FiiO FA19: how much amplifier do you need?

The FiiO FA19 is 10Ω with a sensitivity of 106.0 dB/mW, which is 126.0 dB/V. To reach 100 dB SPL — genuinely loud, louder than most people listen — it needs 0.25 mW, or 50 mV across the drivers.

That puts it in the easy category. A phone, a laptop headphone jack or the cheapest USB dongle will drive it to painful levels. Of the 280 sources in the database, 280 have at least 10 dB of headroom and another 0 have enough. The cheapest portable source that does the job is the Apple USB-C dongle (US) at $9.

The two numbers that decide everything

Impedance10 Ω
Sensitivity106.0 dB/mW
Sensitivity (voltage)126.0 dB/V
Power for 100 dB SPL0.25 mW
Voltage for 100 dB SPL50 mV
TypeIn-ear monitor
Easy to drive — anything will do it
All 280 sources at 100 dB SPL into 10Ω
Comfortable 280Enough 0Marginal 0Not enough 0
Cheapest portable source that does it
$9 · USB dongle · +16 dB headroom
Cheapest desktop amp with 10 dB to spare
$75 · desktop DAC/amp · +23 dB headroom

Sensitivity here is in dB per milliwatt. Why the unit matters.

Where this sensitivity figure comes from

FiiO publishes this directly as 106 dB/mW (@1kHz), per milliwatt, so nothing was converted.

FiiO prints the impedance as 10Ω@1kHz, not as a bare number. Everything on this page is calculated with the nominal 10Ω, and the rest of that line is quoted here rather than tidied away, because how a figure is qualified is part of the specification too.

Source: fiio.com. How this data was built.

What is printed there, and what it is worth

As it is labelledAs printedToleranceStandard
Frequency response20Hz-40kHznot printednot printed

FiiO prints 20Hz-40kHz for the FiiO FA19, under the heading “Frequency response”. Source: fiio.com.

No tolerance is printed with it, so “20Hz-40kHz” says nothing about how loud this headphone actually is at 20 Hz.

Only what the maker printed; maker by maker.

Power, voltage and current by listening level

LevelWhat it isPowerVoltageCurrent
85 dB SPLquiet background listening0.01 mW9 mV0.9 mA
95 dB SPLnormal listening0.08 mW28 mV2.8 mA
100 dB SPLloud listening0.25 mW50 mV5.0 mA
105 dB SPLvery loud0.79 mW89 mV8.9 mA
110 dB SPLpeaks on dynamic music2.5 mW0.16 V15.8 mA

Most people listen between 75 and 85 dB; the 100 dB row leaves room for peaks.

The cheapest sources that drive them with room to spare

The 15 cheapest of the 280 sources here that reach 100 dB SPL into 10Ω with at least 10 dB of headroom and no known hiss or output-impedance problem with these headphones. All 280 sources, judged for these headphones.

SourceTypePricePower into 10ΩHeadroomVerdict
FiiO SnowSky Tiny AUSB dongle$2228 mW+20 dBComfortable
FiiO SnowSky Tiny BUSB dongle$2243 mW+22 dBComfortable
Tanchjim Stargate IIUSB dongle$4051 mW+23 dBComfortable
ddHiFi TC35ALUSB dongle$4666 mW+24 dBComfortable
ddHiFi TC35AirUSB dongle$4666 mW+24 dBComfortable
Fosi Audio N3Bluetooth receiver$5043 mW+22 dBComfortable
Hidizs SD2USB dongle$5022 mW+19 dBComfortable
iFi GO linkUSB dongle$5922 mW+19 dBComfortable
Kiwi Ears Allegro ProUSB dongle$6021 mW+19 dBComfortable
ddHiFi TC35Pro (Mountain2)USB dongle$6620 mW+19 dBComfortable
DUNU DTC 480USB dongle$7020 mW+19 dBComfortable
EPZ TP35 ProUSB dongle$7035 mW+21 dBComfortable
Aiyima A2 Prodesktop DAC/amp$7547 mW+23 dBComfortable
ddHiFi TC35Pro (Eye2)USB dongle$7620 mW+19 dBComfortable
ddHiFi TC44 Pro E2USB dongle$9978 mW+25 dBComfortable

The three ways a source goes wrong

Hiss. At 126.0 dB/V these are sensitive enough to reveal a source's own noise floor. The noisiest source in the database, the Schiit Mjolnir 3, would put its hiss at roughly 34 dB SPL in these headphones — clearly audible in quiet passages. Check your own source.

Output impedance. At 10Ω these want a source output impedance below 1.25Ω to satisfy the one-eighth rule; 46 of the 192 sources that publish one miss it. Check yours here.

Similar headphones

Compared with its stablemates: vs FD11 · vs FH19 · vs FP3 · vs FX15.

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