Hardware design


Haha, this very much resonates with my experience! It’s like it was made by someone who’d never used any other software, and eschews or inverts all the UI conventions that are so ingrained in us. Having said that, I have got used to it (I’ve only designed a few PCBs so I’m no expert). The PCB layout process always strikes me as feeling like an Indie puzzle video game!



I’ve been using KiCAD, and designing the panel as one of the layers I’m not using for anything else.

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So: I’ll be honest and say I have a fair amount of Stockholm syndrome when it comes to EAGLE: the learning curve was hell, and now I’m through it… I kinda understand the way it is like it is, and actually appreciate a lot of its decisions. Some of its crapness is down to how little it’s changed over the years, but some of it is down to the fact that it’s a CAD tool, not a graphics tool. (My experience of other CAD tools has been similar).

Brief tire-kicking of converting EAGLE-to-other formats was not very impressive, so I’d probably not recommend that. Instead, learn the tool you’re planning to use, make parts in that.

I’d also say now that it’s not like anything else is vastly more user-friendly; if you think that user-friendliness is KiCad or DipTrace’s main selling points… you might be disappointed. The one obvious difference is that EAGLE is unusual in how tightly it couples layout (brd) and schematic capture (sch) (and similarly, how its library bundles up part/package/device). Other tools take the more traditional approach of making them very separate: first, layout a schematic just with symbols, doesn’t matter what the parts are. Then, make a layout, matching symbols to physical parts. This is the traditional, old-fashioned way (and indeed, many companies made tools for only one of the parts - use one schematic capture tool, another layout tool).

As a result of this way of doing things, making your own parts isn’t quite as complex in tools other than EAGLE because the symbols often exist. But I’d point out that making your own libraries/parts is a relatively core skill for using these tools, and makes your life so much easier when you know how.

About the only user-friendly tool I’ve used is Fritzing, and my main feedback on it is that Friends Don’t Let Friends Fritzing. I’ve made boards from it, but its parts support is limited to say the least; it’s friendly, and it’s kinda useless.

I am happy to answer or attempt to answer any questions about EAGLE. The learning curve is steep, and it’s only right to share knowledge.

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Has anyone in here tried pcbmodE for inkscape? It seems like a nice in between using a vector application to couple with a new way of thinking about PCB layout. It’s made by boldport and they’ve been making some of the most beautiful boards I’ve seen in a while:



can’t say much about the pcb/circuit design part, but my process for the UI is usually this:

once there is a rough idea about what the circuit/software is supposed to do I’ll try to imagine an interface for it. What helps a lot here is first defining which parameters need to be exposed to the frontpanel and figuring out their hierarchy.

initially I use the Sketch, since that is the quickest, less annoying tool to get something done quick and its symbol feature is very handy to have a library of frontpanel components ready to go.

I’ll use placeholder graphics to mark where still to be done things go, it’s important to me to consider the graphical elements just as part of the panel as everything else, and add them to the sketches from the start (even if they are jus an idea at that point ).

Once things get more defined I’ll move over to illustrator, since that gives me more tools to do all the detail work.

In the middle there’s various iterations of back&forth between the panel design and the pcb, usually the cut layer for the holes and cutouts is done based on the PCB and the final alignment of all the controls is based on that. Always keep in mind that there’s tolerances and you’ll never have perfect alignment of things.



Maybe it’ll be an utter failure, but if I’m lucky, I’ll have an Intellijel-format 1Ux10hp adaptation of a single Nonlinear Circuits Sloth, the current model with CV input and X, Y, and Z CV outputs. In hindsight, I probably would have been better off doing something more modest and with fewer parts crammed into such a small space. I at least feel like I’ve come to some sort of working understanding of Eagle, which is better than I thought possible about two weeks ago!

If it works, it is due in part to what I learned in this thread; if it doesn’t, it’s in spite of the same.



Looks good! I like your LED placement. It’s a bit tight but if you work your way outwards and upwards (start with the ICs) you’ll be fine. Good luck with it! And if you run into any issues, happy to look at files and offer a hand.



thanks! I’m comfortable with tight through hole boards, so I think as long as I am methodical that the build will go well.

I may try solder paste & electric skillet/hot plate for the SMDs as a learning experience. anyone have any experience with that?



The trick to using solder paste is getting the right amount on each pad. Can be done by hand if you’re careful, but gets much easier with a stencil.



I am in the process of laying out a very simple switching Euro power supply/bus board. The plan is to use a MeanWell DKE15A-12 which seems to have the best ripple/regulation specs of any of the similar devices I’ve found. An external MeanWell brick will power it and a Traco TSR-1-24 or similar 5V converter. Befaco’s Jumpskiff uses a similar (maybe identical?) system. I’m not trying to reinvent the wheel, just make something that is inexpensive and easy to build which will also fit in a 42hp case.

Output specs would be:

  • 625mA for each 12V rail
  • 1A for the 5V rail, and 2A would be possible by using a 2A 5V converter in the same footprint as the 1A, offering more headroom for a Grid/etc.

Does anyone have any advice on any sort of noise/ripple filtering, preferably with a focus on low-cost and DIY-friendliness? Does it even need it? The datasheet claims 60mV max ripple/noise, which seems decent as-is. There is also a tremendous amount of information about PSU filtering and it seems like a lot of simple Euro PSUs throw in a few capacitors which may or may not actually help (depending on who you ask). I want to avoid adding parts that don’t do anything, but I also don’t think this needs to satisfy folks who care more about posted specs than whether the thing works properly and reliably enough given that it is just powering a synthesizer.

