BD909

BD909

Analog Bass Drum Generator Module

• An analog remake of the classic '909 kick drum for your Eurorack modular synth
• Includes all the original controls: Attack, Decay, Tune Decay, Accent, and Level
• Additional controls provide a wider array of expression and triggering dynamics
• Continuously control tuning via CV or add tuning attack to create cool pitch effects
• Use CV or gate signal to control the accent volume for dynamic performances
• Overload boosts the wave shaper to add odd-order harmonics for punch or pure chaos
• Only 8HP wide, so you'll have plenty of space for more drum synths

Reverse-engineered from the original machine, our BD909 is an identical recreation of the original all-analog drum circuit of the TR-909. We’ve added additional controls and synthesis features that turn this classic circuit into a chest-pounding analog bass drum laboratory – all tightly packed into an 8HP module. The BD909 sound differs from our BD808 in that the main sonic energy is centered in the mid to low frequency range (as opposed to the low frequency range of the BD808). This frequency range gives the needed headroom allowing your bass lines to deeply fill up the low end while the kick drum rides on top – creating a clear and punchy mix.

The BD909 includes all the controls found in the original: Attack, Decay, Tune Decay, Accent, and Level. We have gone beyond that and added controls that further increase the palette of sound this circuit is capable of. First off, we’ve added a tuning control knob for the oscillator and included its own CV input and attenuator that let you tune the 909 kick with your bass lines. Next, we added control knobs for the tuning attack and extending tuning decay. Each one affects the other, allowing for intuitive and interactive sound shaping, opening Z8000 up numerous “sweet spots” and provides the ability to center the energy peak at different parts of the sound. Finally, we offer additional punch and distortion by giving complete control over the internal waveshaper, which allows you to overload the waveform manually or with voltage control.

Beginning with the classic and pure sound of the 909 kick, these additional functions greatly expand the BD909’s flexibility and let it create powerful analog bass drums that range from soft and smooth to punchy and aggressive – and everything in between.

Flexible tuning control lets you shape your tone

Three tuning knobs dictate the timbre of the BD909 kick drum module, allowing you to shape the frequency of its oscillator to create a wide range of expressive tones. You can set the basic pitch of the oscillator via the Osc Tune knob, but thanks to the Tune Attack and Tune Decay controls, it's easy to add frequency sweeps and pitch-shifting effects to your kick sound. What's more, you can control the BD909's tuning via CV signal, providing you with endless real-time tuning options.

Overload offers warmth, grit, and total insanity

We've seen a lot of '909 clones here at Transistory, but none of them offer the kind of harmonic distortion that the BD909's Overload circuit delivers. Here's how it works. The oscillator of the classic '909 kick is a triangle wave VCO that runs through a sine-wave wave shaper, which increases the ratio of odd-order harmonics. The Overload control lets you amp up that wave shaper, which both increases the odd harmonics and over-saturates the circuitry. Turn it up a bit, and you get a tape-like saturation that adds a hefty punch to your kick. Crank up the Overload, and you won't need a distortion box to lay down a hardcore beat. And best of all, you can control the Overload with CV, allowing you to continuously vary the rudeness of your kick sound.

Add the perfect accent with gate or CV signal

Most people don't think of the classic '909 kick as terribly dynamic, but with the accent options onboard the BD909, you get an amazing array of amplitude control. At its simplest, the accent is an additional volume boost you can dial in with a dedicated control and trigger with its own gate input. You actually don't even need to plug in a gate signal to access this volume boost, since the accent control is normalled internally. If you want even greater control over your dynamics, plug in a CV signal instead, and you can continuously alter the volume from an external source.

*TR-909 is a Trademark of Roland Corp Japan

technical specs

• Width: 8 HP
• Depth: 36 mm (1.42 inches)
• Power: 34mA @ +12V , 21mA @ -12V