Author: Visible Signals

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Pre-order information and official Scanlines forum

*** Pre-Order Extension *** While I was doing a demo video for the Quarterizer I found a bug, so I've had to go back and work on a revision to fix that up.  As a result, I'm extending the pre-order deadline until I have a new prototype back from the PCB manufacturer to confirm it's working 100%.  I messaged everyone who has already ordered to make sure they were OK with this, but for everyone else it's just good news - you have a week or two extra to take advantage of discounted module prices! Here's the updated original announcement: Pre-Order info So, I finally announcement the web site today and as an opening special I'm having a pre-order sale with discounted prices for all modules. The reason for the 'pre-order' is that right now I have a few final prototype board sets for each design but I don't know how much interest there will be, so I haven't sent off an order to stock up on boards to send out just yet.  Once the pre-order period is over (November 1st now extended to mid-November!) I'll see how many people want them and get enough made up, plus some more for stragglers.  It usually takes around 1-2 weeks for the boards to get to me, so I'm expecting to post them out mid-November early December (after a quick check to make sure they're all OK).  I use JLCPCB for PCB manufacture, and so far they've been very good. If you think you'd like some PCBs but aren't in a position to order by November 1st then please feel free to contact me and let me know. Official Forum for Visible Signals The lovely people at Scanlines have kindly agreed to host the official Visible Signals forum.  If you want to discuss or get help with modules then I'd encourage you to head there.  I visit Scanlines most weekdays and occasionally on the weekends, but please remember I'm in Australia so it might be a few hours before I respond if you post while I'm asleep! Another great place for information about the video synth community is the Video Circuits group on Facebook.  There are a lot of knowledgeable people there.

So what’s the Wrangler all about?

The Wrangler is all about interfacing between video modules and non-video modules.  Video modules tend to work with voltages mostly in the 0V to 1V range, whereas non-video modules often use a much wider range of voltages, including negative voltages below 0V.  The eurorack power supply rails are -12V and +12V, which sets the theoretical maximum range of voltages your modules might need to deal with.  The controls on the Wrangler let you scale and offset the input voltage, and the front panel LEDs give an immediate indication of the results of that conversion. When converting from +/-12V CVs for video use, the most important LED is the main (usually green) 0-1V LED in the middle of the meter - if it's the only one lit then the output CV is safely in the video range.  If the 0V LED on the left lights up then the signal contains voltages that are too low and may be ignored by video modules (i.e. interpreted as 0V, meaning "black" or "no modulation" etc.)  Similarly, the +1V LED on the right lights up when the output voltage is too high for video modules and signal detail might be being lost.  By watching these three LEDs and wiggling the offset and scale knobs any CV can be adjusted to make sure it falls within the useful range for video. In the other direction, when processing video CVs for use with audio eurorack modules, the Wrangler can be used to scale the voltages up to the wider voltage range required, and optionally shift the signal to generate a bi-polar signal that is both position and negative.  The -5V and +5V LEDs light up when the output voltages are below -5V and above +5V respectively, indicating that the output CV is spanning a more conventional eurorack voltage range. My two favourite uses for the Wrangler is to boost a horizontal or vertical sync pulse up to a voltage that's high enough to sync a non-video oscillator, and to convert an non-video oscillator's wide range bipolar output into a 0-1V video signal. The clipped output of the Wrangler guarantees an output voltage that will never be less than 0V, or greater than +1V.  This can be useful when interfacing with modules that aren't tolerant of wide voltage inputs, but can also be interesting as a waveform clipping or distortion effect, sharpening the corners of smooth input waveforms.…

Buffered multiple modules for video

There's a lot of interesting discussion you can read about active buffered multiples in this forum post. The Visible Signals Video Mult takes the cheap and cheerful road to solve the main problems discussed in that post.  However, it's not absolutely perfect: a "perfect" buffered multiple would use a lot more op-amps (an extra one per output) and maybe even omit the protection resistors on the op-amp outputs (to completely eliminate all CV loss via the voltage divider formed by the op-amp output protection resistor and the grounding resistor on the input of the destination module - but that comes with it's own risks and downsides!)

The story behind the RGB Matrix

The RGB Matrix is the culmination of a couple of separate ideas and a whole bunch of experimentation, and it draws inspiration from quite a few different sources.  After I built my first video synth modules I found myself generating a lot of images and patterns in primary colours - Red, Green and Blue - and realised that what I really wanted was a way to take one CV signal and individually control the amount of that signal that was sent to each of the three colour outputs.  Basically something like a matrix mixer like the one that I'd seen in Ken Stone's CGS Matrix Mixer for audio synths many years before, and so that module formed the basis of an early prototype of this module. Here's a picture of the original RGB matrix prototype, with knobs, pots and push-button switches all recycled from an old mixer and the whole thing held together by rubber bands!  :-)   The flying wires that you can just see sandwiched between the boards pick up a lot of crosstalk from each other, so it's a good proof of concept but a bit noisy for real use.  The sockets on the right side are the mix outs, plus a direct mix in for each channel (like the Direct In module in the final product).  The socket in the bottom-right corner is a handy fixed +1V reference. As I used it, I often found myself wanting to "mute" an input channel while I tweaked it, and this lead to an early incarnation of the input channel A/B destination switch.  On another day I was using three LZX Cadet VI crossfader modules and a whole bunch of mults, mixers and attenuators to key between the mixer output and another external video luma source, and then later that same day playing with some old consumer video mixing gear (an MX-1).  And so the idea of having separate A and B buses was born, allowing the operator to build up two separate video images in RGB space and then use a "key" input to cross-fade the mix between them. The RGB Matrix has gone through a lot of revisions since that first prototype.  Working out how best to connect the switches to the boards without having a bunch of awkward wires to solder was surprisingly difficult! Of course you aren't restricted to using the "Red", "Green" and "Blue" outputs…

About Visible Signals

Welcome! 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…