| 摘要 |
PURPOSE:To allow the circuit to cope with one input monaural sound regardless of the stereo sound circuit by employing a photo pin jack with a switch turned off when a sound input cable is inserted to one or both of left and right sound signal input terminals of the sound circuit having a stereo amplifier. CONSTITUTION:When a sound cable is inserted to a photo pin jack with a switch used for input terminals 11, 12, the switch contact in the phono pin jack is disconnected thereby disconnecting terminals a, b shown in figure 2. In the case of one input monaural sound input, even with input to any of the left sound input terminal 11 and the right sound input terminal 12, the same sound is heard from a left speaker 5 and a right speaker 6. In the case of stereo sound input, since a signal is inputted to both the left sound input terminal 11 and the right sound input terminal 12, the left and right sound circuits are separated by the photo pin jack with a switch at the sound input terminals and each sound signal is processed and different sounds come from the left speaker 5 and the right speaker 6 as the stereophonic sound. |
