The FiiO FT3 (350Ω) is 350Ω at 100.4 dB/mW; the FiiO JT1 is 32Ω at 88.1 dB/mW. This page is only about what they ask of an amplifier — not how they sound, which no specification on either sheet can tell you.
The JT1 needs 12.3 dB more than the FT3 (350Ω) to reach the same loudness — 15 mW against 0.91 mW.
| Specification | FT3 (350Ω) | JT1 |
|---|---|---|
| Impedance | 350 Ω | 32 Ω |
| Sensitivity | 100.4 dB/mW | 88.1 dB/mW |
| Sensitivity (voltage) | 105.0 dB/V | 103.0 dB/V |
| Power for 100 dB | 0.91 mW | 15 mW |
| Voltage for 100 dB | 0.56 V | 0.70 V |
| Current for 100 dB | 1.6 mA | 22.0 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 43.75 Ω | 4.00 Ω |
| Sources that reach 100 dB out of 280 | 280 | 278 |
2 of the 280 sources have the power for the FT3 (350Ω) but not for the JT1 — Apple USB-C dongle (EU), Steinberg UR22C.
20 sources are low enough in output impedance for the FT3 (350Ω) under the one-eighth rule but not for the JT1 (Zoom AMS-22, Arturia MiniFuse 2, Arturia MiniFuse 1, 17 more).
278 of the 280 sources here reach 100 dB on both. That count is about power only — the output-impedance and hiss lines above are separate questions, and a source can pass this one and fail those.
Each model has a page of its own with the full source list, the hiss estimate and the provenance of every figure above: FiiO FT3 (350Ω) and FiiO JT1. Each figure on this page is labelled on those pages with where it came from, including the ones FiiO never published — what that maker publishes, counted.