Andromeda 2020 vs Solaris 2020: which needs more amplifier?

The Campfire Audio Andromeda 2020 is 9Ω at 94.0 dB (no figure from the maker at all); the Campfire Audio Solaris 2020 is 15Ω at 94.0 dB (no figure from the maker at all). This page is only about what they ask of an amplifier — not how they sound, which no specification on either sheet can tell you.

In amplifier terms these two are the same headphone. The gap between what they need for 100 dB is under half a decibel, which is smaller than the step between two clicks of most volume controls.

The numbers that decide it

SpecificationAndromeda 2020Solaris 2020
Impedance9 Ω15 Ω
Sensitivity94.0 dB94.0 dB
Sensitivity (voltage)114.5 dB/V112.2 dB/V
Power for 100 dB4.0 mW4.0 mW
Voltage for 100 dB0.19 V0.24 V
Current for 100 dB21.0 mA16.3 mA
Highest source impedance
that leaves them alone (one-eighth rule)
1.12 Ω1.88 Ω
Sources that reach 100 dB
out of 280
279280

One caution before reading the rows. For Campfire Audio Andromeda 2020 and Campfire Audio Solaris 2020 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

1 of the 280 sources has the power for the Solaris 2020 but not for the Andromeda 2020 — Steinberg UR22C.

8 sources are low enough in output impedance for the Solaris 2020 under the one-eighth rule but not for the Andromeda 2020 (FiiO KA13, FiiO K11, Schiit Vali 2+, 5 more).

279 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 Solaris 2020 is more demanding than 66% of the 567 non-electrostatic models in this database; the Andromeda 2020 than 56%. 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 SPLAndromeda 2020 powerAndromeda 2020 voltageSolaris 2020 powerSolaris 2020 voltage
800.04 mW19 mV0.04 mW24 mV
850.13 mW34 mV0.13 mW43 mV
900.40 mW60 mV0.40 mW77 mV
951.3 mW0.11 V1.3 mW0.14 V
1004.0 mW0.19 V4.0 mW0.24 V
10513 mW0.34 V13 mW0.43 V

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, Andromeda 2020Headroom, Solaris 2020Output impedanceNoise
JadeAudio JA11$203.3 dB5.5 dB0.5 Ω1.7 µV
FiiO KA11$2915.4 dB17.6 dB0.7 Ω1.7 µV
FiiO BTR11$368.0 dB10.3 dB0.5 Ω8.0 µV

Of the 280 sources here, 279 reach 100 dB on both. That is the easy axis. 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 rest either fail one of those or never printed the number at all, and 207 of them are in the second group.

The cheapest of the 62 is the JadeAudio JA11, at $20. It leaves 3.3 dB of headroom on the Andromeda 2020 and 5.5 dB on the Solaris 2020, its output impedance is 0.5 Ω against a one-eighth limit of 1.12 Ω and 1.88 Ω, and its noise figure puts the hiss floor 21 dB and 23 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 Andromeda 2020 and Campfire Audio Solaris 2020. 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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