Wednesday, 23 May 2018

It's 555 .... resonator (Eurorack version)

This is a set of five 555 based one shot circuits.
Each has CV and pot controlled pulse width and the pulse for each can be set to be negative going or positive at any desired amplitude. The circuit is supposed to be driven by a signal from a VCO, but noise or chaos sorces are fun too. It creates five pulses that can be individually manipulated to create a complex and harmonically rich waveform. A slower clock signal will give clicks and glitches (so, a voltage controlled glitch module).
As the pulse widths can be individually controlled (or controlled en masse by “CV all”), this waveform can be continually morphed to get new sounds. When the 5 pulses are quite thin the effect is that of a resonator. The controls allow a wide pulse width, so fatter, thicker sounds can also be created.
Panel = USD24
assembled = USD230 

Tuesday, 22 May 2018

Kareishuu VCO

PCB set = USD23
10HP Panel = USD22
assembled  = USD210

This VCO was mainly designed as an upgrade for the dual OTA VCO. It is a traditional triangle core VCO with a built in VCA for the FM control section. The design draws on sections of the Electronotes EN1, EN2 and EN3 VCOs along with some NLC injected in there for good measure.
It has much better tracking, a sine output and attenuators for all inputs. The self modulation control via the FM VCA enables voltage controlled waveshaping, the sine and tri waves can morph between their original shape to a pulse.

The pot spacing is quite tight, so I suggest using T18 knurled shaft pots along with the micro knobs. Other than the 1k tempco, no rare parts and a fairly easy build.