Breakout Module / Box for external Gear - Thingie

[JanJuno]

Hey,

so i took some time and took the advice giving me in this post (My Bus/Buffered/Send Thingie where i need help) to think things over. Now i have split my idea into two seperate projects. This one dicusses the first one. I want to create a breakout module for my external gear. So there will be no logic within this module since it is just an extension for external connections.

The Idea is to have a breakout module which contains the main connections i want to have for my external gear. The devices are the following:

• Mackie Mix 8
• Prophet Rev 2
• Behringer RD8
• Octatrack
• Torso T-1
• Mod Dwarf
• McMillen QuNexus

You might ask now how do i get those connections into my eurorack?

So the Idea is to build a wooden box with an Eurorack 3u Frame, Power Supply and “external inputs”. You will see a schemativ below. I will need 3 pcbs, 1 for the Module itself and two which are used on the box for the external connections. All of the three modules will have a frontplate as well. The connections within the box, which connects the 2 PCBs with the breakout module are standard ribbon cables which you might know for the power supply for eurorack modules but as 4 x 40 and 2 x 10.

I thought it might be a good starting point to dive into the whole pcb, schematic, sourcing game when i start with something simple, like you guys mentioned it. So now i have created the first draft of my eurorack breakout module. Below you will find screenshots of the schematic, PCB and 3D Model.

So now i got several Question you guys might help, if neccassary i will post files regarding the schematics i created in EasyEDA. Now to the questions:

1. Did i make the connections for balanced/unbalanced connections correct? Do i miss something?

2. I also need one USB Connection to my Torso T-1. I hope i choosed the correct part for it? Is there anything to know? I find a lot of USB parts so i just choosed one.

3. Regarding the PCB, which is my first ever created, i got scared because i need 63 Thonkicons (Mono/Stereo) + 1 USB connections within an 20HP Module. So the thonks are really close to each other. On the other side i got scared since i need 4 x 40 Pin Conncetors and 3 x 10 Connectors on the backside of the module. What do you think?
   There is a lot of going on, see here:

4. I also got scared of the thonks on the edges of the PCB.

5. I also think that might be the worst placement of those connectors but i wanted to avoid a two PCB layered module. Therefore i placed those 40 pin connectors on the back i hope that it not come in conflict with the thonkicons.

6. Because i am lazy as hell i used the autoroute function in EasyEDA i used 12 mil for lines and spacing, for vias i used 40 mil for pads an 18mil for holes. I optimized the placement of the thonkicons besides the 40 pin connectors good as possible, i was able to achive a 100% autoroute connection. Any experience on that?

7. I also got scared regarding the USB Connection. Any Experience on that?

Any help would much appreaciated since i am a noob and just start loving creating PCB schematics and develop ideas. Thx

[JanJuno]

I think you guys are scared of the size of this post? But the help that i need is really simple questions i think in terms of noobness. This is my first pcb and i have no knowledge in creating them. I try to avoid pitfalls.

Help is much appreciated. I also will keep you informed on the progress i want to share.

[Bpbby]

I think it might be a bit much indeed. If you want to break it down into smaller bits that might help people to take the time to answer.
(I have no experience in designing PCB, it sort of removes the DIY side of it for me.)
Anyway, good luck.

[franktropez]

First; two things. Or, two things firstly; this is my first post here and although it feels a bit too grandiose to say “hello everyone!” I want to signal that it is and my awareness of that being the case. Secondly; never mind the second thing.

I’m going to try to respond to each point/question as you posted them. To be clear I’m just an amateur with way less experience and/or knowledge than most but I think I can relate to your approach here and hope you might find something of value in my post. But; take with grain of salt.

I’m going to try to address your questions as you posted them;

1. Balanced connections correct?
   As far as I can tell it’s correct in that you seem to have assigned 3 lines on each ribbon connector for the balanced connections so as long as you have tip going to tip, ring to ring and sleeve to sleeve you’re good. I take the “have I missed anything” part of your question as an invitation for some unsolicited mental meanderings;

Do you really need to have balanced connections here? Have you considered the practical implications of requiring balanced/trs minijack cables for patching and also the fact that most eurorack modules have unbalanced ins and outs?

