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BD909 Bass Drum Module

Tiptop Audio

  • $ 18000


Reverse-engineered from the original machine, the BD909 is an identical recreation of the original all-analog drum circuit of the TR-909. With added additional control and synthesis features that turn this classic circuit into a chest-pounding analog bass drum laboratory - all tight packed into an 8HP module. The BD909 sound differs from the BD808 in that the main sonic energy is centered in the mid of low frequency range (as opposed to the low frequency range from 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. It has gone beyond that and added controls that further increase the palette of sound this circuit is capable of. First off, it added a tuning control knobs for the oscillator and included its own CV input and attenuator that let you tune your 909 kick with your bass lines. Next, the added control knobs for the tuning attack and extending tuning decay - each one effects the other, allowing for very intuitive and interactive sound shaping - this feature opens up numerous "sweet spots", and provides the ability to center the energy peak at different parts of the sound. Finally, it 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 creates powerful analog bass drums that range from soft and smooth to punchy and aggressive - and everything in between.


  • Output Level - 0 - 10V
  • Original 909 Attack control
  • Extended 909 Decay control for more umphhh
  • New controls for the oscillator tuning:
  • Attack tune
  • Decay Tune - these two will have an effect on each other which makes it really cool
  • Global Oscillator Tune control - this sets an offset for the oscillator, sets the starting frequency for the envelope
  • VC-Tune with attenuator (can go over a wide range)
  • Overload knob - might not be everyone's cup of tea, what it does is overload the sine shapers which adds harmonics and some extra punch, it's an aggressive effect.
  • VC - Overload - Can be CV or even audio
  • Accent in - can be with a pulse or CV 0 - 5V
  • Accent Attenuator
  • Gate in

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