Legato vs Timeless AE: which needs more amplifier?

The 7Hz Legato is 26Ω at 92.1 dB/mW; the 7Hz Timeless AE is 14.8Ω at 104.0 dB (no reference unit printed). 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 Legato needs 11.9 dB more than the Timeless AE to reach the same loudness — 6.2 mW against 0.40 mW.

The numbers that decide it

SpecificationLegatoTimeless AE
Impedance26 Ω14.8 Ω
Sensitivity92.1 dB/mW104.0 dB
Sensitivity (voltage)108.0 dB/V122.3 dB/V
Power for 100 dB6.2 mW0.40 mW
Voltage for 100 dB0.40 V77 mV
Current for 100 dB15.4 mA5.2 mA
Highest source impedance
that leaves them alone (one-eighth rule)
3.25 Ω1.85 Ω
Sources that reach 100 dB
out of 280
280280

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.

Where the two part company

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 Legato 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 Legato 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.

Both pages in full

Each model has a page of its own with the full source list, the hiss estimate and the provenance of every figure above: 7Hz Legato and 7Hz Timeless AE. 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.