LZX Gen3 Primer & FAQ: The Future With Chromagnon & LZX Modular

As we transition into a focus on our third generation of EuroRack video instrument products with Chromagnon, TBC2, ESG3, FKG3, SMX3, DSG3 and DWO3, we agreed it would be good to publish a primer about differences between what we are doing now and what we have done in the past. That’s the purpose of this post, to serve as a living reference and FAQ about anything related to compatibility, new options, or changes in approach.

Supported Video Formats

  • Composite and S-Video inputs/outputs support these 2 timings: NTSC and PAL.
  • Component (YPbPr/RGsB) and Sync inputs/outputs support these 15 timings: NTSC, PAL, 486p5994, 576p50, 720p50, 720p5994, 720p60, 1080i50, 1080i5994, 1080i60, 1080p2398, 1080p24, 1080p25, 1080p2997, 1080p30.
  • In NTSC and PAL modes, full backwards compatibility is maintained with previous LZX modules and instruments.
  • Most previous LZX modules and instruments will be able to integrate into a system running in HD timings.
    • If the earlier module does not have a sync input or output, you can expect the module will function without additional consideration for video standards.
    • If the earlier module has a sync input or output, it likely will not support the new standards, but will still work with the newer modules in their NTSC and PAL modes.
    • There will be some exceptions to the two above statements, we’ll create and maintain a list of those modules along with additional notes.

Power Supply & Form Factor

  • EuroRack form factor with maximum adaptability. Modules follow a consistent set of design constraints related to ergonomics, legibility of function, and mounting tolerances. All modules adhere to a maximum mounting depth of 45mm. You won’t be surprised by a future release that requires a case with more mounting depth, or find many off the shelf enclosure options that are unsuitable for LZX modules.
  • EuroRack power supplies are optional, but not excluded. All modules may be powered directly from a 12V DC input barrel, just like industry standard video equipment from the Broadcast and CCTV industries. However, backwards compatibility is maintained with EuroRack power connectors.
  • Low noise no matter the environment. Each module integrates a noise filtering internal power supply that keeps your signal path’s noise floor low whether the power input comes from a noisy 12V wall wart or a precision EuroRack power rail.
  • Power budget expectations. DC 12V @ 25mA per HP. 3 Amps per 104HP is a good rule of thumb that leaves 15% headroom over this budget.
  • The main things you need to know about power are:
    • If you’re adding a few Gen3 modules to your combined EuroRack system or earlier LZX system, and your EuroRack supply can support the current, you don’t need any kind of special cable or adapter. Just install the Gen3 module as you have Orion, Expedition and Visionary modules.
    • If you’re starting fresh with a Gen3 system, we recommend you skip EuroRack power entirely and power your system with a 12VDC distribution module, bus, or cabling. Combining a passive EuroRack enclosure with our DC Distro module is a good place to start.

The Story So Far

  • In 2019 we reached the decision that we needed to make an architectural shift in the design of our products. We needed to solve for some performance issues introduced by the variable nature of EuroRack power, and create a better power ecosystem for video processing in EuroRack format. We also wanted to make sure we were fully implementing the capabilities of the hardware and format, by introducing a range of new supported video standard timings. Furthermore, we wanted to standardize all of our circuitry to a common library of hierarchical schematic blocks, make some tweaks to our ergonomic standards, and really create a canonical set of core modules we could commit ourselves to in the long term. In other words: we had stuff to change – and it was better if we could do a complete redesign.
  • Throughout the end of that year, we discontinued most of our catalog of modules and began work on Chromagnon, which is meant to be an ark project that allows us to restandardize all the main components of our core circuitry in a single project. Chromagnon is a master design reference for anything to follow (we solve video input, output, tbc, ramp generators, and core analogue circuitry in a single project.) We also swept TBC2, an existing Orion project, into this initiative so that we could ensure we weren’t releasing two TBC type modules back to back with different feature sets.
  • We opened preorders for Chromagnon in early 2020, expecting we could be shipping the complete instrument in full by that Summer. The pandemic forced us to close for a few months right as we were, as a whole team, highly focused on getting that job done. The months of uncertainty that year and isolation from each other pushed our entire schedule into chaos.
  • In 2021, we were finally able to begin production on Chromagnon. During this year, we built over 700 control board assemblies – while these assemblies represent the bulk of the assembly hours required to build a Chromagnon and most of it’s material costs, they are all still waiting on completion of the rear assembly before we can turn them into complete instruments. TBC2 & The Chromagnon rear assemblies are closely linked to each other and firmware development has been slow going. But as we near the end of Summer 2021 we have solved most of our issues with both projects, and have all essential features working, but were about to get distracted.
  • In late 2021 our production team ran out of work, and had taken the Chromagnon assemblies as far as they could go up to that point. Since we had discontinued our previous catalog of products this left us without a product to build, since Chromagnon presales were dwindling and we had no other primary product available for sale. Chromagnon rear board finalization was going well, but we were experiencing setbacks, and new problems – supply chains for our most expensive subcomponent, the Zynq SoC, were becoming more expensive and uncertain. We needed to revise the boards again to take this into consideration – that way we’d have multiple strategies on the path to fulfillment.
  • Running out of revenue in late 2021, we decided that we needed to release the first few modules of our new core modular system, and that we needed to engineer their internal sub-assemblies to also be reusable in the final Chromagnon host assembly, this way we are taking two steps forward at once: One toward Chromagnon fulfillment and one toward having a modular video synthesizer system in stock again. It would mean another overall slowdown in the schedule, but at least we would be moving forward on firm ground.
  • Coming into early 2022, this plan has worked out well, and is allowing us to continue our work through your support of the new module releases. We’re focused right now on delivering on the long term projects most (TBC2 and Chromagnon), as well as introducing our new 5-module modular system into production to support us while we do that. After meeting these deliverables with TBC2 and Chromagnon, we plan to spend a while patching these new instruments, promoting them, and catching up on educational assets and documentation related to them.

