Ferrum ERCO: power output and what it will drive

The Ferrum ERCO is a desktop DAC/amp at $2050. It delivers 1.1 W into 32Ω and 300 mW into 300Ω, which ranks it 76 of 280 for raw power among the sources in this database.

Measured at 100 dB SPL it has comfortable headroom on 561 of the 567 dynamic and planar headphones catalogued here, enough but not generous on 5 and not enough power for 1. Power is published at 50Ω, 300Ω; the rest of the table is derived from those figures. Output noise is not published, so the hiss estimate cannot be run.

What it actually puts out

TypeDesktop DAC/amp
Price$2050
Power into 32 Ω1.1 W
Power into 150 Ω580 mW
Power into 300 Ω300 mW
Power into 600 Ω150 mW
Output impedance0.3 Ω
Output noisenot published
Comfortable headroom on 561 of 567 headphones (99%) · short of power on 1

Where these numbers come from

The manufacturer publishes 1.7 W into 50Ω, 300 mW into 300Ω. The rest of the table is worked out from those.

The balanced output is rated separately: 3.9 W into 32Ω through the 4-pin XLR jack.

Derived rows hold output voltage steady, as an amplifier does (method).

Source: ferrum.audio.

LoadPowerStatusHow it was arrived at
32 Ω1.1 WDerivedbeyond the published loads, holding output voltage constant — which understates rather than flatters
50 Ω1.7 WPublishedthe manufacturer publishes this figure at this exact load
150 Ω580 mWDerivedworked out between two published loads, holding output voltage linear between them
300 Ω300 mWPublishedthe manufacturer publishes this figure at this exact load
600 Ω150 mWDerivedbeyond the published loads, holding output voltage constant — which understates rather than flatters

Against 40 well-known headphones

Easiest to hardest to drive, with headroom at a 100 dB SPL peak.

HeadphoneImpedanceSensitivityNeedsHeadroomVerdict
Shure SE8469 Ω114.0 dB/mW0.04 mW+39 dBComfortable
64 Audio U12t12.6 Ω108.0 dB/mW0.16 mW+34 dBComfortable
Shure SE21517 Ω107.0 dB/mW0.20 mW+35 dBComfortable
Moondrop Aria32 Ω107.1 dB/mW0.19 mW+37 dBComfortable
Audeze LCD-X 202120 Ω103.0 dB/mW0.50 mW+31 dBComfortable
Truthear Hexa20.5 Ω103.1 dB/mW0.49 mW+32 dBComfortable
Sennheiser IE 20018 Ω101.6 dB/mW0.69 mW+29 dBComfortable
Sony MDR-750663 Ω106.0 dB/mW0.25 mW+37 dBComfortable
Meze 99 Classics32 Ω103.0 dB/mW0.50 mW+33 dBComfortable
Focal Clear MG55 Ω104.0 dB/mW0.40 mW+36 dBComfortable
Philips SHP950032 Ω101.0 dB0.79 mW+31 dBComfortable
Focal Utopia80 Ω104.0 dB/mW0.40 mW+34 dBComfortable
Meze Empyrean32 Ω100.0 dB1.0 mW+30 dBComfortable
Campfire Audio Andromeda 20209 Ω94.0 dB4.0 mW+19 dBComfortable
Etymotic ER2SE15 Ω96.0 dB/mW2.5 mW+23 dBComfortable
AKG K37132 Ω99.1 dB/mW1.2 mW+29 dBComfortable
Audio-Technica ATH-M50X38 Ω99.0 dB/mW1.3 mW+30 dBComfortable
Beyerdynamic DT 900 Pro X48 Ω100.0 dB/mW1.0 mW+32 dBComfortable
Audeze LCD-2 Classic70 Ω101.0 dB/mW0.79 mW+32 dBComfortable
Grado SR80x38 Ω98.0 dB/mW1.6 mW+29 dBComfortable
Sennheiser HD 560S120 Ω100.8 dB/mW0.83 mW+29 dBComfortable
HiFiMAN Edition XS18 Ω92.0 dB6.3 mW+20 dBComfortable
HiFiMAN Arya Stealth32 Ω94.0 dB4.0 mW+24 dBComfortable
Dan Clark Audio AEON 2 Closed13 Ω90.0 dB/mW10 mW+16 dBComfortable
Audeze LCD-514 Ω90.0 dB/mW10 mW+17 dBComfortable
Beyerdynamic DT 1990 Pro (250Ω)250 Ω102.0 dB/mW0.63 mW+28 dBComfortable
HiFiMAN HE400se25 Ω91.0 dB7.9 mW+20 dBComfortable
HiFiMAN Sundara32 Ω92.0 dB6.3 mW+22 dBComfortable
Dan Clark Audio Stealth23 Ω90.0 dB/mW10 mW+19 dBComfortable
Fostex T50RP MK350 Ω92.0 dB/mW6.3 mW+24 dBComfortable
AKG K70262 Ω92.9 dB/mW5.1 mW+24 dBComfortable
ZMF Verite Closed300 Ω99.0 dB/mW1.3 mW+24 dBComfortable
Sennheiser HD 650300 Ω97.8 dB/mW1.7 mW+23 dBComfortable
Sennheiser HD 800S300 Ω96.8 dB/mW2.1 mW+22 dBComfortable
Beyerdynamic DT 770 Pro (250Ω)250 Ω96.0 dB2.5 mW+22 dBComfortable
Audio-Technica ATH-R70X470 Ω98.0 dB/mW1.6 mW+21 dBComfortable
ZMF Atrium300 Ω96.0 dB/mW2.5 mW+21 dBComfortable
Abyss AB-1266 Phi TC50 Ω88.0 dB/mW16 mW+20 dBComfortable
Sennheiser HD 600300 Ω91.8 dB/mW6.6 mW+17 dBComfortable
HiFiMAN Susvara60 Ω83.0 dB50 mW+15 dBComfortable

Will it hiss?

The manufacturer does not publish an output noise figure for this source, so there is no hiss estimate here. If you have a measured figure, the hiss calculator takes it.

Output impedance and the one-eighth rule

At 0.3Ω output impedance this source satisfies the one-eighth rule with every headphone in the database, down to the 3Ω in-ears. Nothing here will have its frequency response shaped by the source.

Check any pair.

The cheapest thing here that does the same job

SourceTypePriceInto 300 ΩOutput impedanceOutput noise
Schiit Magni Heresydesktop amplifier$99410 mW0.25 Ω1.5 µV unverified
Schiit Magni Unitydesktop amplifier$119415 mW0.1 Ω1.59 µV
Topping L30 IIdesktop amplifier$149560 mW0.1 Ω0.3 µV

Of the 280 sources here, 35 do everything the Ferrum ERCO does as a headphone output: reach 100 dB on every headphone it reaches and stay inside the one-eighth rule wherever it does. The cheapest of them is the Schiit Magni Heresy at $99, against this one’s $2050 — $1951 less, and a desktop amplifier rather than a desktop DAC/amp.

This counts the headphone output only; inputs, converters, the volume control and the build are outside it.

Other desktop DAC/amps at a similar price

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