Doepfer A-172 User Manual

doepfer

System A - 100

1. Introduction

MAX / MIN

A-172

A-172

MAX / MI N

In 1

In 2

In 3

In 4

Max. Out

+

-

Min. Out

+

-

Module A-172 is a Minimum/Maximum selector. It
has available four analog inputs and two analog
outputs (Minimum and Maximum).

The module permanently picks the maximum resp.
minimum voltage out of the four input signals and
outputs these voltages to the maximum resp. minimum
jack socket.

Two LEDs for each output help you keep track of the
output signals. One LED displays positive, the second
LED negative output voltages.

1

A-172

MAX / MIN

System A - 100

doepfer

2. Overview

➊

➋

➌

➍

➎

➏

Controls and indicators:

1 Max, Ctr. : monitoring LEDs for Maximum

output

2 Min. Ctr. : monitoring LEDs for Minimum

output

In- / Outputs:

! In 1 ... $ In 4 : Signal inputs

% Max. Out : Maximum output

& Min. Out : Minimum output

➀

➁

2

doepfer

System A - 100

MAX / MIN

A-172

3. Basic principles

The module permanently picks the maximum resp.
minimum voltage out of the four analog input signals
and outputs these voltages to the maximum resp.
minimum jack socket. Fig. 1 shows the working princi­ple by means of three sine waves with different fre­quencies and levels. The upper section shows three
input signals , the lower section shows the correspon­ding outputs.

In

Out

Min. Out

Max . Out

4. Controls

1 Max. Ctr. • 2 Min. Ctr.

These LEDs display the positive resp. negative part of
the output signals at the Maximum % resp. Minimum
output &.

Fig. 1: Maximum/Minimum module - how it works

3

A-172

MAX / MIN

System A - 100

doepfer

5. In- / Outputs

! In 1 ... $ In 4

The input signals are connected to these sockets. At
least 2 signals are necessary to obtain the maximum
resp. minimum function. Unused inputs have to be left
open. Do not connect unused inputs to GND as this is
equal to 0V and different from an open socket !

% Max. Out

This is the Maximum output of the module.

& Min. Out

This is the Minumum output of the module.

6. User Examples

The main application of the module is the processing
of control voltages, e.g. random voltages, ADSR,

LFO, S&H, ribbon CV, Theremin CV and similar.

To adjust offset and amplitude for each input inde­pendently (i.e. to bring the signal into the right
"position" with the desired level) we recommend to
combine the module with the A-129-3 Slew Limiter/
Attenuator/Offset Generator (see fig. 2).

In 1

In 2

In 3

In 4

Atten.

Atten.

Atten.

Atten.

A-129 /3

CV
In 1CVOut 1

Offset

CV
In 2CVOut 2

Offset

CV
In 3CVOut 3

Offset

CV
In 4CVOut 4

Offset

A-172

MA X / MI N

In 1

In 2

In 3

In 4

Max. Out

Min. Out

Fig. 2: Max/Min detector with individally adjustable

attenuation and offset for each input signal

The module is useful for audio processing too. Using
the outputs of a VCO as inputs creates new wa­veforms. Using the outputs of two or more VCOs leads
to new interference sounds that are different from VCO
mixing, ring modulation or hard/soft sync.
Even the combination of control and audio signals
as inputs makes sense and causes a kind of pulse­width modulation even for saw, triangle or sine by
clipping the upper/lower parts of the waveform.

4