
DOEPFER System A-100 Trigger-Sequenzer A-157-2/3
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1. Introduction
The Trigger-Output Module A-157-2 and the ControlInput Module A-157-3 are both required to drive the
Trigger Sequenzer A-157-1:
The Trigger-Out Module A-157-2 is where the trigger
signals (+12V) for each sequencer track can be tapped
from.
The Control-Input Module A-157-3 is used to control the
sequencers run functions (start / stop / reset / clock). You
can either control them manually using the push buttons, or
by applying external signals of ≥ +3 Volts.
Please note: To run the sequencer, an external clock signal
has to be patched to the A-157-3 clock input socket. Please
refer to page 2.
2. A-157-2 Trigger Output Module
The Trigger-Output Module A-157-2 is self explaining. The
eight sockets provide the trigger signals (+12V) for each
sequencer track.
IMPORTAND: Before installing the modules A-157-2
and A-157-3 please read carefully the setup
instructions on pages 3 and 4 !

Trigger-Sequenzer A-157-2/3 System A-100 DOEPFER
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3. A-157-3 Control Input Module
The Control-Input Module A-157-3 is used to control the
sequencers run functions (start / stop / reset / clock). You
can either control them manually using the push buttons, or
by applying external signals of ≥ +3 Volts, resp. a clock
signal.
3.1. Control keys / inputs
Start
Hitting the key (or routing a positive pulse into the respective
jack) will get the sequencer going from the current step
position.
Stop
Hitting the key (or routing a positive pulse into the respective
jack) will stop the sequencer at the current step position.
Reset
With the next incoming clock pulse, a key hit (or routing a
positive pulse into the respective jack) will start thesequence
at step #1.
Clock
Each time you are hitting the key (or routing a positive pulse
into the respective jack), the sequencer will advance to the
next step.
A steady clock signal (pulsewave) is used to drive the
sequencer at a steady pace.
Func. 1-4
(not implemented yet)

DOEPFER System A-100 Trigger-Sequenzer A-157-2/3
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4. Setting up the A-157-2/3 modules
The A-157-1 main module needs to be mounted in your
eurorack case side by side the A-157-2 trigger output
module and the A-157-3 control input module. Simply
connect flat ribbon cables with the following sockets:
• (1) the socket labelled „JP2“ of the A-157-2 trigger output
module with the socket labelled „JP3“ on the A-157-1
trigger matrix PCB.
• (2) the socket labelled „JP1“ of the A-157-3 control input
module with the socket labelled „JP4“ on the A-157-1
trigger matrix PCB.
• (3) the socket labelled „JP1“ of the A-157-2 trigger output
module with the A-100 bus power connector.
• (4) the socket labelled „JP1“ of the A-157-1 trigger matrix
module with the A-100 bus power connector.
Please make sure that the position of the flat ribbon cables
coloured stripes fit to the figure on the following page resp.
to the labelling on the PCBs.
The figure on the following page will show you claerly all
necessary connections. Again – please strictly observe
these instructions!
WARNING: STRICTLY OBSERVE THESE INSTRUCTIONS!
Install carefully and gently. Doepfer cannot accept responsibility
or liability for modules damaged by installing them improperly or
by using brute force.

Trigger-Sequenzer A-157-2/3 System A-100 DOEPFER
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