DIY Circuit Demos on YouTube

I’ve just posted my first video in ages of some prototypes made using logic chips, aka Lunetta after Stanley Lunetta, the guy who came up with the idea of repurposing old chips for making sound.

This is in response to a friend asking if I could make one for him, it’s made me dig out a load of bits that have been around since the first lockdown and they still work. Thanks Jim :)

So the plan is to pick one of these ideas to develop and make something he’ll be able to use in his latest musical project. These are the notes on the video and the sorts of things that can be done with this type of DIY circuit. Links to useful stuff at the bottom.

The main chips used for the demo are The 4093 and 40106

4093: four NAND gates on one chip that can be turned into square wave oscillators using capacitors and variable resistors, quite controllable- at least compared to...

© Paul Nicholls
July 2016

40106 - six transistors that can be turned into up to six oscillators - less stable than the above, but I find great for drones

© Paul Nicholls
July 2016

Images from Pin Layouts for commonly used ICs at pfnicholls.com

© Paul Nicholls
June 2021

These can be tamed using buffers, amp circuits, filters and controlled with (basic) step sequencers, shift registers (sort of random step sequencer - near the end of the video) as well as anything that can transmit a voltage (like skin) with a little resistance or output a little voltage, up to 5V is usual and is what comes out of most modular gear and old-school synths.

This stuff can be used standalone either as a drone or a special sound effect (SFX) - I like the term "Weird Sound Generator" (WSG) a circuit developed by Music From Outer Space (MFOS), one of several sites giving ideas, help and advice, selling pcbs and components for DIY. MFOS got me started. Link to MFOS below - quite an amusing read and easy intro.

It can respond to external control voltages from Modular Rigs, synths with CV and Gate outs and gear like the Arturia BeatStepPro. This means it can be synced and even tuned by ear although reliable and stable tuning is more complicated and was the bane of analog synths as they drifted according to temp etc., It's doable, but a bit of a pain. MIDI to CV isn't as difficult and expensive as it was, but it's much easier to use off the shelf equipment.

Other controls can be light, touch, piezo transducers (that you tap like a synth drum), wires attached to plants and fruit, though (I've not experimented much with that - too messy!) I am also trying a sound level trigger - getting a 70s drum-box (from a home organ) to make a pulse that turns on a circuit - could be interesting if I get it working.

The one that got me started Music From Outer Space

The brilliant and entertaining Look Mum No Computer has been very useful for clarifying and then expanding my understanding - I wish I’d seen the “how to…” videos had been around ages ago - would have saved me loads of time

Jon Dent’s pages technical explanation, lots more links - some ten years of blogging and a useful resource

To get going, and get an overview a look through electro-music.com forum is rewarding

Finally, after a couple of years of just hacking around I appropriately went through the Hackaday - Logic Noise step by step - enlightening