Oracle MKII vs Origin: which needs more amplifier?

The Thieaudio Oracle MKII is 15Ω at 104.0 dB (no figure from the maker at all); the Thieaudio Origin is 9Ω at 102.0 dB (no reference unit printed). This page covers what they ask of an amplifier, not how they sound.

The Origin needs 2.0 dB more than the Oracle MKII to reach the same loudness — 0.63 mW against 0.40 mW.

The numbers that decide it

SpecificationOracle MKIIOrigin
Impedance15 Ω9 Ω
Sensitivity104.0 dB102.0 dB
Sensitivity (voltage)122.2 dB/V122.5 dB/V
Power for 100 dB0.40 mW0.63 mW
Voltage for 100 dB77 mV75 mV
Current for 100 dB5.2 mA8.4 mA
Highest source impedance
that leaves them alone (one-eighth rule)
1.88 Ω1.12 Ω
Sources that reach 100 dB
out of 280
280280

One caution before reading the rows. Thieaudio Origin 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. For Thieaudio Oracle MKII the maker publishes no sensitivity figure at all. The number in the table was collected when this database was first built and has never been traced to a manufacturer document, so treat every row below it as an estimate rather than a specification.

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.

8 sources are low enough in output impedance for the Oracle MKII under the one-eighth rule but not for the Origin (FiiO KA13, FiiO K11, Schiit Vali 2+, 5 more).

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

What each one needs from 80 to 105 dB

The Oracle MKII is more demanding than 24% of the 567 non-electrostatic models in this database; the Origin than 24%.

dB SPLOracle MKII powerOracle MKII voltageOrigin powerOrigin voltage
804.0 µW8 mV6.3 µW8 mV
850.01 mW14 mV0.02 mW13 mV
900.04 mW24 mV0.06 mW24 mV
950.13 mW43 mV0.20 mW42 mV
1000.40 mW77 mV0.63 mW75 mV
1051.3 mW0.14 V2.0 mW0.13 V

The cheapest source that satisfies both

SourcePriceHeadroom, Oracle MKIIHeadroom, OriginOutput impedanceNoise
JadeAudio JA11$2015.5 dB11.3 dB0.5 Ω1.7 µV
FiiO KA11$2927.6 dB23.4 dB0.7 Ω1.7 µV
FiiO BTR13$5924.5 dB20.3 dB0.6 Ω1.0 µV

Of the 280 sources here, 280 reach 100 dB on both. 60 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 60 is the JadeAudio JA11, at $20. It leaves 15.5 dB of headroom on the Oracle MKII and 11.3 dB on the Origin, its output impedance is 0.5 Ω against a one-eighth limit of 1.88 Ω and 1.12 Ω, and its noise figure puts the hiss floor 13 dB and 13 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
Oracle MKIInothing printed——
Origin20Hz – 44kHznot printednot printed

Thieaudio prints nothing at all for the Oracle MKII and 20Hz – 44kHz for the Origin.

Oracle MKII: Thieaudio publishes a measured frequency-response graph for this model on the same page. What it does not publish is a range: there is no row of numbers to read the graph against.

So one side of this comparison has a frequency-response number and the other does not — which changes less than it looks. The range printed for the Origin comes with no tolerance beside it, and a range without a ±dB figure says nothing about how loud the headphone is at either end of it: thirty decibels down at the bottom and the sentence would still be true. On the only reading that would have made it a specification, the two sheets say the same amount: nothing.

Not a measurement; maker by maker.

Both pages in full

Both have a page of their own. In full: Thieaudio Oracle MKII and Thieaudio Origin. Each figure on this page is labelled on those pages with where it came from, including the ones Thieaudio never published — what that maker publishes, counted.

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