| 摘要 |
PURPOSE:To use a sound recording microphone terminal also for a mixing terminal with a simple constitution by grounding the output terminal of a mixing amplifier by means of a switch which works in response to a sound recording switch and at the same time adding the output of the mixing amplifier to the outputs of right and left amplifiers after the partial pressure by resistances. CONSTITUTION:When a microphone is connected to a microphone terminal 15L or 15R, the voltage is divided by resistances R11-R15 for the reproduction signal given from the connected microphone. This reproduction signal is supplied to a mixing amplifier 16, and the signals given from the amplifier 16 are supplied to right and left power amplifiers 13L and 13R by resistances R16 and R17 to be amplified there. Then the sound outputs are delivered through speakers 14L and 14R. When sound recording switches S11-1-S11-4 are set at a reproduction position respectively, the reproduction signals given from microphones connected to terminals 15L and 15R are amplified by preamplifiers 12L and 12R and supplied to a sound recording amplifier. While the reproduction signal given from the microphone through resistances R13 and R14 is amplified by the amplifier 16 but receives no microphone mixing since the output terminal of the amplifier 16 is grounded by a sound recording switch S11-3. |
