DOEPFER A-113 User manual

doepfer System A - 100 Subharmonic Generator A-113
1
1. Introduction
Module A-113 (Subharmonic Generator) is an addi-
tional sound source that derives four independend
so-called Subharmonics from an incoming pulse si-
gnal. The module represents the sound generation
core of the Mixtur-Trautonium introduced by Oskar
Sala (ref. chapter 6).
Subharmonic means in this context a sawtooth wave
whose frequency is derived from a master frequency.
The master frequency is divided by an integer 1...24 to
obtain the subharmonic. The subharmonics are avai-
lable as 4 single outputs as well as mix output with
adjustable level for each subharmonic.
The integer divisor for each subharmonic is set with
up/down buttons. The current divisors are displayed
with four 2-digit LED displays.
The combination of 4 divisors is called mixture. 4
mixtures form a preset. 50 presets can be stored and
called up within the module.
Two gate inputs are available to switch between the
4 mixtures within one preset (controlled by any gate
signals, e.g. from foot controllers).
Attention ! The A-113 module requires an additional
+5V power supply with 100mA (e.g. the separate +5V
power supply or the +5V low-cost adapter)
A-113
Subharmonic Generator
Freq.
In
Up
Mix
Out
Dow n
8.8.
Out 1
Level
1
Up
Dow n
8.8.
Level
2
Up
Dow n
8.8.
3
Foot
Ctr. 1
Foot
Ctr. 2
Preset
Up
Dow n
8.8.
Level
4
Out 4
Out 2
Store
Level
Out 3

A-113 Subharmonic Generator System A - 100 doepfer
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2. Basic principles
The Subharmonic Generator A-113 contains four ti-
mes the following elements (see fig. 1)
• digital frequency divider (rectangle outputs) with
2-digit display and up/down buttons for divisor adju-
stment
• rectangle/sawtooth converter (with single output)
• attenuator controlling the amount (i.e. the ampli-
tude) of the subharmonic in the mix output
The incoming signal (preferably the rectangle ouput of
a VCO) is fed into the four frequency dividers. The
frequencies of the rectangle signals generated by the
frequency dividers are determined by the current divi-
sors (1...24).
The rectangle outputs are converted to sawtooth wa-
veforms by means of the rectangle/sawtooth conver-
ters.
Fig. 1: Basic layout of the A-113

doepfer System A - 100 Subharmonic Generator A-113
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Subharmonics
The subharmonics result from integer division of
the frequency of the input signal.
The table in fig. 2 shows the frequencies and corre-
sponding tone pitches of the resulting subharmonics
derived from an input signal with the tone pitch C 5(i.e.
523,2 Hz).
Fig. 2: Subharmonics of a signal with tone pitch C 5
It becomes apparent that the subharmonics are equi-
valent to the tones of the minor chord scale.
By way of contrast the harmonics are equivalent to
the tones of the major chord scale. Harmonics are
integer multiples of the basic frequency (see fig. 3).
The undertone series (i.e. subharmonics) are the
mirror image of the overtone series (i.e. harmonics).
Fig. 3:Harmonics of a signal with tone pitch C 2
Divisor Freq. [Hz]
1523,2C
5
2261,6C
4
3174,6F
3
4130,8C
3
5103,8As
2
687,3F
2
773,4D
2
865,4C
2
Note Factor Freq. [Hz]
165,4C
2
2130,8C
3
3196,0G
3
4261,6C
4
5329,6E
4
6392,0G
4
7466,1B
4
8523,2C
5
Note

A-113 Subharmonic Generator System A - 100 doepfer
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H The term "subharmonic" is not quite correct as
the A-113 outputs are sawtooth waveforms in
contrast to the sine waves used in the harmo-
nics theory. A sawtooth wave has a marked
harmonic spectrum with odd and even overto-
nes in contrast to the sine wave which is a
“pure” wave without overtones. For details con-
cerning harmonic contents of different wa-
veforms please refer to the A-110 or A-111
manual (VCO´s).
We wanted to use the same terms as Oscar
Sala in his Mixtur Trautonium and this is why
we call the outputs of the A-113 subharmonics
though they are sawtooth outputs.
Mixture
The combination of four subharmonics is called a
mixture. Four different mixtures ("00", "01", "10" und
"11") are available but only one mixture is active at a
time. The original Mixtur-Trautonium had only three
mixtures available but due to the binary structure of the
A-113 we introduced 4 mixtures.
The active mixture is selected by the current state of
the two gate control inputs. In the original Mixtur-
Trautonium 2 foot switches mounted left and right of
the volume foot controller are used to switch between
the 3 mixtures.
Preset
A preset consists of 4 mixtures with 4 divisors each
(see fig. 4). 50 presets can be stored and called up
within the A-113 module. The original Mixtur-
Trautonium had no presets available. Each mixture
had to be changed manually.
Fig. 4: Structure of a preset
T1 T1 T1 T1
divisor T2 T2 T2 T2
(display) T3 T3 T3 T3
T4 T4 T4 T4
mixture "00" "01" "10" "11"

