Doepfer A-101-1 Vactrol Steiner Filter User Manual download pdf

doepfer

System A - 100

Vactrol Multitype Filter

A-101-1

1. Introduction

Module A-101-1 is a special multitype filter based on

an idea by Nyle A. Steiner from the year 1974. Injecting

an audio signal into different points of a standard low

pass filter circuit leads to the three filter types low pass

(LP), band pass (BP) amd high pass (HP). For each

filter type a separate input

is available and the sum of

the three filtered signals appears at the common out-

put. Even a notch filter can be realized.

In contrast to the original circuit so-called

vactrols

are

used instead of diodes as variable resistors for fre-

quency and resonance control. A vactrol is a combi-

nation of a light depending resistor (LDR) and a light

emitting diode (LED) both put into a small light-proof

case. Vactrol based circuits are known for their soft

low-distortion sound. For details about vactrols and

the A-101-1 circuit principles please use the correspon-

ding links in the A-101-1 info page on our web site

www.doepfer.com.

The three filter audio inputs are normalled via swit-

ching sockets, i.e. the BP input is connected to the LP

jack socket provided that no cable is plugged into the BP

socket (same applies for HP/BP inputs). Each audio

input is equipped with an attenuator. The audio inputs

are very sensitive and enable distorted sounds too.

For both frequency and resonance manual control and

several control voltage inputs are available.

Two LEDs display the current frequency and reso-

nance settings.

1 2 3 4 5 6

Summary of Contents

Page 1 - 1. Introduction

doepferSystem A - 100Vactrol Multitype Filter A-101-111. IntroductionModule A-101-1 is a special multitype filter based onan idea by Nyle A. Steine

Page 2 - 2. Overview

A-101-1 Vactrol Multitype Filter System A - 100doepfer2Controls:1 Frequency manual frequency control2 CVF2 attenuator for FCV input "3 CVF3

Page 3

doepferSystem A - 100Vactrol Multitype Filter A-101-133. Controls / Inputs / Outputs1 Frequency (control) / ! CVF In 1 (socket)2 CVF2 (control) / &

Page 4

A-101-1 Vactrol Multitype Filter System A - 100doepfer4Resonance can be increased up to self-oscillation . Butdue to the va

Page 5

doepferSystem A - 100Vactrol Multitype Filter A-101-15Pay attention that the notch filter does not arise from acombination of low pass and high pass

Page 6 - 4. User Examples

A-101-1 Vactrol Multitype Filter System A - 100doepfer64. User Examplesnot yet ready• examples with different audio signals (e.g. 3parallel VCOs

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Doepfer A-101-1 Vactrol Steiner Filter User Manual

Browse online or download User Manual for Audio Doepfer A-101-1 Vactrol Steiner Filter. Doepfer A-101-1 Vactrol Steiner Filter User Manual

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