In a scratch effect control device for a digital audio signal playback
apparatus, a control unit controls output of digital audio data recorded
in a data recording medium and read by a data reading device in
accordance with a first control signal representative of angular velocity
and rotational direction of a first encoder disc and obtained from a
first pick-up device, and a second control signal representative of
angular velocity and rotational direction of a second encoder disc and
obtained from a second pick-up device. The first encoder disc is mounted
co-rotatably on an outer sleeve sleeved rotatably on an inner spindle and
coupled co-axially to a lower platter member that is driven by a driving
unit to rotate about an axis. The second encoder disc is mounted
co-rotatably on the inner spindle which is coupled co-axially to an upper
platter member that is superposed on the lower platter member.