I was trying to finish a module, since the last missing piece (an AS3360 - so just put it on and run the thing, i thought) is arriving soon.
I soldered two trimpots, put on switches and potentiometers, took the panel (hand labelled today) and…ran into the same problem i had way too often:
The switches are too high, or the threads on the pots i have, aren’t high enough.
Usually you’re supposted to just drop them onto the pcb, fix them to the panel, solder, done.
But no, i constantly run into the problem, that it just won’t work like that.
So i have some very important questions as i’ am slowly filling my cart on tayda:
Which switches do/did you use for Kosmo Modules? Which height do they have? Or do the vertical pots they have there just fit with them?
It should. Maybe not if you’re using some strange pots or switches, but the ones usually specified in BOMs should work.
Take a look at the datasheets. For instance, for Alpha 16 mm pots (e.g. these):
From the panel to the place where the legs narrow enough to go through the PCB holes is 10.7 mm. The rest of the leg is 5 mm. So if the PCB is 1.6 mm thick, the space between the PCB and the panel can be from 10.7 mm to 10.7+5-1.6 = 14.1 mm. The pot won’t sit flush on the PCB but that’s OK if it’s secured to the panel and the legs poke through the PCB. And that isn’t a hard maximum because you can put a washer or nut behind the panel.
For Dailywell SPDT 1M Series toggle switches like these:
Minimum about 9 mm and maximum about 11.5, but here again you can increase the maximum spacing with washers or nuts — the bushing is 9 mm long so you can add several mm to the height easily.
(Warning, 3PDT switches are higher.)
So a mix of both pot types and that switch will work, with a separation between PCB and panel of about 11 to 12 mm.
As shown above, the Dailywell 1M Series miniature toggle switches are lower than either of the potentiometers. You can find similar switches under other brand names with similar dimensions (but again, check the datasheet if one is available… and if one isn’t, maybe look for another vendor).
I have run into this problem as well. What I did to remedy it was:
1: try to find pots / switches that have the same height as the jacks: this is very difficult / I did not find any which I found worth their price
2: design the pcb so that it has a hole where the switch is meant to be, then instead of soldering the switch to the pcb fasten it to the frontpanel only, stick it through the hole and connect it with some wires to the pcb (blue arrow, for the slim switch). In this way only the pots and jacks determine the distance between the pcb and the frontpanel
3: put a small separator block of some material under the pots. I 3D print a small block of 3 mm thickness that fits beneath the pot between the pot and the pcb (red arrow), this making the pots axis stick out some more. Obviously you need to make sure the pins can reach the pcb. The 3 mm extra makes that the pots are almost level with the top of the jack connectors. B.t.w. I’m using 3.5 mm jack connectors as I’m making euro rack style modules.
Adding this separator block is only necessary for the black pots (see picture) because of their short axis. I want to put a cap on them and for this I need a minimal length of the pot’s axis to stick through the front panel. The black pots I’m using are not threaded because they actually are trim pots. But so far they work well.
Note that the green pot is almost level with the top of the jacks (which is difficult to see in the pic below), so those can be soldered to the pcb.
In my take on the MS20 filter I used the described solutions:
I am designing a semi-modular and am trying to decide on a lot of different choices; pot, switch and knob types, socket sizes, general form factor, and control spacing.
Component specs are an obvious starting point but I find it helpful to double-check stated dimensions against the real thing. A panel/ pcb layout doesn’t tell me how a panel feels, or whether the control spacing is comfortable or even useable.
I am trying to normalise component spacings on a 0.1" matrix where possible, to make panel layout easier and possibly use stripboard for one-offs.
I find that mocking up a control PCB is the best way to decide whether a panel layout is actually useable. CAD layouts don’t give you the ‘feel’.
First thing that comes to my mind is, that i have rather big hands.
I actually never used eurorack. And even as i’m intending to, because there are some modules that i’d love to have, i’m not too comfortable with the idea. While being a fan of space saving solutions (playing anno and thinking of ways to use the given room properly or cramming as much usable stuff in a sims house always pleased me) and it’s cool to have as much possibilities as… possible, it’s just not easy to overlook things.
And, if i may use your picture as an example, one problem i see when i think of modules are jack cables. More often than not i think “scratching the neighboring plug again, don’t ‘press/bend’ it, don’t put too much stress on it”.
I don’t know, maybe it’s only in my mind, but stuff like that always bugs me.
Sorry for the late reply. Just wanted to say: a huge “thank you!”. That will really help me out. There’s just a little too much variety, so i’m glad it’s a bit easier now to understand which ones would be better.
Here are the Switches i used. I only used the blue until now, so the reds might be better.
I put one of the pots i used into the picture, so that people who may read this, don’t make the same mistake i made.
Look into the measurements and don’t go for saving every little cent/penny/etc.
I use an extra hex nut on all pots behind the panel. Aligns the switches better. In terms of a standoff when required 11mm is my friend. I use 10.5mm LED standoffs. Extra Nut on a switch that is short. This also takes up any discrepancies with Board to Board connector gaps in regards to 1/4" vertical jacks
I have just used sub-miniature toggle switches from Thonk, and they:
(A) match the height of Alpha pots and Thonkiconn jacks, and
(B) have pins that fit through normal perfboard, and are 1/10" pitch
