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If you want to turn your transients to gates, a logic module for each drum sound would be helpful. Once the audio goes above a certain voltage, you'll generate a gate through the logic module... just tap the "or" output. From there you can apply whatever you'd like. Envelope followers were also mentioned. That will generate CV based on the instantaneous amplitude of the signal.

And a third device would work if the solution is to simply open/close a gate: a comparator. These also play nice with logic gates to allow strange polyrhythms and weird timing manipulations. But Ronin's on point when he says...

Honestly, Eurorack isn't the best solution. You'd be better off with a laptop with an 8-in and 8-out interface and software like Ableton. From there you can process, envelope follow, and whatever the heck you want out of your inputs. But using Eurorack is just going to be a cluster with meager results.

Eurorack ain't for everything.
-- Ronin1973

And I agree 100% there. This isn't really the right application for Eurorack, as such. It might make more sense to use an electronic drum kit and process its output mix through a Eurorack system, thereby avoiding the need for the piezos, the extra modules, etc etc etc. But doing this purely in Eurorack will get expensive and unwieldy pretty quickly.

That's not going to work, as such. You can't exactly "amplify" CVs or modulation signals and arrive at a useful result most of the time. What you can do, though, is to use an adder to add a DC offset voltage of a given amount to raise the CV/mod level. But the sort of amplification you're talking about here would probably be pretty useless...and potentially destructive, as an x2 'amplification" of a 10V p2p modulation signal would give you a 20V p2p one, and that's apt to damage circuits that're used to seeing no more than 10V or so at their inputs.

Have a look at the Doepfer A-185-2, vpme.de's T43, or Tiptop's MISO...all of which are useful for modifying CV/mod levels. But the thing that I'm wondering here is that, if Eurorack and the Roland System 100 use the same CV/gate standard, why do the levels need boosting from the Eurorack to the Roland system? Everything should track 1:1 between those two.

EDITED Oct 30th 2019, 19:02

That's not enough information. Is the signal in question audio or a CV or modulation signal?

Technically, you don't "play" the VCAs. But what does happen is that you work with the control and/or modulation sources connected to them in order to control either audio or CV/modulation levels. It's sort of like how you also don't "play" a sample and hold...the sample and hold is what "plays" other things instead.

The entire point of the voltage-controlled synthesizer is to put many different electronic music functions under a fairly minimal set of controls, and this goes back to both Buchla's and Moog's original concepts. The idea is that if you press a key (more typical in a Moog system), you can control pitch and duration, but also trigger other circuits such as envelope generators, etc with the same key-press gesture. So, if you wanted to create a neat lead sound with some VCO sync sweeping, a nice rubbery filter sound, and a slowly-building vibrato, you'd connect up the controller's CV output with the VCOs and VCF, then set up a few envelope generators...one to do the VCO2 sweep, one to get the filter contour, and a third for controlling the slow-rise on a linear, DC-coupled VCA that's passing an LFO to VCO1. Oh, and you'd probably also want to mult up the VCF envelope to yet another VCA (exponential in this case) to contour the sound's level. And this is all on one keypress.

And why? Well, prior to the development of this, electronic music was a massive PITA to work with, and Herb Deutsch (on the East coast) and the composers at the San Francisco Tape Music Center (West coast, natch) asked Bob Moog and Don Buchla (respectively) to come up with some sort of solution to simplify and power up these processes through some sort of technological solution. In short, they were trying to get to a point where it was possible to do less for more results, and both cases here were successful. But the thing they were trying to avoid was where you address every...single...frickin'...control...one...at...a...time in order to arrive at a result. So the point of a synthesizer's controls isn't that they're necessarily supposed to be performance controllers, but that when you can bring several aspects of control into play, you have the ability to make adjustments when needed, and let your controller systems do the heavy lifting.

Well, the problem with the Ears should be pretty apparent: you're paying for an onboard contact mic that's not useful for the purpose you have in mind here. I also feel that putting a contact mic in a patchpanel is a pretty bad idea unless you can disable it somehow to avoid lots of extraneous clunking and banging around that'll get into your signal path. It might be cool-looking and all...but it's not the right tool.

Basically, you're talking about using this sort of thing: https://reverb.com/item/2274010-2x-piezo-elements-for-drum-triggers-contact-mics-fast-shipping , which is a piezo sensor that can also act as a contact microphone. These need a good bit of amplification to be musically useful along with the other parts of the needed module, namely the envelope follower. My concern is whether the Ears's input preamp is capable of the necessary level of amplification...if it's designed for line-level input signals, it might not be. But both my Dean Markley and John Pearse contact mic/pickups do need that, so I'm basing my observations on those. There are a few that have high outputs (AKG makes one that I've used before to amplify a chalkboard through a Peavey stack via its guitar-level input), but they're not piezos.

