Should there be a 14-pin sync header on Castle 010 Clock VCO?

Continuing the discussion from Connecting your sync generator to other modules:

No 14 pin sync header on the back on mine as far as i can see… :blush:

Guess i have to connect to the front sync jack in stead? But what do i input here?

(Tried uploading illustrative picture of input front sync jack, but new users can only upload one picture for each post!?)

Really Looking forward to the rest of the Castle Walk Through videos @pbalj :wink: . And more documentation for the Cadets @creatorlars :wink:.

Best. Lau

Can confirm no sync header or RCA jack option on back for my Castle VCO:

Syncing via the front input works great, and you input sync signals from Visual Cortex (from the Sync Generator section with H, V, Frame, Dither) or from a Cadet I (H, V, Frame).

I currently am syncing mine Castle VCO via the power distribution bus on the back just like I do with my Prismatic Rays. See here for some additional details:


Castle VCO receives sync through the CV/Gate bus on the EuroRack power header, or directly from the frontpanel input.


Why was it done differently on this module ?

I also noticed this when doing a custom layout. I made separate pads on the pcb.

Both methods (CV/Gate sync and 14-pin sync) are valid and have been supported by LZX since the beginning, so I guess Phil decided he preferred the CV/Gate sync method for the Clock VCO. With the Cadet series, the boards are designed to be multi-purpose, so I wanted the pads of the pin header available for wiring, even if the 14-pin sync wasn’t populated.

14-pin sync in general is a bit of a hassle for our production modules, going with the single RCA sync/genlock input is easier and is also an established standard in the broadcast world – but the extra circuitry it requires in some cases is outside the scope of a DIY module build, where parts count needs to be low, so that’s why we’re using the 14-pin sync in Cadets.


Thanks for the clear explanation Lars!
I was wondering about that RCA sync cable;
I did not know how that worked / how to fit all data (H-sync/V-sync/C-sync/Blanking/Burst/Odd-Even) in a RCA connector.
Most of the time it is the H&V sync , I presume.
but then in a encoded stream, instead of dedicated pins.

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Take a look at the LM1881 datasheet. This won’t give you everything on the 14-pin sync header, but if you need to extract hsync and vsync for oscillator syncing, for example, this is a pretty easy way to do it!

So, the RCA sync… are LZX modules that pass sync in this configuration sending “composite-sync” signals (like those that come out of the LM1881)… or a full composite video signal… or something else? I ask because if I wanted to DIY an LZX-compatible module that utilized incoming sync on the RCA, would I need an LM1881 to digest the LZX sync prior to separating H & V sync signals? Or can I skip the LM1881 and just logic the sync signals apart?

@drumasaurusrex It is composite sync driven at video amplitudes 0.6Vpp thru 75R resistor, buffered with video opamp. So you should use LM1881, or if you’re feeling thrifty you could design a sync tip clamp (budget DC restore) circuit and drive that into a comparator. LM1881 is much easier. :slight_smile:

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