Alright, here goes nothing. This is mostly for posterity. I also like to hear myself talk.
This is my first-ever, self-designed Eurorack case. I bought an Erica Pico III in November of 2019 and challenged myself to build my own "Pico System"-like case to work with it, since, although I loved it, it was missing some of the functionality I wanted it to have after jamming with it for a few weeks. I knew I wanted to keep it to just Erica modules, and I was interested in having at least one Black series module in there just so it wasn't exactly like the Pico II with switched modules. I also didn't wanna deal with drum programming cuz it seemed like a hassle. More on that later (with maybe a little irony if you enjoy that kinda thing).
This case has evolved a lot since I first conceptualized it, but it has done so through hours and hours of jamming (solo and with a good buddy of mine) and patching. Eventually, I purchased a 6U 84HP skiff from Erica which most/all of these modules will move in to once I'm done, but I have that in mind when choosing how to build this thing.
The first few modules I chose and purchased were the Black Modulator and the A Logic. The PSIII has a lot of good sounds, but it's lacking modulation sources. At the time I had no idea how to utilize the EGs or the LPGs well (and I'm still getting used to those concepts, by the way). Between the BM and the AL, I was thinking it would add 11 (net 9 since two inputs into the AL are required, and those had to come from somewhere) new outputs into the combined system, which is a lot more ways to, well, modulate stuff. I got the BM on sale, but I didn't realize that the "clock in" only affects the S&H output, which was a weird design choice... makes sense that there's a V2 of this module now, which has a "clock in" that affects all of the outputs. Anyway, I still like it, and the price was definitely right ($50 off regular price for the win), but not sure it'll make the cut into my new 6U.
The A Logic is a fantastic module and I'm very happy I chose it. I have had a lot of fun feeding it tons of different stuff, and trying different outputs to modulate the same thing somewhere else has led to a lot of happy accidents in patching ("I wonder what the minimum voltage curve of a distorted pulse wave and a mellow triangle wave would sound like when used as a CV for envelope decay...?"). That said, I still wanted more (Eurorack understatement of the century, perhaps). And the voices on the PSIII are a little rudimentary (though very harsh and intense if you want them to be, plus the "Mod" module, which is essentially the Pico RND, has a Noise and S&H output so there are actually a lot of good choices especially if you have stack-cables available). So, I opted to get perhaps a bit more musical and dip into the Pico Voice and Pico Seq. I also grabbed the Pico Scale on sale and ended up grabbing a Pico Trigger as well (hint: it's not just good for drums).
The Voice and Seq took me a little while to wrap my head around... after all, they both have multicolor LEDs (the Seq has TWO, which reveal a ton of amazing options, all of which are superbly performance-friendly) and lots of hidden options. However, this is also where things started to come together really well. After getting the hang of the basic controls, I started patching unusually; using an oscillator from the PSIII to modulate the CV of the Voice module while the Seq controls the Gate of said oscillator (via an envelope and the PSIII's onboard VCO Ctrl module, of course), and the pitch/CV out from Seq controls the Voice's notes really opened my mind to how nuts this whole thing can get. Yikes. It's just intense. Not always great-sounding, but learning these interactions started cementing in my mind the point-of-view that I needed to keep developing what I had.
The Pico Scale is something I mostly picked up because it was a). cheap as hell due to Erica discontinuing it, and, b). it can send both normal and inverted signal from whatever's patched in. The attenuation/boosting part is just icing on the cake to me. The Trigger seemed cool but I didn't really know what I would use it for. It ended up being a lot more useful than I thought it would be. I immediately programmed it with some simple clock divisions (quarter-notes, eighth-notes, dotted eights, and sixteenth-notes) and fed it clock from the PSIII's Mod Pulse output, which was getting clock from my Volcas/Minilogue XD. This instantly allowed me to trigger multiple oscillators/LPGs/EGs with different timings, and I had an "a-ha" moment that led to lots of fun patching.
After those last two modules, I purchased the Pico Ring, a ring modulation circuit that's pretty self-explanatory. I have yet to use it to its full potential, but I figured it would be fun (and it is, even with nothing plugged into the second input as it has its own sine wave internally routed to modulate the carrier). It's an affordable, interesting effect. And, now I'm at the point where I'm not quite sure what I want to do. I decided I wanted to use my Korg Volca percussion synths (Kick and Drum) in conjunction with my rack. They sound super cool run through the LPGs on the PSIII, for instance (especially with some clever CVs on the LPG circuits), and I love the tactile, immediate feel of these two, especially in tandem. They're also superb for performances; responsive and rewarding to play. They just don't work well when mixed in with the other oscillators and sounds due to the differences in signal amplitude, so I opted to grab a Pico Input for the small rack. It was affordable and seemed like a logical choice to bring them up to the "Eurorack standard," plus I can just leave them plugged into that between other patches (like a permanent "mix" input or something).
Over the past few weeks I've also learned that, well, you can never have enough VCAs. This is apparently common knowledge among modular fans, but I've mostly been building my rack for apparent sounds (voices and effects; subtle modulations be damned!). Therefore, I took an opportunity to snag an Erica Pico VCA, which is discontinued. Found one used and in excellent condition for under $100, though, and it seems like a cool device. No pots, very simple and straight-forward, but from my quick perusal of the manual, it seems to normalize the second input to the first, and even has a jumper on the PCB you can utilize to make the second input's CV independent from the first even if its input is normalized. Split VCA modulation with only one input, for the win? For the price, definitely. Now I'm looking into grabbing another Pico Seq (likely going to use with one of the PSIII oscillators for now to make a polyphonic synth voice and potentially polyrhythmic sequences) and the Pico VCF1 (cuz who doesn't love a nice Russian lowpass filter?). I mean, if I'm depending on the PSIII for filters, it's gonna be rough going, because those LPGs are intensely resonant and tough to control.
Cheers if you read this. This is mostly for my own use, so I can see where I was at one point once I inevitably build into that 6U monster rack. At least, it seems monstrous compared to the 42HP case this one is. Humble beginnings...