Building my shit in general
Why build my modules?
Well I do it because sometimes a particular module that I want to use does not exist, sometimes it does exist but I am not interested in the particular feature set and sometimes it exists but I cannot afford it, while living amongst a ton of electrical components. I get a whole lot of satisfaction out of finishing an actual working module as well, which may be the main reason. Build something yourself and you get more of an attachment with it.
For you guys I guess the latter two might be the most viable reasons. While eurorack has exploded over the last few years with regards to how many different types of modules exist nowadays, not every single module is easily accessible to everyone due to money or plain limited availability.
SDIY fills a gap that at first doesn’t even seem to be there.
Furthermore I had a talk with a fellow soldermonkey the other day about the importance of understanding what goes on under the hood. Surely knowing what goes on inside your modules helps you understand why some patches work out great and others simply won’t at all.
From building modules I have learned pretty much everything I know about electronics right now (which isn’t incredibly much but it got me thus far…) and it might teach you a thing or two, if only by seeing how others solve problems you may have been (successfully) struggling with.
Why SMT? Isn’t hand-soldering SMT hard to do?
I tend to use a lot of SMT because of wiring. I hate wiring and I don’t want anything to do with it.
By using SMT you greatly reduce the space on the PCB necessary to place your components, allowing you to place your potentiometers and 3.5mm jack connectors on it as well. Because SMT is generally a single sided affair, you can even solder components where on the other side of the board is a pot or a switch or what have you. That really saves real estate and makes for compact and shallow modules fit for use in a skiff, which is something that I also prefer.
Soldering SMT seems hard at first because the parts are so tiny. This is a silly turnoff however because if you have steady hands, it is not hard at all and it is even a somewhat faster method of soldering. There is no snipping of legs on the backside of the board, which is messy anyway.
IMHO even desoldering is easier with SMT. Just heat up your component for a little while, and you can just shove it off.
You quickly get used to the size of the components. I stick to 0805 anyway, which isn’t that ridiculously small.
Note that the electrolytic capacitors in my builds are through hole, because hand-soldering these in SMT really is too much of a hassle.
I learned how to hand solder SMT from youtube and so can you. Don’t try to invent new techniques yourself!
Generally my projects consist of a PCB to solder the circuit on and a faceplate. These are held together by PCB mounted 3.5mm phono connectors and potentiometers. The height of these phono connectors (I use Kobiconn 16pj138) and potentiometers (mostly Alpha 9mm PCB mount types) isn’t exactly the same, which may result in a board being mounted in a slight angle with regards to the faceplate. This doesn’t matter at all.
The best way to go about mounting the components that hold the faceplate to the board is by placing them on the PCB (DO NOT SOLDER YET), putting the faceplate on (might be a tedious job for some builds, but you’ll manage with some patience), use a rubber band to hold the whole contraption together, screw on the nuts for the pots and jacks and only then you start soldering.
The good thing about doing it this way is that there is no physical stress on your soldered connections. The bad thing may be that you don’t like the look of jacks not fully touching the PCB or the board being at an angle with the faceplate. Once the module is in you cabinet however these worries are quickly forgotten.
A module may consist of several PCBs which are connected by headers. This asks for pretty much the same procedure, ie not solder on all headers first, but try and install the whole construction first, then solder.
For ease of work, on the Spaeterneisa and Quad Patternizer soldering on the male headers to the Brainboard first is still a good idea. Just do it neatly so they don’t all point in an other direction…
I designed these modules to work within the eurorack system (size, connectors, power) and the shrouded headers are correct. Of the 10 pads that you stick the metal pins of the header in, there is one that is square and 9 that are round. The square one (plus the one adjacent to it) take -12V. These aren’t connected on every module, in fact only the drum clones use +12V and -12V. The other modules only use +12V.
Building these projects in another modular system format may be challenging, as the mechanical construction highly depends on the mini jacks and not all the boards have mounting holes. I am contemplating producing frontpanelcomponent-PCBs for other systems though.
There is no reason these circuits shouldn’t work on +/-15V, although a re-jiggling of component values may be needed here and there.