Tuesday, January 20, 2015

Simple cv circuits

Here is some small bits that i have used in my synths and they might be helpful for others building experimental synth stuff. Opamps to use are lm324 (quad)or lm358 (dual). Op amps powered +9 (single supply)

Screaming CD4069 filter + distortion

Here is veroboard layout and schematic of my 4069UB based filter. It is pretty easy to build and makes quite rough sounds. It will oscillate when resonance is kranked also the distortion part oscillates quite easely. It has lots of gain so a volume pot before the final output might be a good idea :)

Most of the component values are tweakable. The two filtering caps (10n in schematic+vero layout) can be changed anything from 4,7n to 47n (larger values for more bass) It works from +5 to +12v. pin 14 on 4069 is not connected directly to +voltage but through 1k resistor and then a 47uF from pin 14 to ground (this part is missing from my schematic but it is drawn on the vero layout).