| 摘要 |
PURPOSE:To suppress the occurrence of howling by connecting a circuit detecting automatically the quantity of a line loss circuit in parallel with a channel circuit. CONSTITUTION:When the loss of a line network 9 connected to terminals 1, 2 is small, the rectified output voltage of a bridge rectifier 3 is high, a Zener diode 6 reaches a Zener voltage, an N-MOS FET 8 is turned on and a capacitor 7 is connected in parallel with the channel circuit network 9. The capacitor 7 offers a loss at the high frequency of sound signal to prevent howling.
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