[Project] 3TrinsRGB-1c output expander

(Eurorack) Interface board for the Gieskes 3TrinsRGB-1c video synth.

project stage: 1st proto pcbs are in.


  • LZX RGB outputs for each oscillator
  • additional composite output
  • additional s-video output

The Eurorack panel will be 4HP.
The module is powered by the 3TrinsRGB, the pcb has a MTA input header for all signals coming from the TrinsRGB. I am going to test if this is a good solution.
Tips for this connector are welcome! It should have 8 separate lines. maybe a VGA or CAT5 cable?

The panel is not done, because I have to test the hole position and shape af the right-angled s-video connector. I’ll test this with lasercut panels.


the prototype is tested and it works.
s-video output = OK
Composite output = OK
The LZX jacks can have some scrolling, this can be fixed by plugging in the composite output of the expander to the Sync input on the LZX system. (I recall that the original plugin had the same issue)

The wire connectors can be a right-angled 8pin boxed header with a flatcable, or MTA
Maybe some other fancy solution. I’ll think about it. suggestions are still welcome

Maybe I can add another composite RCA jack to facilitate this routing, without losing that extra composite output.
I’ll also add a 5v + gnd connector for other future modules, to save some wiring.


the next (hopefully final) prototype is ordered.
If everything is working, I will have enough for a first run.

new features:
10pin IDC connection header for flatcable connection to the 3TrinsRGB
Black panel with correct hole positions :slight_smile:


ps: I’m also working on a slimmer triple comparator, 8HP
pcb material panel instead of wood lasercut :slight_smile:


This is very cool! I dunno where everyone is hiding !

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the 3trins output Xpander pcbs are in. the panels look good. I’ll test it and then it will be released!

panel pic

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…it is actually a great project, yes. And i would be very interested if there was some possibility to buy some more LZX-modules, especially Decoder and most prominent an Encoder…

…but as those basic functions are not available all those nice projects are (for me) nice to watch and very desirable but have no practical use…

…perhaps that is why it is so quiet here?…

I ordered new pcbs for this project a few days ago:

  • helper pcb for easy connections
  • panel with side slits to fit the flatcable through
  • main pcb with some parts moved around & better spaced pinheader text
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3TrinsRGB-1c output expander

This expander gives you two extra video outputs (1x composite and 1x s-video) and the RGB VCO outputs in LZX format. You need to sync the 3TrinsRGB to your LZX video synth to use these RGB outputs.
The pcb is powered by the 3trinsRGB via the 8pin connector that connects to the sub-board, the frontpanel has openings (both left and right side) to allow the flatcable to exit your eurorack case.
The sub-board can be manually wired to the 3TrinsRGB or connected via the rightangled pinheader.

This expander requires some soldering on the 3TrinsRGB pcb, so it is not a plug and play project!

1x S-Video (miniDIN 4 pin) output
1x Composite (RCA) output
3x VCO channel outputs (Red, Green and Blue VCO channels of the 3TrinsRGB)
1x 8 pin header (2×4 pin IDC) to sub-board that connects to the 3TrinsRGB via flatcable
This module is powered by the 3TrinsRGB
(but could be powered externally, pads are available on the pcb)

Gijs Gieskes for this excellent 3TrinsRGB video synth
LZX for the RGB output schematic

More info, Sync information and BOM:

Pcb set: 35,- euro
Full kit: 90,- euro
Prepared module: 125,- (some DIY skills are required to attach the expander to your 3trinsRGB)

Shipping is 15,- euro tracked worldwide

Please reply with your preference (kit or pcb set) so that I can make a list and order all parts.