Analogue Solutions oberkorn User manual

ANALOGUE SOLUTIONS oberkorn e&oe (c) 10-2001 1
o be rk o r n
(it’s not a small sequencer)
analogue sequencer user manual
analogue sequencer user manual

ANALOGUE SOLUTIONS oberkorn e&oe (c) 10-2001 2
Contents
Intro - OBERKORN - Professional Analogue Sequencer............................................3
About Analogue Sequencers.........................................................................................5
Quick Start.......................................................................................................................5
CV + Channels In Details................................................................................................7
Gate Channels A, B, C ................................................................................................................................ 8
...................................................................................................................................................................... 8
Additional Gate Channels - bottom row of toggle switches .................................................................. 8
CV and Gate Output Sockets ..................................................................................................................... 8
Gate Output Signals and Gate C Legato Mode ........................................................................................ 8
Varying Gate Note Length .......................................................................................................................... 9
Splitting CV and Gate outputs ................................................................................................................... 9
Step Indicator LED...................................................................................................................................... 9
MIDI to Trigger Converter............................................................................................. 11
Sequencer Control Section..........................................................................................13
Reset In Socket: Changing the Pattern Length of the Sequencer ....................................................... 14
Reset to 16 Button .................................................................................................................................... 14
MIDI Synchronisation ...................................................................................................16
MIDI Clock Sync with MIDI Trigger #9..................................................................................................... 16
Controlling Step Order .................................................................................................18
.................................................................................................................................................................... 18
Quick Start To Step Control Using MIDI Notes ...................................................................................... 18
Step Control In Details .................................................................................................20
Advanced Information On How Step Control Works - Step Control Input Sockets A, B , C, D......... 20
MIDI Sync Switch ...................................................................................................................................... 22
Other Non Standard Uses ............................................................................................24
Audio Waveform Generator ..................................................................................................................... 24

ANALOGUE SOLUTIONS oberkorn e&oe (c) 10-2001 3
Intro - OBERKORN - Professional Analogue Sequencer
Inputs Outputs Power Supply
MIDIIn MIDI Out +/- 12V, 5V
External Clock Internal Clock
4x Mux control Step 1 Pulse
Reset MIDI Triggers x11
CV x3
Gate x5
Controls Indicators Size
16 CV pots /Gate Switches x3 Blue Tempo LED 84HP
16 Gate switches (3 position) MIDI activity LEDs x16
Tempo pot Coloured Step LEDs x16
MIDI Program button
Int/Stop/Ext Run/Stop switch
MIDI Sync switch
CV Range switch x3
Reset to 1 button
Reset to 16 button
Step button
Introduction
Oberkorn is a fully fledged professional analogue sequencer providing plenty of control outputs and inputs and with
some uniquely creative features never before seen.
Overview
Whilst most new analogue sequencers only offer a limiting 8 steps, the Oberkorn offers the all important 16 steps. It
is a multi-channel true analogue sequencer with some remarkable features. Below are a list of main features:
√3 separate Control Voltage channels. Each has a range switch providing approx. 2.5V, 5V and 10V CV ranges.
√5 separate Gate channels. 3 of the gate channel switches are built into the CV pots. The remaining 2 are on a
separate row of toggle switches. The switches are 3 position providing the 2 Gate outputs, with centre being off.
√Gate channel C is in ‘Legato mode’. More on this later.
√Clear step LEDs. The 16 step LEDs are colour coded so locating whole note steps is easy.
√8 channel MIDI to Trigger/Gate converter (with an additional 3 spare channels available internally for those
who wish to do modifications.
√MIDI Sync cabability, but using a MIDI note instead of MIDI clock. This method has major, important advan-
tages covered later.
√MIDI/CV control of the multiplexer (the multiplexer, or Mux, controls which step the sequencer is on). This is
a major new and unique facility that allows any of the 16 steps to be played in any order and any direction, missing out
or duplicating steps at will. Please read full details about this important creative tool later in the manual. When using
this feature, it is possible to activate ‘legato mode’ for all gate channels.
√Ability to lock onto your MIDI sequencer to the nearest 16th note, whether stopping, starting, or jumping to
another bar in your MIDI sequencer. Will lock on perfectly regardless.
√Reset to 16. Just about all other analogue sequencer have an inherant error, in that after reseting the machine
(to step 1), when restarting the sequencer, it actually starts on step 2! With our Reset to 16, this problem is overcome.
For more details on all features of Oberkorn , please read the whole manual - don’t miss any of it’s cool features!

