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).

Police

My first contribution for 101 Sequencers project, named Police after inscription found in the box that became the encasing.

The core parts of this sequencer were assembled during Modular Collective Instrument workshop (given by Kokomys in Mansedanse 2011 festival) as the master clock for the Instrument. The core has a simple 4060 binary counter with internal clock, with two outputs with 1/4 frequency ratio and a pot for frequency control.

For 101 sequencers project, I expanded the sequencer to have four outputs and external clock signal input, selectable by switch. When the external clock is in use, 4060 performs frequency division, giving out 1/64, 1/256, 1/512 and 1/1024 of the input signal. This will be used to create longer sequences. With one hundred and one sequencers on the stage, we can afford very long sequences also.

Since 4060 is a ripple counter, the circuit also contains an inversion stage, making the different outputs change state in a maybe more musical way. NAND gates are used for inversion instead of simple inverters simply because 4093 was on hand at the moment.

Lofi mixer with cd4069

Here is a lofi mixer+distortion, the component values are examples...

It uses one inverter from cd4069 as a summing amplifier. You can add more channels by repeating the input circuitry (100k pot, 0,1uF cap, 47k resistor) The 500k pot is gain and will give a nice amount of distortion if/when needed :) You can use a single 4069 chip to build both filters in the previous post and this mixer.

Filters with cd4069

Here are two easy to build filter circuits based on the cd4069 chip. I´ve used them in my recent projects and I´m quite pleased how they work. These schematics are examples meant to be a starting point and the component values are examples so feel free to experiment with different values.

First a lowpass filter

It uses three inverters. So you can build two with a single 4069. R1 and R2 are the cutoff frequency use a 10k-20k stereo pot or two ldrs and leds driven with a cv source (lfo,sequencer etc.). Cap values are drawn 0,1uF but I´ve built one with 0,047uF and it worked fine. The 100k pot is resonance, and this filter will oscillate when resonance is turned up. There are two output options drawn in the schematic "out" (wich is more bassy) and "out2". You might want to use a output cap (1uF).

Second one is a bandpass filter.

This thing uses only one inverter. Try different cap values instead of 0,01uF ones(maybe from 0,001 to 0,068) and they dont all need to be the same. This is also voltage controlled with the npn-transistor you can use a pot to ground, ldr etc. insead if you like.

cmos-lizard

I made this cmos 40106 based noisemaker as a dubsiren or something. It has 1 oscillator and 2 LFOs. I didn´t have any plans when i started just a 40106 chip and some components. First i built a simple squarewave osc from 1/6 of the chip ran it through pulsewidht modulator (again 1/6 of 40106) with Lfo (1/6)

Then i added second lfo with led and ldr for pitch modulation. The best part was "starve" pot ->just a 10k pot in series with battery + to ic pin 14. Some really crazy sounds can be made with playing with this pot. Here is a schematic of the oscs and lfos

The component values are what i happened to have so try different values for the results you like. Add more buttons, switches etc. for more playability (only 1 button in the schematic for output) for example i did a powercut button (normally closed) with cap in parallel (47 uF)

work in progress videos http://www.youtube.com/watch?v=-Obpgbwqqg0 and http://www.youtube.com/watch?v=2lUz9t-jzKM and a video of the finished piece http://www.youtube.com/watch?v=WF3NOiu0AUY

here is a picture of the finished piece.

Cardboard pcb and recycled parts

Cardboard pcb and recycled components

The idea for making electronic projects on cardboard came from Ciat Lonbardes paper circuits. I had used veroboard previously. But it was a bit difficult to change more complicated designs to work on veroboard. Also making pcb:s at home seemed complicated with all chemicals, UV-lamps etc. Cardboard may not be the most sturdy material, but it is cheap, always available, environment friendly and it works. I also have a pretty good collection of circuit boards from broken equipment. A lot of components (resistors, caps, transistors etc.) can be recycled from these. So using cardboard pcb and recycled components you can build electronic projects at home more environment friendly and you don’t need to spend any money on the parts. (Of course some parts are a bit difficult to find from random broken equipment.)

1. you can print picture of the pcb you want on paper and then glue it on a piece of cardboard. Or design your own circuit by drawing it. Postcards can easily be used as material.

2.poke holes for the components with a needle or other sharp object.

Top wiew of my wp-20 board.

3. insert the components and solder them according your pcb design. In most cases components reach each other with no jumper wire. But when using recycled components the pin are often cut bit too short so you might need jumper with them.
Bottom wiew of my wp-20 board

4. because device made on cardboard may be damaged easily. Protect it with proper housing.