A quick and dirty recording of the Squascillator VCO - the first 30 seconds are a simple sequence with the pulsewidth being modulated by hand (could also use an LFO or other modulation source), whereas the remainder is a constant frequency with PW modulation alone.

No effects or postprocessing other than removing periods of silence and adding the fade in/fade out sections.

Squascillator VCO

Quick and dirty recording of the DWS diode waveshaper - no post processing other than adding the fade in/out.  This is the output from the DWS on its own - mixing the 'clean' and 'folded' signals can yield some very interesting results.

Constant frequency sine from an AVR VCO followed by random knob-twiddling on the DWS. There's a bit of a learning curve involved, but there are a lot of timbral sweet spots if you're prepared to put the effort in.

The 'default' version of the DWS has 8 diode stages for fiddling with - there may be an 'instant gratification' version available with only 4 stages at some point in the future.

DWS waveshaper demo

The diode ladder VCF in action - nothing fancy; Behringer Neutron providing the sounds, with the pitch controlled by the S&H to keep things interesting. Sawtooth wave to begin with, changing to pulse train towards the end.

Random knob-twiddling - self-oscillation is easy to find.

Diode ladder VCF

The Lockhart wavefolder as popularised by Ken Stone with his CGS-52 module. 

With a difference (or two)

With this module, it's possible to control the amount of current running through the positive and negative arms of the wavefolding section, which can lead to some interesting results irrespective of whether you're fettling VCO or control voltages.

The 'main' output gives the folded waveform whilst the 'square' output will, under certain circumstances, give an arrhythmic pulse train which can be used either as a modulation source or a square-wave oscillator in its own right. Keep in mind, though, that the depending on the biasing of the transistors you may not get anything out of the square output despite there being a folded waveform present on the 'other' output.

Works best with sine or triangle-based waveforms but there's nothing to stop you putting, well, anything into it - altering the level of the input signal can lead to some very interesting filter-like effects. If you really want to fatten up a sound, run it through a low-pass filter (or any filter) before feeding it into the wavefolder. Works _really_ well on basslines if you use a resonant filter.

Finally, on a technical note, the input signal must be at least 1.4V p-p - this is due to the voltage drops created by the two transistors in the circuit; the practical upshot is that this module will not work with audio signals unless they're amplified (a lot!) whereas most VCOs and CV generators will work just fine.

Lockhart Wavefolder sample

Multi-feedback resonant bandpass filter - no musicality implied etc.etc.

Resonant bandpass filter sample

Let's make some noise ....

A CD40106-based drone generator - no real changes from the original design: four channels of the 40106 set up as tunable(ish) oscillators, mashed together using a CMOS logic chip and then output through a Sallen-Key filter. Throw in the current-starve option and sonic wackiness can often ensue.

Use it as a standalone drone generator, as it's capable of producing some fairly dense textures in the right hands, or use it with an envelope generator and a VCA and you've got a source of nice, clashy percussion sounds.

XO106 (4/4.5) - sample 1

XO106 (4/4.5) - sample 2, in a percussion stylee

BE AWARE! This is a deliberately lo-fi module - if you want crystal clear sound reproduction, fidelity or whatever then you won't find it here. The module relies on the properties of a photo-transistor to generally dirty up any signal coming passing through it; think of it as kind-of like a low-pass gate with built in distortion and a few other properties too.

Optothing - Ghetto VCA

The Chaos Filter is/was a clockable, switched capacitor comb filter built around CMOS chips - there were only a short run made originally, but the module may make a comeback if there's sufficient demand (there's a voltage-controlled version on the drawing board ...)

The biggest issue with this particular design that the output tended to be a bit 'clicky' at lower clock speeds. Even so, it was quite possible to coax some ... interesting ... sounds out of it.

Glitch-mongers will probably dig this one.

Chaos Filter sample

Demo output of the AVR VCO - approximately 10 seconds of each of the 'default' waveforms: sine, triangle. square, sawtooth, multi-pulse and digital noise.

Simple sequence provided via the SOGv2 stacked octave generator module. No postprocessing.

AVR VCO demo

The vactrol VCA in action - a simple sequence with a sine wave generated by my AVR VCO.

Response isn't super snappy because it's a vactrol - however, it preserves the sound pretty well and you can get some lovely bell-like distortion as the signal levels and gain are increased.

VACVCA

Overqualified software developer and builder of Eurorack synthesiser modules.

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