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Intro + quick start

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About Analogue Sequencers
Analogue sequencers are devices that allow a sequence (up to 16 steps in the case of Oberkorn) of voltages and
gate signals to be ‘played back’ in order from 1 to 16. Each step has its own pot to vary CV and a switch to turn the Gate
on or off for that step. As the sequencer advances through each step, the CV and Gate signals for that step are
outputed at the CV and Gate sockets. When step 16 is reached, the sequencer resets to step 1 and starts all over
again. Oberkorn has 3 CV and 5 Gate channels.
CV is normally used to control an oscillator’s pitch, but can be used to control any module that has a CV input, such
as filter cut-off. The Gate signal is usually used to trigger an envelope, but can be used to control any module with a
gate, trigger or clock input.
There are many controls and features on an analogue sequencer to give more overall control over the way the
sequencer opperates.
The major advantage over an analogue sequencer compared to a MIDI/Digital sequencer are:
You have direct access to each note pitch (CV) and note on/off (Gate) as there is a separate control for each step.
Software sequencers do not offer this advantage, and very very few hardware MIDI sequencers do either. This makes
analogue sequencers more immediate and hands on. With this immediate hands on control, you can experiment by
altering the controls as the sequence plays, to evolve and manipulate your patterns in real time. As the signals coming
from the sequencer are analogue voltages, they can be added, inverted, slewed, or whatever, and can be used as
audio or control signals to feed into other analogue devices.
Quick Start
If you just want to jump straight in and use Oberkorn in it’s most basic form - to play an analogue synthesiser - here’s
how to do it:
•Take CV-A out into the CV (VCO pitch) input of your synth.
•Take Gate X out into the Gate (or EG trigger) input of your synth.
•Press the Reset to 16 button to reset the sequencer. It will reset to step 16. This is correct!
•Flick the Run/Stop switch left to ‘Int’ - ‘Internal’. The sequencer will now run off its internal clock at the speed set
by the Tempo control starting at step 1.
•Flick the row of Gate switches up (to ‘X’) to produce a Gate pulse to trigger your synth. Return the switch to the
centre off position for no Gate.
•Alter the CV-A pots to change to pitch CV for each step.
•Alter the Tempo control till the sequencer runs at the desired speed.
•If you want to restart the sequencer, move the Run/Stop switch to the centre position ‘Stop’. Press the Reset to
16 switch, then restart the sequencer with the Run/Stop switch.
•Basically, just keep playing around till you get a great sequence!

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CV+Gate channels

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CV + Channels In Details
Oberkorn has 16 steps. (This can be reduced to any number from 1 to 15. More on that later).
Each column of three CV pots and 1 switch is a step. There are 16 columns.
CV Channels
CV-A This sets the voltage for CV channel A from 0V upto the range set by the A Range switch.
CV-B This sets the voltage for CV channel B from 0V upto the range set by the B Range switch.
CV-C This sets the voltage for CV channel C from 0V upto the range set by the C Range switch.
Range Switches
Each CV channel has a separate range switch with 3 positions:
H ‘High’ - The CV range become 0 to 10V
M ‘Medium’ - The CV range becomes 0 to 5V
L ‘Low’ - The CV range becomces 0 to 2.5V
Step LED
Gate X/Y Switch
CV A, B &
C, and Gate A,
B & C Control/
Switches

