Synth on Simon Juhl

ATtiny85 Based Sampler

Wed, 22 May 2024 10:22:19 +0000

This project combined two objectives. The first was to create an ATtiny85-based sampler that plays small random sections of a chirp sample, designed for use in a modular system. This is useful for rhythmic synth percussion or sound effects. The second part of the project involved designing a PCB that accommodates all components on one side of the board, with holes for mounting the panel in a Eurorack modular system, integrating both the PCB and front panel.

Source code and schematics for the project can be found on GitHub.

Undervolting Casio SA-20

Sun, 26 Dec 2021 21:14:00 +0000

I have experimented with the Casio SA-20, by reducing the power-supply voltage from 7.5V down to 4.1V. at this voltage the instrument starts to sound strange and become very glitcy. The keyboard makes random noises in a way that seems like internal datalines are being filled with errors resulting in wrong serial messages, hence the random sounds. It is still keeping up rythms very nicely though, so i have recorded some of the rythm/accompaniments from it, and uploaded them at freesound.org.

The sample-pack can be found here

Here is an example of how the Casio SA-20 acts when undervolted

Noise Toolbox

Tue, 21 Jan 2020 21:09:25 +0000

This is a modular synthesizer build with focus on noise music or non-musical purpose. Using different effects, filters distortion etc. weird noise can be generated through feedback loops or external input.

Overview

The unit contains the following modules:

3 delay modules
3 distortion/wavefolds
2 tone controls
1 dual equalizer
1 3×3 matrix mixer
1 oscilator/LFO
1 VCO module
1 external instrument input
1 digital noise module
2 resonance filters
2 mults
2 mixes
1 mixer for output

4 Voice drone-machine

Thu, 31 Oct 2019 22:18:25 +0000

This is a drone machine consisting of four identical oscillators. Each oscillator can be tuned by two potentiometer; course and fine.

A patch-bay on the instrument are used to cross modulate the different oscillators, through frequency divisions.

The machine also have a tone-control and volume control for controlling the output.

Conductive Touch synthesizer

Sun, 23 Sep 2018 17:44:53 +0000

This is a polyphonic synthesizer made schmitt-trigger oscillators. Signals from each Individual oscillator is transfered through finger/flesh and into the mix. This also make it super noisy.

The circuit for this projects is very simple. 12 schmitt-trigger oscillators are all connected to different copper-pads, which line up with copper-pads going to the output-mix. When both copper-pads are touched by skin or other conductive material, the singal goes though to the mix and the sound can be heard.

Since the mixer has a lot of unconnected parts when not touching anything a lot of noise i coming out of the amp (i used a LM386, maybe a less noisy application?).
I tried putting a capacitor on the mixed signals, this seems to be making the signal sort of weak but more soft and less noisy.

Electric Motor Synth/Drone

Fri, 20 Apr 2018 17:38:15 +0000

This is a homemade synth/drone is based on 4 tiny electric motors, each with 0-5v CV. An internal piezo amplifies the vibrations from the motors so the sound can be plugged into a mixer etc.

Schematics

Here are some more build pictures on instagram: Link

Each motor is driven by an NPN-transistor in this case: 2N2222. An opamp is controlling the voltage aplied to the motor.
I used a TL074 op-amp for my project, but any op-amp should do.
potentiometers can be put between CV or 5v to attenuate the speed of the motors.
For the amplifiing the piezo i used a LM386.
I am not an expert in electronics so these scehamtics can problerbly be improved