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Ferrum

OOR

Power link cable carries two power wires and two feedback wires so the supply voltage stays flat at the amplifier input.

Type
Solid-state headphone amplifier
Output
8 W into 60 ohms
Weight
1.8 kg
List
$2,275

Output into any load

The line is what the OOR delivers, estimated from its published ratings. Each square is a headphone in the catalog at the power it needs for a loud 110 dB peak.

Grado Signature HP100 SE: needs 0.20 mW at 38 ohmsFocal Stellia: needs 2.51 mW at 35 ohmsFocal Clear MG: needs 3.98 mW at 55 ohmsFocal Utopia (2022): needs 3.98 mW at 80 ohmsSony MDR-Z1R: needs 10.0 mW at 64 ohmsMeze Audio Elite: needs 7.94 mW at 32 ohmsFinal D8000 Pro Edition: needs 15.8 mW at 60 ohmsAudeze MM-520: needs 6.31 mW at 18 ohmsFostex TH900mk2: needs 10.0 mW at 25 ohmsYamaha YH-5000SE: needs 15.8 mW at 34 ohmsZMF Caldera: needs 31.6 mW at 60 ohmsRosson Audio Design RAD-0: needs 15.8 mW at 29 ohmsHIFIMAN HE1000se: needs 25.1 mW at 35 ohmsMeze Audio ARTA: needs 15.8 mW at 225 ohmsZMF Vérité Closed: needs 12.6 mW at 300 ohmsAudio-Technica ATH-ADX5000: needs 10.0 mW at 420 ohmsSennheiser HD 820: needs 16.6 mW at 300 ohmsSennheiser HD 800 S: needs 20.9 mW at 300 ohmsAbyss Diana TC Signature: needs 100 mW at 72 ohmsAudeze LCD-5s: needs 100 mW at 35 ohmsMeze Audio Empyrean II: needs 100 mW at 32 ohmsAbyss AB-1266 Phi TC: needs 158 mW at 50 ohmsDan Clark Audio Expanse: needs 100 mW at 26 ohmsDan Clark Audio Stealth: needs 100 mW at 23 ohmsHIFIMAN Susvara: needs 501 mW at 60 ohmsPublished: 8 W into 60 ohmsPublished: 1.6 W into 300 ohms
Output into each loadPublished ratingHeadphone it drives at 110 dB (25)Needs more (0)Load in ohms across, power up, both on log scales

Build a setup with it

Start with the HIFIMAN Susvara, the hardest headphone here it drives with power in reserve.

Open in the setup builder →

Where to buy

$2,275

Price: Headphones.com and HeadAmp US price, OOR only; Ferrum's own page says 1.995 EUR/USD.

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Title block

Maker
Ferrum
Model
OOR
Type
Solid-state headphone amplifier
Made in
Poland
Output impedance
0.3 ohms
Weight
1.8 kg
List price
$2,275 USD
Output power
8 W into 60 ohms; 1.6 W into 300 ohms
Topology
Fully balanced, proprietary discrete power amp technology; four-wire Ferrum Power Link DC input with sense lines; output transistors biased never to turn off

What it drives

How the matching works

Plenty in reserve

10 dB or more above loud 110 dB peaks.

25

Other solid-state amplifiers

Sources