Building the Mainbow (v2)

building video synth modules!

Because I am restless I have begun to expand my eurorack format gear into the wild, expensive, and rare world of ~Video Synthesis~

(this is not from my gear)

While I have been slowly gathering some LZX modules after their GEN3 modules started rolling out, I've also been hanging out* on the LZX discord which has been helping me find other video synth makers. It's seemingly a much more DIY community than your typical eurorack group (which is saying something) so finding all these individual bespoke creators not only fun, but crucial.

* seriously how do people keep up with Discord servers as social media? Can we please go back to forums I can't keep up with y'all

The first non-LZX, non-prebuilt video gear I picked up was the Mainbow from Chroma Cauldron.

this is chroma cauldron's product image

Aside from the attractive price for the features, I just wanted to do something more DIY and this machine included some cool features I wanted like external video input/processing and a basic audio analyzer to incorporate some more reactive elements from my audio tools.

One of the best parts – I must say – was the packaging of the kit itself. The PCB and the faceplate were wrapped and protected while ever other part was stapled to an enlarged BOM where it was marked what the part was and how many you should have. It basically took out the first 45 minutes or so of organizing and preparing that usually comes with pulling out a kit.

There was even an error in one of the resistor values on the silkscreen of the PCB so that single resister came pre-soldered to avoid any confusion with having to put a 'wrong' resistor in yourself according to the labeling. Top notch thoughtfulness.

Then of course the PCB layout itself was really well designed. All the resistors are in a neat row & everything was clearly marked – I had no issues whatsoever putting this together it almost felt too easy.


and so it came to plugging in and testing (without external input).


and then with external video! Here I plugged the output of a VCR playing an X-Files episode in and made it all liquid


So much fun! Now I just need to add more power and space to the existing LZX rack...