The Campfire Audio Andromeda 2020 is 9Ω at 94.0 dB (no figure from the maker at all); the Truthear Zero:RED is 17.5Ω at 99.9 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 Campfire Audio Andromeda 2020 needs 5.9 dB more than the Truthear Zero:RED to reach the same loudness — 4.0 mW against 1.0 mW.
| Specification | Campfire Audio Andromeda 2020 | Truthear Zero:RED |
|---|---|---|
| Impedance | 9 Ω | 17.5 Ω |
| Sensitivity | 94.0 dB | 99.9 dB/mW |
| Sensitivity (voltage) | 114.5 dB/V | 117.5 dB/V |
| Power for 100 dB | 4.0 mW | 1.0 mW |
| Voltage for 100 dB | 0.19 V | 0.13 V |
| Current for 100 dB | 21.0 mA | 7.6 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 1.12 Ω | 2.19 Ω |
| Sources that reach 100 dB out of 280 | 279 | 280 |
One caution before reading the rows. For Campfire Audio Andromeda 2020 the maker publishes no sensitivity figure at all. The number in the table was collected when this database was first built and has never been traced to a manufacturer document, so treat every row below it as an estimate rather than a specification.
1 of the 280 sources has the power for the Truthear Zero:RED but not for the Campfire Audio Andromeda 2020 — Steinberg UR22C.
11 sources are low enough in output impedance for the Truthear Zero:RED under the one-eighth rule but not for the Campfire Audio Andromeda 2020 (FiiO KA13, FiiO K11, Schiit Vali 2+, 8 more).
279 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: Campfire Audio Andromeda 2020 and Truthear Zero:RED. Each figure on this page is labelled on those pages with where it came from, including the ones Campfire Audio and Truthear never published — what Campfire Audio publishes and what Truthear publishes, both counted.