2. USB connector
   It is impossible to tell if it’s the correct part by looking at the schematic symbol. I haven’t used EasyEDA but am familiar with KiCad and assume that there is a similar separation between schematic design and pcb design. In that first you design the schematic with the symbols of your choosing, when that’s finished you assign parts to those symbols. To find the correct usb connector part you need to either accept trial and error or figure out the dimensions that will most suit your design and then find the correct part by googling furiously and checking datasheets. I guess what might help narrow down your searches is that you’re looking for a connector that will line up with thonkiconns so any pre-existing module or device that has thonkiconns and a usb connector sharing the same panel that has a DIY build guide or bom or whatever available should set you in the right direction.

3. 63 Thonkiconns
   I think having that many connectors within only 20hp will make for a very non-ergonomical patch panel that might be downright frustrating to use. Besides the physical handling it will leave very little space for labeling and when in use you might find the labels obscured by cables. This might not be an issue for you as some people are way more comfortable with tightly packed patch/control panels than others and you could always work around the labeling thing by having some sort of printed legend/map of the panel handy but mentioning this anyway because these things are easily overlooked when making your first (or from my own experience way beyond first…) design.

4. Thonkiconns on edge
   Yeah, could be problematic. Mostly depends on how much space you have left between the edges of the pcb and the mounting rails. I think most (maybe all? no idea) PCB manufacturers will at least check the viability of your design in terms of drilling. IE they probably will ask you to confirm that the pcb should have a bunch of plated througholes that are basically ratbites because they are so closely situated to the edge.

5. Connector placement
   Shouldn’t be a problem as long as you solder the ribbon connectors before soldering on the thonkiconns… I think. In my experience however hope is generally useless in pcb layout.

No experience but it looks like there’s a bunch of unrouted thonkiconn pins but it’s really hard to tell for me.

See earlier comments.

Again; this is just my take and its only possible value might come from having made many mistakes and sort of remembering some of them.

A couple of additional afterthoughts on the side;

I see there’s also pins labelled “midi $1 etc” on your schematic, how will these physically manifest? Asking because DIN midi takes more than 1 pin and there are (at least) two standards for minijack MIDI.

Do you have any components handy already? I’d at least order some thonkiconns some pcb headers/boxed headers and maybe try to find some usb connectors and lay some things out on cardboard (serving as a faux frontpanel) to get an idea of what works for you in terms of spacing/layour etc.

But mostly I’d try to break this project into even smaller bits than you already have and start by making one breakout panel for one or maybe two external piece(s) of equipment. IMHO even though this is as you say a “simple” project which might be conceptually very simple in practice there’s so much to consider, as you’re finding out, and even a seasoned designer/engineer/etc would probably go through a couple of prototypes/iterations of this project before coming to a somewhat final version. Besides the somewhat banal physical hurdles to take there’s all the practical use implications and such that tend to only reveal themselves when a design is actually being used and you go “oh snap, this should’ve gone there and I don’t need this and 10 more of that.” which in my experience is slightly less overwhelming to deal with if you go at it bit by bit. Again, hope this was at least of some use.

[analogoutput]

@JanJuno

i need 63 Thonkicons (Mono/Stereo) + 1 USB connections within an 20HP Module

At this point ask yourself honestly (if you haven’t already) why it needs to be 20 HP. (And, I suppose, why it needs to be 63 jacks.)

Maybe you have a 20 HP hole in your case and that’s that; fine. But if there’s any way to go bigger, ask yourself why not.

It’s a thing I find puzzling about the Eurorack community, this “cult of slenderness” where making a module narrower is always regarded as better, no matter at what cost, and where the first thing anyone wants to know or say about a module is what its width is. There is something to be said for putting maximal functionality into as small a package as possible, but there are things to be said against it too, and obsessing about it the way so many do is unhealthy. To my mind if one can’t just reach out and grab a knob and turn it without bumping into other knobs, or unplug a cable without having to unplug all the ones around it too (or pulling on the cord rather than the plug: Bad idea!), then the design has serious usability problems. I recommend reading about the first 1/3 of this (after that it sort of goes off the rails): Reality check: HP - North Coast Synthesis Ltd.

Anyway, if at all possible, I would suggest you put significantly more space between your jacks, and if that means a 30 HP or even wider panel, do it. I’m guessing the connections to these jacks won’t be changing often, so some crowding may be okay, but don’t squeeze for the sake of squeezing.

