a157b – Manual

a157b

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Idea

The Doepfer A-157 is a pure trigger sequencer. Among other applications, it is used for controlling drum modules – including in live performances. The a157b software gives the module added functions and offers an alternative operating concept. It is not self-explanatory, this was not completely possible without a display, unfortunately this manual is necessary.

Installation

Carry out the following seven steps to install the software:

    1. Download the corresponding ZIP file and unzip the “uploader” program.
    2. Switch off the module.
    3. Connect the module to a computer (Windows, Mac or Linux) via USB cable. Do not remove the ribbon cable leading to the Eurorack.
    4. Start the module, making sure to press and hold down the Shift key at the bottom right on the module while the power is switched on. This sets the module into a special upload mode. It remains unlit and appears deactivated – this is normal. (To reset to normal mode, briefly interrupt the power supply to restart the module.)
    5. Start the “uploader” program on the computer:
      • Windows: Double-click on “uploader.exe” or start in the panel.
      • Mac: Double-click on “uploader” or start in the terminal with “./uploader”.
      • Linux: Start with “sudo ./uploader” and then enter the administrator password.
    6. The program now connects to the module, displays the name of the current software, then copies the new software to the module and verifies the procedure. Finally, the module is restarted automatically in normal mode. The entire process takes around 30 seconds.
    7. Remove the USB cable.

If the uploader program does not find the module, check the USB cable connection, whether the A-157 module has power and whether it was started with the Shift key held down.

To reinstall the original software, please use the Doepfer installation program.

When the a157b software is installed, the files stored using the Doepfer software are not transferred. However, they are not lost. After the original software is installed, they are available there once again. This also applies to the files stored using the a157b software – these are not affected by the installation. This means that users can easily switch between the two solutions without losing any data.

Overview

The A-157-1 module consists of four sections:

Matrix with steps
A pattern is usually shown on the left of the module. This pattern consists of 8 tracks, each with 16 steps. If the steps are set, the corresponding output on the A-157-2 module is triggered. A step is set or removed by pressing the buttons on the matrix. Each track has its own playhead. Steps with the playhead flash if the sequencer is stopped.

If numbers and texts are displayed in the matrix when using a157b, these can be changed with the buttons on the matrix. For example, if the lower part of a number is pressed, the next value is selected. If the upper part of the number is pressed, the previous value is selected. In the same way, a system parameter is changed by pressing one of the buttons in the upper or lower part of the displayed parameter – just like on a touchscreen. 

For some functions, the buttons on the matrix can also be used to carry out other actions, such as setting the clock divider per track, or “Chains” and “Effects”. These special screens are described in more detail under the corresponding functions.

Mute
This column with 8 buttons allows for individual tracks to be muted. If the Shift key is active, the corresponding track is set to “solo” (all others are muted). If the track is already set to “solo”, this action is reversed.

If you first hold down the Shift key and then press additional mute buttons, the corresponding LEDs will blink and all changes will be made all at once when you release the Shift key.

Other functions also use the mute buttons; these then also always represent a track.

Select
The column highlighted in black with 8 LEDs and buttons is used to display the patterns. The pattern that is active and visible in the matrix is lit. Additionally, the patterns that have a playhead always flash.

Normally, the pattern that has the playhead is active and can be seen in the matrix. If different patterns have a playhead (as the tracks have different clock dividers), the pattern is displayed where the playhead of the “Follow Track” is located. The standard setting for this is the first track. A different track can be set in the system menu (see below). The function can also be deactivated here. Additionally, the automatic switchover is prevented if a Pattern Select button is held down – or one of the Set or Copy functions is active.

The Select buttons are also used by the “Library”, “Effects”, “Loop” and “Copy” functions. They also always represent a pattern in this case.

Functions
The 16 buttons on the far right are used to activate functions. Using the Shift key, you can change between the normally labeled functions and those highlighted in black. Important: The key does not have to be held down here, Shift works more like a Caps Lock. This also applies to all other keys. In order to be able to use them better in live performances, all buttons are designed so they don’t have to be held down. To deactivate a function, either press the button again, select another function or press the Shift key.

