momoscillator

I've been developing a circuit for my mother's birthday present. Initially I was going for a modified version of the gift Jeramie, Jenny and I made for Luna, but things have changed.

The circuit in Luna's present was a simple 3-voice sequencer using gated oscillators for the voices and a binary divider for the clock signals. This way, the tempo could be modified separately from the pitch of the three tones. The fourth oscillator remained ungated and controlled the clock signal for the divider IC.

This system is nice and orderly, like a music box, but electronic. Unfortunately, the momoscillator differs from this model with the use of feedback resistors. Simply by mixing a portion of the divider circuit's response with the +9v bus and sending the result to the second input of the gated oscillator circuit, extremely complex patterns emerged. Additionally, the input signal to the amp circuit was omitted, and instead the amp circuit output the difference between the ground coming into it and the 'rest' input to the 4040, which is also nominally 'ground'. so the circuit contains both feedback and instability from a split ground. A demo of that unstable version is on my youtube channel now.

Later versions of this circuit omit the split ground phenomena, as it renders the breadboarded prototyped version significantly dissimilar from the final version.  Since many different circuits can perform the same theoretical tasks, there can be a lot of variation from the theoretical system and an instance of that system in implementation.  These changes don't normally matter ie in a well-grounded, stable circuit, but they do here.

The instability of circuits as the result of conflicting feedback loops, or attractors, is far more interesting to me as a composer.  More documentation to come.

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