[JanJuno]

Hey franktropez,

firstup, thank you for your feedback and welcome. I will dive into your post way more deeper and try to update if needed on this thread. Thans for your time.

Below some feedback/explainations.

Do you really need to have balanced connections here? Have you considered the practical implications of requiring balanced/trs minijack cables for patching and also the fact that most eurorack modules have unbalanced ins and outs?

Those Balanced outs are used for midi connections into my euroreck and get verything in sync. But i will also have balanced audio outs of my gear. So therefore i will use it like now, this should be no problem, i guess?

I see there’s also pins labelled “midi $1 etc” on your schematic, how will these physically manifest? Asking because DIN midi takes more than 1 pin and there are (at least) two standards for minijack MIDI.

I hope i understand you point here. In general the input will be the other 2 1U Modules that are contain a DIN in for midi i will do the conversion to midijack out on the board. For Type A/B problem i got adapters. In an earlier version i got switches, but ineeded jacks

Do you have any components handy already? I’d at least order some thonkiconns some pcb headers/boxed headers and maybe try to find some usb connectors and lay some things out on cardboard (serving as a faux frontpanel) to get an idea of what works for you in terms of spacing/layour etc.

This would be one of the next step. For now i try get the schamatics and pcb close to done. So therefore feedback is important. Thanks again.

But mostly I’d try to break this project into even smaller bits than you already have and start by making one breakout panel for one or maybe two external piece(s) of equipment.

In an early concept i did single breakout modules fo each external instrument but it needed way to much space.

IMHO even though this is as you say a “simple” project which might be conceptually very simple in practice there’s so much to consider, as you’re finding out, and even a seasoned designer/engineer/etc would probably go through a couple of prototypes/iterations of this project before coming to a somewhat final version. Besides the somewhat banal physical hurdles to take there’s all the practical use implications and such that tend to only reveal themselves when a design is actually being used and you go “oh snap, this should’ve gone there and I don’t need this and 10 more of that.” which in my experience is slightly less overwhelming to deal with if you go at it bit by bit. Again, hope this was at least of some use.

I get your point here. As an packaging engineer i might know here and there issuess in terms of construction that might happen, but this is my first electronical project. So i saw it more of like: hey is just a bunch of thonkiconns on an easy pcb, whats the issuee?

But now i am there asking for help For now i am still in for it. Where is the fun in not doing it. The least that can happen is i will order another pcb learning from the mistakes i did.

Regarding the usabilitiy of the module. The main thing is i got all connections inside my eurorack. A lot of cable messyness will be gone. When i visit one of my buddie in the basement it will be easy set up. Also it will be in parts hard patched so it won’t change much.

[JanJuno]

At this point ask yourself honestly (if you haven’t already) why it needs to be 20 HP. (And, I suppose, why it needs to be 63 jacks.)

I got greedy.

Maybe you have a 20 HP hole in your case and that’s that; fine. But if there’s any way to go bigger, ask yourself why not.

It will be a 126 hp frame some of my important modules will be placed in that row. Also 2 x 10hp modules will be planed for that row i will create after this project.

It’s a thing I find puzzling about the Eurorack community, this “cult of slenderness” where making a module narrower is always regarded as better, no matter at what cost, and where the first thing anyone wants to know or say about a module is what its width is.

You are right, i own several wide modules, all of the moog, the recent taiga, deckards voice and so on.

There is something to be said for putting maximal functionality into as small a package as possible, but there are things to be said against it too, and obsessing about it the way so many do is unhealthy. To my mind if one can’t just reach out and grab a knob and turn it without bumping into other knobs, or unplug a cable without having to unplug all the ones around it too (or pulling on the cord rather than the plug: Bad idea!), then the design has serious usability problems. I recommend reading about the first 1/3 of this (after that it sort of goes off the rails): Reality check: HP - North Coast Synthesis Ltd.

I own wide modules, thats one of my problems So there isn’t much space. So in this project i create a utility module for my external instruments with less space as possible.

Anyway, if at all possible, I would suggest you put significantly more space between your jacks, and if that means a 30 HP or even wider panel, do it. I’m guessing the connections to these jacks won’t be changing often, so some crowding may be okay, but don’t squeeze for the sake of squeezing.

I will consider it, but i will also squeeze. Thx analogoutput