Functions – mode selection

When using the a157b software, the module has three basic functions:

    1. “Single Pattern”: Only one pattern with 8 tracks of 16 steps is used. In this mode, the start and end point and direction can be defined for each track. Each track has its own clock divider and playhead.
    2. “Multi Pattern”: 8 patterns are available here. The “Repeat”, “Loop” and “Chain” functions (see below) define how these patterns are played. The start and end point can also be defined here for each track (this then applies for all eight patterns, such as for making a song in ¾ time), although the direction in this mode is “Forward” for all tracks. As each track also has its own clock divider and playhead in this mode, it can occur that the played triggers come from different patterns – in other words, several patterns are played simultaneously.
    3. “Mixed Pattern”: This mode corresponds to the “Multi Pattern” mode, however individual tracks can be classified as “Single”, which can then have their own direction and not follow the sequence according to “Repeat”, “Loop” and “Chain”. These tracks can be used for a module-internal or external controller, or for instruments that are identical for all patterns.

Single/Multi (known as “AB” on original module)
This button is used to switch from “Single Pattern” to “Multi Pattern” mode and back. As long as the button is pressed, the Select display briefly shows how many patterns (1 or 8) are available. The LED of the button is lit when “Multi Pattern” is active.

Data is never lost when switching the mode. Information that is only available for “Single Pattern” (track direction) or “Multi Pattern” (Repeat, Chain, Loop) is not deleted or reset when the mode is switched, and is present in its identical form when the original mode is accessed once again. This of course also applies to the parameters that are available in both modes (Clock, Gate Mode and Len, Effects, Misc, System) and the steps for all patterns.

Mixed (known as “ABCD” on original module)
This button is used to convert a pure “Multi Pattern” into a “Mixed Pattern” mode, in other words to set individual tracks to “Single”. The track is selected on the left of the matrix and the track mode “MU” (Multi) or “SI” (Single) on the right. If all tracks are set to “SI”, the sequencer behaves as if it were in “Single Pattern” mode. If all tracks are set to “MU”, this is then in full “Multi Pattern” mode.

Functions – setting steps

Steps can be set manually for each pattern, either at your convenience or using “Live Record”. Entire patterns can also be copied from the integrated library, which contains around 100 different patterns. Additionally, “Effects” can be used to add euclidean rhythms to the patterns or also play them in the background – including with small, random deviations.

Tr Set, Tr Delete, Shift L, Shift R, Invert, Swap
If one of these functions is active, then either a step in the matrix can be selected (the function then relates to the entire column, i.e. all steps above and below) or a Mute button is pressed and the function operates on the selected track. In both cases, only the currently active pattern is affected.

    • Tr Set: Sets all steps of the column or track.
    • Tr Delete: Deletes all steps of the column or track.
    • Shift L, Shift R: Shifts the column one step up or down, or the track one step to the left or right.
    • Invert: Inverts the column or track, i.e. deletes the set steps and vice versa.
    • Swap: Swaps the top 4 steps of the column with the bottom 4, or the first 8 steps of the track with the last 8.

Live Recorder (known as “Note” on original module)
This function can be used by the musician to play a pattern while the sequencer is running. If a button on the matrix is pressed, a step is set at the playhead for all tracks. If a Mute button is pressed, this only occurs for the corresponding track. This input can also be quantized: Using the “Quantize Live Recorder” parameter in the system menu, a specification can be made that only each second, third or fourth step is set, for example. If necessary, the set steps can then be moved to the desired position using the “Shift L/R” function.

Library (known as “Accent” on original module)
This function offers a library of around 100 templates with 6 tracks each, divided up into 7 music genres. These can be rehearsed and then copied into one of the eight patterns.

The library assumes that the tracks are assigned the following instruments (though a different assignment is of course possible):

    1. HH – (Closed) hi-hat
    2. CY – Cymbal, sometimes open hi-hat
    3. TT – Tom-tom
    4. SD – Snare drum, in rare cases rim shot
    5. BD – Bass drum
    6. AC – Accent, emphasizing a step

If the “Library” function is active, the first 6 rows of the matrix show the template. A template is selected using the buttons on the bottom two rows: the music genre (row 7) and the pattern itself (row 8). The bottom Mute button can be used to select a random template from all genres.

