The Moondrop KATO is 32Ω at 108.1 dB/mW; the Moondrop May is 30Ω at 104.8 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 May needs 3.3 dB more than the KATO to reach the same loudness — 0.33 mW against 0.15 mW.
| Specification | KATO | May |
|---|---|---|
| Impedance | 32 Ω | 30 Ω |
| Sensitivity | 108.1 dB/mW | 104.8 dB/mW |
| Sensitivity (voltage) | 123.0 dB/V | 120.0 dB/V |
| Power for 100 dB | 0.15 mW | 0.33 mW |
| Voltage for 100 dB | 70 mV | 100 mV |
| Current for 100 dB | 2.2 mA | 3.3 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 4.00 Ω | 3.75 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.
3 sources stay below the audible-hiss threshold with the May but cross it with the KATO (FiiO BTR11, FiiO K11 R2R, Rupert Neve RNHP).
280 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: Moondrop KATO and Moondrop May. Every figure on this page comes from what Moondrop published, or is derived from it — what that maker publishes, counted.