doepfer System A - 100 Subharmonic Generator A-113
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2. Overview Controls:
1Display : displays the current divisor
2Up : button to increase the divisor
data
3Down : same to decrease
4Level : output level control (mix out-
put)
5Preset : preset selection button
6Store : preset store button
In / Outputs:
!In : common audio input
(rectangle input)
"Foot Ctr. 1 : gate input 1 to switch bet-
ween the mixtures
§Foot Ctr. 2 : gate input 2 to switch bet-
ween the mixtures
%Mix Out : audio mix output
$Single Out : audio single output
A-113
SHG
Foot Ctr.
In 1
Level
Mix Out
➊
➋
➌
➍
➎
➀
➂
➃
Subharmonic Generator
010
010
010
010
➁
8
.8 .
Preset
Foot Ctr.
In 2
8
.8 .
8
.8 .
8
.8 .
➄
Store
Level
Level
Level
1
2
3
4
Single
Out
Divisor
Divisor
Divisor
Divisor
➅
In
Single
Out
Single
Out
Single
Out

A-113 Subharmonic Generator System A - 100 doepfer
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3. Controls
1 Display
This is the 2-digit LED display that shows the current
value of the divisor.
In addition the decimal points of the displays are
used to display the current mixture (see fig. 5):
• no decimal point is on: mixture "00"
• right decimal points are on: mixture "01"
• left decimal points are on: mixture "10"
• both decimal points are on: mixture "11"
The mixture selected depends upon the states of the
two gate inputs $und %(see chapter 4).
2 Up • 3Down
The Up button 2resp. the Down button 3are used to
adjust the divisor (range 01
0101
01 to 24
2424
24) for the correspon-
ding frequency divider.
Fig. 5: Display of mixtures by means of decimal
points (from left to right: "00", "01", "10", "11")
H Before you adjust the divisors be sure that
you have selected the right mixture!
The Up/Down buttons of frequency divider 4 are
used for preset selection instead of divisor adjstment
if the preset button 5is operated simultaneously.
4 Level
The attenuators 4control the amount of the
respective subharmonic present at the mix output
%.
1
2
3
4
1
2
3
4
1
2
3
4
1
2
3
4

doepfer System A - 100 Subharmonic Generator A-113
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5 Preset
While button 5is operated one reaches the preset
mode (see chapter 2 concerning the term preset). In
this state the displays of the third and fourth frequency
divider show “Pr" resp. the number of the preset
currently selected (e.g. “45", see fig. 6a):
Fig. 6: (a): display of the current preset
(b): store preset with new preset number
To select a new preset the up/down buttons 2and 3
of the fourth frequency divider are used while the
preset button 5is operated until the desired preset
number appears in the fourth display.
As soon as the preset button 5is released the module
returns to the normal mode. The displays show the
divisors of the new preset and the divisors can be
adjusted with the corresponding up/dow buttons.
6 Store
The store button 6is used to store presets. The
following steps are required to store a new preset:
D Operate the preset button 5and keep this button
pressed down (see fig. 6a).
D The up/down buttons 2and 3are used to select
the preset number in which the current preset will
be stored (preset button 5remains operated).
D Pressing the store button 6(preset button 5still
remains operated) causes the storage of the cur-
rent preset into the preset number selected. In the
upper displays appears "St" and "or" as confirma-
tion of the storage process (see fig. 6b).
H Pay attention not to select a preset num-
ber that already contains preset data you
may need in the future. Any former preset
data in the selected preset number are
deleted!
As soon as both buttons preset 5and store 6are
released the module returns to the normal mode. The
displays show the divisors and the divisors can be
adjusted with the corresponding up/dow buttons.
1
2
3
4
(a) (b)
1
2
3
4

