Doepfer A-157 1/2/3 Trigger Sequencer Subsystem

A-157 is a trigger sequencer subsystem that is used to generate up to eight trigger signals controlled by a 8x16 LED/button matrix (some customers call it "Miniature Schaltwerk" as it is based on the same matrix as the no longer available Schaltwerk). The system is still in the prototype state. Consequently the specifications on this page are still preliminary !

The subsystem will probably contain several modules:

• the LED/button matrix module A-157-1
• the trigger output module A-157-2
• one of the control modules (A-157-3, A-157-4 ...)

The LED/button matrix module A-157-1 is the core of the subsystem. It is used to set or reset the trigger event on each of the 16 steps of each of the 8 rows.
The trigger output module A-157-2 outputs the 8 trigger signals and has an LED display for each trigger. We will probably add a mute button or mute switch for each row that allows to turn the trigger output off/on independent for each row.
In the final version the modules A-157-1 and A-157-2 will be probably merged into one module only because both modules are essential for the subsystem.

The module A-157-1/2 (or the merged module that will contain both units) can be connected to a simple control module or a more sophisticated control module which is planned for the future (similar to the A-155 and A-154 conceptual design where the A-155 includes a simple control unit that can be replaced by the A-154 which offers a lot of additional functions).

At the beginning a simple control module A-157-3 similar to the A-155 control unit will be available. It offers only the functions clock, start/stop and reset (both with manual controls and control inputs). For this standard control unit the tempo (clock) is the same for all 8 rows, the direction is forward and the length of each row is 16.

We also plan a more complex control module A-157-4 that allows additional functions like 128 memories for trigger sequences, different clock/start/stop/reset for 2 or 4 groups of rows (e.g. common for rows 1-4 and 5-8, or in pairs), independent first/last step for each row, independent direction (forward/backward/pendulum/random) for each row, one-shot mode, LC display and so on. But these ideas are very preliminary and we will have to find out which functions are essential.

There are also plans for a stand-alone version adapted to the design of Dark Energy and Dark Time with the same case dimensions and wooden side panels (provisional name "Dark Flow")

Latest news (as of July 2014):

Based upon suggestions of customers the matrix board has been completely redesigned. The functions MUTE, SELECT, SHIFT LEFT, SHIFT RIGHT and INVERT ROW (when shift left and right are operated simultaneously) have been added for each row. This requires also a redesign of the processor board to support the new functions. Therefore the planned release date has to be postponed (without any obligation).

Latest news (as of May 2015):

Based upon suggestions of NAMM and Musikmesse visitors the matrix unit has been revised once again:

• additional bright vertical separation lines in the black blocks

• double functions for some buttons to obtain more buttons for additional features (e.g. Shift Left + Right = Swap, Forward + Backward = Pendulum)

• two unused buttons (labelled "???") for new functions

• some LEDs with different colors (e.g. steps 1/9 and Mute, just a suggestion, it's not for sure that different colors will be used and if applicable which colors will be used)

• maybe we can add the ratcheting feature (but it's still unclear how to operate this feature with the existing buttons and LEDs

• Two function inputs that can be assigned to any of the functions normally controlled by buttons (e.g. shift or invert), maybe they can be used also as additional clock signals (to have 2 or 3 different clocks available)