From the Documentation...


This unique VCO consists of an  ultrasonic oscillator core followed by a parallel pair of waveform generators. Each waveform generator consists of a switched multi-octave divider followed by circuitry to generate a 10-step waveform using a set of 10 slider potentiometers.  Also included are a novel synchronization circuit with two different operating modes and a built-in "digital ring modulator" (DRM) for producing a wide variety of synchronized and anharmonic sounds.  The oscillator core is highly stable (better than 20 ppm/K in the prototype) and features wide-range, accurate tracking (better than 0.05% over fifteen octaves).  The variable waveform generator provides fine control over an enormous range of available timbres.

From Ian Fritz, The DoubleDeka Ultrasonic VCO is here!!!

There are two PCBs -- the oscillator core and the waveform generators/ slider board. You will need both to build the DoubleDeka.


$350        Full Kit


$550        Assembled Module


$85          Panel


$65          PCB Set


$75          Components Kit


$135        Components-and-Slider Kit



Ian’s Sound Samples!

Demo -- Switching through the octaves and then moving the sliders around.


Demo -- With fixed waveforms, switching through all the combinations of the octave switches.


Demo -- A patch with the two waves fed through two VCFs.


Demo -- Four waves from two units; raw sounds without filtering.


Demo -- Sweeps of a Tri VCO fed into the the sync input (two sync modes) and then into the RM input.


Demo -- "Harmonic Sync" A few seconds of the unsynced sequence, then the sync master is plugged in, then the sliders are shoved around.


Demo -- "Anharmonic Sync" Truly hideous sounds, with a brief respite when switched over to "Harmonic" mode and back. Again, with different slider positions.


Demo -- "FM" Similar to other VCOs. The ADAR EG is used, with different settings of Mono Width and Decay Time.


Demo -- "DRM" The digital ring modulation input used to make some bell sounds.