanchjim Space · vs Truthear SHIO. Each of those pages lists the headphones that tell the two apart.
Or put any two side by side in the source comparison tool, or run your own headphones through the amplifier matcher. Or see every FiiO source in the database, and how much of what this site says about them came from FiiO’s own documents.