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Gate Channels A, B, C
Each row of CV pots CV-A, CV-B and CV-C, has a built in switch. Turn the switch fully anti-clockwise (you will feel
and hear a ‘click’) and the switch is off. Turn to the right (after the click) and the switch is on. The integral switches built
into the 3 rows of CV controls provide the Gate signals for channels GT-A, GT-B and GT-C.
As the Gate switch is built into the CV pot, we realise that this means that to have the step produce no gate output
means that the CV level will also be zero, but this was the only way to add a Gate channel in such a compact module
and also without adding to the cost. We could have left it out leaving nothing to complain about. But it does NOT add to
the price, so you are getting 3 extra Gate channels for free! So no complaints about the zero-CV with no-Gate situation.
If you do wish to use CV and Gate together controlling pitch and EG triggering, there are some ways around this
problem:
Add some Glide to the CV signal. In some situations this will hide/eliminate the side-effect.
Put the VCA control signal into ‘Gate’ not ‘EG’ amount mode (or have zero release time on the EG). So as soon as
the Gate goes to zero, the output of the synth patch will also be zero so you will not hear the pitch drop.
Additional Gate Channels - bottom row of toggle switches
GT-X When the switch is up, the Gate for channel GT-X is set for that step
GT-Y When the switch is down, the Gate for channel GT-Y is set for that step
Off When the switch is in the centre position, no Gate is set for either channel X or Y
CV and Gate Output Sockets
The resulting CVs and Gate patterns created from the CV/Gate channels are outputed via the CV/Gate sockets.
The CV sockets are labelled CV-A, CV-B and CV-C. These correspond to the appropriate row of CV pots. The CV
signals are normally used to control any control voltage input on a synth or modules, e.g. pitch, filter cut-off, VCA, etc.
The Gate sockets are labelled GT-A, GT-B, GT-C, GT-X and GT-Y. These correspond to the appropriate Gate
channels. The Gate signals are normally used to trigger envelope generators, or anything with a Gate/Trigger input
(drum machine/module, monosynth, another analogue sequencer, sample and hold, etc.).
The Gate output level is +7V. This can be changed to any value from 0 to 12V by changing some internal zener
diodes.
Gate Output Signals and Gate C Legato Mode
Normally, for each gate switch that is in an ‘on’ position, a gate signal is sent out of its gate socket. If 2 or more gate
switches in a row are all on, then the gate signal will go off briefly before going on again for the next consecative gate
signal. This way, for instance, an envelope will re-trigger. This is how gate channels X, Y, GT-A and GT-B work.
CLOCK
GATE SWITCH
UP=On
Gate output for channels
X, Y, GT-A and GT-B.
See how each gate switch
produces an individual gate
signal.
GATE OUT SIGNAL
The following section is for advanced users. It describes in more technical detail how gate channels X, Y, GT-A and
GT-B work. You only need to tackle this if you wish to fully exploit the direct MUX feature covered later in the manual.
The gate signal output is actually produced by ANDing (a boolean term) the state of the gate switch with the clock.
Gate Switch Clock Gate Signal output
off off off
on off off
off on off
on on on
From the above table, you can see a gate signal is only created when the gate switch is on and there is a clock
voltage present. As soon as the clock signal goes low (0v) or the gate switch is off, then there is no gate output.
figure 1

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Varying Gate Note Length
All the gate outputs (except GT-C) will have a gate length that is equal the the clock pulse width. You can see this
by looking at figure 1. So to alter the gate pulse width you simply have to alter the clock pulse width. Most VCOs have
square wave outputs whose pulse width can be altered. This output can then be used to clock the sequencer. The
Concussor VCO-RM is one such module.
Splitting CV and Gate outputs
All CV and Gate channel outputs are buffered. This means their signals can be split many times with a multiple
without losing any level.
Step Indicator LED
Each Step has an LED indicator to show which step the sequencer is on. The LEDs are just to the right of each step.
LEDs 1, 5, 9 and 13 are red to indicate quickly the whole notes in a 4/4 pattern.
LEDs 2, 3, 4, 6, 7, 8 are yellow to indicate the notes in the 1st half of the sequencer.
LEDs 10, 11, 12, 14, 15, 16 are green to indicate the notes in the 2nd half of the sequence.
CLOCK Example showing the ef-
fect a clock signal with vary-
ingpulse widthhas onthegate
signal. This does not apply to
channel GT-C.
GATE OUT SIGNAL
GATE SWITCH
UP=On
For Gate channel GT-C the output is different. It is in Legato mode. This means that when consecutive gate switches
are all on, then the output will stay on, adding the output of the on gate switches together creating a longer gate signal.
This way, for instance, an envelope will not re-trigger, but stay on for consecative on switches, only going off when it
meets the first off gate switch. This is because the GT-C gate switch condition is not ANDed with the clock signal.
CLOCK
GATE OUT SIGNAL
GATE SWITCH
UP=On
Gate output for channels
GT-C.
Seehowthe 2consecative
on gate switches produce a
gate signal that is on for the
duration of the switches.
figure 2
figure 3
When the sequencer is not running, the voltage represented by the relevant CV control is continuously available at
the relevant CV output. It will not change till the sequencer is either manual stepped or clocked to the next step. The CV
controls can be altered in real time to alter the CV output whilst the sequencer is stopped.