And I should note...the next consideration is going to be what you plan to do with the envelope following function, since there's no VCAs here or, for that matter, much else that the envelope follower can interact with. And if you're planning to use this with drums, that consideration is key.

EDITED Oct 27th 2019, 22:14

You're going to be rather short on inputs if the idea here is to contact mic the entire kit. To do this optimally, EVERY drum needs to be fitted with a contact mic, each going to its individual preamp/envelope follower. Doing this with just one...well, if you're trying to create a single percussive effect device like a Syndrum or Clap Trap, that would be fine, but there's no decent way to make this work with a single Ears.

And for that matter, I don't think Ears is the right choice here. Something like Bastl's Kong, which is specifically designed for drum pickups like this and which also manages to cram two of the needed functions into 5 hp would be a far better choice.

Thus far, I think there's only been one synth manufacturer that's released a stompbox case, the Pittsburgh Modular Patch Box. And there is one specific, overriding reason for this:

Do you really want delicate module controls in the same enclosure that you're supposed to be poking at with your shoes? A single misstep can be awfully expensive.

Don't do this. Put the controls on the floor, sure...but NOT the modules!!!

Ha, ha, looks like we three got the same thinking here and thanks a lot Lugia for starting the initial part of the document!
-- GarfieldModular

TBH, tho...it's sort of hard to keep motivated to work on it, mainly because I know that it'll be rather long. And this kicks in the TL;DR response from the exact crowd that 100% needs to "R" it, regardless of how "L" it is.

Which is effing stupid and irresponsible, really. Probably too effing stupid and irresponsible to even be all that concerned about when you're trying to be helpful and let people know that they're in the process of making critical errors, some of which can theoretically cost a couple of grand to fix. So there's times where, yes, I do care about seeing users make the most of getting into modular synthesis with a minimum of hassles. But then, there's also plenty of instances where I'll just look at a post and go "nooooooo..." when seeing some build that really could only be improved upon by fire/tannerite/catapult-into-brick-wall. Worse still, you'll try and point out to those people that, um, hey...you really can't have a synthesizer that doesn't have basic things like VCAs, mixers, etc...and they promptly try and end-run everything you're putting forward as build-saving advice by trying to change up the fancy stuff when all that's really necessary is a few hundred $$ of basic/utility modules at the expense of removing one or two costly space-gobblers.

Now, I love ModularGrid. It's an amazing resource. And it surely could benefit from hosting a primer text on how to do a proper modular build. But while working on this, I keep having this nagging doubt about the real worth of the effort. Because it's not merely new users that are part of this issue, but I think you can also add to that quite a bit of the retailers of the modules. Note that I'm NOT pointing at any of the respected modular dealers, but instead at the MI crowd...Sweetwater, GC, Thomann et al...that sell this stuff on a large scale with absolutely NO acumen on how to build one of these systems. Their attitude is "you got money? we got stuff!" and if someone creates an utterly foobar build on their sayso, they benefit later on when said user comes back to "fix" what's wrong with the build that...had there been proper advice...they shouldn't have ever built in the first place. Yes, yes, I know the old adage of "The customer is always right"...except that when the customer is WRONG and is about to blow wads of ca$h, then someone needs to step up and let them know this. Profit-driven MI firms just don't do this, from my experience, or even know how to...in fact, the first time I went to our local GC when it opened a few years back, one of the salesforce asked me what kind of music I did. I answered that I worked a lot with electroacoustic media, studied composition in Germany w/ Stockhausen, etc...and this dolt thought I was talking about acoustic guitars with electronics added, to say nothing of not knowing who the hell Stockhausen was. Natcherly, this store's most sophisticated synth at that time was a MicroKorg...a decade-plus-old design that doesn't reflect much of anything that's going on in synths now, and tbh, the place really hasn't improved any since. Another instance happened at Sweetwater a few years ago, trying to explain why they just might want to carry things like multiples, attenuators, and other such utility modules even though they're 1) not as expensive, ergo Sweetwater would make less on them while they take up the same space in the warehouse and 2) they don't look as cool. Mind you, I think Sweetwater finally had enough knowledgable users calling them out on this that they DID clue up a bit and add these things, but even with that, how many people on their sales force know how to configure a basic modular synth? Probably only a handful.

