I have yet to build a kosmo module that’s particularly cramped. Maybe the triple splashback. Even the 2.5cm modules were pretty wide open as far as soldering goes.
I like this though it’s not what I had in mind for this project, it could be a separate one. I’d give it at least one more knob, a detune CV attenuator. Maybe even fold in the built-in sub osc.
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For sure. I think figuring out the right combo of additional controls/input/output would be fun.
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What about adding a changeable ‘Flavour’ section, if its possible to reduce them to their own board and have the same panel ports.
Something simple In, Out and a Knob or two. Like Sams simple distortion in a cereal box, an extra AD or AR.
It just seems there’s a few ‘parts’ or flavours people want. If its possible… Why not pick n mix =)
Edit - The panel should definitely be ‘Letter box Friendly’ nothing worse than a ‘missed post’ letter in the morning.
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That’s a super rad idea, even if it doesn’t happen on this project haha. Different color daughter boards for different effect or option
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What is the cost of the socket vs the cost of having JLC solder the chip?
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That’s here:
and it’s a very different circuit. Passive, and not resonant.
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The socket is about $1.50 from digikey, so you can probably get it cheaper. Having JLC do it is an unknown, I have never used their SMD service to be frank, we’d have to investigate.
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I reckon if we go QFN then a socket would be the best way forward.
I’d prefer not to tie the project to a specific PCB manufacturer.
I’d like to see gerbers or kicad_pcbs or schematics released so people can get their own boards fabbed if they wanted.
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It would be socketed either way, whether we have it SMD’d by the fab or whether we spec the thru hole part. Nobody would be mounting the SSI VCO chip, becuase (as fredrik points out) it won’t be in the fab’s part library.
Right, from the feedback we have been getting I have mocked up another panel design, this time its an East Coast variant, single oscillator, ADSR, AD, LFO, VCF, VCA and most crucially I have managed to squeeze it into 20cm, although I still think the spacing is a little cramped. I have also tweaked my West Coast panel design to include some improvements to the LFO and Noise I had thought about previously, and include some extra logic on the Function Generators.
East Coast:
West Coast:
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One could consider adding some switches for normal connections. For the East Coast:
VCF in: VCO or noise
VCF CV: LFO or AR
VCA CV: LFO or ADSR
and similarly for the West Coast.
To make room for them, I’m not too sure about the mixer section. For the East Coast especially, there’s not that much within the voice you’d need to mix. You might want to mix inputs from, or outputs to, other modules, but then you probably have mixer modules that can do that. Maybe you’d want a single-knob mixer for VCO and noise. For the West Coast you do have multiple audio sources to mix, but not five of them.
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I envisioned the normal connections on the switched normals of the jack outputs, so they would be normalled unless you plug something in to the destination. This is something I particularly enjoy when using my 0-Coast, so I had never even considered normal’s being routed in an almost Minimoog style with switches like that.
As for the mixers, I personally like mixing multiple waveforms in a single oscillator synth to give extra harmonics, but it is possibly a little redundant in the East Coast design. Dropping it would give extra room on the panel for all kinds of extra goodies, especially since that design doesn’t include a noise source. And the West Coast has a 5 input one simply because those VCO chips have a 5 input mixer built in to them, so in the circuit design we would just break one of them out to knobs and jacks.
[Ramble]
With that big mixer on the West Coast I had envisioned its use to allow you to blend all the inputs bar the Sine out on VCO 2 (which in my mind I would have normalled to the FM in on VCO 1) mixing the FM’d VCO 1 outputs with the more fundamental tones coming from VCO 2 (if you see where I am going with that). Similarly, the user might want to break the sine FM normal with the output of the passive LPG (modulated by something - take your pick, that design has plenty of sources) having routed the sine out to its input to give the FM input CV control that isn’t already on the panel as a dedicated input. Or route the resonant LPG out back into the mixer for some crazy feedback, then process the final output through the passive LPG with one of the functions. Again, that design has some real depth once you start patching it, and I am not sure adding switches for convenience of CV routing would help. Hell, it might even hinder creativity because it would encourage people to just use the built in routing rather than trying crazy crap - which I know means that all the inputs and outputs will need buffering, reverse voltage protection etc but, to my mind at least, this would be worth the effort.
[End Ramble]
I think your right about adding some routing switches to the East Coast though if we drop the mixer, that would certainly make it easier to change the modulation around on the fly, and still leave a little space to squeeze in a noise source (which I was sad to see go when I was trying to get stuff to fit).
With both of them, though, the default routing is up in the air (as this is supposed to be a collaborative effort after all), hence not marking any of them on the panel designs, so suggestions for what to route where would be good from everyone 
Is there a way to do that? From my look at the SSI2130 block diagram I thought three channels were hard wired to the tri, saw, and pulse. All five channels have CV inputs but it looks to me like only two have external signal inputs.
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Ahhhh crap! Your right! I had misread the data sheet. That would need to be a separate set of op amps then.
My original 40cm version had all four outputs plus a ‘blend’ for each VCO and I just assumed I could break out the mixer section. Obviously that had to go when I shrank the module to 30cm
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There is no need to use a linear converter. The design could include a buck converter, which is significantly more efficient than the 7805.
@analogoutput Very nice initiative!
What do people think about adding digital control to the mix? I think that such a complex module would benefit from being able to save and exchange patches. A button matrix to patch things up internally would be a good combination with this. Also, it should be possible to modulate the sound sources completely (e.g. frequency, phase, amplitude for oscillators). An inspiration could be one voice of the Roland JX-10.
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Have you taken a look at the Null-A2 from NLC ?
OK, it’s a full synth in a module, not just a “voice”…
But it’s easy to leave things out…
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Fully surface mount, though.