I believe this 12V converter also is not designed to be used with less than a 10% load, though I haven’t found a specific spec on that - if true, it seems wise to place a dummy load resistor between the output of each supply rail and ground before they branch out to the headers, right?



hey, I bought the DKE15a-12 after you mentioned it here. I’m using very little support circuitry (a reverse-protection diode and 470u capacitors on this busboard), powered from a 15v wall wart. I haven’t rigorously tested it or anything but I haven’t noticed any noise.

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yeah opinions really differ about that. Of course you’ll always have ripple/noise with switchers, but depending on the intended use of the skiff that might be still totally acceptable. I think the important thing is to be clear and transparent about it. The main argument about the filtering caps is that they usually are too small in capacitance to be able to do something at the low frequencies, and mostly only act on the higher frequencies, which are outside of the audible spectrum.
I’d be more worried about the voltage accuracy of +/-2%. This means that 12V will not be 12V but might oscillate between 12.24V and 11.76V, if you have modules that reference that directly you might get that things are a bit wobbly maybe? Not sure, but maybe look into that.

I’d be careful with the minimum load thing. I used to have a Traco Power PSU in one of my early cases and it would make my digital modules go all bonkers if I didn’t put enough load to it.

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In my day job, I work as a product/graphic designer, but to be honest I never contemplated the possibility of designing module panels or other interfaces until literally 3 minutes ago. The world of industrial design is new to me, and therefore exciting :slight_smile:

I know of @papernoise’s terrific work (from whom I’d love to hear), but I’m assuming a number of folks here have done graphic design work for modular as well. I thought it would be really interesting to hear about your various practices, and any insights you might be willing to share about them.

  • How did you get your start?
  • How many of you work primarily as graphic designers in collaboration with module designers/engineers?
  • What is your technical workflow like?
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@Olivier I highly recommend the push turn move book (and I imagine, the new modular focused one that is coming soon, patch and tweak.) the informational part of the book is laid out in a very engaging way, imo, and there are a lot of good interviews.

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How did you get your start?

Totally by chance. :slight_smile:
I did try to become a graphic novel author at one point, but I’ve made a couple of bad choices and one project in particular totally beat the joy of drawing out of me, so I started to solder DIY kits. Just to do something that didn’t have anything to do with drawing.
This brought me to build one of the early Shruti-1 kits (the one before the Shruthi).
Through that I met Olivier, and the rest kind of snowballed from there.

How many of you work primarily as graphic designers in collaboration with module designers/engineers?

I think I can say that, that is a big chunk of what I do. Though what I do now is only 50% or less graphic design. The rest is a mix of product design and UI design.

What is your technical workflow like?

Ok, this is complicated, but I’ll try to sum it up.
There’s a big part of work that comes before the actual module is even conceived: defining the maker’s visual style, module design language, etc.
When it comes to desinging a panel for a maker I already work with, my preferred way of working is: I get a rough idea of what the module should do and what the controls could be. Then I make mockups after mockups in illustrator until I come up with layout that feels like it could work. There’s a lot of back&forth with the module designer/engineer at this stage.
I always include graphics early on, you can’t design a UI just with the hardware controls.
Once the layout is feeling good, I do all the fine tuning on the graphics.
Then I build some prototypes (for modules it’s usually a matter of printing out the panel and sticking knobs and other fake controls to it, for pedals I make 3D papercraft protos).
Then at one point I also get an actual hardware proto to see if everything makes sense and works correctly UI-wise.



did this ever work out?

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I got PCBs made and then summer happened, which tends to pause my synth DIY activities. Having them in hand taught me that things look a lot bigger/easier to build on the zoomed in screen than in real life, but I should get my protos built in the next month and will update!



To all of you making your own modules and selling them: how does manufacturing work out?

I’d like to gain a realistic idea of what manufacturing and selling Eurorack modules on a small scale (one to a few dozen) implies in terms of costs, time, and bottlenecks. I am especially interested in comparing different manufacturing methods (i.e. having boards made pre-assembled vs having PCBs made then hand assembling & soldering them).

While I am not an engineer, I am a programmer in it’s first years of study with a love for maths and sound. Over the past few years I’ve toyed around with analog circuit design and more recently DSP — and have amassed some ideas and designs that could make for some interesting Eurorack modules. Additionally I will be writing a short feasibility report about this as a university project.

Any insights would be greatly appreciated!

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I run AI Synthesis. I get this question a lot. Selling one to a few dozen won’t be very profitable. You typically need to sell a bare minimum of 100 to make something work out (not counting paying for your time).
So assuming you’re going to sell ~100 of each module.

You will spend most of your time on fulfillment, support, documentation, accounting, parts ordering, and manufacture. I get to spend maybe 5% of the time on circuit design (but I do my own manufacturing, which makes for a lot less stress.) The point is: if you don’t want to spend a significant amount of time on the types of tasks you would be doing if you were, say, selling reams of paper, business might not be a great idea.

To answer your actual question: Doing your own manufacturing will provide more profit, and you don’t have to worry about costly buy-backs if your modules don’t sell, so you can take advantage of quantity discounts. The Downsides is that you are on your own for parts sourcing and distribution.

Having someone else make your product means less profit, but it’s pretty darn turnkey, including distribution, and that is what most of the small, non DIY companies do (at least here in Portland). The downside is that if your modules fail to sell quick enough, you have to buy back your stock and figure out how to sell it elsewhere. That limits the quantity of runs you can make.

Hope that helps, feel free to ask follow-ups.



If anyone can recommend resources/vids/etc for learning KiCad I’m all ears