The Tanchjim FOLA is 16Ω at 108.0 dB/mW; the Tanchjim OLA II is 30Ω at 105.8 dB/mW. This page covers what they ask of an amplifier, not how they sound.
The OLA II needs 2.2 dB more than the FOLA to reach the same loudness — 0.26 mW against 0.16 mW.
| Specification | FOLA | OLA II |
|---|---|---|
| Impedance | 16 Ω | 30 Ω |
| Sensitivity | 108.0 dB/mW | 105.8 dB/mW |
| Sensitivity (voltage) | 126.0 dB/V | 121.0 dB/V |
| Power for 100 dB | 0.16 mW | 0.26 mW |
| Voltage for 100 dB | 50 mV | 89 mV |
| Current for 100 dB | 3.1 mA | 3.0 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 2.00 Ω | 3.75 Ω |
| Sources that reach 100 dB out of 280 | 280 | 280 |
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.
14 sources stay below the audible-hiss threshold with the OLA II but cross it with the FOLA (FiiO BTR11, FiiO K11 R2R, Lake People G103-S Mk II, 11 more).
280 of the 280 sources here reach 100 dB on both.
The OLA II is more demanding than 27% of the 567 non-electrostatic models in this database; the FOLA than 11%.
| dB SPL | FOLA power | FOLA voltage | OLA II power | OLA II voltage |
|---|---|---|---|---|
| 80 | 1.6 µW | 5 mV | 2.6 µW | 9 mV |
| 85 | 5.0 µW | 9 mV | 8.3 µW | 16 mV |
| 90 | 0.02 mW | 16 mV | 0.03 mW | 28 mV |
| 95 | 0.05 mW | 28 mV | 0.08 mW | 50 mV |
| 100 | 0.16 mW | 50 mV | 0.26 mW | 89 mV |
| 105 | 0.50 mW | 90 mV | 0.83 mW | 0.16 V |
| Source | Price | Headroom, FOLA | Headroom, OLA II | Output impedance | Noise |
|---|---|---|---|---|---|
| JadeAudio JA11 | $20 | 19.8 dB | 20.3 dB | 0.5 Ω | 1.7 µV |
| FiiO KA11 | $29 | 31.9 dB | 28.9 dB | 0.7 Ω | 1.7 µV |
| FiiO BTR13 | $59 | 28.8 dB | 25.8 dB | 0.6 Ω | 1.0 µV |
Of the 280 sources here, 280 reach 100 dB on both. 57 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 57 is the JadeAudio JA11, at $20. It leaves 19.8 dB of headroom on the FOLA and 20.3 dB on the OLA II, its output impedance is 0.5 Ω against a one-eighth limit of 2.00 Ω and 3.75 Ω, and its noise figure puts the hiss floor 9 dB and 14 dB below the 20 dB SPL this site treats as the point where a quiet room stops hiding it.
| Model | As printed | Tolerance | Standard |
|---|---|---|---|
| FOLA | 2-48 kHZ | not printed | not printed |
| OLA II | 8-48 kHZ | not printed | not printed |
Tanchjim prints 2-48 kHZ for the FOLA and 8-48 kHZ for the OLA II.
FOLA: 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.
OLA II: 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.
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 FOLA and Tanchjim OLA II. Every figure on this page comes from what Tanchjim published, or is derived from it — what that maker publishes, counted.