Stereophonic audio amplifier, esp. for vehicle radios - has wide dynamic response and uses operational amplifiers with outputs fed to anti-parasitic chokes

摘要

The stereo audio amplifier is for low voltage supplies esp. for car radios. The amplifier has a wide dynamic range with two loudspeaker channels, including tweeters, and a 180 deg. phase changing network. A third loudspeaker is connected into the two channels via a low-pass filter. The phase change is made using an operational amplifier in each of the two speaker channels. Each input line is fed to the inverting input of an amplifier and the non-inverting input of the other from an RC low frequency connection network including tone and volume control potentiometers. A further potentiometer fitted between the two input channels provides balance control. Both amplifier outputs are fed via anti-parasitic chokes to sockets, the third loudspeaker being LC coupled across the left and right speakers.