Abstract: Improved circuitry for providing stereo separation control in audio playback systems wherein undesirable volume level change and undesirable signal degradation due to noise, distortion and crosstalk are substantially reduced or eliminated by utilizing, in a preferred embodiment, a precision difference amplifier, a signal inverter, a tapped separation control, and a crosstalk-cancelling resistor.

Abstract: Improved circuitry for providing bass control in audio playback systems using feedback circuits wherein undesirable deviations in frequency response above the bass region exhibited by previously available Baxandall feedback circuits are substantially eliminated by utilizing, in a preferred embodiment, a voltage follower amplifier, such as an emitter-follower transistor circuit in association with a single capacitance in the bass control circuit, which eliminates the undesirable frequency response deviations at the mid-frequency and higher frequency ranges so that frequency response curves at all settings of the bass control substantially coincide above the bass region.