Modutronic Messmaker

The Modutronic Messmaker is a simple, lo-fi AM/FM synthesizer that runs on a 9V battery. Below is an updated version of the schematic, which removes the additional output & inputs for the sake of simplicity and slightly lower cost.

Schematic:

Schematic for the Modutronic Messmaker

In case anyone wants it, the original version of the schematic is still available here.

What’s basically going on:

This circuit uses the classic 555 timer chip in astable mode to create a simple squarewave oscillator, which feeds the input of an LM567 tone decoder IC. The 567 is capable of more sophisticated things than what it’s being used for here, but for our purposes, it’s useful for providing amplitude modulation and an oscillator in a single small package (and for simple power requirements).

The squarewave from the 555 is amplitude-modulated by the oscillator in the 567, and the output of the 567 is then fed back to the 555’s CV input, as well as to the audio output of the device.

There are potentiometers for controlling the frequency of both oscillators, the modulation amount from the 567 to the 555, and for the “power starve” effect which provides extra lo-fi, glitchy fun.

The original version of the circuit included inputs for the 555 CV and for replacing the signal to the 567 with an external input (both provided on switching jacks), but these were removed for the reasons noted above.

modutronic2

Demo videos:

Modutronic Messmaker- guided tour

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Modutronic Messmaker- small, lo-fi DIY synthesizer

The Modutronic Messmaker is a lo-fi DIY synth based on an LM567 tone decoder chip and a 555 oscillator, housed in a plastic VHS tape case. See my blog for more info: http://blog.skincontact.com/?ta…

more Modutronic Messmaker

another demo video for the Modutronic Messmaker lo-fi AM/FM synth & fx box. This one is built in a black plastic VHS tape case.

Old build notes here.

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