Connecting your sync generator to other modules

This is a guide to understanding video sync distribution in your modular video synth. Some video synthesis modules require connection to the master timing references of the system generated by the system’s video sync generator. A sync generator module sends sync pulses to modules which require them.

There have been 2 standards for distribution of master sync in the history of the LZX video synthesis standard:

  • Video Reference via rear RCA Connectors. This is the current standard for production modules. There is an RCA jack input / output on the rear side of modules that require these connections. The output from the sync generator module is connected to the input of the next module which requires it, and this connection is daisy chained throughout the case from module to module.

  • 14-pin Sync Distribution Cable. This standard was using with our first generation modules (Visionary series) and is still in current use by our DIY series modules (Cadet, Castle.) A 14-pin ribbon cable with multi connectors is used to send 5V TTL level signals from the Sync Generator module to other modules in the rack.

Modules that can generate master sync include:

  • Visual Cortex (Rear RCA Sync In + Rear RCA Sync Out + Rear 14-pin Sync Distribution Cable Out)
  • Cadet I Sync Generator (Front RCA Sync In + Front RCA Sync Out + Rear 14-pin Sync Distribution Cable Out)
  • Memory Palace (Rear RCA Sync In + Rear RCA Sync Thru + Rear RCA Sync Out)

Modules which require connection to a sync generator include:

  • Prismatic Ray, since 2018 production (Rear RCA Sync In + Rear RCA Sync Thru)
  • War Of The Ants (Rear RCA Sync In + Rear RCA Sync Thru)
  • Diver (Rear RCA Sync In + Rear RCA Sync Thru)
  • TBC2 (Rear RCA Sync In + Rear RCA Sync Thru)
  • Fotress (Rear RCA Sync In + Rear RCA Sync Thru)
  • Navigator (Rear RCA Sync In + Rear RCA Sync Thru)
  • Liquid TV (Rear RCA Sync In + Rear RCA Sync Thru)
  • Cadet IX VCO (Rear 14-pin Sync Distribution Cable In)
  • Cadet II RGB Encoder (Rear 14-pin Sync Distribution Cable In)
  • Cadet IV Dual Ramp Generator (Rear 14-pin Sync Distribution Cable In)

Modules which receive sync via the EuroRack CV/Gate connections on the power header:

  • Prismatic Ray, before 2018 production
  • Castle Clock VCO
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Can you also talk a bit about the power bus sync which was used on Prismatic Ray and the Castle VCO prior to the move to RCA sync jacks on the back (at least for PR) in 2018?

Edit: I found this relevant post:

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Is it possible to use the Visual cortex composite output #2 instead of the rear rca sync output to sync a memory palace. I tried but it doesn t work.
Will it work with the tbc2 ? i want to sync 2 cases with front rca input output sync.

You should be able to send one of the Visual Cortex front composite outputs to the rear RCA sync input on Memory Palace. Just make sure that the Palace is set to external sync.

Yes. but it doesn t work. same cable same input in mp. work with rear rca vc output, but not with the front composite output.

My VC is in pal.
when i connect it to MP via VC rear sync output, it syncs in pal. When i m using the VC front composite output to sync MP it syncs in NTSC. So it s scrolling. Weird no ?

If my understanding is correct, Video Waveform Generator can be added to the CV/Gate list. I’d also mention that the Vessel supports CV/Gate sharing between cases.

(with the caveat that both of those products are discontinued)

Is there any way to sync the Cadet Series video modules to the Vidiot without the Cadet I which is no longer available? Does anyone make an RCA to 14 pin sync module? Or does anyone have a Cadet I for sale?

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there is some talk on the scanlines forum on diy sync generators

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I was also wondering lately if TBC2 can distribute sync to another case through the RCA sync output to another module (like visual cortex, or chromagnon) through the video in, without the need for a distribution amp taking sync from the front to back panel. In other words, distributing sync through front panels of LZX options only.

You could make/buy a passive panel like this to take sync from front to back (or vice versa):

See also discussion here:

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See I’ve been looking into all the sync distribution options and I feel like having to use up hp for it is not ideal. Especially with so many new projects lined up, I’d like to leave as much space open as possible. The reason I think Visual Cortex would work in this instance is this mention of accepting sync in product descriptions on a couple websites.

Edit: So I read through the Visual Cortex documentation, and it looks like this would be a totally valid method of synchronizing between two racks. If TBC2 front panel sync out is linked to the Visual Cortex via the decoder, it should sync the two systems together.

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If you’re feeling adventurous, you can just drill a hole in your case and put a pass through RCA connector or two there. Has helped me with routing sync around cases, anyway.

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You could also get a camera with sync in, sync that from TBC2, and then use that to input into Cortex.

That’s how I’ve gotten around the sync limitations of Vidiot, so I don’t lose an input dedicating it to sync.

On the other hand, I do wonder if it mightn’t just be easier to use one of the Cortex composite outputs to sync TBC2? As no one (but LZX) has one in their hands yet, hard to tell how much advantage there is to using TBC2 as master sync gen over Cortex.

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I suppose it will just be up to testing when the modules are in our hands. Though reading the documentation makes me feel very likely that this will be a perfect way to distribute sync through two cases with TBC2 as master sync.

I think I might set up a test scenario tonight using mem pal as master sync and see if its sync out will work through the vc decoder in as a proof of concept.

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Hi, newbie here. Newbie to lzx synthesis - I’ve been doing video for a looong time.

With the rest of you, I’m awaiting the new crop of equipment. My rack is still mostly empty so I’m trying to learn as much as I can before my stuff is shipped.Rack

If I understand correctly, lzx sync is composite sync; but a color video signal will also work?

After perusing my collection of ancient video equipment, I see I have a broadcast-style black burst generator. I’m curious if there is any advantage to using this directly to each module rather than looping?

Yes, for all modules that accept an RCA sync input.

Yes, assuming the color video signal is an NTSC or PAL composite video signal. The genlock circuit includes a sync extractor so anything with appropriate sync embedded should work, like a green channel from an RGsB (sync-on-green) component feed or something.

This is probably a good sync generator and may produce a more reliable sync signal than some other equipment you might have. If it has multiple buffered outputs you can connect several downstream modules to each of them. Daisy chaining sync through several LZX modules is nice because you generally get buffering at each module can get buffering from certain modules, generally those which genlock / generate their own sync. But if you have a black burst generator with enough outputs or can pass the black burst to a distribution amplifier with enough outputs then this should work.

So composite sync means the actual video coming out of the Vidiot, for example, has the sync in it? Does that mean that all composite video sources can be synced with any expedition or Orion module without a Vidiot?

Oh, I didn’t realize that. I suspect that the benefit would be minimal then. I was assuming it was a passive loop through