The following genres are available (from left to right): dance, rock/pop, funk, R&B, Latin American, traditional, miscellaneous.

(Thanks here to my wife Junko, a drummer)

The selected template is then released for rehearsal, but only when the corresponding “Rehearsal” parameter is set in the system menu. In this way a template can be selected without being played, including in live operation. During rehearsal, none of the specified settings (e.g. Clock Divider, Direction, Gate Mode or Len) are taken into account.

To use a template from the library, a Pattern Select button is pressed. This copies the template from the library to the selected pattern and then exits the function. Using the “Copy All” system parameter, it can be specified whether just the steps themselves are copied, or the track properties as well (length, direction etc.). Without “Copy All”, it can occur that the template has a different sound after copying compared to rehearsal as it was only 12 steps long there, for example.

Effects
On the first 6 tracks, the “Effects” function can be used to define a euclidean rhythm that can be rehearsed and then either copied into a pattern or played as background music for all patterns.

Each of the six tracks has four values that define the rhythm.

    1. Length: This is entered directly on the track in the matrix. A length between 2 and 16 is chosen by pressing one of the buttons. For example, to select a length of 10 for the first track, the tenth button from the left is pressed on the first row. If the length 1 is selected, no pattern is output for this track and it remains mute.
    2. Number of set steps per track: This input is made in the bottom row. It must be less than or equal to the selected length, which is shown in this row as a flashing LED. To set this value without setting the length beforehand, the track can also be selected using the first 6 Mute buttons.
    3. Shift: The generated pattern is shifted right by 0 to 8 steps. This parameter can be set using the 8 buttons at the far left in the second row from the bottom.
    4. Skip: On each track, it can be defined how probable it is that a step is skipped (i.e. not played). The values here are 10% to 80% depending on how many LEDs are lit on the right side of the second row from the bottom.

The shift and skip parameters can be reset to 0 or 0% by pressing the set value a second time.

Using the four parameters, a pattern – or euclidean rhythm – is calculated. This is displayed in the matrix and also output for rehearsal (provided the system parameter “Rehearsal” is set).

The six tracks from “Effects” can be used in two ways:

    1. All tracks with content can be copied into a pattern. To do this, one of the Pattern Select buttons is pressed (as seen in Library). The system parameter “Copy All” also defines here whether only the steps or also the track properties are adjusted. The “Skip” parameter is not considered when copying.
    2. The second-bottom Mute button can be used to activate or deactivate whether the “Effects” are played in the background in addition to the manually set steps of the pattern. As during rehearsal, the entered skip probability is taken into account here.

P.S.: The bottom Mute button is used to generate a random rhythm for all “Effects”.

Copy
This function is used to copy an entire pattern. To do this, a different pattern is clicked on in the Select section while the Copy function is active. This pattern is then overwritten.

Functions – settings per track

A setting can be made on each track for how many steps it has (First/Last), how the clock is applied on the track (Clock Divider), how the steps are output (Gate Mode and Len) and – for tracks in Single mode – in which direction the playhead is shifted (Forward, Backward, Pendulum, Random Walk).

First, Last, Forward, Backward, Pendulum, Random Walk
The matrix changes if one of these functions is active. The steps are no longer shown, but instead the start point, end point and direction are indicated: With Forward, the First step is two LEDs wide, with Backward the Last step, with Pendulum both First and Last, and with Random Walk both consist of just one LED. The playheads of the individual tracks are also visualized here. They are all consolidated on a single matrix – including in “Multi Pattern” mode – regardless of in which pattern they are currently located.

The First, Last and direction parameters can be controlled and set as follows:

    • For the First and Last function, press a step in the matrix to set it. If one of the Mute buttons is pressed, First or Last is reset to the first or last step for this track.
    • The Forward, Backward, Pendulum and Random Walk direction functions are only available for tracks in Single mode. Both pressing the matrix or one of the Mute buttons adjusts the direction of the corresponding track according to the active function. On Random Walk, there is a 50% probability of the playhead moving one step forward and a 25% probability of it either moving one step back or remaining where it is.

