From the same electro-music thread mentioned in the last post, here’s a website (just a folder actually) with a number of interesting video circuit ideas and scans from manuals for some video processing modules, including schematics (check out the Velleman K4600 Video and RGB Processor).
The online forums dedicated to video synthesis harbour a huge wealth of information relevant to the aspiring VSDIYer. For most of the months that I’ve been obsessively trying to figure out how to build one of these damn things, my main go-to resource has been the Muff Wiggler video synthesis forum. I could get effusive talking about how excellent the forum is, but suffice to say that there are some extremely knowledgeable and experienced people there, and it’s a truly welcoming and generous community.
Recently, I’ve been poking around the Electro-Notes forum, another major resource for synth DIY info. I’d been there before, but until today I’d never realized that there was a video synthesis subforum on the site. It’s small compared to the MW one, but has some very worthwhile posts. In particular, this one is worth reading – it features, among others, one of the brilliant folks behind LZX Industries writing before the LZX system was developed and working through some of the basic problems of video synthesis, including sync separation and video reencoding. Quite amazing as a piece of recent vsynth history, considering how quickly the LZX Visionary has developed into a very full-featured and professional device.
A lot of questions are raised in the thread concerning one of the most important and fiddly parts of an analog video synth – sync (generating it, stripping it from composite signals to get RGB video, recombining it with RGB to get composite), but these issues are left tantalizingly unresolved! I’m still figuring this all out myself, but one of the things I’m hoping to put together is a discussion of desyncing and resyncing video that’s, and accompanying schematics, that are approachable for beginners. I think that the lack of a cheap-and-simple solution to the barrier posed by sync requirements is one of the biggest hitches preventing more DIYers from experimenting with video synthesis.
The thread contains tons of great info. Some interesting chips come up that I’d never heard of, including the MC1377 RGB-to-NTSC Encoder (replaced at Mouser by the NTE879 RGB to Pal/NTSC Encoder), the LM1889 TV Video Modulator (replaced at Mouser by the NTE846), and the AD724 and AD725 RGB to NTSC/PAL Encoders. There’s a page explaining the workings of the MC1377 a bit archived here.
Not least, the post contains something I’ve been wanting to see for ages – an online copy of the Sandin IP plans/schematics/distribution religion. The schematics for the Supernova 12 video synthesizer were even posted, though later taken down. This thing was built by Jeffrey Siedler and Stephen Jones of the amazing Severed Heads, so in honour of them, here’s the video from the SH single Dead Eyes Opened.
Does anyone out there have good info on sync solutions that could easily be built into a DIY video synth?
Since putting this site up a couple of months ago, I haven’t posted anything here. What happened? In part, something that I might call research-stage feature creep. The more I read about modular synth design and video synthesis, the more I realized there was to know. As the the scope of a project like this deepens and widens, it threatens to become overwhelming and impossible to complete. To counter this risk, I’m going to start posting regular development updates to this blog (as in, at least once a week). Hopefully this will enable me to set some achievable goals and provide useful information to others.
The widening of my reading for this project has stemmed from practical concerns. So far, my approach to building circuits has been pretty slapdash – lots of messy improvised breadboarding and very little documentation of what I’ve been doing. The results have sometimes been exciting, but I feel that I’ve hit an impasse. I find dealing with more than a few simple circuits on the breadboard headache-inducing and fairly difficult to troubleshoot. This, coupled with a frustrating history of building electronics projects in a quick-cheap-and-dirty style only to have them gradually disintegrate, has convinced me to be more deliberate about design and construction.
I’ve decided that I’m going to build this project as a more-or-less conventional Eurorack modular synth. Choosing this route brings a number of related fields into play:
-power supply selection and/or construction
-PCB design (and thus, learning EDA software)
-PCB fabrication (ah, the toner transfer method)
-front panel design and production
… not to speak of trying to understand some of the underlying electronics theory, ha! I plan to post updates on my progress in all these areas, and would be happy to hear feedback from you about your own experiences.
My goal is still to produce plans for a simple, cheap and easy-to-build DIY vidsynth, and so when the dust settles I’m planning to distill my findings into some simple circuit recipes. For now, though, it’s time to roll up the sleeves and get messy…
This blog is intended as a notebook for my research into analog video synthesis. Posts will cover the technical aspects of DIY video synth electronics, and will also discuss techniques and aesthetics. Hopefully it will be of use to others.