So, with THESE sorts of people out there working to make sure that future modular users get BENT OVER for their bucks instead of getting BANG for their bucks, and those future users being all too willing to accept advice from people who get a check each week for whatever sales they can wrangle instead of expertise under their belts, coming up with a comprehensive beginner's manual sometimes feels like a fool's errand. I want to do this, mainly because MG is such an excellent resource that it needs its own in-house primer, something authoritative to go alongside their authoritative information on modules. But part of me just wonders "is there a point to all this typing?" if so many people have been conditioned into that TL;DR mentality, often to the point that not even rudimentary research has been done before setting out on this technically-complex and usually-expensive path.

EDITED Oct 23rd 2019, 22:39

I bought a Plaits module and a Wasp filter. I also threw in a Maths. Do I need anything else?
-- Ronin1973

Duct tape. ;-) Get the most expensive kind you can find.

Exactly what I had in mind, Ronin...lemme get the initial text done, then it looks like it's you, me, and Garfield that'll be hashing out a final version.

Actually, MG's already got me working on something of a "how-to" on constructing a proper, functional modular. It's coming along slowly, though, mainly because I'm trying to work on my studio refit in amongst everything else that threatens to suck the brains out of my head at present. But a collaborative effort might not be a bad idea...would just take some judicious editing to mash the various docs together into a single one, but working from a multi-user perspective could be quite useful.

OK...go here: https://www.flickr.com/photos/8429881@N06/sets/72157602899680757/

What you're looking at is a collaboration between Bob Moog and the composer Joel Chadabe that was installed at SUNY Albany back in 1969. This was known as the "Coordinated Electronic Music System" or CEMS, and was the first modular rig specifically intended to do what we now call "generative music". Chadabe's "Ideas of Movement at Bolton Landing" was one of the first such works that explored this process, and you can hear that here: https://joelchadabe.net/ideasofmovement/

Now, for those trying to build a proper generative rig...pay very close attention to those pictures of the CEMS. Yes, those ARE eight Moog 960 sequencers. Yes, that IS a custom triggering/timing system at the top of one rack. And so on...

"Ideas of Motion..." actually sounds rather simplistic when compared to present-day generative work. And that's because it is. Even with this large Moog rig, you don't get too much going on.

So...if the result from this monster system is actually as simplistic at it sounds, what's actually going on here?

Well...like many generative builds, there are a lot of modulation sources here, notably in the form of those eight Moog 960s that also control pitches and the usual sequenced stuff. But the sound generation aspect is pretty simple, which is typical for that time period; it would be another year or two before Dr. Tomita started showing everyone how to do really nuanced sound on the Moog. And as we know, nuance needs more of...everything, tbh.

So, sure...Eurorack makes things physically smaller. But not functionally. Not even close. To get Chadabe's results in "Ideas of Motion...", you still need much of what you see in those pics of the CEMS, or similar. Then, to get that ambient sonic complexity, you need the nuance of later synthesists...so, let's see what Tomita was up to in the mid-1970s: http://www.isaotomita.net/interviews/KEYBaug1977/images/1.jpg

Oh...snap.

Even if you shrunk all of what you see in that pic down to Eurorack dimensions, you would STILL have something pretty damned big. I mean...that's a IIIp, a 55, and there's even more that's not in the frame. Slap THAT together with the CEMS's control systems, though, and you'd have a top-shelf generative ambient rig. But the problem is that you'd really need to be working on that scale to get something that's musically effective. True, we have denser functionality on modules these days, and everything's smaller and so on, but you'd still probably be talking about a rig that would take up a whole Doepfer A-100 12U Monster Case at minimum.

Now, hopefully this explains why some of us keep saying that you can't do a proper, musically-interesting ambient generative setup in a two-row 84 hp cab. Even if you could jam a lot of the "voicing" in with 4 hp and smaller modules, you would still have issues with supplying enough integrated timing/sequencing/modulation sources to make it do something interesting. Hopefully this explanation is helpful to those of you contemplating this concept. Note that I'm not saying "don't do this"...instead, if you're going to do this, look at this as an example of how TO do it, understand the scale you'd be working on, and THEN start working out ideas. Anything too much smaller isn't going to work as well as you'd think.

Why all the buffered mults? Really, you only need one of those to make sure you're not getting voltage sag on a CV path that's critical to tuning. And if you yank a couple, you then have room for a comparator, and maybe a discriminator. These are very useful in time-heavy rigs, since they can "read" moduation signal behavior and output more gates/triggers based on those, which can then be run thru the Plog for more Boolean complexity. The 2hp Buff at the top-right probably could be changed out to an unbuffered mult, also.

