PRX vs ZS10 Pro: which needs more amplifier?

The KZ PRX is 15Ω at 94.0 dB (no reference unit printed); the KZ ZS10 Pro is 30Ω at 111.0 dB (no reference unit printed). This page covers what they ask of an amplifier, not how they sound.

The PRX needs 17.0 dB more than the ZS10 Pro to reach the same loudness — 4.0 mW against 0.08 mW.

The numbers that decide it

SpecificationPRXZS10 Pro
Impedance15 Ω30 Ω
Sensitivity94.0 dB111.0 dB
Sensitivity (voltage)112.2 dB/V126.2 dB/V
Power for 100 dB4.0 mW0.08 mW
Voltage for 100 dB0.24 V49 mV
Current for 100 dB16.3 mA1.6 mA
Highest source impedance
that leaves them alone (one-eighth rule)
1.88 Ω3.75 Ω
Sources that reach 100 dB
out of 280
280280

One caution before reading the rows. KZ PRX and KZ ZS10 Pro 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.

3 sources are low enough in output impedance for the ZS10 Pro under the one-eighth rule but not for the PRX (Astell&Kern HC3, RME Fireface UFX II, RME Fireface UFX III).

16 sources stay below the audible-hiss threshold with the PRX but cross it with the ZS10 Pro (FiiO BTR11, FiiO K11 R2R, Lake People G103-S Mk II, 13 more).

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

What each one needs from 80 to 105 dB

The PRX is more demanding than 66% of the 567 non-electrostatic models in this database; the ZS10 Pro than 10%.

dB SPLPRX powerPRX voltageZS10 Pro powerZS10 Pro voltage
800.04 mW24 mV0.8 µW5 mV
850.13 mW43 mV2.5 µW9 mV
900.40 mW77 mV7.9 µW15 mV
951.3 mW0.14 V0.03 mW27 mV
1004.0 mW0.24 V0.08 mW49 mV
10513 mW0.43 V0.25 mW87 mV

The cheapest source that satisfies both

SourcePriceHeadroom, PRXHeadroom, ZS10 ProOutput impedanceNoise
JadeAudio JA11$205.5 dB25.5 dB0.5 Ω1.7 µV
FiiO KA11$2917.6 dB34.1 dB0.7 Ω1.7 µV
FiiO BTR13$5914.5 dB31.0 dB0.6 Ω1.0 µV

Of the 280 sources here, 280 reach 100 dB on both. 55 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 55 is the JadeAudio JA11, at $20. It leaves 5.5 dB of headroom on the PRX and 25.5 dB on the ZS10 Pro, its output impedance is 0.5 Ω against a one-eighth limit of 1.88 Ω and 3.75 Ω, and its noise figure puts the hiss floor 23 dB and 9 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
PRX20-40000Hznot printednot printed
ZS10 Pro7-40000Hznot printednot printed

KZ prints 20-40000Hz for the PRX and 7-40000Hz for the ZS10 Pro.

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: KZ PRX and KZ ZS10 Pro. Each figure on this page is labelled on those pages with where it came from, including the ones KZ never published — what that maker publishes, counted.

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