Case two

My new synth case was planned in mid spring as a replacement for and expansion upon my temporary Eurorack case, but making it was delayed in the futile hope the pandemic would abate more and sooner than it has. During said pandemic I’ve done a lot of building, so by the time I finally made the case it was close to full. It’s now closer than that; as far as the Kosmo space is concerned, basically it’s gone. So I’ve built another case, and the new case is now the older case. I’ve also made a power supply, bus board, and plans.

The case

I like the angled rows of the older case, but my woodworking tools and abilities aren’t really quite as good as I’d like for such stuff, so I decided this time to make a more plain case with square cuts everywhere. There are two rows, both of Kosmo height and both 30.5″ wide, that being the length of half a Vector rail (they’re nominally 60″ but actually 61″). The wood is select pine. I’d used up the ebony stain I put on the older case and forgot to buy more, so I decided to use the stain I did have which was cherry. I was pleased enough with the result that I went to the trouble of applying a layer of polyurethane finish over that.

For now at least there’s no side-mounted power jack and switch like on the older case. I might add them later.

The power

As for what they’ll switch, I built that too. A Frequency Central FC Power board (minus the +5V components), and an Analog Output bus board. That should handle the first twelve modules.

back to basics

And what will those first twelve, or so, modules be? Some that I’ve built that don’t fit in the older case, and whatever I make next, but what’s that?

About five months ago I started building Kosmo format, and focused mainly on sort of oddball and unusual sorts of modules, because I felt I had enough bread and butter stuff — VCOs, filters, VCAs, envelope generators, and so on — already in my Mother-32 and Eurorack modules. Now, though, the pendulum’s swung the other way: there’s plenty of offbeat stuff here (and more planned), but there needs to be more basic stuff. I kind of feel the new case should be something of a fresh start. Not that I’m leaving the older case behind, but (for no good reason) I’d like the new one to be able to stand on its own as a purely Kosmo synthesizer. So aside from a couple of projects in progress, most of the next several modules are going to be fundamentals.

Of which I have almost none queued up and ready to go. I did just recently buy some PCBs from Barton Musical Circuits including a VCF and an output module, and those qualify. They’ll need panels, though, and probably FR4 ones; any of these basic modules is something I may at some point want more than one of, so might as well get several fabbed rather than hand making each one.

I also have a board and panel for Cory Torpin’s Passive and Buffered Multiples, and that’ll take care of one of the basics. But that brings up another thing. I feel like I want the new case to be more visually unified. So I’m doing an overlay for the multiples panel, aligned with my own panels style.

Those are all the modules I’ve firmly decided upon. The rest, I have to make choices. I might go with LMNC boards and panels — with overlays — for a few. I think mainly they’ll be other peoples’ designs, whether on commercially available PCBs or my own layouts, but there might be a few circuits I design or at least significantly modify.

Very tentatively, subject to change, and in no particular order, I’m thinking of the following:

  • Clock
  • LFO
  • Envelope generator (x2)
  • Noise
  • VCO (x2)
  • Attenuators
  • VCF (Barton Sallen-Key)
  • Fixed filter bank
  • Mixer
  • Multiples (CTorp Passive/Buffered Multiples)
  • VCA (x2)
  • Output (Barton Stereo Output)

And beyond the current projects, I expect I’ll throw more occasional weird or at least specialized, non-standard modules. Certainly I don’t plan on filling this case with bread and butter.

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