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).
3 sources stay below the audible-hiss threshold with the Zero:2 but cross it with the Timeless AE (FiiO BTR11, Rupert Neve RNHP, Schiit Mjolnir 3).
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.
The gap between these two in decibels does not change with volume — it is a property of the two headphones. What changes is the size of the numbers, and it changes fast: every 10 dB costs ten times the power. The row that matters is the one nearest the level you listen at, and for most people that is nearer the top of this table than the bottom.
The Zero:2 is more demanding than 68% of the 567 non-electrostatic models in this database; the Timeless AE than 24%. Both figures use the same measure as the rest of the site: whichever runs out first against a 2 V, 100 mW dongle, voltage or power.
| dB SPL | Timeless AE power | Timeless AE voltage | Zero:2 power | Zero:2 voltage |
|---|---|---|---|---|
| 80 | 4.0 µW | 8 mV | 0.02 mW | 25 mV |
| 85 | 0.01 mW | 14 mV | 0.06 mW | 45 mV |
| 90 | 0.04 mW | 24 mV | 0.20 mW | 80 mV |
| 95 | 0.13 mW | 43 mV | 0.63 mW | 0.14 V |
| 100 | 0.40 mW | 77 mV | 2.0 mW | 0.25 V |
| 105 | 1.3 mW | 0.14 V | 6.3 mW | 0.45 V |
105 dB is included because forum power figures are usually quoted there or higher. It is also a level that damages hearing in minutes — how many minutes is its own calculator.
| Source | Price | Headroom, Timeless AE | Headroom, Zero:2 | Output impedance | Noise |
|---|---|---|---|---|---|
| JadeAudio JA11 | $20 | 15.4 dB | 11.8 dB | 0.5 Ω | 1.7 µV |
| FiiO KA11 | $29 | 27.6 dB | 20.0 dB | 0.7 Ω | 1.7 µV |
| FiiO BTR13 | $59 | 24.5 dB | 17.0 dB | 0.6 Ω | 1.0 µV |
Of the 280 sources here, 280 reach 100 dB on both. That is the easy axis. 67 of them also publish an output impedance low enough for both under the one-eighth rule and a noise figure that stays below the audible-hiss threshold with both — the rest either fail one of those or never printed the number at all, and 208 of them are in the second group.
The cheapest of the 67 is the JadeAudio JA11, at $20. It leaves 15.4 dB of headroom on the Timeless AE and 11.8 dB on the Zero:2, its output impedance is 0.5 Ω against a one-eighth limit of 1.85 Ω and 4.00 Ω, and its noise figure puts the hiss floor 13 dB and 23 dB below the 20 dB SPL this site treats as the point where a quiet room stops hiding it.
Cheapest that satisfies three published numbers is not the same as best, and none of it is about how either headphone sounds. To put either model against a source this page does not mention, or to change the target loudness, use the amplifier matcher.
| Model | As printed | Tolerance | Standard |
|---|---|---|---|
| Timeless AE | 5-40000hz | not printed | not printed |
| Zero:2 | 10HZ-20KHz | not printed | not printed |
HiFiX Audio, a dealer lists 5-40000hz for the Timeless AE. Linsoul, a Chinese-audio retailer lists 10HZ-20KHz for the Zero:2. Both of those figures stand on a shop page rather than a document published by the maker.
Neither range has a tolerance printed beside it, and that is the whole of what this section can tell you. A wider range on one sheet is not deeper bass or more treble on that headphone: without a tolerance, neither number says how loud either model is at the ends of its own range, so the difference between the two is a difference between two pieces of marketing copy. A ±dB figure is what turns a range into a specification, and of the 490 models whose maker prints a range, 58 print it.
None of this is a measurement. What each maker publishes, and what it is worth, is set out in the frequency response audit.
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.