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MIDI to trigger

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Oberkorn features a 16 channel MIDI to Trigger/Gate converter.
It allows a number of devices to be triggered directly from a MIDI note, indepen-
dently from the sequencer. Some of the MIDI-Trigger channels have special func-
tions described later.
The MIDI-Trigger outputs can be used to trigger drum voices, EGs, analogue
sequencers, or anything else with a clock/trigger/gate input.
Channel Overview
Channels 1-8 (1-8) These triggers are freely available to use on the front
panel via 8 jack sockets.
These allow devices such as envelope modules or drum modules to be
triggered independently of the sequencer by a MIDI note.
Trigger 9 (SYN) This is hard wired to the Clock input of the sequencer,
so a MIDI note can be used to synchronise Oberkorn to a MIDI sequencer.
More on this later.
Triggers 10-13 (A/B/C/D) These are hard wired to the Mux. More on chan-
nels 10 to 13 later.
Trigger 14 (INternal1) This is hard to Reset. When this trigger is acti-
vated the sequencer will reset to step 1. This will work whether the sequencer
is running or stopped.
Triggers 15-16 (IN2/3) These are spare and internal and effectively unused.
They can be utilised via modifications. E.g. they could be wired to additional
jack sockets on the rear panel.
MIDI to Trigger Converter
Connecting
Connect the MIDI sequencer or other MIDI device to the MIDI input of Oberkorn . Connect the trigger outputs to
device you wish to trigger.
Programming
•Programming the MIDI channel is a very simple proceedure.
•Press the PROG button. The 1st LED will flash, and triggers will be sent out of output 1.
•Oberkorn will now be in MIDI omni-on mode, so it will receive information on all MIDI channels.
•Press the MIDI key you wish output 1 to be assigned to. Output 1 will be assingned to that note
number. Oberkorn will set its MIDI receive channel (which will be the same for all outputs) to the MIDI
channel the keyboard is transmitting on.
•Continue to program the following 15 outputs by pressing each key your wish to assign them to in
turn.
•As each key is pressed, the next LED flashes and triggers are sent out of the respective output.
•After all 16 outputs are assigned the unit returns to normal mode.
•If you wish to skip programming any individual output, simply press the PROG button to skip
outputs.
Set-up information is stored in non-volatile memory. Information is retained when the power is switched off or module
disconnected from power board. No battery back-up is required!
If the set-up is altered for any unpredictable reason (for example power disconnected during programming), the
factory default program will be loaded at start-up. Factory default is MIDI channel 1, Output 1 set to C60, the next 15
outputs set to the next 15 keys.

