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 covers what they ask of an amplifier, not how they sound.
The NORA needs 13.0 dB more than the EA FORCE to reach the same loudness — 0.20 mW against 0.01 mW.
| Specification | EA FORCE | NORA |
|---|---|---|
| Impedance | 17 Ω | 16 Ω |
| Sensitivity | 120.0 dB | 107.0 dB/mW |
| Sensitivity (voltage) | 137.7 dB/V | 125.0 dB/V |
| Power for 100 dB | 0.01 mW | 0.20 mW |
| Voltage for 100 dB | 13 mV | 57 mV |
| Current for 100 dB | 0.8 mA | 3.5 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 2.12 Ω | 2.00 Ω |
| Sources that reach 100 dB out of 280 | 280 | 280 |
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.
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.
58 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, 55 more).
280 of the 280 sources here reach 100 dB on both.
The NORA is more demanding than 14% of the 567 non-electrostatic models in this database; the EA FORCE than 0%.
| dB SPL | EA FORCE power | EA FORCE voltage | NORA power | NORA voltage |
|---|---|---|---|---|
| 80 | 0.1 µW | 1 mV | 2.0 µW | 6 mV |
| 85 | 0.3 µW | 2 mV | 6.3 µW | 10 mV |
| 90 | 1.0 µW | 4 mV | 0.02 mW | 18 mV |
| 95 | 3.2 µW | 7 mV | 0.06 mW | 32 mV |
| 100 | 0.01 mW | 13 mV | 0.20 mW | 57 mV |
| 105 | 0.03 mW | 23 mV | 0.63 mW | 0.10 V |
| Source | Price | Headroom, EA FORCE | Headroom, NORA | Output impedance | Noise |
|---|---|---|---|---|---|
| FiiO BTR13 | $59 | 40.7 dB | 27.8 dB | 0.6 Ω | 1.0 µV |
| iBasso DC03 Pro | $69 | 37.2 dB | 23.9 dB | 0.12 Ω | 0.9 µV |
| Topping L30 II | $149 | 55.3 dB | 42.4 dB | 0.1 Ω | 0.3 µV |
Of the 280 sources here, 280 reach 100 dB on both. 11 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 cheapest of the 11 is the FiiO BTR13, at $59. It leaves 40.7 dB of headroom on the EA FORCE and 27.8 dB on the NORA, its output impedance is 0.6 Ω against a one-eighth limit of 2.12 Ω and 2.00 Ω, and its noise figure puts the hiss floor 2 dB and 15 dB below the 20 dB SPL this site treats as the point where a quiet room stops hiding it.
| Model | As printed | Tolerance | Standard |
|---|---|---|---|
| EA FORCE | 8-48 kHZ | not printed | not printed |
| NORA | 2-48 kHZ | not printed | not printed |
Tanchjim prints 8-48 kHZ for the EA FORCE and 2-48 kHZ for the NORA.
EA FORCE: Tanchjim prints this row in Chinese and puts the unit only on the upper figure. Read strictly, “8-48 kHZ” starts at 8 kHz; read the way everyone reads it, at 8 Hz. The maker does not say which.
NORA: Tanchjim prints this row in Chinese and puts the unit only on the upper figure, so the lower number carries no unit of its own.
Neither range has a tolerance printed beside it, so a wider range on one sheet is not deeper bass or more treble.
Not a measurement; maker by maker.
Both have a page of their own. In full: 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.