The FiiO FA19 is 10Ω at 106.0 dB/mW; the FiiO FD11 is 24Ω at 111.0 dB/mW. This page covers what they ask of an amplifier, not how they sound.
The FA19 needs 5.0 dB more than the FD11 to reach the same loudness — 0.25 mW against 0.08 mW.
| Specification | FA19 | FD11 |
|---|---|---|
| Impedance | 10 Ω | 24 Ω |
| Sensitivity | 106.0 dB/mW | 111.0 dB/mW |
| Sensitivity (voltage) | 126.0 dB/V | 127.2 dB/V |
| Power for 100 dB | 0.25 mW | 0.08 mW |
| Voltage for 100 dB | 50 mV | 44 mV |
| Current for 100 dB | 5.0 mA | 1.8 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 1.25 Ω | 3.00 Ω |
| Sources that reach 100 dB out of 280 | 280 | 280 |
Every source in the database that drives one of them drives the other. On power, the choice between these two changes nothing about what amplifier you need.
8 sources are low enough in output impedance for the FD11 under the one-eighth rule but not for the FA19 (FiiO KA13, Schiit Vali 2+, Astell&Kern HC3, 5 more).
2 sources stay below the audible-hiss threshold with the FA19 but cross it with the FD11 (Grace Design m900, FiiO K17).
280 of the 280 sources here reach 100 dB on both.
The FA19 is more demanding than 11% of the 567 non-electrostatic models in this database; the FD11 than 8%.
| dB SPL | FA19 power | FA19 voltage | FD11 power | FD11 voltage |
|---|---|---|---|---|
| 80 | 2.5 µW | 5 mV | 0.8 µW | 4 mV |
| 85 | 7.9 µW | 9 mV | 2.5 µW | 8 mV |
| 90 | 0.03 mW | 16 mV | 7.9 µW | 14 mV |
| 95 | 0.08 mW | 28 mV | 0.03 mW | 25 mV |
| 100 | 0.25 mW | 50 mV | 0.08 mW | 44 mV |
| 105 | 0.79 mW | 89 mV | 0.25 mW | 78 mV |
| Source | Price | Headroom, FA19 | Headroom, FD11 | Output impedance | Noise |
|---|---|---|---|---|---|
| JadeAudio JA11 | $20 | 15.7 dB | 24.5 dB | 0.5 Ω | 1.7 µV |
| FiiO KA11 | $29 | 27.9 dB | 34.3 dB | 0.7 Ω | 1.7 µV |
| FiiO BTR13 | $59 | 24.8 dB | 31.2 dB | 0.6 Ω | 1.0 µV |
Of the 280 sources here, 280 reach 100 dB on both. 51 of them also publish an output impedance low enough for both under the one-eighth rule and a noise figure that stays below the audible-hiss threshold with both.
The cheapest of the 51 is the JadeAudio JA11, at $20. It leaves 15.7 dB of headroom on the FA19 and 24.5 dB on the FD11, its output impedance is 0.5 Ω against a one-eighth limit of 1.25 Ω and 3.00 Ω, and its noise figure puts the hiss floor 9 dB and 8 dB below the 20 dB SPL this site treats as the point where a quiet room stops hiding it.
| Model | As printed | Tolerance | Standard |
|---|---|---|---|
| FA19 | 20Hz-40kHz | not printed | not printed |
| FD11 | 20Hz-40kHz | not printed | not printed |
FiiO prints the same thing for both the FA19 and the FD11: 20Hz-40kHz.
Neither range has a tolerance printed beside it, so the matching numbers say little.
Not a measurement; maker by maker.
Both have a page of their own. In full: FiiO FA19 and FiiO FD11. Every figure on this page comes from what FiiO published, or is derived from it — what that maker publishes, counted.