Eurorack Development Advice - Jackalope dev diary


There seem to be a few people on this forum that work in the design and production cottage industry that is eurorack.

I don’t want to say too much at this early stage, but I have had an idea knocking around my head for about 6 months, and have finally designed something and am ready to start order parts and making a few prototypes. I see this as an art project, not a business idea or serious foray into instrument making.

Module makers:

  • What do you wish you knew when you were starting out?

  • What mistakes did you make that I could avoid?

  • How do you qualify the “success” of a module?

  • What other advice can you offer?



I wrote a wee bit about this in this interview I did recently - bear in mind I’m making tiny kits, not finished projects (yet).

But to kick off:

  • everything will take longer to get to production than you think, even when you have an 100% working proto on your desk. this is triply true if you like detail and are caring about the final outcome.
  • if you’re assembling them yourself (rather than having contract manufacture done), make damn sure that you’re charging appropriately for your time as part of the cost, otherwise you’ll end up with something cheap you can’t afford to build
  • if this isn’t a main business, you have to find a way to keep it manageable - both in terms of setting expectations of others, and also in terms of corralling it. if it’s related to something you enjoy, you have to find a way of not burning out on playing your synth because you spend all day thinking about this.
  • design-for-manufacture is different to design-for-working-out-an-idea. Once it’s working, there are ways to bring the costs of production units down. it’s worth doing this, even for simple things.

Beyond that, I might drop in later once the dialogue emerges. If you want to chat more via DM (I’m UK-based), more than happy.


Thanks Infovore! Great to have someone in the UK for advice too. So much of what I’ve researched recommends US suppliers.

I’m planning on doing limited runs, and not selling anything until it’s built. That way I can make a run of modules, and sell them without having to worry about fulfilling orders, etc. I’ve just finished a successful kickstarter for a book I wrote, so am aware of how time consuming and expensive just packing stuff up and sending across the world can be.

Hopefully that way I can keep things manageable and if I’m not enjoying it can just do one run and then never again.

Is it digital or all-analog? If you’re writing code, ordering a Clouds and using that as a development board is a very cheap way to prototype with stereo in/out and lots of CV:


All analogue, but thanks for the tip!

…Also laughably simple.

My main advice would be to start small and simple. That said, my first module was Turing Machine which is anything but.
Think about the sales channels - the routes into people’s heads (and hearts) - awareness / consideration/ purchase / use / advocacy.


Keep in mind that the eurorack world is getting pretty crowded, so consider carefully if what you have in mind is interesting enough to be worth it for people who are now spoilt with choice.
Then of course you might be mainly doing it for yourself, which is fine also, just don’t make too many units in the first batch.


Thanks guys!

Definitely doing it for myself, and starting with a run of 10 modules which seems to be the lowest number I’d start making a saving on producing multiple.


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Ok that seems like a good way to start!

Some more practical things that could be useful to know: Always make at least one prototype and have different people test it (ideally for a bigger batch of modules you should make 5 or 10 protos), or you might end up with something like the Verbos Pan&Scan, which got produced with a big bug in the circuitry (and that’s just one example… there’s way too many examples like that in the eurorack world).

Try to stick to the standards. There’s already enough people making their own version of eurorack. People will thank you for that.

Doefer has a great page with all the sizes for panels and these have worked great for me so far.

There’s a lot of small details that might spawn unnecessary service requests, some silly examples: I got one module that had the power connected on the busboard end connected the wrong way. As long as you don’t have an un-shrouded busboard you won’t notice, but with a shrouded one you’ll connect the cable upside down (possibly thinking that since you have a shrouded busboard you can’t connect the cable wrong) and possibly damage something.

People are very sensitive to wobbly pots. Sometimes these are not bad quality ones… but a nice firm turn will make everybody more happy. Be cautious with encoders, they seem to solve a lot of problems but are tricky to implement properly and often have either a high price or a very low life-cycle. Though I guess this only applies to digital modules.

Don’t try to cram too much on a panel. make sure the fingers fit between the knobs and that tweaking them will not make you accidentally move something you don’t want.

Keep in mind that the rails need some space, keep a generous clearing on top and bottom, i.e. don’t make the PCB(s) too big)


Thanks! Some great practical advice there!

I’m very wary about sizing issues, because no one wants a module that just scrapes into place, or with a hairline crack between modules - really bugs me when things are a little off. I’m using Doepfer standards for the panel, so hope to avoid this.

The “wobbly pot” thing I just don’t get, but I understand some people are all over it. I blame Nick Batt who always comments on how sturdy the pots are. I mean, I’ve had wobbly pots that have worked well for years and super-tight ones that have become scratchy within a few months… doesn’t seem to make much sense. I understand that panel-mounted knobs should present less problems than pcb-mounted knobs, but it’s certainly not what I’ve experienced.

