ModularGrid Rack

Finishing up my first rack. I'm trying to do some experimental club, like a sort of freeform techno or broken, disjointed sci-fi and bass. Influence from Objekt, Jesse Osborne-Lanthier, Rabit, etc. I own the top row, plus the midi, umod, grandpa, and buffmult. Lots of people saying you should have more VCAs than voices, but I've only found marginal use for them. As far as generative stuff, I'd only be looking to farm out 8 bars at a time. I'm wondering if I should sacrifice anything for more VCAs and filters, or if I'd benefit from a gate generator (I like the 4ms SCM.) Been hashing this out for a few months now and I'm wondering if any experienced users have an idea to improve efficiency or functionality. Much appreciated, thanks.

I took it out back 'n' beat 'er with an ugly stick!
ModularGrid Rack
OK, this seems better. All of the voicing is up top, control and modulation is down. I yanked a few things you didn't have already for some improvements:

The Sub Ring. This thing gives you a few more options for mixing, plus it can provide suboctaves and act as a second ring mod source. The suboctaves are the important part, though; if you're doing heavy bass work, nothing punches the crap out of it like an octave-down or two.

VCAs. Yep, there they are. Your problem with them was kind of obvious: no exponential VCAs, plus no actual envelopes. Put those two together, and that's what gives you that 'THWACK' that only a good, snappy attack thru an exponential VCA can get. Why? Well, a linear VCA changes gain based on a linear mathematical relationship with the control signal. But an exponential works on a 'law of squares'-type model, resulting in more abrupt dynamic changes. So a typical sharp envelope attack into a linear VCA is sort of 'sound turns on', but into an exponential it's more like 'sound punches WAY UP'. The Quad VCA has the extra plus of being able to vary its VCAs behaviors between these two, so with a little creativity you can have a whole continuum of 'smooth' to 'OW!'

Power. Try the Row Power 40 instead. Having more current headroom is a good thing, because the farther you can get from maximum load capacity on your p/s, the less thermal wear you'll have. Result: more reliability over time. Never use a supply where your supply capacity is anywhere near the current draw on any rail. ALWAYS leave plenty of headroom for unexpected current issues, such as switch-on inrush loads, etc. The uZeus is great for single skiff builds, but if you've got something more on this size, go big or go home is the rule of the day.

Yes, envelopes. Erica's kickass dual EG/LFO gives you a pair of ADSRs (which you'll want for audio and filter cutoffs, to be sure), plus if needed, these envelope curves can cycle, giving you two more modulation sources in addition to the Maths. And in order to make that fit better, I scrunched the output down to a 4 hp Ladik that also gives you metering on your output level. You'll need to watch your input level to that, as it has no attenuation, but if you need that feature, Ladik has other output modules (as do other makers) that fit the slot that provide an attenuator.

Flow now makes loads more sense. Left to right on audio chain, control/modulation upwards into that. Power next to MIDI, to avoid placement near any audio hardware, in case (not likely, but still...) of any power-line crud that might try and creep into your audio. All input and output is on the bottom, at the ends. Looks more playable as an instrument now. Howzzat?

Hell yea! Good tip on the exponential VCAs. I wasn't sure how big the difference was, but I do love that ripping and tearing sound. I think the only thing I'd want to work in somehow is an external input, to do some weird things with the ringmod especially. Is it bad to swap the Ladik Line Out with something like a Gozinta? The sub ring is a great idea, extra evil. Sidenote: do you have any experience with the ADDAC power starvation? Looks interesting. Thanks for the help!

Here's an idea: take out the SSF noise source and replace it with a Ladik A-530 dual line input preamp. Then remove the 2hp sample and hold and replace it with a Zlob Entropy, which gives you a S&H circuit plus three noise colors in just 2 hp. Nails it! You definitely want an output module; the signal levels coming out of the modular need to be stepped down to line level from the higher levels in the synth itself. Plus that Ladik output has the plus feature of MOAR BLINKKY LITEZ!!!

As for the power, don't do that. The idea behind it is that the lower voltage level (such as from a worn-out battery) will result in some interesting sound characteristics, and while that works well with more robust circuitry like stompboxes (especially fuzz, overdrive and the like), my concern would be that the more twiddly circuitry of a typical Eurorack module might not be too happy with the lowered voltages, and the results could potentially be tragic. Some modules, obviously, would be a good candidate for this, but pretty much nothing in my version of the build would fall into that category. In fact, even in your version, only the Optodist comes to mind as something that the ADDAC 300 would play nice with.

Basically, if the power specs say +12 and -12, make sure you're feeding those voltages to your modules. They (and you) will be happier in the long run if you give them what they want.