jbdiver Posted January 14, 2013 Report Share Posted January 14, 2013 (edited) I created a little board to connect my core32 midibox seq4 to an external breakout panel containing an AOUT module. The board is based on a design created by smokestackproductions. I've never created a board before and I'm hoping someone can take a look at it and let me know if there are any omissions or mistakes. I plan to create a second board which will sit behind a eurorack panel and connect the 25-pin connector, AOUT module, eurorack power, and panel jacks. Edited January 14, 2013 by jbdiver Quote Link to comment Share on other sites More sharing options...
TK. Posted January 14, 2013 Report Share Posted January 14, 2013 Looks good so far. Only observation: it makes sense to connect the grounds of J19/J5A/B/C together, so that the circuit is always grounded, independent from the plugs to the core. Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
NorthernLightX Posted January 15, 2013 Report Share Posted January 15, 2013 2 comments: - make the tracks bigger. This way it's easier to home-etch your PCB, and harder to accidentally lift tracks when fiddling while soldering. - Try to keep everything on one layer. A fairly standard trick to use one layer without using wire bridges is to route tracks under resistor bodies. It looks like this could be a completely single sided board with some moving around of tracks in that manner. Quote Link to comment Share on other sites More sharing options...
jbdiver Posted January 16, 2013 Author Report Share Posted January 16, 2013 Okay, I've reconfigured the board so that all the traces are on one layer. I also increased the size of the traces to 20 mil. I don't plan to try etching my own board, but hopefully this design is more DIY friendly if someone else wants to go this route. Quote Link to comment Share on other sites More sharing options...
NorthernLightX Posted January 16, 2013 Report Share Posted January 16, 2013 (edited) Looks better indeed. One last comment: you could eliminate the track on the right side by routing the ground pin of the connector under R9 and R10 to the ground pin of U2. That way the board could be a bit smaller as well. [edit] and another one (minor): you could place C2 closer to the power pins of U2, like you did with C1 and U1. Edited January 16, 2013 by NorthernLightX Quote Link to comment Share on other sites More sharing options...
jbdiver Posted January 16, 2013 Author Report Share Posted January 16, 2013 I made the changes you suggested NorthernLightX. Thank you for your guidance. I fixed a couple little trace issues and tightened up the board layout a little bit so that it is smaller. The current board size is based on the pcbexpress miniboard service (3.8x2.5in), so that's why the board has unused space. I reconfigured the connections to the capacitors. Hopefully those are connected properly. I've wondered about the open connections on U2 pins 11-16. It's not clear to me if those need to be connected to anything. Quote Link to comment Share on other sites More sharing options...
NorthernLightX Posted January 17, 2013 Report Share Posted January 17, 2013 I've wondered about the open connections on U2 pins 11-16. It's not clear to me if those need to be connected to anything. My guess is that it does not matter. The pins of the other IC are connected to the connector through resistors, when there is nothing connected to the connector those pins are technically floating as well. Quote Link to comment Share on other sites More sharing options...
jbdiver Posted February 3, 2013 Author Report Share Posted February 3, 2013 Quick update on this topic. I received the finished boards last week and added the components. Everything seems to check out okay so far. I haven't added the aout module yet, but I've tested the gate functionality. Thanks for the help on this part of the project. I have two extra boards if anyone is interested in one for their midibox seq4. I would just sell them at cost+postage. The next step is to create the connector board for the eurorack module. I've attached two pictures showing the circuit board and the board populated with components. Quote Link to comment Share on other sites More sharing options...
jbdiver Posted February 4, 2013 Author Report Share Posted February 4, 2013 A couple more updates today. I created a little board to take the db25 serial input coming from the midibox seq4 and expose the inputs as headers for easy wiring behind the eurorack panel. This board seems a little trivial, but it will make mounting the aout_ng board to the eurorack panel a little easier. I plan to use the db25 serial interface as a key mounting point to the panel. Hopefully this is strong enough. I also created a eurorack panel design using Front Panel Designer. It's an 8HP panel with the boards mounted on the left-hand side. I plan to use mattson modular jacks. I'll hand solder connectors to all the jacks and plug them into header pins on the serial input board. My only concern is the spacing between the db25 input and the CV5-8 jacks. I created an engraving outline to show the size of the serial cable connector. It's pretty tight, but I think there's enough space to still access those jacks. I appreciate any feedback! Quote Link to comment Share on other sites More sharing options...
jbdiver Posted February 5, 2013 Author Report Share Posted February 5, 2013 I created a cardboard mockup of the eurorack panel to check cable spacing and board placement. I think this 8HP design will work. The cable spacing is tight but certainly workable. This panel won't be skiff friendly because of the way I plan to mount the circuit boards behind the panel. That's not an issue for me. Quote Link to comment Share on other sites More sharing options...
