Alpha 3 vs KIMA 2: which needs more amplifier?

The Dunu Alpha 3 is 32Ω at 105.0 dB (no reference unit printed); the Dunu KIMA 2 is 20Ω at 108.0 dB/mW. This page covers what they ask of an amplifier, not how they sound.

The Alpha 3 needs 3.0 dB more than the KIMA 2 to reach the same loudness — 0.32 mW against 0.16 mW.

The numbers that decide it

SpecificationAlpha 3KIMA 2
Impedance32 Ω20 Ω
Sensitivity105.0 dB108.0 dB/mW
Sensitivity (voltage)119.9 dB/V125.0 dB/V
Power for 100 dB0.32 mW0.16 mW
Voltage for 100 dB0.10 V56 mV
Current for 100 dB3.1 mA2.8 mA
Highest source impedance
that leaves them alone (one-eighth rule)
4.00 Ω2.50 Ω
Sources that reach 100 dB
out of 280
280280

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.

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.

9 sources stay below the audible-hiss threshold with the Alpha 3 but cross it with the KIMA 2 (FiiO BTR11, FiiO K11 R2R, Lake People G103-S Mk II, 6 more).

280 of the 280 sources here reach 100 dB on both.

What each one needs from 80 to 105 dB

The Alpha 3 is more demanding than 34% of the 567 non-electrostatic models in this database; the KIMA 2 than 14%.

dB SPLAlpha 3 powerAlpha 3 voltageKIMA 2 powerKIMA 2 voltage
803.2 µW10 mV1.6 µW6 mV
850.01 mW18 mV5.0 µW10 mV
900.03 mW32 mV0.02 mW18 mV
950.10 mW57 mV0.05 mW32 mV
1000.32 mW0.10 V0.16 mW56 mV
1051.0 mW0.18 V0.50 mW0.10 V

The cheapest source that satisfies both

SourcePriceHeadroom, Alpha 3Headroom, KIMA 2Output impedanceNoise
JadeAudio JA11$2019.8 dB20.7 dB0.5 Ω1.7 µV
FiiO KA11$2928.0 dB31.5 dB0.7 Ω1.7 µV
FiiO BTR13$5925.0 dB28.4 dB0.6 Ω1.0 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 20.7 dB on the KIMA 2, its output impedance is 0.5 Ω against a one-eighth limit of 4.00 Ω and 2.50 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.

Try any other source.

What each sheet prints, and what it is worth

ModelAs printedToleranceStandard
Alpha 35Hz-40kHznot printednot printed
KIMA 25 Hz - 40 kHznot printednot printed

Dunu prints 5Hz-40kHz for the Alpha 3 and 5 Hz - 40 kHz for the KIMA 2.

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 pages in full

Both have a page of their own. In full: Dunu Alpha 3 and Dunu KIMA 2. 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.

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