Ferrum OOR: “Compact, Powerful & Simply Brilliant!”Ken from Fumore takes an in-depth look at the Ferrum OOR, exploring its studio-grade precision, immense power, and analytical sound quality. Is this the ultimate headphone preamp for professionals and audiophiles alike? 
Key topics covered in the review: Studio-grade precision & power
XLR vs. 1/4-inch output comparison
Gain settings, input/output options
Why HYPSOS is the ultimate upgrade?The review features top-tier headphones like Audeze LCD-5, Austrian Audio Composer, and Neumann NDH 30, putting OOR through its paces.