D-420 Drum Girl (4HP)


D-420 Drum Girl drum pattern generator module for Eurorack / Doepfer A100 system.

From the top down:
Kick trigger output jack + LED
Snare trigger output jack + LED
Hi-Hat/percussion trigger output jack + LED
Kick pattern selection knob + LED
Snare pattern selection knob + LED
HiHat/percussion pattern selection knob + LED
Pattern Length Selection and Bank Selection button + LED (short press = pattern length selection: values 8, 16, 24, or 32; long press = bank selection 1, 2, or C)
Clock input jack + LED

The D-420 generates drum patterns in three channels: kick, snare, and hi-hat/percussion.

The patterns can be 8, 16, 24, or 32 beats long. The currently selected length is indicated on the three top output LEDs: 8 beats is indicated by the kick LED being on in a dimmed state in between triggers, and 16 beats by a dimmed snare LED. 24 beats (selectable only if the middle jumper is removed on the back of the module) is indicated by both kick and snare LEDs being on dimly. 32 beats is indicated by a dimmed hi-hat/percussion LED.

The patterns are selected by the corresponding knob for each instrument track; the banks are changed by pressing the LEN BANK switch for over 1 second: bank 1 = LED off, bank 2 = LED on, LED = dimmed for the special Counting bank. There are 16 patterns available for each of the two banks and four pattern lengths. This means a total of 49,152 different pattern combinations are available! (Of course, some combinations may not make sense is “ordinary” music compositions, but are still useful for experimentation, or for triggering other events in your modular.)

Patterns are sorted from sparse to dense, making it easy to select compatible patterns such as a sparse kick (counter-clockwise setting) and dense snare (clockwise setting) . The hi-hat/percussion patterns are organized in reverse order, with full counter-clockwise (CCW) usually resulting in a trigger on each clock – good for hi-hat patterns.

If the middle jumper on the back of the module is removed, an optional Counting (C) bank becomes available. It contains some regular clock divisions or regular patterns. It can be used for driving drums as well, but it is particularly useful for driving sequencers using divided clocks, so that different sequenced lines can run at different rates.

There are three jumpers on the back of the module that can modify the D-420’s behavior:
• The top jumper determines the output trigger length: jumper present = 10ms; removed = 1ms.
• Removing the middle jumper enables both the Counting bank and 24-beat patterns. If this jumper is present, operation of the D-420 is simplified by only allowing “powers of two” pattern lengths of 8, 16, and 32 beats, and by disabling the Counting bank so that you will always get “useful” drum patterns out of the D-420.
• The bottom jumper determines the auto-reset behavior. If the jumper is present, auto-reset is enabled. This means that if no clocks are sensed at the CLK IN jack for a few beats, the D-420 will automatically reset its patterns so that the next clock received will be the downbeat (the first step in the patterns). When an auto-reset occurs, you will see all of the LEDs blink briefly. When the bottom jumper is removed, the D-420 will not lose its place in a pattern, even if the input clocks are paused; the next clock with trigger the next step in all the patterns.

D-420 Drum Girl is a great companion for the D-430 Drum Boy three-channel drum sound generator (I hope “Girl” controlling “Boy” is sexistic enough).
For pattern generator with editable patterns check D-425 3-track.


Width: 4TE/ 4HP/ 20mm
Depth: 40mm /1,6″ max.
Current: 20mA
Power cable included

Double check power connection before powering your system please.
„Red strip“ means -12V connector side in Eurorack standards.
In some power distribution systems connector key can be reverted.
In this case cut connector key and plug power connector right way (with respect to red strip) or use different power cable appropriate to your power system.

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