Ara vs Chimera: which needs more amplifier?

The Campfire Audio Ara is 8Ω at 94.0 dB (no figure from the maker at all); the Campfire Audio Chimera is 5.5Ω at 108.1 dB/mW. This page is only about what they ask of an amplifier — not how they sound, which no specification on either sheet can tell you.

The Ara needs 14.1 dB more than the Chimera to reach the same loudness — 4.0 mW against 0.15 mW.

The numbers that decide it

SpecificationAraChimera
Impedance8 Ω5.5 Ω
Sensitivity94.0 dB108.1 dB/mW
Sensitivity (voltage)115.0 dB/V130.7 dB/V
Power for 100 dB4.0 mW0.15 mW
Voltage for 100 dB0.18 V29 mV
Current for 100 dB22.3 mA5.3 mA
Highest source impedance
that leaves them alone (one-eighth rule)
1.00 Ω0.69 Ω
Sources that reach 100 dB
out of 280
278280

One caution before reading the rows. For Campfire Audio Ara 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

2 of the 280 sources have the power for the Chimera but not for the Ara — Apple USB-C dongle (EU), Steinberg UR22C.

42 sources are low enough in output impedance for the Ara under the one-eighth rule but not for the Chimera (FiiO SnowSky Tiny B, FiiO KA11, JDS Labs Atom+ (2nd gen), 39 more).

28 sources stay below the audible-hiss threshold with the Ara but cross it with the Chimera (Kiwi Ears Allegro Mini, FiiO BTR11, Fosi Audio SK02, 25 more).

278 of the 280 sources here reach 100 dB on both. That count is about power only — the output-impedance and hiss lines above are separate questions, and a source can pass this one and fail those.

What each one needs from 80 to 105 dB

The gap between these two in decibels does not change with volume — it is a property of the two headphones. What changes is the size of the numbers, and it changes fast: every 10 dB costs ten times the power. The row that matters is the one nearest the level you listen at, and for most people that is nearer the top of this table than the bottom.

The Ara is more demanding than 54% of the 567 non-electrostatic models in this database; the Chimera than 3%. Both figures use the same measure as the rest of the site: whichever runs out first against a 2 V, 100 mW dongle, voltage or power.

dB SPLAra powerAra voltageChimera powerChimera voltage
800.04 mW18 mV1.5 µW3 mV
850.13 mW32 mV4.9 µW5 mV
900.40 mW56 mV0.02 mW9 mV
951.3 mW0.10 V0.05 mW16 mV
1004.0 mW0.18 V0.15 mW29 mV
10513 mW0.32 V0.49 mW52 mV

105 dB is included because forum power figures are usually quoted there or higher. It is also a level that damages hearing in minutes — how many minutes is its own calculator.

The cheapest source that satisfies both

SourcePriceHeadroom, AraHeadroom, ChimeraOutput impedanceNoise
JadeAudio JA11$202.8 dB15.2 dB0.5 Ω1.7 µV
FiiO BTR13$5911.8 dB24.3 dB0.6 Ω1.0 µV
iBasso DC03 Pro$697.9 dB20.4 dB0.12 Ω0.9 µV

Of the 280 sources here, 278 reach 100 dB on both. That is the easy axis. 25 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 rest either fail one of those or never printed the number at all, and 206 of them are in the second group.

The cheapest of the 25 is the JadeAudio JA11, at $20. It leaves 2.8 dB of headroom on the Ara and 15.2 dB on the Chimera, its output impedance is 0.5 Ω against a one-eighth limit of 1.00 Ω and 0.69 Ω, and its noise figure puts the hiss floor 20 dB and 5 dB below the 20 dB SPL this site treats as the point where a quiet room stops hiding it.

Cheapest that satisfies three published numbers is not the same as best, and none of it is about how either headphone sounds. To put either model against a source this page does not mention, or to change the target loudness, use the amplifier matcher.

Both pages in full

Each model has a page of its own with the full source list, the hiss estimate and the provenance of every figure above: Campfire Audio Ara and Campfire Audio Chimera. Each figure on this page is labelled on those pages with where it came from, including the ones Campfire Audio never published — what that maker publishes, counted.

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