The Dunu Alpha 3 is 32Ω at 105.0 dB (no reference unit printed); the Dunu Titan S2 is 16Ω at 107.0 dB/mW. This page covers what they ask of an amplifier, not how they sound.
The Alpha 3 needs 2.0 dB more than the Titan S2 to reach the same loudness — 0.32 mW against 0.20 mW.
| Specification | Alpha 3 | Titan S2 |
|---|---|---|
| Impedance | 32 Ω | 16 Ω |
| Sensitivity | 105.0 dB | 107.0 dB/mW |
| Sensitivity (voltage) | 119.9 dB/V | 125.0 dB/V |
| Power for 100 dB | 0.32 mW | 0.20 mW |
| Voltage for 100 dB | 0.10 V | 57 mV |
| Current for 100 dB | 3.1 mA | 3.5 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 4.00 Ω | 2.00 Ω |
| Sources that reach 100 dB out of 280 | 280 | 280 |
One caution before reading the rows. Dunu Alpha 3 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.
9 sources stay below the audible-hiss threshold with the Alpha 3 but cross it with the Titan S2 (FiiO BTR11, FiiO K11 R2R, Lake People G103-S Mk II, 6 more).
280 of the 280 sources here reach 100 dB on both.
The Alpha 3 is more demanding than 34% of the 567 non-electrostatic models in this database; the Titan S2 than 14%.
| dB SPL | Alpha 3 power | Alpha 3 voltage | Titan S2 power | Titan S2 voltage |
|---|---|---|---|---|
| 80 | 3.2 µW | 10 mV | 2.0 µW | 6 mV |
| 85 | 0.01 mW | 18 mV | 6.3 µW | 10 mV |
| 90 | 0.03 mW | 32 mV | 0.02 mW | 18 mV |
| 95 | 0.10 mW | 57 mV | 0.06 mW | 32 mV |
| 100 | 0.32 mW | 0.10 V | 0.20 mW | 57 mV |
| 105 | 1.0 mW | 0.18 V | 0.63 mW | 0.10 V |
| Source | Price | Headroom, Alpha 3 | Headroom, Titan S2 | Output impedance | Noise |
|---|---|---|---|---|---|
| JadeAudio JA11 | $20 | 19.8 dB | 18.8 dB | 0.5 Ω | 1.7 µV |
| FiiO KA11 | $29 | 28.0 dB | 30.9 dB | 0.7 Ω | 1.7 µV |
| FiiO BTR13 | $59 | 25.0 dB | 27.8 dB | 0.6 Ω | 1.0 µV |
Of the 280 sources here, 280 reach 100 dB on both. 62 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 62 is the JadeAudio JA11, at $20. It leaves 19.8 dB of headroom on the Alpha 3 and 18.8 dB on the Titan S2, its output impedance is 0.5 Ω against a one-eighth limit of 4.00 Ω and 2.00 Ω, and its noise figure puts the hiss floor 15 dB and 10 dB below the 20 dB SPL this site treats as the point where a quiet room stops hiding it.
| Model | As printed | Tolerance | Standard |
|---|---|---|---|
| Alpha 3 | 5Hz-40kHz | not printed | not printed |
| Titan S2 | 5 Hz - 40 kHz | not printed | not printed |
Dunu prints 5Hz-40kHz for the Alpha 3 and 5 Hz - 40 kHz for the Titan S2.
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: Dunu Alpha 3 and Dunu Titan S2. Each figure on this page is labelled on those pages with where it came from, including the ones Dunu never published — what that maker publishes, counted.