A-113 Subharmonic Generator System A - 100 doepfer
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4. In / Outputs
! In
Socket !is the subharmonic generator’s audio input.
Connect up the signal you wish to use as master
frequency signal (normally the rectangle output of a
VCO).
" Foot Ctr. In 1 • §Foot Ctr. In 2
The gate inputs "and §are used to select the
mixture. Any gate type signals may be used (e.g. Foot
Controller, Sequencer gate outputs, MIDI interface)
(see fig. 7).
Fig. 7: Selecting mixtures with gate signals
(0: gate = low or no gate signal applied,
1: gate = high)
The mixture is displayed with the decimal points (see
chapter 3, fig. 5).
$ Single Out
Sockets "outputs the single subharmonic of the
respective frequency divider. The attenuators 4do not
affect the level at these sockets.
% Mix Out
At output §the mix of the 4 subharmonics adjusted
with the 4 attenuators 4is available.
Foot Ctr.
In 1
Foot Ctr.
In 2 Mixture Display example
00"00"
01"01"
10"10"
11"11"

doepfer System A - 100 Subharmonic Generator A-113
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5. User Examples
Simulation of a Mixtur-Trautonium
The Trautonium is an electronic musical instrument
invented by Friedrich Trautwein in the thirties in Berlin,
Germany, with enhancements made by Oskar Sala in
the fifties which led to the well known Mixtur-
Trautonium. The Trautonium can be divided into two
logical sub-units: the control unit and the sound gene-
ration unit.
A detailed description of the Mixtur-Trautonium and
the realization with the A-100 modular system can be
found on our web site www.doepfer.com.
The replica of the Trautonium sound generation with
the A-100 presents itself as the A-113 contains all the
basic sound source elements of the Trautonium. The
Trautonium Format Filter A-104 completes the sound
generation as it is a copy of the lowpass/bandpass
arrangement of the Mixtur Trautonium. Only a few
A-100 standard modules (VCO, VCA, LFO, ADSR)
have to be added to obtain the typical Trautonium
sound.
Fig. 8 shows the schematic construction of the Trauto-
nium sound generation using A-100 modules.
A-113 as a complex sound source
A-113 in combination with a VCO makes available a
very complex and powerful sound source for a lot of
sound experiments. The four subharmonics generated
by the A-113 contain strong harmonic spectra with
even and odd harmonics. They represent ideal basic
sound sources to be modified with separate sound
processing modules.
Fig. 9 shows an example. "XYZ" represents any sound
processing combination of modules: e.g. VCF, VCA,
Phaser, Distortion, Ring Modulator, Vocoder, Fre-
quency Shifter, Spring Reverb and so on with control-
ling modules like ADSR, LFO, Random, S&H, There-
min, Light-controlled CV, Joy Stick, MIDI interface and
so on. The controlling modules may be triggered or
synchronized (e.g. with a keyboard or sequencer con-
trolled gate) or free running.

A-113 Subharmonic Generator System A - 100 doepfer
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Fig. 8 : Schematic construction of the Mixtur-
Trautonium sound generation
(part 2 see next page)

doepfer System A - 100 Subharmonic Generator A-113
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A-113 Subharmonic Generator System A - 100 doepfer
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Fig. 9: A-113 as a complex sound source
A-135
VC-Mixer
Audio
Out
Audio
In 1
A-113
SHG
4
Single
Out 1
XYZ
MOD
VCO
Trig
ext . CV
In 1
MOD
Trig
VCA
VCA
MOD
Trig
Mix

doepfer System A - 100 Subharmonic Generator A-113
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7. Patch-Sheet
The following diagrams of the module can help you
recall your own Patches. They’re designed so that a
complete 19” rack of modules will fit onto an A4 sheet
of paper.
Photocopy this page, and cut out the pictures of this
and your other modules. You can then stick them
onto another piece of paper, and create a diagram of
your own system.
Make multiple copies of your composite diagram, and
use them for remembering good patches and set-ups.
P • Draw in patchleads with colored pens.
• Draw or write control settings in the little
white circles.
A-113
SHG
Foot Ctr.
In 1
Level
Mix Out
Subharmonic Generator
010
010
010
010
8
.8 .
Preset
Divisor
Foot Ctr.
In 2
8
.8 .
8
.8 .
8
.8 .
Store
Level
Level
Level
1
2
3
4
Single
Out
Divisor
Divisor
Divisor
Divisor
In
Single
Out
Single
Out
Single
Out

A-113 Subharmonic Generator System A - 100 doepfer
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