Anyhow, nice to know what other people find important.

For that same “what other people find important” reason I’m using aluminium panels. I don’t care if panels are aluminium, plastic or fiber, but other people obsess over it, or obsess over having everything grey, or black… Anyhow, I’m going for aluminium with black print, because, well, that’s kind of standard. Much as I’d like to go with bright blue and yellow! :stuck_out_tongue:

I used this diagram (imgur) for reference. @papernoise is right about PCB sizing - I tend to be reasonable conservative on PCB size - so on a 4HP panel (20.58mm wide) my PCB is 19mm wide, but on something wider I’d probably add another mm of width clearance. The one to be most careful on is PCB-vertical-dimension - some rails are a bit bulgier on the inside than others (Z-rails have a bulge, Vectors don’t). TBH, if you have a few mm of wiggle room,you’re fine. Basically - you should be fine if you copy Dieter, so it all sounds good.

Wobbly pots is a bizarre obsession, until you feel some super-crap ones. I personally think PCB mounted + screwed to panel are absolutely fine; I use 9mm Alphas with threads and all is good - securely soldered, and then a nut to keep them against the panel. Nothing wobbles. (I mount my PCBS parallel to front panel).

(My personal bugbear, by contrast, is cheap-feeling knobs - there’s at least one manufacturer I can think of who makes really nice equipment but uses knobs that feel horrid to me).

+1 to everything about ergonomics that @papernoise said.

aw man, bright blue and yellow would be awesome. Almost team colours for Greenock Morton! (My team).

I’ll do a custom one just for you and your scottish championship friends.

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I like it when manufacturers provide slots for the screws rather than round holes as it allows for a little wiggle room to line things up.

I’m looking forward to seeing what you come up with!

Not sure you should serve people’s request like this! :slight_smile: There’s always grayscale for people who like things tat are totally neutral and… well… gray.

I’ve been pushing people a lot to make stuff that isn’t what some OCD people make us think, and most of them went pretty well (like the Alright Devices stuff).

I actually hate the oval holes (though that is mostly my own OCD acting here). In a world where people make the panels and rails following the standards there would be absolutely no need for oval holes, but unfortunately this is often not the case. So we need those ugly looking holes on the panels…

When I got in to making Euro as AI Synthesis, I contacted Grayscale and had him design my panels. I had used his panels in prior projects and knew that he knew how to make a quality panel. It adds cost, but quality was and is my priority and I really wanted my modules to look and feel great no matter what they were racked next to.

PCB height is definitely a challenge. I was shocked to learn about the lack of standards in rails - I wrongfully assumed those would be standardized.

The main advice I can give is: 1) Don’t do business unless you really like business. I spend most of my time packing kits, shipping modules, and doing boring stuff like accounting. I love business though, so it’s fun for me.



Ooo. Speculation time @Simeon

Distortion based on the legendary howl of the Jackalope? :rofl:


My advice would be to make something genuinely different - not just a compilation of other peoples designs.
If its remotely close to another module design, then scrap it. Please don’t make a filter or drum module :slight_smile:

The other thing i’d say is it must be skiff and hp friendly. hp wise - no more than a Maths 20hp - ideally 10 hp or less. If its a utility module 4hp is ideal. If its more than 20hp then it better be amazing and completely unique.

Stiff knobs, not wobbly knobs. No matter what people say about how great wobbly knobs are to the actual function it doesn’t matter. Its about the user experience and wobbly knobs subconsciously doesn’t make you feel good. I am saying this as a Harvestman and Buchla user that both user wobbly knobs. You will alienate buyers with wobbly knobs. No fancy bold graphics / no colour - think Greyscale not Snazzy Effects. Sorry, no offence Papernoise, but in my opinion, its a no to cartoon graphics. It looks like a kids toy, again you will alienate your users - i’m looking at the likes of Endorphin here. The best example i’ve seen with nice graphics and no colour would be the Manniquins stuff which is quite arty, its minimal, but not in your face. If i was making a module i’d just let greyscale design the visuals. They are boring, they are plain, they are clear, concise and whats most important is no one complains about them. It saves people spending extra money changing knobs / faceplates in the long run. Also no colour, use silver faceplates. The only manufacturers that can get away with that in my opinion are Metasonix and Cwejman.

Unique knobs can be handy to make it stand out - not the cheapo nasty ones on the PEG but solid ones like on the DLD.

I live in a humid environment and my other pet peeve is the materials for some components - like screws, standoffs, washers and metal shafts in encoders (i prefer plastic) in knobs being open to corrosion. Its easy for me know which manufacturers scrimp on this after a few years in my case.

Benchmark modules that have passed the test of time component wise with zero corrosion would be Livewire, Cwejman, Synthesis Technology, Mannequins. I know why their stuff is more expensive!