The other glaring issue here is modulation sources. I see a Maths, a single ADSR, the Black Modulator, and the Pam's...and with all of the other sources and such in here that really would benefit from more elaborate modulation, that would seem to be the "somethings missing" you've noticed. There's 10 VCAs, for example (yay!!!), but only those mod sources to control them (boo.). So, something's got to go so that you can get more cyclical sources. My suggestion would be to lose the Shelves (which is sort of an odd fit here) and then drop in a Batumi (four LFOs) and perhaps a Doepfer A-141-4 (quad VC ADSR) which would then balance out your modulation needs. This also eliminates any pressing need to use the Pam's as an LFO or EG source, which then frees it up for more elaborate timing/triggering trickery.

Lastly, that Pittsburgh mixer...now that you've got more modulation sources, you could step up to a much better mixer that offers VCA control over levels, panning, AUX send/returns, etc...Toppobrillo's Stereomix 2 drops right into that 24 hp space and allows a lot of stereo placement and effects tricks than the Lifeforms System Interface. And if you lose the Pittsburgh Outs, you can then swap to a Happy Nerding OUT, which gives you not only the same functions as the Pitt unit, it adds metering and a second stereo bus which would allow you to easily parallel another effect in onto your final output mix. That would let you do something such as having both the Erbe-verb and the DLD on the same stereo pair...just put the Erbe-verb on the Toppobrillo's AUX send/return (they're really perfect for each other...mono in, stereo out on the 'Verb, the opposite on the Toppo's AUX) and fly the DLD in on the second stereo bus on the OUT. Anyway, just a few suggestions that came to mind...

What Maths is is a simplified analog computer that's been set up to work in a Eurorack synth environment. As such, it outputs complex voltage curves (like an actual one does) but it doesn't use Boolean logic per se. Boolean works well in a digital environment, but it wouldn't really be useful in an analog one unless you had some way of translating voltage levels/behaviors into on/off pulses, such as with a bunch of comparators.

Marbles is similar...but again, not a Boolean device.

Honestly, this build has some very serious problems. You only have one mixer, a linear one. There are no VCAs here for either audio or CV/mod level control. Having the M32 in the cab with everything else is expensive and a waste of space...unless you like paying to power and case a device twice, don't do this. There's nothing to correct the crosspatching issues between Eurorack and the Moog. And why in god's name is the P/S in the _middle_of the row where you'll have the power cable subject to easy disconnection while patching?

OK...you have the M32 already. Do you feel that you've exhausted the possibilities it offers, and this is why you "need" Eurorack, or is this just "something cool" that looks right...until you run smack-dab into the wall of technical issues and MONEY that Eurorack poses?

I strongly suggest some considerable time be spent with VCV Rack before going further. The extreme "Sexy Module" problem above indicates to me that, while you have an idea of what's needed, you don't understand what else has to be there to make those "classics" work in the way they can. There are a LOT of "boring" modules that modular synths require in addition to the snazzy ones; get a copy of VCV Rack and you'll see what I mean.

Drones are easy; probably one of the very best primers on how that's done well has to be Klaus Schulze's "Cyborg". But then, "Cyborg" also shows how you have to keep a degree of variation in the soundscape to maintain listener interest.

Eno's processes are really different, though. He tends to think more along the lines of interacting systems (probably a lot of his Stafford Beer influence coming thru there) and how to get them to continually output a changing result across time. This is why you have the odd interlocking sequencer parts working how they do in "Discreet Music" and then, of course, the inequal-length tape loops of "Music for Airports". As opposed to Klaus Schulze above, Eno's works of these sorts are just as capable of NOT being listened to actively as otherwise; try this with "Cyborg", though, and the results just sound like your HVAC system is malfunctioning or something similar.

TBH, you're making this more difficult than it should be by having that PICO System III in the Eurorack case instead of its own case. That eats up far too much panel space for something that's already got a cab and power on its own. By taking that out and putting it back where it belongs, you then have ample room for modules that will work to expand this AND which can be big enough to be easily controllable and well-featured. Another consideration would be to remove anything that doesn't have clear and apparent functionality; while o-scopes are nice if you're doing complex sound design where you need to know waveform content, they're pretty much pointless for a gigging instrument. Lose that, then you have space for the clocking, etc that's on the Intellijel Noise Tools tile...which, fwiw, is a far more functional and essential module than the Zeroscope.

