Ferrum Oor

The Ferrum OOR is the headphone amplifier that Ferrum built as their defining statement, a fully balanced, discrete design with a proprietary output stage that keeps transistors permanently active, eliminating the zero-crossing distortion that plagues conventional topologies and delivering 8 watts balanced into 60 ohms with vanishingly low noise.

Type and Technology

Desktop headphone amplifier, fully balanced, solid-state. Proprietary discrete power amp technology developed in-house. Truly balanced signal path from XLR input and electronically balanced from RCA input. Three-position gain switch for headphones of any impedance and sensitivity. Optional connection to Ferrum HYPSOS linear power supply via the proprietary Ferrum Power Link (FPL) cable for further performance improvements. Made in Poland.

Upgrade Path

The OOR's performance improves meaningfully when powered by the Ferrum HYPSOS via the FPL connector, a dedicated linear supply with 4-Terminal Sensing specifically designed for Ferrum products. Pair with the Ferrum Wandla 2.0 DAC/preamp for a matched, all-Ferrum source and amplifier system.

Sound Character

Transparent, dynamic, and effortlessly controlled. The OOR has complete composure across the frequency range, ultra low distortion, a silent noise floor, and enormous headroom. A headphone amplifier that disappears from the chain and lets the recording, source, and headphone speak for themselves.

Build and Finish

Compact aluminum chassis at 21.7 x 20.6 x 5 cm and 1.8 kg. Comes with a carefully selected DC power adapter. Upgrade path available via the Ferrum HYPSOS and FPL cable. Available in silver and black.

Best For

Audiophiles who want a transparent, high-power headphone amplifier that never limits the headphone's potential, particularly effective with demanding planars. An ideal partner for the Ferrum Wandla 2.0 DAC.

What's in the Box

• Ferrum OOR headphone amplifier
• DC power adapter
• Documentation

Specifications