Having spent extensive time on open source projects, the trick here is to keep the goal very focused or it won’t move quickly. Creating a voice is pretty abstract so perhaps some parameters to narrow the focus could help or we will all be envisioning very different things.
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kinda why I suggest a list , the top 3 or 4 things with most votes is the focus .
Do we want this to be educational for a newcomer to the synth DIY world or just a cheap way to have a voice?
If it’s the former than I’d shy away from using complete VCO or Filter ICs, they’re kind of black box and you probably won’t learn as much from them as having everything broken out separately.
If we’re trying to keep component count and cost down, then have at the single IC solutions. But if we’re going to go down the QFN route that’s making it a little more difficult for DIYers, and we may as well allow monolithic matched pairs in surface mount packages in a discrete VCO build.
Swings and round-abouts really.
Cheers
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From what I gathered from @analogoutput’s first post, we are after a single module (so one panel) housing all the necessary ingredients in order to design a sound that can then be played via CV. So that means a sound source, a shaper of some description, and modulation sources in a single unit. As small as resonably possible, whilst keeping in mind the design considerations set out in the Kosmo standard - so a playable user interface and big jacks and knobs.
Personally, my thoughts immediately jumped to a well rounded ‘starter’ module, that doesn’t have much in common sonically with what we currently have available but builds on what do have and something I have been brewing myself in isolation - a west coast style voice complete with a complex FM oscillator, the basic modulation sources required to produce west coast sounds (LFO/Noise/AD Function Generators) and a Resonant Low Pass Gate. I didn’t have it as ‘educational’ in the sense of learning circuit design, but rather experemental in terms of usage and learning to patch creatively. The kind of thing that could be put together by a novice, from easilly sourced parts, which gives a lot of rewards when it comes to cross patching it with itself and wouldn’t be instantly replaced when the system was upgraded to include other modules. Similarly it would be something that we as current Kosmo users/builders would actually want in our systems by its very nature of being radically different from the voice architecture we usually get from Sam’s ‘official’ modules.
Also @jaradical those QFN chips we have been talking about can be mounted using through hole sockets, so it’s no different to soldering a DIP socket, it’s the SOIC ones we would need to avoid to prevent scaring folks off 
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sounds like a good basic idea .
Fair. I suppose I found most of the proposals well within reach of what already is available currently as PCBs/panels (outside of maybe a function generator and noise noise source). To me, the proposals seem like multiple modules on one panel which doesn’t sit well with me. However, my opinion shouldn’t stop you if that’s the end goal.
Similarly it would be something that we as current Kosmo users/builders would actually want in our systems by its very nature of being radically different from the voice architecture we usually get from Sam’s ‘official’ modules.
I’m not sure how much of the above differs just yet. The biggest deviation is the function generator which I would absolutely LOVE as a stand-alone so I can sell Maths. As for the FM, I found Sam’s oscillator modules already are an FM playground with FM, sync, and cv inputs.
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LOL so basic or unique . dam I like ease of build to be all inclusive of everyone but why build something that isn’t different from everything else out there ?
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Would it be possible to add a second ADSR for filter envelopes? I get that it’s supposed to be a ‘basic voice’ but 2 ADSRs provides a lot more flexibility for different sounds. Just my 2 cents/pence
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Add a keyboard and you have the first Kosmo all-in-one monosynth.
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distortion , wave shaping , sub osc. spice up the " basic " a bit .
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Think of it kind of like a drum module that consists of a noise source, an oscillator, an envelope generator, and a VCA all in one module. It’s not intended as a substitute for separate modules, and it’s not intended to have the full functionality of separate modules. But it is a relatively compact and inexpensive combination that serves certain purposes well and frees up your noise source, oscillator, EG, and VCA modules for other things.
That’s how I think of a voice module.
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The oscillator section is fairly similar to a 3340 in terms of basic functionality, in order to keep it novice build friendly and still have a clean 1v/Oct response. However, the SSI2130 chips I have been advocating are thru-zero FM, which can make some wild sounds that Sam’s performance VCO’s just can’t.
And there is nothing to say that a Math’s clone couldn’t be produced from the basic function generators I am proposing, but you’d need to do a whole lot of extra work in order to get the logic functions out of it. I believe @CTorp is working on a port of the DUSG which is probably what you are more after - I mean, I sure as hell will be buying one, lol. Still, why would you sell your maths?? Buy another one!
The biggest difference is probably actually the LPG (we do have basic AD functions kicking about in both LMNC stripboard form, and from CTorp with his stripboard inspired EG’s), we don’t have any modules that produce that kind of sound at the moment.
My vision of a voice module is what I wanted about 6-7 years ago now when I first started in Eurorack, shortly before the introduction of the 0-Coast and Mother-32. Something I can build in a single shot, then put other stuff with later. My ‘West Coast’ leanings come from my first experience on a modular being an old Buchla at Uni and then buying lots of Make Noise stuff when I got into Euro, and I am just saddened by the fact that we haven’t got much like it in Kosmo. Again, I am seeing this from a different perspective to @analogoutput, as I look at it as a jumping on point for someone who doesn’t know if Synth DIY is going to be fun for them, but wants to make something that would be useful on its own, and is still useful to everyone else.
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Got it. Hmm. Perhaps some inspiration from the Ctorp 25 series or the pico system could help here to reduce the size and get the module down to 15cm (or 10?). The 25 series pack eight modules into 20cm which is all sorts of goodness in a tight space.
I would include:
- 1-2 oscillators
- 1-2 LFOs
- 1 EG (ADSR or just AR)
- 1 filter
Nice to have:
- Noise source
- Sub osc (fore extra beef)
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Nice idea! Sounds a bit what I’m trying to do with my Polykit project but as a single voice/module. I tried to only use standard components that are broadly available. It’s generally cheaper but usually needs more space on the PCB and is slightly more complicated. In my experience these specialized ICs are often hard to get.
I also have the VCA/ADSR in place, maybe a good starting point for this project: GitHub - polykit/vca-adsr: VCA and ADSR schematics and PCB layout
I have a thread over here where I was cloning a single channel from a Bucla 292c with a resonance mod and offset CV attenuversion, with the aim of producing it as a Kosmo format PCB, and it works a treat, but still fiddling with the resonance circuit to get it to scream the way I know it can (it has been done before in many different formats). This is the circuit I was proposing in the voice I described.
The end result would be similar to the old MN QMMG when chaining four of them in that project
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probably not less than 15cm , still need the Kosmo play ability . saying that looking at my racks going were the hell am I going to put this thing ? . like your list by the way and like the idea of the sub osc.
Yeah, I’m definitely not the target market for this. It won’t fit in my current setup and I’ll have to wait to hear it before I make the call to put it in a future case.
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I wouldn’t make it too small. It’s easier to layout and to build for beginners. Also actual component board is smaller than the panel.
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going to trade off one of my MFOS filled cases to my friend in exchange for helping me get everything working . soon hopefully dam covid .
so I will have space for new empty case .
which of course won’t stay empty to long , already enough stuff to half fill it .
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