tiptop-audio-bd909

Tiptop Audio BD909

Authentic 909 bass drum engine for modular systems

8 HP Eurorack module

The BD909 is a Eurorack recreation of the Roland TR-909 analog bass drum sound generator, faithfully reproducing the original circuit while adding extended tuning controls, voltage-controllable overload, and independent accent. Its energy is centered in the mid-range of the sonic spectrum, sitting naturally in a mix alongside deep bass lines without frequency conflict.

Features

  • Authentic analog recreation of Roland TR-909 bass drum circuit
  • Triangle VCO with sine wave shaper for core sound generation
  • Three tuning knobs: OSC TUNE, Tune Attack, Tune Decay for wide tonal range
  • VC-TUNE input with attenuator knob for voltage-controlled pitch
  • Overload control adds odd harmonics from subtle punch to full distortion
  • VC-OVERLD CV input for voltage-controlled waveshaper distortion
  • Independent ACCENT level control (original 909 had only one global accent)
  • ACCENT IN normalized to GATE IN when no plug inserted
  • ACCENT IN accepts gate, trigger, or CV signal
  • ACCENT knob acts as fine output gain control when accent input is not patched
  • Dynamic accent physically hits the internal envelope harder for louder and punchier response
  • LEVEL and ACCENT provide two-tier gain staging for precise mix placement

Controls & Jacks (15)

  • Overload— Controls the amount of harmonic distortion added to the waveshaper. Low doses add punch; higher settings create increasingly distorted and d
  • VC Overload CV In— Control voltage input for overload modulation
  • Accent In— Accent/dynamic control input accepting gate or CV signals
  • Level— Sets the output volume level for mixing with other drum sounds.
  • Decay— Controls the decay time of the envelope segment.
  • Osc Tune— Offsets the starting and ending frequency of the bass drum sound; main tool for shaping overall pitch range.
  • BD Out— Bass drum audio output
  • VC Tune— Attenuator knob for scaling control voltage to the tuning circuit.
  • Attack— Controls the attack time of the envelope segment.
  • Accent— Sets the accent level. Acts as a fine gain control when no external accent signal is connected; controls the difference in gain between acce
  • Tune Attack— New control that adds variation to the sound and affects the Tune Decay knob, creating additional sweet spots beyond the original TR-909.
  • Gate In— Trigger input for the bass drum sound
  • Tune Decay— Original tune knob from the 909 machine with extended range; controls the frequency decay behavior of the bass drum pitch.
  • VC Overload— Attenuator knob for scaling control voltage to the overload circuit.
  • VC-OVERLD— Control voltage input for overload modulation

How-To Guides

  • Classic 909 Kick
  • Punchy Overloaded Kick
  • Total Destruction Kick
  • CV-Controlled Overload Swell
  • Wide Pitch Sweep Kick
  • Dynamic Accent Groove
  • Accent as Fine Gain Control
  • CV Pitched Kick
  • Kick and Sub Bass Layering
  • Short Snappy Click Kick

Explore the interactive BD909 panel on BleepDex — tap any control to learn what it does.

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