Belle vs Stardust: which needs more amplifier?

The Kiwi Ears Belle is 32Ω at 103.0 dB (no reference unit printed); the Kiwi Ears Stardust is 13Ω at 107.0 dB (no reference unit printed). This page covers what they ask of an amplifier, not how they sound.

The Belle needs 4.0 dB more than the Stardust to reach the same loudness — 0.50 mW against 0.20 mW.

The numbers that decide it

SpecificationBelleStardust
Impedance32 Ω13 Ω
Sensitivity103.0 dB107.0 dB
Sensitivity (voltage)117.9 dB/V125.9 dB/V
Power for 100 dB0.50 mW0.20 mW
Voltage for 100 dB0.13 V51 mV
Current for 100 dB4.0 mA3.9 mA
Highest source impedance
that leaves them alone (one-eighth rule)
4.00 Ω1.62 Ω
Sources that reach 100 dB
out of 280
280280

One caution before reading the rows. Kiwi Ears Belle and Kiwi Ears Stardust printed a decibel figure with no reference unit, so this page reads it as per milliwatt. If it is really per volt, each of them 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.

5 sources are low enough in output impedance for the Belle under the one-eighth rule but not for the Stardust (FiiO KA13, Schiit Vali 2+, Astell&Kern HC3, 2 more).

14 sources stay below the audible-hiss threshold with the Belle but cross it with the Stardust (FiiO BTR11, FiiO K11 R2R, Lake People G103-S Mk II, 11 more).

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

What each one needs from 80 to 105 dB

The Belle is more demanding than 41% of the 567 non-electrostatic models in this database; the Stardust than 12%.

dB SPLBelle powerBelle voltageStardust powerStardust voltage
805.0 µW13 mV2.0 µW5 mV
850.02 mW23 mV6.3 µW9 mV
900.05 mW40 mV0.02 mW16 mV
950.16 mW71 mV0.06 mW29 mV
1000.50 mW0.13 V0.20 mW51 mV
1051.6 mW0.23 V0.63 mW91 mV

The cheapest source that satisfies both

SourcePriceHeadroom, BelleHeadroom, StardustOutput impedanceNoise
JadeAudio JA11$2017.8 dB17.9 dB0.5 Ω1.7 µV
FiiO KA11$2926.0 dB30.0 dB0.7 Ω1.7 µV
FiiO BTR13$5923.0 dB26.9 dB0.6 Ω1.0 µV

Of the 280 sources here, 280 reach 100 dB on both. 56 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 56 is the JadeAudio JA11, at $20. It leaves 17.8 dB of headroom on the Belle and 17.9 dB on the Stardust, its output impedance is 0.5 Ω against a one-eighth limit of 4.00 Ω and 1.62 Ω, and its noise figure puts the hiss floor 17 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
Belle20Hz-20kHznot printednot printed
Stardust20Hz–40kHznot printednot printed

Kiwi Ears prints 20Hz-20kHz for the Belle and 20Hz–40kHz for the Stardust.

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: Kiwi Ears Belle and Kiwi Ears Stardust. Each figure on this page is labelled on those pages with where it came from, including the ones Kiwi Ears never published — what that maker publishes, counted.

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