The 7Hz Timeless AE is 14.8Ω at 104.0 dB (no reference unit printed); the 7Hz Zero:2 is 32Ω at 97.0 dB (no figure from the maker at all). 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 Zero:2 needs 7.0 dB more than the Timeless AE to reach the same loudness — 2.0 mW against 0.40 mW.
| Specification | Timeless AE | Zero:2 |
|---|---|---|
| Impedance | 14.8 Ω | 32 Ω |
| Sensitivity | 104.0 dB | 97.0 dB |
| Sensitivity (voltage) | 122.3 dB/V | 111.9 dB/V |
| Power for 100 dB | 0.40 mW | 2.0 mW |
| Voltage for 100 dB | 77 mV | 0.25 V |
| Current for 100 dB | 5.2 mA | 7.9 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 1.85 Ω | 4.00 Ω |
| Sources that reach 100 dB out of 280 | 280 | 280 |
One caution before reading the rows. 7Hz Timeless AE printed a decibel figure with no reference unit, so this page reads it as per milliwatt. If it is really per volt, that model needs far more than the table says. Why the two readings differ by so much. For 7Hz Zero:2 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.
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 Zero:2 under the one-eighth rule but not for the Timeless AE (Astell&Kern HC3, RME Fireface UFX II, RME Fireface UFX III).
2 sources stay below the audible-hiss threshold with the Zero:2 but cross it with the Timeless AE (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: 7Hz Timeless AE and 7Hz Zero:2. Each figure on this page is labelled on those pages with where it came from, including the ones 7Hz never published — what that maker publishes, counted.