EA FORCE vs NORA: which needs more amplifier?

The Tanchjim EA FORCE is 17Ω at 120.0 dB (no reference unit printed); the Tanchjim NORA is 16Ω at 107.0 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 NORA needs 13.0 dB more than the EA FORCE to reach the same loudness — 0.20 mW against 0.01 mW.

The numbers that decide it

SpecificationEA FORCENORA
Impedance17 Ω16 Ω
Sensitivity120.0 dB107.0 dB/mW
Sensitivity (voltage)137.7 dB/V125.0 dB/V
Power for 100 dB0.01 mW0.20 mW
Voltage for 100 dB13 mV57 mV
Current for 100 dB0.8 mA3.5 mA
Highest source impedance
that leaves them alone (one-eighth rule)
2.12 Ω2.00 Ω
Sources that reach 100 dB
out of 280
280280

One caution before reading the rows. Tanchjim EA FORCE 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.

49 sources stay below the audible-hiss threshold with the NORA but cross it with the EA FORCE (JadeAudio JA11, Kiwi Ears Allegro Mini, FiiO KA11, 46 more).

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: Tanchjim EA FORCE and Tanchjim NORA. Each figure on this page is labelled on those pages with where it came from, including the ones Tanchjim never published — what that maker publishes, counted.