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Sequence control

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Sequencer Control Section
EXT jack socket in
If you wish to use an external clock or other gate signal to control the
speed of the sequencer, feed a clock signal into the EXT socket. When the
Run/Stop switch is set to EXT, the sequencer will run at the external clock
rate.
INT jack socket out
The internal clock signal is constantly available from this socket to al-
low other devices to be sync’ed to Oberkorn
Step 1 jack socket out
Each time step 1 is reached, a gate signal is output from the Step 1
socket. This allows control of other devices, e.g. it allows the FS01 fill-in
module to count whole bars. It can also be used to trigger drum voices or
envelopes once per bar. It can be used to clock another sequencer 1 step
each time Oberkorn makes a complete pass.
Reset jack socket in
When a 5V signal is input to the Reset socket, the sequencer will reset
to step 1. One of the gate outputs can be patched into here to change the
sequence length.
Tempo control
This control sets the tempo speed of the internal clock.
Run/Stop
When the switch is to the left (INT) the sequencer will run (play). It will
use the internal clock as a tempo control. When to the right (EXT) the se-
quencer will run at the tempo set by any external clock signal fed into the
EXT clock jack socket. The clock signal from the internal MIDI-Trigger unit
is also wired to the external socket. When in the center position the se-
quencer will not run (stop).
Reset to 1
When this button is pressed, the sequencer will jump straight to step 1.
This button will work even when the sequence is running. The sequencer
can also be reset via the Reset in jack socket (see below), or using the IN1 MIDI to Trigger Channel (See MIDI section).
Reset to Step 16
When this button is pressed, the sequencer will jump straigh to step 16. This button will work even when the se-
quence is running. More on the need for this below.
Step
When this button is pressed, the sequencer will advance one step. This button is best used when the sequencer is
not running. By pressing the Step button, you can set the controls for each step in turn in your own time. If the sequencer
is on Step 16 (or whatever the last step is if set up to have less than 16 steps), pressing the Step button will return the
sequencer to step 1. This button will work even when the sequence is running.
A, B, C, D in
Details about the Multiplexer control inputs A, B, C, and D and the MIDI Sync switch are covered later.
MIDI Sync
For normal use it does not matter on this switch’s position. But it will be described in more detail later.

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Reset In Socket: Changing the Pattern Length of the Sequencer
To change the pattern length to anything lower than 16, you must feed one of the Gate channel outputs into the Reset
input socket. As the sequencer plays, as soon the first gate on signal is reach for the Gate channel you are using, the
sequencer will reset to step 1.
For example you want an 8 step pattern. Feed the GT-X gate channel output into the Reset input. Position all the GT-
X gate switches to Off (or in ‘Y’ position), except switch 9. As soon as 9 is reach, the seqeucner will reset. The pattern
will be 8 steps long. Note, step 9 is never actually reached or played. Another example, for a 12 step sequence, you
would have switch 13 on (but none before step 13).
In short, patch a gate output to the reset input. The sequencer will reset to step 1 and continue running as soon as it
reaches a gate on switch for the gate channel you are using.
This features, like all others on Oberkorn, can be operated in real time to allow you to change the pattern length in
real time as the sequencer is running.
The sequencer can also be reset to step 1 using the Reset1 button, or the IN1 MIDI to Trigger channel.
Reset to 16 Button
Pressing this button will reset the sequencer to step 16, not the usual step 1 like other sequencers (although this
feature has been included with the Reset to 1 button).
With just about all other sequencers the sequencer must manually be stepped to the last step, otherwise when the
clock is started (whether an internal or external clock is used), step 2 is in fact the first step to be played (the CV and
Gate settings for step 2 are the first to appear at the sockets, not step 1). In a few situations this might not be a problem,
but as soon as you try syncing another analogue sequencer, or use a MIDI sequencer as a master (along with some
sort of MIDI to clock converter) it becomes a problem. The analogue sequencer will always be 1 step ahead of the
other.
In these situations you would normally have to manually step the sequencer to the last step each time the sequencer
is started. Oberkorn is as far as I know the only sequencer to automatically go to the last step eliminating this problem,
speeding up operation and making you life that much easier!

