The FiiO FT3 (350Ω) is 350Ω at 100.4 dB/mW; the FiiO FT5 is 36Ω at 96.0 dB/mW. This page covers what they ask of an amplifier, not how they sound.
The FT5 needs 4.4 dB more than the FT3 (350Ω) to reach the same loudness — 2.5 mW against 0.91 mW.
| Specification | FT3 (350Ω) | FT5 |
|---|---|---|
| Impedance | 350 Ω | 36 Ω |
| Sensitivity | 100.4 dB/mW | 96.0 dB/mW |
| Sensitivity (voltage) | 105.0 dB/V | 110.4 dB/V |
| Power for 100 dB | 0.91 mW | 2.5 mW |
| Voltage for 100 dB | 0.56 V | 0.30 V |
| Current for 100 dB | 1.6 mA | 8.4 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 43.75 Ω | 4.50 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.
20 sources are low enough in output impedance for the FT3 (350Ω) under the one-eighth rule but not for the FT5 (Zoom AMS-22, Arturia MiniFuse 2, Arturia MiniFuse 1, 17 more).
280 of the 280 sources here reach 100 dB on both.
The FT3 (350Ω) is more demanding than 89% of the 567 non-electrostatic models in this database; the FT5 than 75%.
| dB SPL | FT3 (350Ω) power | FT3 (350Ω) voltage | FT5 power | FT5 voltage |
|---|---|---|---|---|
| 80 | 9.1 µW | 56 mV | 0.03 mW | 30 mV |
| 85 | 0.03 mW | 0.10 V | 0.08 mW | 53 mV |
| 90 | 0.09 mW | 0.18 V | 0.25 mW | 95 mV |
| 95 | 0.29 mW | 0.32 V | 0.79 mW | 0.17 V |
| 100 | 0.91 mW | 0.56 V | 2.5 mW | 0.30 V |
| 105 | 2.9 mW | 1.00 V | 7.9 mW | 0.53 V |
| Source | Price | Headroom, FT3 (350Ω) | Headroom, FT5 | Output impedance | Noise |
|---|---|---|---|---|---|
| JadeAudio JA11 | $20 | 4.8 dB | 10.3 dB | 0.5 Ω | 1.7 µV |
| FiiO KA11 | $29 | 13.2 dB | 18.5 dB | 0.7 Ω | 1.7 µV |
| FiiO BTR11 | $36 | 4.5 dB | 10.3 dB | 0.5 Ω | 8.0 µV |
Of the 280 sources here, 280 reach 100 dB on both. 70 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 70 is the JadeAudio JA11, at $20. It leaves 4.8 dB of headroom on the FT3 (350Ω) and 10.3 dB on the FT5, its output impedance is 0.5 Ω against a one-eighth limit of 43.75 Ω and 4.50 Ω, and its noise figure puts the hiss floor 30 dB and 25 dB below the 20 dB SPL this site treats as the point where a quiet room stops hiding it.
| Model | As printed | Tolerance | Standard |
|---|---|---|---|
| FT3 (350Ω) | 7Hz-40kHz | not printed | not printed |
| FT5 | 7Hz-40kHz | not printed | not printed |
FiiO prints the same thing for both the FT3 (350Ω) and the FT5: 7Hz-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 FT3 (350Ω) and FiiO FT5. Every figure on this page comes from what FiiO published, or is derived from it — what that maker publishes, counted.