About Visible Signals

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Hello, weary internet traveler, and welcome to the fascinating rabbit hole that is video synthesis.

My Story

I’ll start with my story.  I’m an electronics enthusiast from Adelaide, Australia, and I’ve been a passionate player, builder, collector and lover of musical synthesisers since a good friend introduced me to them in 1986.  Over the years I’ve built my own synths, spent countless hours looking at circuit diagrams and service manuals, made a lot of electronic music, and watched that industry go through many changes and grow into what it is today.  One of the most amazing success stories has been the eurorack modular market – from its inception in the late 1990s at the hands and mind of Dieter Doepfer (to whom we all owe a huge debt of gratitude) to the current sprawling industry with thousands of companies, large and small, offering a bewildering array of compatible modules covering pretty-much every function you could possibly imagine.  If you don’t believe me, just take a look at Modular Grid and prepare to have your mind blown!

I can’t remember when I first heard about the rather specialized branch of the eurorack modular world that is video synthesis, but for many years I stopped myself from getting involved – because I knew I already had too much going on on the audio side!  However, one day an old friend visited, hoping to get some help resurrecting his Amiga computer in order to copy off some old files.  He didn’t have a monitor for it any more, so finding a suitable screen was the first order of the day.  To cut a long story short, I realised then to my chagrin that I didn’t really know much about how video actually worked.  I knew TV used to be a “composite” signal and often came on an RCA connector, and that professional video came on BNC connectors, and VGA (analogue) generally couldn’t be used for as high resolutions as DVI (digital).  But what were the actual signals on all of these connectors and cables?  I’ve never been one to let myself stay uninformed, so I figured it was time to get myself a video edumacation.

When I discovered how the RCA engineers managed to add colour to composite video in the 1950s and ’60s, I was in blown away.  What those guys achieved was pretty impressive – backwards AND forwards compatibility with the existing black and white TV networks!  Learning about the technical issues they were faced with and found ways to overcome with was inspirational, and honestly I don’t think enough people really appreciate their efforts.

By the time I had spent many idle hours reading, learning and absorbing all the information I could about video, I was fascinated and hooked.  My early experiments were around trying to convert from and to composite video, extracting the sync information needed to do that, and performing simple signal manipulations and pattern generation.  So the LM1881, TDA3330, MC13077 and 4040 ICs were all my good friends in those days.  As well as numerous random web pages there were two particularly helpful sources of information and community for video synthesis: the video forums on electro-music.com and Muffwiggler.  Of course by then I knew about LZX Industries, by far and away the biggest player in the contemporary video synthesis electronics scene.  Unfortunately their modules were pricey… and I was a DIY guy!  But then I read this thread talking about LZX’s newly released Cadet range of modules and my first thought was – hey, I could build that myself, on veroboard!  And so I did, making a few tweaks here and there to incorporate my own ideas.  Of course, electronics is a journey – those original designs of mine barely worked, chips overheating and terrible cross-talk and signal quality, and you know what?  I really had quite a lot to learn 🙂

And so the years have passed, and learn I did.  Along the way I had a few ideas, and built up one-off DIY modules with functionality that I wanted, sometimes variations on existing equipment and other times new and innovative ideas.  Along the way I’ve discovered a few ICs and ways to use them that other people don’t seem to be aware of, and so finally I’ve decided it’s time to share my inventions more widely, by releasing my own video modules, and that’s the reason why Visible Signals exists.

Thanks Go To…

There are a number of people whose help has been invaluable, and it is important to me that I acknowledge them here.

  • Dieter Doepfer repurposed the eurorack standard for modular audio synthesis and defined related standards that made it possible
  • Lars Larsen brought video synthesis into the eurorack world, and elevated it from an obscure historical footnote into a modern reality
  • Ken Stone and his DIY Cat Girl Synth circuits taught me so much about electronics, and I am honoured to have him as a friend (and fellow organ parts scrounger!)

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