| 摘要 |
PURPOSE:To reduce a pop noise in power-off operation by providing a transistor (TR) which turns off when powered off and a sucking circuit which turns off an output amplifier circuit. CONSTITUTION:The TR30 whose base is connected to the connection point of a constant voltage circuit 17 and a resistance 19 turns off when powered off. Further, the sucking circuit consisting of TRs 31, 32, and 35 and resistances 33 and 34 is provided. This sucking circuit receives the output of the TR30 to control the output amplifier circuit formed of TRs 20 and 22. Namely, the TR30 turns off when powered off, and the TR32 also turns off to flow a current through the resistance 34, turning off the TR35. Consequently, a TR9 turns on and an output TR22 also turns on to cut off the output amplifier circuit. Thus, the pop noise in power-off operation is reduced.
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