According to HARP IN LA, “In general, the Chicago harps have a warm, even tone, and overall tend to project well. The 85 series harps have a bright tone quality, particularly full and resonant, with a rich, deep bass.” I guess the eyelets may partly contribute to the difference in the tone of Chicago series and Style 85 series, i.e. warm versus bright. According to the photos I saw, the Chicago harps may use nylon (or plastic?) eyelets, while the Style 85 harps may use metal eyelets.