Got my first boards back! Ahhhhh! I hope they work!
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It works! Built a quick prototype out of some salvaged components and a 15 volt power supply because that’s all I have available right now, but it works! Yesssss!
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Whats it do? I’m assuming by the name that it combines signals at unity?
Yep, pretty simple, just a mixer without knobs that I can fit in a 2.5cm Kosmo slot. The idea is to combine CV or trigger signals.
For instance, if you’ve got a trigger for a kick drum on 4/4, bum-bum-bum-bum, then you can pepper in some random other triggers to funk it up a bit, but still keep the main rhythm, bum-bum-babum-babum-bum-babum-bum-babum…
This can be further temporally quantized by use of an AND gate. So, send a fast clock and a random source/lfo into an AND gate, then feed the divided clock and the AND output into the unity mixer outputting to the drum. Then you’ll get occasional on-beat extra drum hits.
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thanks for the patching / sound lesson that will come in handy .
Number 3!
FZEQ, a 3-band equalizer and fuzz. I found the schematic on a random polish guitar website and have no idea if it works, but I’m willing to give it a shot. This is 25x100mm, so should make a 2.5cm Kosmo module and be small enough to be made as the super cheap JLCPCB “prototype” boards. The layout is pretty ugly but I got fed up with rerouting, so it is what it is. I don’t think I can make them much denser than this.
I also made a Rev 0.2 of the FWR since I realized I made a big mistake right after I sent it off to the printers…
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No ground plane? Makes it a hell of a lot easier to route, especially on larger boards.
I don’t know how to do that 
I’ll YouTube it
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One more, ATNV4, a quadruple attenuverter.
Not entirely convinced of the circuit though, anybody want to double check?
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I put an attenverter on my little mixer, I based it off of this:
Check the way the inverting/non-inverting inputs are connected - it seems maybe back to front? If in doubt, breadboard!
EDIT: I think the resistor values are important too - the pot should match the values used for the feedback for the maths to work out.
Cheers
Nah, on the + side what matters is the voltage, not the current.
Great blog post, wish I’d seen that earlier. I stole this atv cell from BMC again: http://www.bartonmusicalcircuits.com/atnmix/documentation.pdf but isolated them and didn’t send to a mixer.
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Thanks, I was puzzling over those resistors in the OBA schematic, now I understand!
I’m surprised Sam didn’t include current limiting resistors on the outputs, though.
in all others schem, the signal seems to go to the Inverting input of the opamp, not to the non inverting one like in your schem
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Giggled a little at buttered muffiple 
I’m with you on this one, no need for reverse polarity protection when you provide space for a keyed connector. But maybe put 10R on the supply lines, just in case anything shorts?
Anyway, do you have time to talk about our Lord and saviour ground planes?
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I don’t buy into 10R resistors despite their near ubiquitous use. If you’re using them as fuses, they’re not designed as fuses, they won’t work reliably as fuses, and if they do you have a mess to unsolder and replace before you can get it working. Whereas polyswitch fuses really are designed for the job and will reset once you’ve cycled the power.
As for keyed power headers, I use them, but they aren’t perfect. An incorrectly made cable has been known to defeat one. True, I have and use a cable tester. In fact I can’t recall ever having connected power backwards to a module, nor burned up anything (other than on a breadboard) with a short (I always test for shorts before first power up, and there are polyswitch fuses in my power supplies).
I use diodes, but more out of habit than anything, and because you have to put something in that footprint if it’s not your PCB, and if it is, someone else is going to want that footprint there.
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I will not digress into it in this thread, but I think this discussion is roughly as old as modular synths themselves. Maybe 5 minutes younger.
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