Double Drum

Double Drum

Our CircularThing has two full drum voices that can cross-modulate with each other, giving you more complex drum sounds.

Our Double Drum started with the BEFACO KickAll schematic  that we doubled and extended in various ways.  The top drum is an extended KickAll giving you toms and special effects. The bottom drum also has noise added and can do snares or hihats and more wacky effects. Crossing the drums lets you “smash sounds into each other” in interesting ways – and we think CircularThing gives you the entire drum circle.

The top drum (blue) has Tune to adjust the bass pitch for the drum tone with a CV input that tracks 1V/Oct. With Shape you can morph from triangle to pulse wave and with Decay you control the amplitude decay time while Time controls the pitch envelope decay time. Bend lets you control the amount of effect on the tune that the pitch envelope has – going negative as well as positive. Cross adds the output of the bottom drum to the pitch CV of the top drum. Volume has a CV for the master VCA so you can control  the volume of each drum separately and each drum has a separate output.

The bottom drum (yellow) has all the parts of the top drum AND Noise. By twiddling Noise you crossfade the bottom drum oscillator with a built-in white noise source, giving you an extra spectrum of drum sounds. Badumm tssch!

The Mix balance (green) determines how much of each drum goes to the mix out.

There is also a White noise output (white) which is a straight feed from the built in noise generator –because sometimes you just need some noise.

Don’t ignore the backside because the jumpers add a whole bunch of extra options:
Both drums have three options per drum

  • Hard sync on trigger – this resets the oscillator to a known state on each trigger making each hit consistent – this is especially useful for cross modulation
  • Cross modulation polarity – the pitch can either go up or down – arrange your preference here
  • Linear or exponential cross modulation – we advise linear for more classic FM sounds and exponential for wild effects

There are two jumper options for everything

  • Noise type – add (or not) a filter over the white noise – giving a more retro drum machine vibe to the noise
  • Link between drum triggers – connects the default input of the bottom drum trigger to the trigger of the top drum (or not) keeping everything more together as one complex sound

The artwork on the front and back of the module reflects the crazy times we are currently living through, and the coincidence that Corona is a CircularThing.


Type double drum
Width 24 HP
Depth 20mm (skiff friendly)
Power usage +12V
Power usage -12V

Resellers across the globe

This is a limited run of 20 modules. 10 of which we have already given away to friends and artists (and ourselves) and 10 we would like to sell. Update: SOLD OUT

BEFACO is currently looking at CircularThing with the intention of making kits out of it – so keep an eye out for that!


400 EUR (ex tax and shipping)