Why did you make it?

I enjoy bwooung blang bwong bwong sounds. I use a crude chip from the 1970s that puts out a harsh square wave. This circuit board allows me to focus on the fun stuff; creating sounds and interfaces that jiggle and blip.

What is it?

A sound fx machine, a sonic experimenter kit. The austrian tutorial video will guide you through all the steps.

The Inverterchip at its core allows you to play up to six oscillators simultaneously. Dedicated sockets on the circuit board enable you to experiment with different frequency ranges and mixing techniques. You'll get to decide how your machine is going to sound.

Find some experimental sounds in the video below.

Alter the frequency range

It is possible to give each individual oscillator a different frequency range. Simply insert different capacitors into the sockets where it says „Freq“. The kit comes with two common capacitor values, 0,1uF (higher frequency range) and 2,2uF (lower frequency range). You may connect multiple capacitors in order to get the frequency range you want.

Mixing

In order to actually hear the individual oscillators you have to connect them to the mono output of the circuit. The sockets saying „Mix“ will help you to do so. For a linear mono mix, simply insert the provided 10k resistors for each oscillator you want to hear. You may experiment with different resistor values. A smaller resistor will increase the volume of an individual oscillator. A non-linear mix however, will give you sounds in the area of wooop bzzz wobble. Start with two oscillators with different frequency ranges. Insert the provided diodes into the „Mix“ sockets and listen.

Interaction

Photo-resistors are in place to change the pitch of an individual oscillator. Use any kind of light source to play your sound machine. Prefer turning knobs instead? The dedicated MOD-section of the manual will show you how to put potentiometers in place instead.

Loudness

To be able to use cheap guitar fx pedals, I added a volume drop circuit to the circuit board. It will ensure a line-level output that can be modulated by any pedal I already own.

BOM

The full kit comes with

• 1x circuit board
• 1x 40106 inverter chip
• 1x 14pin socket
• 1x 9V battery clip
• 1x power switch
• 7x LDRs/ photo-resistors
• 7x 10kΩ resistors
• 6x N4148 diodes
• 1x 100RΩ resistor
• 6x 0.1μF capacitors
• 6x 2.2μF
• 1x 6,3 mm Mono output jack