When HEM’s boss Marcin Hamerla announced a Ferrum headphone amplifier/converter combo some time ago, I spontaneously thought of a DAC with headphone output. But the ERCO is anything but that: Not only at first glance it looks like a headphone amplifier hosting an additional converter. In its development, Ferrum took the successful OOR as a starting point and looked for ways to integrate a digital section. Adopting the OOR’s circuitry one-to-one quickly proved impossible for both space and cost reasons, as Marcin Hamerla revealed. In the end, his engineering team developed an integrated circuit-based output stage that provides slightly less power than the OOR’s discrete design, but without seriously sacrificing its sonic benefits. Read the full review by Dirk Sommers @ HIFIstatement