| 摘要 |
PURPOSE:To reduce switching circuits and spatial restriction at the time of printed circuit board design, by changing a time constant of a feedback circuit in interlocking with a function changeover switch through the use of an FET. CONSTITUTION:Function changeover switches S3, S4 performing changeover of equalizer of plural functions having a plurality of inputs, the 1st FET-Tr1 which turns on when the changeover switch S4 is in the phonomotor position and short- circuits C1, R1 functioning as a part of the 1st negative feedback circuit of an amplifier 21, and the 2nd FET-Tr2 which turns on when the changeover switch S3 is in the tape position and short-circuits C2 functioning as a part of the 2nd negative feedback circuit, are provided. Further, position changeover switches S1, S2 which provide a time constant in matching with a changed over tape to the negative feedback circuits in changing over the tape to that having different characteristics, are provided. |
