Archive for December, 2012

Here’s a quick demo of the SET. It’s got some pretty bad playing in it, but it was a bit of a rush job just to get something done so it is all done off the cuff, just to give people an idea of what it is all about.

The circuit still isn’t finished and has a few popping issues, so go easy on it!

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I’ve quickly made this diagram to show how the square wave outputs from the two oscillators a and b can be added together using the various gates on the SET.

By the nature of the logic and with the oscillations both having 50% duty cycles the or gate will always allow the signal through more than the and gate. A only is simply the output of just a. In this mode the B led will not be flashing to avoid confusion. You could actually create the output wave from these examples with a single oscillator with a variable duty cycle, but in practice the dual oscillator approach creates many unique patterns you couldn’t create with a single oscillator.

Square Earth Theory Wave Examples

Just a quick update on the SET audio slicer I’m developing.

The logic side of the circuit that is used to control the stuttering is all up and running well, but I’m still having trouble slicing the audio without introducing noise. I’ve removed the 4066 chip and redesigned the circuit to use a JFET as the switch. By having this in a shunt arrangement where the source and drain are biased to a reference voltage I can eliminate most of the popping, but there is still a little bit of ticking on the audio line. I’ve also tried using a LED and LDR to shunt the signal without allowing any noise from the oscillators, but it isn’t perfect either way. It may be that the noise is on the supply rail and I need to filter the supplies, but I’m not sure with very limited time to spend on it at the moment.

The controls will also have changed by the time this comes out. At present they stand at Rate A, Rate B pots, long/short range  toggle, A/AB toggle, and/or toggle.

Whatever happens, I have learnt a lot from this project, one being that nothing is as easy as it first seems!