Doepfer A-101-3 Vactrol Modular Phase Filter User Manual download pdf

doepfer

System A - 100

Modular Vactrol Phaser

A-101-3

1. Introduction

Module A-101-3 is a 12 stage phase shifter with vac-

trols as phase shifting elements. A vactrol is a combina-

tion of a light depending resistor (LDR) and LED both

put into a light-proof case. They are known for their

smooth sound behaviour as vactrols are distortion-free

linear elements in contrast to any semiconductor (like

transistors or OTA in other designs). For more general

details about vactrols please look at the vactrol basics

page on our web site www.doepfer.com.

In contrast to other phaser designs the A-101-3 is much

more flexible and offering a lot of new features not

available from other phasers on the market. The A-101-

3 offers access to each of the 12 input and output

stages leading to a lot of new filters that cannot be

obtained in other ways. Especially the free patchable

feedback loops

(yes, not only one feedback loop is

possible) between each of the 12 stages, the separate

phase shift control for the stages 1-6 and 7-12, and

the 2 polarizers intended to control the feedback loops

lead to completely new filter types (a polarizer is a

circuit that is able to generate positive and negative

amplifications in the range -1...0...+1 with -1 = inversion,

0 = full attenuation, +1 = unchanged signal, for details

concerning the polarizer function please look at the

A-133 VC Polarizer or A-138c Polarizing Mixer module).

On our web site are lot of frequency response curves

availabe that show which filter types can be realized.

Internally the module is made of 2 independent 6 stage

phase shifters (1-6 reps. 7-12) with separate audio

inputs (with attenuators), audio outputs (with mix con-

trol), and phase shift control units. The phase shift

control units feature both manual and voltage controlled

phase shifting (e.g. from a LFO, ADSR, Random Vol-

tage, Theremin CV, Foot Controller CV ...). For each

sub-module a phase shift display (LED) is available.

The LED shows the illumination state of the 6 vactrols of

the sub-module in question as it is connected in series

with the internal vactrol LEDs.

Each of the 12 phase shift stages is equipped with an

audio output socket and feedback input socket to

obtain full flexibility to create a multitude of different

filters. The audio input signal and the output signals of

stage 6 resp. stage 12 are mixed with 2 manual controls

to obtain effects at two audio outputs (for normal

phase shifting effect this is 50% input signal and 50%

phase shifted signal).

The two submodules are internally connected via nor-

malled sockets so that two 6 stage phase shifters can

be obtained without external patches.

1 2 3 4 5 6 7 8 9 10

Summary of Contents

Page 1 - 1. Introduction

doepferSystem A - 100Modular Vactrol Phaser A-101-311. IntroductionModule A-101-3 is a 12 stage phase shifter with vac-trols as phase shifting elem

Page 2

A-101-3 Modular Vactrol Phaser System A - 100doepfer10

Page 3 - 2. Basic principles

A-101-3 Modular Vactrol Phaser System A - 100doepfer2Fig.1: A-101-3 Overall view

Page 4

doepferSystem A - 100Modular Vactrol Phaser A-101-332. Basic principlesThe module is made of two identical units that differonly in the normalling

Page 5 - 3. Overview

A-101-3 Modular Vactrol Phaser System A - 100doepfer4that no plug is inserted into this socket. To obtain aphaser with more or less stages the out

Page 6

doepferSystem A - 100Modular Vactrol Phaser A-101-353. Overview"§3! 1(/2$45&%6

Page 7 - 4. Controls

A-101-3 Modular Vactrol Phaser System A - 100doepfer6Controls:1 Level: attenuator for audio input !2 CV: attenuator for CV input "3 Shift: ma

Page 8

doepferSystem A - 100Modular Vactrol Phaser A-101-374. Controls! Audio In / 1 LevelSocket ! is the audio input with the assigned attenuator1. Feed

Page 9 - 5. User Examples

A-101-3 Modular Vactrol Phaser System A - 100doepfer8stages can be obtained. The output of stage 1 does notlead to a phaser but a high pass or low

Page 10 - System A - 100

doepferSystem A - 100Modular Vactrol Phaser A-101-39( Stage Out (6x)These are the outputs of the phase shifting stages.Applications of these outputs

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Doepfer A-101-3 Vactrol Modular Phase Filter User Manual

Browse online or download User Manual for Audio Doepfer A-101-3 Vactrol Modular Phase Filter. Doepfer A-101-3 Vactrol Modular Phase Filter User Manual

Summary of Contents

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