Key data

Topographic drum sequencer

Parameter Value
Width 16HP
Depth 25mm
+12V current 25mA
-12V current 1mA
Lifetime 08/13 to 03/21
Modulargrid Link
Processor ATMega328p @ 20 MHz

Original printed manual

PDF download

Settings reference card

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  • Internal clock with a 40 to 240 BPM range.
  • Beat indicator / Tap tempo button (reconfigurable as a reset button).
  • External clock input, with selectable resolution (24, 8 or 4 ppqn).
  • Pattern reset trigger input.

Drum pattern generator

Based on a compressed representations of drum patterns and their variations.

  • X/Y (pattern selection) knobs with CV inputs.
  • Pattern complexity/density knobs for channels 1, 2, 3, with CV inputs.
  • Pattern randomization knob with CV input (reconfigurable as a swing control for the internal clock).
  • 3 output channels (BD, SD, and HH/percussion).
  • 3 additional outputs, configurable as Accent/Clock/Reset or per-channel accent.
  • Outputs can be either triggers or gates.


  • Input impedances: 100k.
  • CV acquisition: 8-bit, 1kHz.
  • Output level: +5V.
  • Clock resolution and processing latency: 120µs.
  • Worst case jitter < 0.5% at 120 BPM.

Revisions and variants


Hardware revision labelled "v0.2" with the following differences:

  • 2x5 power connector (originally 2x8).
  • Built-in 5V regulator.
  • Milky, diffused LEDs (originally clear).