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MIDI synchronisation

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MIDI Synchronisation
MIDI Clock Sync with MIDI Trigger #9
MIDI Trigger #9 (this is labelled ‘SYN’ on the front panel LED) is hard wired to the external clock input of Oberkorn.
Each time the MIDI key programmed for MIDI-Trigger #9 is pressed, the sequencer will advance 1 step. This means by
programming a string of notes in the MIDI sequencer, Oberkorn can be made to keep perfect time with the MIDI se-
quencer.
Note, this feature works best if the internal clock is in STOP mode. Otherwise the internal clock will also try to clock
to sequencer. Also, the MIDI Sync switch must be selected to ‘SYNC’.
‘Why not just use a standard MIDI clock to analogue clock converter?’ I hear you say. Simple reason. When using
standard MIDI clock converters, you cannot start and stop the analogue sequencer at any point while the MIDI se-
quencer is running. This is because MIDI clock runs continuously while the MIDI sequence runs. This means you cannot
get the analogue sequencer to pause for a number of bars mid way through the MIDI sequencer. By using a MIDI note
rather than MIDI Sync signals this problem is overcome, as to pause Oberkorn mid-MIDI sequencer, you simply just
mute the track that has you MIDI note sync pattern programmed in. Also there is no reason why the MIDI notes have to
be a stream giving a steady clock signal. Some sort of syncopated pattern can be written to get Oberkorn to step how
you want. Also effects like shuffle or triplets could be programmed.
Each time the MIDI sequencer is stopped and advanced or rewound, the analogue and MIDI sequencers must be
stopped before restarting. This is only neccessary if step 1 of Oberkorn must sync with step 1 of the MIDI sequencer.
Thismethodof synchronisationis notintelligent, thatmeans thereisnopositioninformation, soif theMIDI sequencer’s
position is changed, the analogue seqencer has no way of knowing where to skip to.
The next section explains how to make the Oberkon lock on as if it has intelligent sync signals (with position informa-
tion).

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Step Control
to access any step

ANALOGUE SOLUTIONS oberkorn e&oe (c) 10-2001 18
Controlling Step Order
One common feature of all analogue sequencers is that they always run from left to right, i.e. from 1 to 8 or 1 to 16,
(depending on how many steps it has). OK, some let you skip steps, but it is still essentially running in numerical order.
Oberkorn is the first analogue sequencer that allows you to overcome this problem. Oberkorn can be programmed
to run through the steps in ANY ORDER you wish. Steps can be repeated or even missed out altogether. In order to
describe how this function opperates, it is best to briefly explain how analogue sequencers work.
Below is a quick guide on how to get the Oberkon to step in a pre-programmed way. Also read through the section
‘MUX Control Input Sockets A, B , C, D’ if you want to understand the workings of this mode in more details. It will also
help you to get more out of thesequencer if you can fully understand it.
Quick Start To Step Control Using MIDI Notes
1/ Program the MIDI to Trigger channels to Note numbers that will control the Oberkorn step number (See MIDI to
Trigger Converter section on details on how to assign MIDI Triggers to MIDI notes):
MIDI Note Trigger # Control
C5 MIDI Trigger #9 Sync
C4 MIDI Trigger #10 Control A
C3 MIDI Trigger #11 Control B
C2 MIDI Trigger #12 Control C
C1 MIDI Trigger # 13 Control D
You can of course use any MIDI note numbers you wish. We have given the MIDI note numbers for MIDI patterns
that are available for download off our web site. Many examples are given and we will upload more with time.
(Note: MIDI Triggers 1-8 are for the front panel MIDI Trigger outputs, and 14 to 16 are generally not used)
2/ Put Run/Stop switch to stop
3/ Press the Reset to 1 button
4/ Put the Sync switch to MUX
Run the MIDI sequencer with the Note pattern programmed in and the Oberkorn will Sync up as programmed.
To access any step you need to program in note combinations as shown below:
D C B A Control inputs Step #
0 0 0 0 step 1
0 0 0 1 step 2
0 0 1 0 step 3
0 0 1 1 step 4
0 1 0 0 step 5
0 1 0 1 step 6
0 1 1 0 step 7
0 1 1 1 step 8
D C B A Control inputs Step #
1 0 0 0 step 9
1 0 0 1 step 10
1 0 1 0 step 11
1 0 1 1 step 12
1 1 0 0 step 13
1 1 0 1 step 14
1 1 1 0 step 15
1 1 1 1 step 16
1= Note present (Note On) 0=No note (Note Off)
MIDI Trigger #9 (Sync) is only neccessary if you are using gate outputs GT-A/B/X/Y. If you are only using the CV
outputs then you do not need to program in MIDI notes for Trigger #9.
Trigger #9 decides how long each gate will play for. A continues note will hold the gate output high (on) continuously.
Show durations allow short notes. Normally a string of 32nd notes will be programmed in at 16th note intervals. To help
you understand this examine the MIDI file ‘1to16’ - a screen shot can be seen below;

