VIP-bleep

from an idea by A Buhlmeier 66 noise gate and two regulator sections are re- quired. For a double mono version, two control sections and two regulators are needed. One LM13600 or LM13700 will thus suffice for all these requirements. Opamps A: and Az form a full-wave rectifying circuit. Opamp A3 com- pares the peak value of the signal with the direct voltage set by Pz. If the peak value is larger, capacitor C7 is charged via Ti: the attack time is set by P3. The time lapse after which the audio signal is switched off is de- termined with P4. The control of the voltage-controlled amplifier (VCA) and the LED indicating whether there is a signal present is effected by A4. Diode D4 ensures that the am- plification of the VCA is really zero when the output of A4 is low (i.e. less than -15 V). The input of the regulator section has an impedance of about 10 k52 and is designed for audio signals of 1 V.. Noise on an audio signal becomes more troublesome as the signal itself becomes small...