Circuit Designer Notes

  • The Gen3 circuitry is built on the Patchable Video Standard.
  • All analogue functions are on 6-layer PCBs with dedicated internal planes for power and ground connections. We found this was one of the most effective methods we have for improving overall performance of the system.
  • Texas Instruments LMH1980 is used exclusively to extract timing from sync inputs, using the recommended application circuit in TI’s datasheet.
  • All video and sync output jacks are buffered by video opamps and intended to drive a standard 75 ohm video transmission line. There are no 75R termination / loop through options to ensure the transmission line is not hindered by electromechanical contacts in switches. All outputs must be buffered.
  • To minimize stackup of propagation delay along a series of rebuffered sync outputs, place modules with lower timing requirements towards the end of your sync chain, or use a video distribution amplifier to distribute sync from your source generator in parallel to all modules. We don’t expect this to be a practical concern for most users.
  • Our local analog power supply for most modules uses +/-5V power rails, generated from internal switching DC converters and ultra-low noise low dropout regulators (such as Texas Instruments TPS7A4701 and TPS7A3301). Power supplies for digital parts such as systems-on-module and FPGA subsystems are typically derived directly from the 12V power entry with separate power supplies designed for their needs.

[UNDER CONSTRUCTION: Additional sections will be added to this document over time, as relevant – please feel free to discuss or add questions below]

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Does this mean we need to use a 75R terminator for the end of a sync chain?

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Not quite, it just means every sync input is already terminated, and all sync outputs are buffered transmission lines. No 75R switches or loop thru option. This allows for a much more consistent expectation in terms of sync distribution and performance, and is most reflective of how modern broadcast gear works when dealing with sync references.

There is a 10ns propagation delay per buffer, so at worst, that means that if you have your TBC2 downstream from your ESG3 through a few buffers, you’ll have to adjust the pixel delay on TBC2 to get pixel-perfect alignment relative to output sync. So this is what I mean by “not a practical concern for most users.”

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Ah, got it. Thanks. I figured I was misinterpreting it.

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3A per 104HP? Wow, no wonder y’all moved to 12VDC and onboard power. That’s fully bonkers. The step up to HD bandwidth requires that much more overhead?

How does the onboard power compare to say a linear supply?

Here I was expecting to power my system over euro for ultra low noise but sounds like even a 25A supply might be getting close to the power budget :joy:

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Looking at the total load, it’s not too far from our previous recommendation of 20mA per HP (10mA per HP on +12V and 10mA per HP on -12V.) It’s just all on one bulk rail. It sounds like a lot until you realize you can get 3Amps of 12VDC on a wall wart for much cheaper than any EuroRack options available. Just look for power supplies designed for CCTV equipment and LED lighting.

There’s also a lot more circuitry behind the panels of these new modules compared to anything we’ve done before. These are new, all-discrete circuit design topologies, which run a little bit hotter than some of the ASIC parts we’ve used in the past like LT1256.

None of this really relates to HD vs SD bandwidths specifically – it’s more about improving the performance of the environment all these signals live inside across the board.

How does the onboard power compare to say a linear supply?

Typical ripple in a linear supply is 3-4mV. Our power board’s noise floor is < 1 mV ripple. It’s analogue, so I’m sure there will always be some noise beyond that to contend with, especially if you’ve got lots of gain stages in your patch. But this is far and beyond cleaner than what we’ve done before.

Here I was expecting to power my system over euro for ultra low noise but sounds like even a 25A supply might be getting close to the power budget

Yeah no need for that – that’s part of the point – you don’t need to speed hundreds of bucks on low noise EuroRack power supplies or busboards – because on these modules you’ve already paid for that (they’re integrated into the power entry, and part of the module’s price tag.)

If you’ve got existing power solutions for your earlier modules that are working out great for ya then just stick to those! No need to change anything. You can squeeze a couple Gen3 modules in if you want. But if you’re planning a whole Gen3 row, just skip the Euro power supply and power it from the bulk DC12V instead.

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By my rough calculations, that’s around 2A per 84hp row. A 12U rack cabinet gives me 4 rows, and require maybe 8A of power.

