Button wiring is different than v5. New webconfig kit (e.g. Mini v3) need to be developed so that users do not tediously do configuration from scratch through webconfig. Current v5 layout will not work anymore.
Also LCSC part ids need to be added to the schematics so that BoM exported from Kicad is enough for manufacturers to order parts. Probably footprints should be replaced with LCSC easyeda one.
Finally if we are going with smd version of mini we need to add some other value to the whole pcb because it is going to be more expensive to produce it and adding smd components are not going to increase cost further. For example, we should add audio in and audio out so that there is no need for these additional boards. I am investigating at the moment should we simple reuse v5 audio/out/in/headphone schematics or do something simpler with pcm5102 and pcm1808. That investigation is still in progress.
IMO there is no point of publishing current design without doing this additional work.
I manually add the LCSC to my kicad components then use a plugin to create the required files that can simple be uploaded to JLCPCB. Itâs pretty good. Iâm not at home to check the plugin name.
I look for components that avoid the additional costs of fabrication. I tend to do a search for the component, sort by available quantity then look for any with the lower cost installation. I go for the components with high availability to reduce the risk of challenges sourcing obscure components.
With regards to Eurorack version, please remember that eurorack levels are not the same as line levels, meaning both inputs and outputs may need adjustments depending on what you are connecting to:-
I expect the quick fix is to use something like this :-
With regards to eurorack power⊠while there is a standard for the pin outs, as @riban demonstrates, there is a lot more variance in the actual power supplies. Many popular eurorack PSUâs can only support up to 1000mA of work at +/-12V. Also, they often donât provide a 5v feed directly, but rather through a 12v-5v converter. As such, I think it is still important to âofferâ a front panel usb power option, to avoid saggy oscillators on the eurorack side, and issues on the Pi itself.
Also, most midi compatible eurorack use 3.5mm TRS connectors. I would suggest a dipswitch or a jumper on the board to configure which way around (a/b) is used.
More than happy to work with you to find a solution to all these and run tests if required⊠PM me if you need to.
Agreed. I have almost finished design for it. I will share it for review here this evening or tomorrow for final review before I order the first batch for testing.
@le51 and I would appreciate others to join us in testing dac+adc prototype and developing driver for it. I am happy to send first prototypes for free to people that really can help us.
Some more feedback, after looking at these eurorack imagesâŠ
Please do not design TO 162.3mm wide⊠design to fit IN 162.3mm wide⊠i think 161mm is still tight⊠i will do some research but my best guess figure would be 160mm on the panel. I would probably say you want to take another 10mm off the pcb board too. Remember⊠we want to insert these devices into 32hp holes though.
Also, please expand the eurorack screw holes horizontally. so they are sized the same as 2 of the holes next to each other but with a flat top and bottom. just adds a little left/right play.
each strip could be totaly independant: with its own clock, 2X4 header pins for Digital in and out, MCLK (comming from strip 0/or internal see below), BCK, LRCK, 5V, 3.3V, GND . So a complete board could be sliced to get single 4 codecs => for testing purpose
they are solder jumpers on bottom for each ICâs configuration: master/slave, sample rate and to choose clock source between MCLK0 (<=> first strip = codec 0) or use stripâs own clock,. On top side, with pin headers jumpers, you can choose to power or not each IC (this makes sense on a completre board regarding @stojos question above)
It still a WIP right now, but Iâm quiet decided to achieve that and have it to work.
32hp = 32x5.08mm = 162.56mm. Doepher docs suggest to only take out 0.3 mm from it. Hence my width of 162.25mm. One of screenshot shows 162.3 but this was changed.
Good idea for expanding screws horizontally. I will do that.
I can only reduce width of pcb board for another 4.25 mm (around 2mm from each side).
pcm1808 need +5V and +3.3V for its operation. Here the 10uF caps for power pins (and others) are all ceramic but X7R rated.
Also, they are 47 ohm resistors in serie on all digital lines (they are not present on pcm5102 EVM)
Aluminium electrolytic capacitors (my above design needs 4 different refs) are all extended parts at JLCPCB, and unfortunately the (at least the 10uF) X7R ceramic caps too
For codec development (we do not need yet high quality audio), Iâm considering
droping ALL these 10uF around both ICs and put big through holes capacitors close to the Pi header to filter the +3.3V and +5V provided by the Pi.
using basic ceramic caps instead of electrolytic
Any opinion and suggestion on this statement is welcome.
Are these resistors on digital lines really needed ? (I guess no, but Iâve read elsewhere that itâs a good practice) Can just a single set of resistors be enough for all the 8 audio ICs, or they must be placed around each IC ?
Hey this is exactly what Iâm, in fact, was doing !
I will put not populated footprints for big electrilytics c apacitors close to the ou header as well.
Actually, would it be possible to have four of each for eight inputs and eight outputs? (or 4 stereo inputs & outputs). Doesnât the Pi5 have four bidirectional stereo I2S ports?
