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Ferrum OOR

Name: Ferrum OOR
Brand: Ferrum
SKU: oor-headphone-amplifier
Price: 2275.00 USD
Availability: InStock
Rating: 4.6 (9 reviews)

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OOR will redefine the category of headphone amplifiers. OOR will drive any headphones effortlessly to the max of their potential, while preserving the essence of the music it amplifies. Zero distortion, zero fatigue, huge dynamics and unrivaled detail result in ultimate enjoyment. OOR actually makes something that is very difficult to accomplish, seem like the most natural thing on earth.

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Overall Score 92/100

Deliciously Crispy

Ferrum OOR — concise overview

Ferrum's OOR is a compact, fully balanced head‑amp/preamp that excels at delivering razor-sharp resolution, nimble transients and deep, clean bass when paired with the optional Hypsos power supply. As reviewed by Srajan Ebaen / 6 Moons it impressed with extremely low noise and wide bandwidth, plus muscular low‑impedance outputs that drive demanding planars like the Susvara with authority. The sonic signature is neutral-to-analytical with heightened contrast, precise imaging and strong macro- and micro-dynamics. Build quality is purposeful—a steel chassis with aluminum front and neat fit-and-finish—and the OOR doubles as a tidy preamp. With multiple gain settings and balanced I/O it suits critical listeners who run sensitive IEMs and low-impedance headphones and who value control and immediacy. Consider the Hypsos upgrade to unlock its full potential.

6 Moons

"The takeaway is that into our most demanding loads, Oor nearly equaled our very best headfi machine and certainly didn't trail it on what most would call raw resolution."

Pros

Exceptionally low noise floor and high resolution, enabling deep image separation and retrieval of low-level detail.
High current, low output impedance and multiple gain options—able to drive demanding planars (e.g., Susvara) while remaining suitable for sensitive IEMs.
Strong dynamics and transient control, especially when used with the Hypsos power supply, producing tight bass and authoritative timing.
Solid industrial execution in a compact chassis with balanced connectivity and preamp functionality for system versatility.

Cons

Optimal performance relies on the optional Hypsos external PSU, which adds significant extra cost to the system.
Limited preamp conveniences—no remote control and only two inputs—may frustrate users who want more front-end flexibility.

Sound Quality

92/100

Reviewer specifically cites steep timing, high beat fidelity and excellent driver control with the optional Hypsos PSU, and attributes perceived higher contrast to extra dynamic differentiation. The OOR handled big dynamic swings (e.g., Susvara with Zimmer) without seam frazzle, indicating strong transient and macro-dynamic performance.

Noise Floor

91/100

Described as having "extremely low noise" and enabling an enhanced "edge differential of sonic substance against silent space," indicating a very quiet background. The review language supports a near-black background suitable for sensitive headphones and revealing quieter recording detail.

Headphone Compatibility

92/100

Specifications and review notes show very low output impedance (<0.3 Ω) and generous power: 400 mW into 300 Ω (6.3mm), 1.6 W over XLR4, and substantially more into lower impedances (review cites up to watts into 60 Ω), plus balanced outputs and multiple gain settings. That combination supports both sensitive IEMs (low Z) and demanding planars, as evidenced by testing with Susvara and other high-current headphones.

Build Quality

90/100

The chassis is a steel case with an aluminum front, well finished and weighing 1.8 kg; the reviewer notes fine fit-and-finish and production quality that "look[s] the business." Mechanical execution and industrial design are presented as high quality for the class.

Features Connectivity

92/100

OOR is a fully balanced headfi amp/preamp with RCA and XLR inputs, balanced XLR4 headphone output, RCA/XLR line outs, low output impedance and multiple gain settings (-4/+6/+16 dB balanced). It also supports external Hypsos power and offers wide bandwidth (20 Hz–100 kHz), giving it a well-rounded connectivity/feature set for a high-end desktop amp.

Value for Money

86/100

Retail is listed at €1,995 for the unit, with an optional Hypsos PSU adding €995; the review mentions the combined cost candidly without calling it a bargain. The coverage emphasizes performance and build but also notes the significant extra cost for the external PSU, so value is assessed as neutral-to-premium rather than an exceptional value.