The Hitachi HD-90 is a pair of headphones produced by Hitachi during the late 1970s, specifically from 1977 to 1979. A part of a series that includes models such as the HD-9, HD-50, HD-60, HD-70, and HD-80, the HD-90 was priced around 140 DM at its launch. It is characterized by its design and audio performance, catering to users seeking quality audio reproduction. The construction reflects the era's focus on durability and sound integrity, making it a notable entry in the headphones market of its time.
