The 1989 Sony D-Z555 was a game-changer for portable CD players. It packed dual 16-bit DACs, an 8x oversampling filter, gold-plated connectors, a spectrum display, and an optical digital output. With features,Sony Diskman D-350,Sony Diskman D-350,In 1991, Sony introduced the D-350 Discman, its top offering of the year, featuring extensive programming and track selection options and a smooth, detailed sound comparable to full-sized systems. : r/ObsoleteSony