Clock
This function is used to set the clock divider for each track, in other words how many external clock signals are required to move the playhead of the step one step forwards (or according to the set direction).

The divider can be seen for each track in the matrix: for example, if 4 LEDs can be seen in the first row, then the clock divider of the first track is 4. The standard value for all tracks is 1 and the maximum value is 16.

Gate Mode and Gate Len
The “Gate Mode” and “Gate Len” functions are used for each track to define how a set step is output on the A-157-2 module.

If the Gate Mode or Len function is active, the track is shown on the left of the matrix and either the mode or length to the right of this. As usual, these values can be changed by pressing the buttons on the matrix.

The following gate modes are available for each track:

    • TR (Trigger): The step is output for between 1 and 9 milliseconds, depending on the Gate Len value.
    • RA (Ratchet): If this gate mode is active, a trigger signal (1 millisecond) is output as many times as Gate Len is set. For example, if Gate Len is set to 5, then 5 short triggers are output per set step. The triggers are divided up evenly across the entire duration of the step here.
    • RD (Random): The step is output as a trigger, but only with a probability of between 10 and 90% as set with Gate Len.
    • SW (Swing): With Swing, each odd step is output with a slight delay. Gate Len defines how long this delay is, this can be between 5% and 45% of the length of the step. For example, if a clock signal comes every second and Gate Len is set to 25%, then each second note is played a quarter second later than normal.
    • ED (Envelope Discrete): The step is output as an envelope curve with a variable voltage of between 0 and 10 V. The appearance of this envelope curve can be specified via Gate Len. To do this, press the small envelope curve displayed here to the right of the track number. The matrix then changes and the envelope curve can be “drawn” here. To exit the curve screen, a different function is selected as usual with the buttons at the far right (or Gate Len is pressed again) to go back to the original point.
    • ES (Envelope Smooth): An envelope curve is also output here. However, in contrast to “Envelope Discrete”, this curve is smooth. Using this gate mode, an envelope curve can be defined visually and a VCA thus controlled directly.
    • GA (Gate): The step is output for the first half of the duration of the step.
    • HI (High): The step is output for the entire duration of the step.
    • F1-4 (routing to the “Func” inputs): In this gate mode, the step is not output in the A-157-2 module. Instead, it controls the “Func 1” to “Func 4” inputs of the A-157-3 module – in addition to the buttons and input sockets there. In this way, the “Misc” functions (see below) can be controlled with the set steps on a track on the A-157 itself. Tracks in gate mode F1 to F4 are not influenced by “Effects” and “Misc” activities, but they can be muted manually.

Three notes regarding timing:

    1. The modes Ratchet, Swing, Envelope and Gate must know how long the step is going to be. The last clock signal is used here. In order for these gate modes to function correctly, the external clock must have previously sent at least one correct signal.
    2. The external clock can be a gate or trigger, only the rising edge of the clock is taken into account by the software. Even in “Gate” mode, the output is maintained for half the step duration regardless of the falling edge of the clock.
    3. The aforementioned modes take into account the clock divider for each individual track. For example, if Gate Len of a track is set to 3 and Clock Divider to 8 for “Ratchet”, the 3 requested ratchets are divided up across the partitioned, slower time, i.e. across 8 clock signals. This also applies to the Swing and Gate mode: with a clock divider of 3, a gate is thus 1.5 clock signals high and just as long low. Exciting rhythms can be created using this feature.

In addition to the gate modes mentioned above, which operate on the set steps, there are five Performance Modes. They enable the A-157 to be used as a controller, for example to operate other modules – with its many buttons it does that well! If one of the tracks is in this mode, this row of the matrix becomes its own tool, e.g. a button, switch, fader. This allows the musician to directly control the corresponding output of the A-157-2 module. The steps and settings for this track are not lost, but will not be used for the output. Also Start, Stop and Clock are not relevant.