ANALOGUE SOLUTIONS oberkorn e&oe (c) 10-2001 19
MIDI Sync - Trigger #9
Control A - Trigger #10
Control B - Trigger #11
Control C - Trigger #12
Control D - Trigger #13
The above example shows a simple pattern that will play Oberkorn from steps 1 to 16 then repeat.
Real Time Variation
If each string of notes is placed on separate MIDI tracks, then you can mute any of the tracks at will. This will result
in the Oberkorn stepping in different ways. Try it and see! It’s great for real time variation.
More Simple Experimentation
Normally Oberkorn should be reset to step 1 when using Step Control Mode. But now try manually stepping the
sequencer (whilst the MIDI sequencer is running) using the Step button. See how Oberkorn now will step in a different
order!
Patch one of the Gate outputs to either the A, B, C or D Control input jacks. Run the sequener from its internal clock
and see how the step order changes as you switch on different Gate switches.
Now read on! I will try and help you understand the inner working of analogue sequencers and Oberkorn in particular,
and how to get the most out of the Step Control feature!

ANALOGUE SOLUTIONS oberkorn e&oe (c) 10-2001 20
CLOCK COUNTER MUX CV Output
CV controls x 16
The clock is basically a square wave LFO.
The counter counts the clock pulses. The counter produces a 4 bit binary output (an address) to represent step
positions 1 to 16 (see conversion table below). This is transmitted via a 4 bit address bus to the multiplexer. Each
address line can have a high or low output.
The multiplexer is an electronic analogue switch. It can have a number of inputs and outputs, in this case 16 inputs
and 1 output. The 16 inputs are the voltage output from each CV control. The output is routed to the CV output socket.
The 4 bit binary address signal (representing the numbers 1 to 16) selects which of the 16 inputs to the multiplexer is
switch to the output, i.e. which voltage from the 16 CV controls is routed to the CV output.
As the counter counts clock pulses, it counts up from 1 to 16. When it reaches 16 it resets to 1. It is in this way that
the 16 different CV controls are routed to the CV output socket in turn.
How Oberkorn Can Access Any Step
Counters always count in upwards and in order from 1 to a higher number. (There are counters that count down, but
you never see these incorporated into sequencers). The way in which Oberkorn can be made to step in any order is by
completely bypassing the counter, feeding your own signals into the 4 bit address bus of the multiplexer. The multiplexer
address bus can be programmed via the control input sockets on the front panel, or by using the built in MIDI to Trigger
converter on Oberkorn.
Using MIDI to Trigger to control the Mux
MIDI Triggers #10 to 13 are hard wired to the multiplexer control inputs. That means different combinations of the 4
note on/off conditions allows you to create you own 4 bit pattern to select any of the 16 steps. You can build up a library
of MIDI note patterns to give you different stepping orders. (MIDI sequencers demonstrating this are available for
download off our web site).
When using the Step Control inputs, the Run/Stopswitch must be in the STOP position, and the Reset to 1 button
must be pressed to reset the sequencer to step 1.
Using the Control Input sockets (A, B, C & D) on the front panel.
Use any 0/5V signal to control these inputs, e.g. LFO, Gate, etc. It will have the same affect as if using the 4 MIDI
Triggers were used.
Now to understand how to access each step, refer to the binary conversion table below:
4 bit
control
bus
D C B A Control inputs Step #
0 0 0 0 step 1
0 0 0 1 step 2
0 0 1 0 step 3
0 0 1 1 step 4
0 1 0 0 step 5
0 1 0 1 step 6
0 1 1 0 step 7
0 1 1 1 step 8
D C B A Control inputs Step #
1 0 0 0 step 9
1 0 0 1 step 10
1 0 1 0 step 11
1 0 1 1 step 12
1 1 0 0 step 13
1 1 0 1 step 14
1 1 1 0 step 15
1 1 1 1 step 16
There are 3 main elements to the sequencer:
figure 4
Step Control In Details
Advanced Information On How Step Control Works - Step Control Input Sockets A, B , C, D
How analogue sequencers work:
1= Note present (Note On) 0=No note (Note Off)