The ADS design includes two pure analog frequency generators featuring low distortion and noise; a high current Class-A/B amplifier that is transformer-coupled to the turntable output; analog control logic for low noise operation; 33/45 RPM analog speed adjustment controls with center detente positions that are factory calibrated. Created by our Director of Electrical Engineering, Michael Bettinger. The platter is started and stopped by the front panel Run/Stop momentary push button switch. The front panel contains a two-position push button switch for selecting either 33 RPM or 45 RPM operation. There are separate speed adjustment controls for 33 and 45 RPM. The controls have a detented center position that is factory calibrated for 60 Hz (33 RPM) and 81 Hz (45 RPM). The speed is continuously adjustable +/- 3 Hz Blue LED indicators adjacent to the controls indicate which speed is set at a glance.