nILS Posted February 6, 2013 Report Share Posted February 6, 2013 Unless you're already committed to the 3.5mm jack's I'd recommend considering banana jacks. I've used 3.5mm ones in my modular at first but they're almost all flimsy pieces of sh*t. The tiny nuts holding them in place tend to not grip tight enough or wear out... Quote Link to comment Share on other sites More sharing options...
orange_hand Posted February 14, 2013 Report Share Posted February 14, 2013 Hi Guys, is it possible to get the PCB definition files in order to be able to reproduce them ? Cheers orange Quote Link to comment Share on other sites More sharing options...
latigid on Posted February 14, 2013 Report Share Posted February 14, 2013 orange_hand, this may also be of interest to you: (would depend on your usecase) Quote Link to comment Share on other sites More sharing options...
jbdiver Posted February 14, 2013 Author Report Share Posted February 14, 2013 Hi Guys, is it possible to get the PCB definition files in order to be able to reproduce them ? Cheers orange Absolutely. Maybe I should see if there is a wiki page or something I can use to post all the documentation and files. I created these boards using PCBExpress which was probably a mistake in terms of portability. I'm happy to share these files. Otherwise, it should be pretty easy to recreate the design using the design tool of your choice.orange_hand, this may also be of interest to you: (would depend on your usecase) That board looks really nice. It's interesting to see a different approach to this solution. I considered building a board to sandwich with the aout_ng, but figured the learning curve and time investment would be too high.I built my second little board yesterday. This board is sort of trivial, but I figured it would make the wiring behind the eurorack panel a little cleaner. The board simply connects the db25 pins to wiring headers in a logical organization. The physical board is a little big because I had to use a standardized size for cost savings. I can always cut off the excess material if necessary. I'm finally in a position to start building some cables to connect power and the aout_ng data connections. Once I test everything (cross fingers) I can order the panel. Quote Link to comment Share on other sites More sharing options...
jbdiver Posted March 16, 2013 Author Report Share Posted March 16, 2013 Okay, this project is finally back on track. I ran into a problem getting the stm32 core board to work consistently with the aout_ng module. I replaced the stm32 board with a new LPC17 core and was able to successfully communicate with the aout module. I also connected the aout module to my two serial boards and 3ft serial cable. Success! I should have no problem communicating with an aout module located behind a eurorack panel. I'll put the finishing touches on the panel design this weekend and place the panel order next week. Quote Link to comment Share on other sites More sharing options...
jbdiver Posted March 31, 2013 Author Report Share Posted March 31, 2013 I've got an Easter update. The AOUT eurorack module is close to completion! I've got to do some tedious soldering and testing over the next week. Switching from the core32 to the LPC17 core delayed the project a bit. The switch forced me to redesign the back panel on my seq4 case and redo most of my ribbon cable connections. I received the new back panel and the eurorack panel this past week. Now I'm starting to cable up the eurorack panel. Hopefully I can wrap this work up in the next two weeks. Here are some pictures so you guys can see my progress. Quote Link to comment Share on other sites More sharing options...
jbdiver Posted March 31, 2013 Author Report Share Posted March 31, 2013 I cabled up the eurorack panel and mounted it in a rack for testing. I've only tested CV1 so far and it's looking good. Quote Link to comment Share on other sites More sharing options...
jbdiver Posted April 1, 2013 Author Report Share Posted April 1, 2013 Done. Seriously. The midibox aout eurorack module works great. My quest to connect the aout_ng module to the midibox has taken me over 2 years to complete. I've learned a ton in the process. Like everything else with these midibox projects, I'm not sure I would have started this project if I knew it would take so long. ;) I want to thank smokestacksproductions for giving me the idea to build the aout_ng module into a eurorack panel. Now that I've done it I can't imagine doing it any other way. I replaced the core of my seq4 with the newer LPC17 core. I also replaced the green 40x2 lcd displays with blue displays from EastRising (www.buy-display.com). The box just looks amazing right now. I hope to produce a demo video over the next couple weeks so you guys can see the eurorack module functioning. Quote Link to comment Share on other sites More sharing options...
jbdiver Posted April 1, 2013 Author Report Share Posted April 1, 2013 One more thing. I had to modify my midibox-aout connection board to work porperly with the LPC17 core. The core32 module uses J5C whereas the LPC17 module uses J28. The pin assignments differ on the two modules. I just cut the incorrect traces on my board and soldered in some wire jumpers. Here's an updated board design showing the proper wiring for the LPC17: Quote Link to comment Share on other sites More sharing options...
latigid on Posted April 2, 2013 Report Share Posted April 2, 2013 Great work and good perseverance! Quote Link to comment Share on other sites More sharing options...
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