The Moondrop S8 is 16Ω at 104.0 dB/mW; the Moondrop Variations is 15.2Ω at 99.8 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 Variations needs 4.2 dB more than the S8 to reach the same loudness — 1.0 mW against 0.40 mW.
| Specification | S8 | Variations |
|---|---|---|
| Impedance | 16 Ω | 15.2 Ω |
| Sensitivity | 104.0 dB/mW | 99.8 dB/mW |
| Sensitivity (voltage) | 122.0 dB/V | 118.0 dB/V |
| Power for 100 dB | 0.40 mW | 1.0 mW |
| Voltage for 100 dB | 80 mV | 0.13 V |
| Current for 100 dB | 5.0 mA | 8.3 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 2.00 Ω | 1.90 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 are low enough in output impedance for the S8 under the one-eighth rule but not for the Variations (Astell&Kern HC3, RME Fireface UFX II, RME Fireface UFX III).
2 sources stay below the audible-hiss threshold with the Variations but cross it with the S8 (FiiO BTR11, 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 S8 and Moondrop Variations. Every figure on this page comes from what Moondrop published, or is derived from it — what that maker publishes, counted.