The following Performance Modes are available:

    • PB (Performance Button): As long as a button on the row is pressed (which one is not important), a signal is output.
    • PL (Performance Latch): If a button on the row is pressed once, the switch is activated and there is a signal on the output. Pressing the button a second time stops this signal.
    • PC (Performance Click): A short trigger signal is output immediately each time one of the 16 buttons in the row is pressed.
    • PK (Performance Key): The 16 buttons of the row represent a small keyboard. As long as a button is pressed, a voltage from 0 (far left) to 10 volts (far right) is output.
    • PF (Performance Fader): The voltage on the output is between 0 and 10 volts, depending on which button is pressed. The button on the far left corresponds to 0 volts and the button on the far right 10.

Functions – pattern sequencing

The “Repeat”, “Loop” and “Chain” functions are only available in Multi Pattern or Mixed Pattern mode, and define in which sequence the patterns are played. As an exception, the rows on the matrix are used for patterns and not tracks for all three functions. A common feature of all three functions is that all patterns flash that have a playhead.

Repeat
If this function is active, the appearance of the matrix changes. You can now see how often the pattern will be played when it is the pattern’s turn to play. For example, if 5 LEDs light up in the second row, the second pattern is always played 5 times before the next element (according to “Loop”) starts. Pressing a button on the matrix defines how often a pattern is played each time (1 to 16).

Loop
This function defines in which sequence the patterns are played. Moving from left to right, the next pattern is always taken. Once the end is reached, the first pattern is taken again.  For example, if an LED lights up at the far left in the first row and then an LED in the second row, the first pattern is played first (“Repeat” defines the number of times) and then the second pattern. By pressing a button on the matrix, the musician can specify which pattern comes and when. For example, to only play pattern 3, all buttons in the third row are selected from left to the far right.

The “Loop” is specified at the start so that only the first pattern is played. To quickly generate a simple sequence, one of the Select buttons can be pressed while the “Loop” function is active. A repeating sequence is then defined up to the selected pattern.

Chain
This function is used for integrating patterns into the defined loop live and spontaneously. By pressing a button on the matrix, either a new pattern can be set at the end of the chain, an already planned pattern replaced by another one or – if an already lit LED is pressed – a pattern removed from the chain. This also applies for patterns in the middle, the a157b software then rearranges the chain automatically.

If the chain is empty, the loop cycles as normal. However, if at least one pattern is present in the chain, it is played. In doing so, the chain is shortened by one link and the next pattern of the chain is played, when present. The sequence defined by “Repeat” and “Loop” does not play a role here, the chain always has priority. At the end of the chain, the sequence continues at the exact position where “Repeat” and “Loop” were previously interrupted. The chain can be saved, but it is empty once it has been completely used.

Three notes:

    1. Only “Multi” tracks are affected by the chain.
    2. The filled chain is started separately for each of these tracks when its current pattern has ended. This can occur for all tracks simultaneously or also one after the other if they have individual clock dividers and playheads.
    3. Once all tracks have run through an element in the chain, it is removed.

Functions – activities

Using “Misc”, a special activity can be assigned to each of the four inputs “Func1” to “Func4”. This is executed providing there is voltage present on the input or the corresponding button is pressed – or there is a track in gate mode “F1-4” and has a set step.

These activities do not change the steps entered by the musician, nor do they change the entered “Effects” or other parameters. They are only taken into account as long as the inputs are active. Following this, the original value applies again.

Misc1, Misc2
If the Misc1 or Misc2 function is active, the input (F1-F4) is displayed on the left of the matrix, followed to the right by the activity (with Misc1) or track selection (with Misc2). The numbers “1” to “8” represent the corresponding track here. “A” (All) means that all tracks are affected. As on all other functions, the values can be changed by pressing the upper or lower part of the letter.

The following activities are available:

    • –: No action, the Func input is not used.
    • M (Mute): Mutes the selected track.
    • S (Set): Always plays a step on the selected track, irrespective of whether a step would be available due to the matrix or “Effects”.
    • R (Ratchet): Changes the gate mode to ratchet for the step. In the bottom row of the display, you can select how many triggers this should have (1 to 8). The gate mode of the track is overridden here, with one exception: random gates are also output in this case, but with ratcheting as defined by Misc.
    • E (Effect): Adds an additional background effect. This is entered in the same way as for the “Effects” function (see above) – in this case, in the bottom three rows of the matrix. As with other background effects, the “Skip” parameter is taken into account and the First/Last step of the track is not changed.

