Electric Intonarumori

This noise board is a combination of two Paper Bits, the PB701 Electric Intonarumoriand the PB109 Voltage Controlled Oscillator II.

It has two build in feedback, one for the voltage control of the VCO and the other for the delay control. They can be turned on and off.
It also comes with a chip noise on/off button, a the boost and a mute button.
The VCO has three waveforms: sine, triangle and square. In the square/triangle mode one can change with a potentiometer from triangle to a sawtooth wave or change the duty cycle of the square wave. In sine wave mode one can shape the sine wave to an interesting “sea saw” wave.

The core of the board is the digital delay chip PT2399. It has some OpAmps build in to filter the sound and do the echo. In this application everything that helps to get rid of the noise of the chip itself was avoided, that leads into a self sustainable noise source.
The “echo” could be changed with a potentiometer, the “delay” could be adjusted with a potentiometer or it could be set in a feedback mode. A Low Pass filter could be adjusted with the third potentiometer.

The board is an homage and is named after the instrument “Intonarumori” of the Italian Futurist, painter, composer and the author of the manifesto The Art of Noises, Luigi Russolo.


Paper PCB


  • Resistors:
  • 1x 120 Ohm
  • 3x 220 Ohm
  • 1x 330 Ohm
  • 2x 470 Ohm
  • 2x 910 Ohm
  • 4x 1 kOhm
  • 5x 2 kOhm
  • 1x 3.9 kOhm
  • 4x 4.7 kOhm
  • 1x 5.6 kOhm
  • 1x 8.2 kOhm
  • 3x 10 kOhm
  • 1x 20 kOhm
  • 4x 51 kOhm
  • 2x 100 kOhm
  • Capacitors:
  • 1x 100 pF
  • 1x 1 nF (foil)
  • 1x 3.3 nF (foil)
  • 1x 4.7 nF (foil)
  • 1x 22 nF (foil)
  • 1x 39 nF (Foil)
  • 5x 100 nF (foil)
  • Electrolytic Capacitors:
  • 1x 4,7 µF
  • 1x 10 µF
  • 2x 47 µF
  • 2x 100 µF
  • Semiconductors:
  • 2x OpAmp MCP6002
  • 1x digital delay PT 2399
  • 1x optocoupler TLP521
  • 1x LED
  • 1x BAT43
  • 4x BC547
  • Mechanical:
  • 1x IC socket, 16 pin
  • 1x IC socket, 4 pin
  • 2x IC socket, 8 pin
  • 1x Thonkiconn 3.5mm jack socket
  • 5x mini switch
  • 2x push button
  • 1x micro USB adapter board
  • 2x pin strip 4 pin (for the USB adapter board)
  • Potentiometers:
  • 3x 10 kOhm
  • 1x 50 kOhm
  • 1x 100 kOhm
  • 1x trimmer 500 Ohm


- Urs Gaudenz for the Chaos Looper design.
- Analog Devices for the sine wave shaping circuit.


The Electric Intonarumori was designed by Wolfgang Spahn 2019.
It is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

Creative Commons License