So my plan is to a pair of DC Distros to power a 12U cabinet for my Gen3 modules. Anything standalone, like Chromagnon, can sit outside the cab. I have an existing 12U cabinet using a pair of Malekko PSUs for older modules.

I love Gen3. It solves all the power issues that have been bugging me since 2015. Thanks!

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Hadn’t considered that it’s all on the bulk rail - that’s more promising for a DIY clean power scheme - was thinking 3A± per 104.

I’m in the camp of having gone through the massive pain & expense of building/designing a clean power solution for my setup so was just trying to wrap my head around if/how that fits into Gen3 going forward.

Thats really impressive that they’re sub-1mv, brilliant move by you cats for building an onboard power solution - too long has power been the bane of video modular. Hell, eurorack in general, but video especially.

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RE the dc distro
is the preferred use case that each output gets its own module or will it be ok to daisy chain multiple modules together?

iirc from the original spec for it, you should be able to daisy chain multiple modules together

hopefully this will also work with just putting a hole in the case and daisy chaining a 3A (or more) 12V power supply…

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We won’t officially be supporting any daisy chain cables just because it’s a potential liability. You do not want to have loose/disconnected hanging DC barrels crammed behind the modules in your rack after installation – that could short against parts or connectors on the rear circuit boards and cause issues. So if you have unused connectors on your daisy chain cable, be sure you cap them with an insulated barrier or insulate them with electrical tape, etc before power up.

Also, with daisy chaining it would be possible to connect more modules than your power barrel/brick can support. So it puts you in the position of adding up your current ratings. On the LZX DC Distro the connector itself is rated for 5A maximum. So even if you had a 15A brick for example, you wouldn’t want to push 15A of current through the connector.

Also, if you are going to daisy chain you need to ensure you are using a wire gauge thick enough to carry the current. So you’d want to do it in segments, not in one long row. For example a 1 in, 5 out chain cable per row, with each cable going to a DC distro outlet, would be better than several daisy chain cables in series with each other.

TLDR; Daisy chain is okay, but you need to know what you’re doing. If you stick with DC distro or a limited scheme, you don’t have to think about it as much.

I prefer parallel distribution like DC Distro or these kind of supplies, where you have parallel output adapter from the power brick directly:

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this looks to be the same thing but for uk!

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Yes, you shouldn’t have trouble finding a wide variety of DC12V solutions! There are CCTV supplies designed to be used with pigtail leads as well, and rackmounted options. Also any generic 12V switcher closed frame supplies like from Meanwell, etc – or DIN rail mount bulk 12V supplies, are all options if you want a dedicated install without wall warts.

I’m sure some of these 12VDC parts are better than others (connector/cable quality, power output stability, expected lifetime of use, etc) but the great thing about any of them is that they are all easy to replace or maintain if something burns out – and most importantly, the Gen3 modules should perform consistently regardless.

Anything we stock at LZX will have to be marked up over what you’d get on the open market, but I view that more as the cost of a verifiable supply chain – if we’re offering something like DC Distro, DC jumpers, power bricks, etc it will be after we’ve put in the work to test them with the system and ensure that a user with no desire to learn the ins and outs of DIY power options can just plug it all in and it works.

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For the DC Distro, that’s the “this will work, I don’t have to add anything up” approach. If you start daisy chaining, just make sure to add up all your module currents and make sure it does not exceed either 5A (the connector rating) or the DC brick rating. (And insulate any unused output connectors!)

There will be some revised DC distro options coming as well as barebones rack ear + rail kits. The current plan is to have those ready at the time DWO3 is put up for sale (the last of the 5 module basic modular set we’ve been working on.)

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That’s why I plan to use a selection of 2-waym/3-way splitter cables with my DC Distro, with the splitters “upgrading” as I add more modules, up to a max of 14 modules on one brick (using up to four 3-way splitters and a single 2-way splitter).

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That sounds like a good plan. Little velcro straps to keep things tidy as you go is probably a good investment. Due to the L shape of the gen3 modules, there’s a kind of cavity created just below the DC barrel connectors on the rear, the intention is that even if you have a shallow case, this pocket area is enough room to keep any rear cables neatly wrapped rather than potentially smashed against the back of the case.

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If you are adapting an existing case and want a no-soldering easy install (and don’t want a DC power entry module up front) you could use a DC feed thru bulkhead, like this:

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Well, I’m using 19" racks with an 8" depth. I think that should be deep enough for Gen3!

I like the cable-tie tip. I have some simple “wire” cable-ties that came with various cables, so I coudl make use of them in my Gen3 case. However, I shall now also consider using velcro. Thanks.

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I’ve just got this one. The output jack from the PSU isn’t 2.1mm. The adapter has 2.1mm outputs but isn’t suitable for bulkhead mounting. Just something to keep an eye out for.

Edit: the other thing that I’m seeing is a lot of adapters with a 2.5mm internal that are being advertised as 2.1mm. They only show the dimensions on a small diagram and claim that they are compatible.

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