As detailed above, the “Func” inputs can also be set by the sequencer itself – not using a cable (not possible due to the short delay) but instead via internal routing. To do this, the gate mode is set to F1-F4.

If multiple “Misc” activities are applied to a track, the a157 software will try its best to meet them all: multiple “Effects” are overlaid, “Mute” taken into account at the end and “Ratchet” also applied to effects.

Functions – management

Recall, Store
The a157b software can manage 32 storage slots. All information is stored here. The 32nd slot is special in that it is always completely empty. This can only be used for loading, not saving.

With these two functions, the slots are visualized in the bottom two rows of the matrix: if a slot is present, an LED is lit here. Each slot has a title comprising four letters. This is displayed in the upper part of the matrix. The name of the empty 32nd slot is “DEL” (delete).

To be able to load and save, a slot must be selected so that it flashes and then – for security reasons – pressed once again. Only the filled slots can be selected for loading. All slots except the 32nd slot can be used for storage. The function is automatically exited following loading or saving, which is here practical. In addition to Copy (including for Library and Effects), this is the only function in a157b that is exited.

The name of the slot is displayed during loading and defined before storage is carried out. To do this, one of the four letters displayed in the matrix can be pressed in the Store function. Pressing the bottom part of the letter selects the next letter up and pressing the upper part the previous.

The last slot stored is automatically loaded when the sequencer is started.

System
This function is used to set universal parameters. These are stored for each slot.

As in the other functions, the matrix is used to select the parameter and its values (and not the Mute buttons, as suggested by the printing on the panel): Pressing the first or second letter at the top or bottom selects the parameter. Pressing the number scrolls the number up or down.

The following parameters can be set:

    • FT (Follow Track): The pattern where the playhead of the “Follow Track” is currently located is displayed automatically in the matrix. The default value is “1”. This function can be completely deactivated with “-”.
    • QR (Quantize Live Recorder): Possible values for this parameter are 1 (default) to 4. These define whether each step can be set by the “Live Recorder” function, or only every second, third or fourth step.
    • HE (Rehearsal): This parameter defines whether the musician wants to rehearse the patterns and rhythms in the Library and Effects function (1, default) or not (0). Especially in live operation, rehearsals may not be wanted.
    • CA (Copy All): This parameter defines whether only the steps from Library/Effects are copied to the selected pattern (0, default), or also the track settings as well (1). The following values are then set here: Clock Divider = 1, Direction = Forward, First = 1, Last = length of the library or euclidean rhythm, Gate Mode = Trigger, Gate Length = 4 milliseconds. If the parameter is set to “1”, a reset is also carried out during copying in order to synchronize all playheads.
    • RE (Reset Handling): This value defines how many clock signals the A-157 should wait after a reset until the first step is played. If “0” is set, the first step is played directly as the reset is made and the next clock signal plays the second step. This setting may be necessary if the clock arrives shortly before the reset or the A-157 is used with another sequencer with this behavior. If the parameter is “1” (default), all playheads are reset, but the first step is only played with the next clock signal.
    • BR (Brightness): The brightness of the LEDs on the A-157-1 module can be set with this parameter. The possible values are 1 to 4. The default value is 3.

Controls

The buttons and inputs Start, Stop, Reset and Clock are implemented in the same way as in the original software:

    • Start and Stop control whether the sequencer reacts to the incoming clock signal or not. Even if the sequencer is stopped, the clock is processed in order to define the duration of a step. This is necessary so that a correct duration is known for the Ratchet, Swing, Gate and Envelope gate modes when the sequencer is started.
    • Reset is used to reset all playheads and immediately plays the first step depending on the “Reset Handling” parameter – or waits until the next clock signal.
    • Clock: Each rising edge of this input is processed, firstly to define the step duration and secondly to move the playhead on each track according to the clock divider.
    • Func1 to Func4 are used by the Misc1 and Misc2 functions.

Feedback

One button is still unassigned: Midi/USB. Which function could this button be used for? Ideas are welcome! Notifications of errors or inconsistencies are also greatly appreciated. These can be sent to the following address: a157b@rusche.ch

Christian Rusche, 2019