| 摘要 |
PURPOSE:To simplify the power supply circuit, by switching the operating and inoperating state of a recording amplifying circuit and a preamplifying circuit without switching the power supply voltage. CONSTITUTION:In applying a power supply voltage to a terminal 106 and recording signals at input terminals 29a, 29b, a recording mode switching signal is applied to a terminal 108, a transistor TR64 is set on and a transformer 36 is grounded. Further, a TR65 is turned off and the preamplifying circuit 40 is inoperative. Since no switching signal is applied to a terminal 107, a TR63 is turned off. In completing loading and having no control signal from a terminal 109, a squelch circuit 31 is turned off, the recording amplifying circuit 30 is operative and the signals at the input terminals 29a, 29b are applied to a head 37. In this case, since the amplifier 40 is inoperative, no recording signal is leaked to the amplifying circuit 40. In case of the reproduction mode, a switching signal is applied to the terminal 107 and the amplifier 30 is inoperative. Further, no switching signal is applied to the terminal 108 and the circuit 40 is operative. |
