Interfacing VGA to the LZX Standard

Hey y’all,

Been wanting to dip my toes into modular but want to incorporate it with VGA feedback which is a system I’m fairly familiar with already. I made a general kinda schematic of how I will go about converting and scaling the different signals. Open to any feedback no pun intended lol. In the meantime I’m waiting on some LM6172s to begin breadboarding. Cheers!


I think you might have made a mistake with U5A. You’re mixing the R, G, and B channels into a signal called LZX_V which is also connected to the signal coming from the VGA’s vsync. Doesn’t sound right to me. There’s no sync in that signals going into U5A, so I suspect you meant to have the output of U5A be LZX_LUMA or something like that.

That’s LZX_Y for luma - sorry I just updated the post with a higher quality screen grab

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Ah, good. Makes sense!

I’m curious how this will work out for you. Especially using the VGA timings for sync. I suspect it won’t matter for some more analog modules that need sync (like a non-Gen 3 oscillator) but it might matter for more digital sync uses (like anything Gen 3 that needs sync). Have you already tried it out with any synced modules, and if so, how was it?

I own zero modular gear unfortunately. I’m planning to acquire and first try this with a castle VCO. If the sync plays nicely on that then I’ll consider investing in a newer generation module to test it on.

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Any recommendations for a module with digital utilization of the sync signals that I should test it on? The more affordable the better lol

I don’t know. It all depends on what timings you’re going to use. If it’s close to the same timing as NTSC or PAL, then pretty much any of them might work, depending on just how close. The Gen 3 stuff is some of the pricier LZX gear and the sync for all of those are processed digitally, though with more timings available. So maybe gen 3 stuff would be better since you have more timings you could try to match?

Either way, I strongly suggest you look up what composite and component video timings are and then see if you’re able to use any VGA modes that match those timings (or are very close). And if not, then don’t waste you’re money on the ones that need sync and handle it digitally since it probably won’t work.

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Btw these timing issues I keep mentioning are exactly why what you’re attempting isn’t done more. People usually use a TBC to go from VGA to component or composite timings. LZX has a nice TBC module, the TBC2, but it’s far from cheap.

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