The more I think about it, the more I think this is the way to go :
the alpha 9mm pots are hard to get, use “standard”, “horizontal” 16mm ones.
5cm wide panels don’t leave much room on the PCB once you have the pots on it and reserved the space for the jacks, in the “parallel” configuration, in “perpendicular” you’ll have much more space (3 to 4 times more space).
debugging is so much easier when you have access to both sides of the PCB.
the pots/PCB solder joints should be strong enough to hold the PCB without problems (if there are enough pots… 2? 3?). Having to add brackets would be a small drawback…
the only real drawback is you need to wire the jacks and switches. And maybe some of the pots if they are not nicely lined up. I can live with that given the other advantages.
While I learned Kicad by designing “parallel” modules (none of them built yet, thanks to the french postal service which returned my jlcpcb package…), I think from now on I’ll go “perpendicular”, with maybe an exception every now and then for simple modules with few components (I don’t want to go SMD…)
So, do we need a spec for max depth of the modules ?
If we go with Sam’s 20cm deep cases (the closest to a spec we have), 15cm deep modules will leave enough space for the busboard, but you’ll need to put a shallow/parallel module in front of the PSU… which isn’t that big a problem. A FrequencyCentral PSU is way smaller than a single 10cm wide module, to give an idea.
I get what you’re saying, but the perpendicular boards and little to no panel wiring is just nice. The 9mm pots may be sold out at a given retailer at a specific time, but I wouldn’t exactly say they’re hard to find.
Let’s rephrase that :
“Hard to find at a reasonable cost+shipping when I need them…”
Yes thonk has them often, but the shipping to anywhere outside the UK is expensive.
Same goes for US suppliers to Europe.
Assuming you mean perpendicular to the jacks and pots, but parallel to the front panel, then I totally agree with you.
5cm wide panels only allow for one Kosmo-size knob wide so they’ll probably be the exception rather than the norm. The only 5cm panel I have is the buffered multiple, it has 10 jacks and two LEDs, and the PCB is far from crowded. If it had pots instead of jacks, there would be even more space on the PCB.
Looking at what 5U manufacturers do (leaving out power modules and blanks)
(1 column of buttons = 5cm, 2 columns = 10cm, more = +10cm) :
MOTM (Synthesis Technology - MOTM Modules) :
(I know there are other 5U manufacturers, Club of the Knobs, Curetronic, Moon, Oakley… if you want to count their modules to improve these statistics…)
You can put a lot in 5cm, with big buttons and big jacks, without crowding the panel…
If you have to go 10cm, that means your circuit is more complicated (in general… I have a filter that’s 20cm…), and the ratio of components vs controls stays more or less the same.
The buffered multiple falls in my “simple modules with few components” category…
The PCBs I designed while learning Kicad include a quad attenuverter with mixer (Kassutronics attenuverter: 4 knobs, 10 jacks) in 5cm in “parallel”…
And no, if it works, I won’t be redesigning it in “perpendicular” because this particular one would have too much wiring to do even for me…
But I am not very happy with the resulting construction. Others may love it…
It’s all a question of compromises.
I’ve been designing front panels for the next several Kosmo modules I want to do and the widths are:
1 x 2.5 cm
6 x 5 cm
2 x 7.5 cm
3 x 10 cm
1 x 20 cm
Only one 2.5 cm, alas, I thought a couple more would be but that requires maybe four jacks and one knob maximum.
To some degree it’s a matter of taste, of course: The Performance Filter’s 20 cm has its defenders, I find it preposterous. (My next filter will be 5 cm, but doesn’t have multiple signal inputs.)
Not necessarily so much more complicated as just having more knobs or jacks, maybe. One of my 10 cm modules will be based on a PCB that’s only 4 cm wide, but it has 9 knobs and 7 jacks.
I’ve done a few modules as 2.5cm. But they’re very simple ones. My avalanche VCO, Simple LFO, Single PT2399 delay, and my original noise drum. But I redid the noisedrum as 5cm so I could add LED’s and CV controls over the delays. My simple dual VCA is also 5cm but only uses 2.5cm for each of the two VCA’s so it’s kind of 2 2.5cm modules just built as one 5cm.
My two widest so far are my MS-20 Filter and the CV outputs from my midibox sequencer. The CV outs had to be 7.5cm wide to fit the 25 pin RS-232 it uses to connect to the sequencer. The Filter I coul dhave fit into 5cm but 7.5 just made for a nicer layout with a bit more room.
The 20cm Kosmo filter is too big for me Though it does have that mixer section as well that helps justify the space a little.
Overall I like 5cm for most…with 2.5 being ok for very simple modules and 7.5 being nice for those that need a bit more space. The only 100’s I’ve done so far are the LMNC modules and I have two of @analogoutput’s on deck to build…but those are also all more complex modules with more jacks and knobs so they need the space.
There’s something fishy here…
Don’t get this as criticism, it’s just my opinion for my synth.
You have your own rationale that may fundamentally differ from mine.
Having done your own modules with PCBs is something I still have to achieve
Congrats for that !
And for proving it is possible to squeeze a lot in a narrow module. Which was, I think, what sparked this discussion.
Exactly, just like parallel vs perpendicular
I love MOTM’s look and feel… Ok I never “feeled” a MOTM synth in real life, sadly.
(I think I have said it already)
It will depend on what modules you have on each side…
MF-A02 is 23mm, that leaves 1mm to the left and the right… if the neighbor modules don’t have a knob at the same height it will be OK.
Just dropping a quick thought here. Kosmo is almost entirely DIY. I think about the only things I’m concerned about as far as spec goes is the height of modules and where the screw holes go. I also happen to prefer multiples of 2.5cm for width of modules. Everything else, like case depth feels out of place for this type of system.
Case depth may not be a “spec”, but still, knowing what most people use, I/you can design the modules so most people can just send the gerbers somewhere and be confident the result will fit their case (or not, but then they know it beforehand).
Anyway, I’m happy I can do that with the published modules.
That leaves more time for my own designs/ports of eurorack modules…
Well, I should have maybe gone with 12 lines and had every other one be a ground to reduce crosstalk. On the other hand, I can just use another jack if it becomes a problem. I have enough of them
Though it does have that mixer section as well that helps justify the space a little.
