Ilse

ILSE. An Analog Monophonic Synthesizer Module

Ilse is designed as a low cost, easy to build, but still flexible and feature rich synthesizer. It is based on Syntherjacks single-chip synthesizer Totoro and extends the design for voltage control on filter, oscillators and LFO.

History

If you want to see the revision 1 of ILSE (as a reference if you have a REV 1 layout) make sure to check out the rev1 tag with git checkout tags/rev1

If you want to see the revision 2 of ILSE (as a reference if you have a REV 2 layout) make sure to check out the rev2 tag with git checkout tags/rev2

Features

10 HP Eurorack module

Components:

• two saw tooth oscillators
• brigded-T low pass filter with resonance switch
• triangle LFO with speed control, and routing to filter or oscillators
• simple mixer and detune for oscillators
• level control
• external filter input

Modulation Inputs:

• 1V/Oct input for oscillators
• Gate
• Filter Cutoff (exponential)
• LFO Speed (linear, via pin header)
• Oscillator 2 detune (linear, via pin header)

You might as well just examine the schematics in the simulator and build your own synthesizer from it. It uses a neat trick to build the exponential converters directly into the saw tooth oscillators as you can see from the simulation below. Note that the tuning of the oscillators is not temperature compensated and will thus change with room temperature. We would not recommend using Ilse in a stage situation where reliable and exact pitches are important.

Saw Tooth Oscillators

It features a simple voltage controllable low pass filter that you can modulate with the inbuilt LFO or an external source.

Voltage Controlled Filter

Ilse was designed for educational use and was used in an introduction to electronics course. For more details on the schematics see the course material.

Kit building

Here you can find the schematic and build instructions. The iBOM will help you assemble the kit.