Guys, is there just ANY video, where we can see how this module is operated by a professional theremin player playing a melody?
-- spooncrackling

Probably not. If you read the info on Doepfer's site, you'll notice that this isn't exactly a "traditional" gesture controller. It has some obvious drawbacks, especially regarding the capacitance, that would tend to make it less of a "proper" rod or ring. It seems to me that it would make infinitely more sense to use a Moog Etherwave Plus to send proper CVs and gate to a modular, given that the Etherwave has its aerials in optimized positions already and the circuitry is designed to deal with this sort of thing. Plus, it's a wooden box (NOT metal) which should be easier to control and calibrate, and it can be located away from metal or other things that might cause an unexpected signal.

In theory, yes. However, unless you already have a Eurorack rig, this seems sort of inefficient. You're talking about $519 for the modules alone, plus whatever case/power you'd have to get if you don't already have that on hand. And then, you'd only have two channels (and no velocity...the Bloom doesn't transmit that). Plus, both of those Elektron boxes already have sequencing onboard.

If the idea here is to employ a master sequencer to control the Elektrons, or to inject random variables into the behavior of those boxes, it would seem to me to make more sense to employ a standalone device such as a Squarp Pyramid (if you don't have a Eurorack rig already) or a Squarp Hermod (if you do). The Hermod has MIDI (no need for the Doepfer module), does transmit velocity and aftertouch (bonus), has ample randomization and parameter stacking for days. And the Pyramid is basically a beefier Hermod in its own self-contained case. Plus the Hermod actually comes in at $20 less than the Qu-bit/Doepfer pair and gives you eight tracks whereas the original idea only offered two.

My comments here: https://www.modulargrid.net/e/forum/posts/index/8186 seem applicable here as well.

In a generative environment, you'll see loads of sequencers, switches, LFOs, VCAs, and clocking sources. You'll find sample & hold circuits, lots of effects, etc. I think there's a false believe that generative, ambient, or "drone" set-ups are simple.
-- Ronin1973

A very false belief, indeed! While drone can be simpler, it gets very irritating without some subtle internal variation, which means extra modulation sources and the right utility modules to keep them reined in.

But where it really goes off the rails is with ambient and generative.

One look at the history of ambient AND generative music brings us to a very important nexus: Brian Eno's "Music for Airports". If you are trying to do this sort of music, you need to be familiar with those four pieces! All of these pieces are both ambient and generative...but the generative process is being driven not by synth circuits, but inequally-long tape loops. I remember seeing Bang on a Can Allstars performing these back in the early 2000s (at the U of IL...which is a hilarious joke in of itself if you know anything about Illinois' composition department) and I asked Evan Ziporyn afterward about the process of trying to transcribe something like that. He showed me the transcribed score to "1/1", with lots of weird incremental time signature changes, strange notational values and the like...because it was accurate to Eno's original late 1970s tape loop realization.

Now, let's forward to the present. Technically, yes, you can do something very much like "1/1" in a modular environment. But consider...the thing that makes the original work is the slow drift-apart of the various looped fragments, ALL of which are on loops that mathematically should NEVER match up again. Now, try and figure how to translate that sort of temporal drift into a set of modules and patch connections. Ain't so easy, izzit?

First of all, you'll notice that using 2-3 modules for your generative process "core" just won't cut it. Instead, you'd be looking at a pretty complex concatenation of modulation sources, none of which should match up again once in motion. Some are faster, some are slower, and a few "governor" sources will be running at extremely slow speeds. Think hours here. Then from this, you'll need to extract various timing information...clocking, clock modulators, triggers and gates to fire other things, etc. These build up a web of conditional logic processes and resultant states. In some cases, actual Boolean logic processes can get used to alter timing positions, and in others, gradual reshaping of modulation curves can do some of this.

The funny thing is, a generative rig will likely wind up having more "process" architecture than "voice". Once you've gotten some experience with ambient and/or generative music, you tend to find that simpler sounds = more cohesive results. This doesn't mean you can just hook up your VCOs to individual VCAs, set up the triggers, and walk off, though...rather, like in drone music, some slight timbral variation is critical. BUT NOT MUCH. A good example would be this thought experiment: take the beginning of Miles Davis' "Kind of Blue" and rip out the rhythmic cohesiveness...let all the sounds just drift in time. Simple, effective. And interestingly, that pretty well describes the feel on a lot of Miles' later "In a Silent Way" just ten years later.

One other thing to keep in mind: this sort of music can be actively listened to...but that's actually not the original intent. Instead, most ambient, most generative ambient, and some drone (as long as you're not talking about Sunn o))) or something similar) is meant to NOT be listened to, but as an "acoustical colorant" for spaces. You should be able to set up a generative patch of that sort, start it up, then lower the volume to near-liminal levels to experience how it should sound. Then leave it on for...oh...a day or so and see if it works (which includes being able to all but ignore it). If you eventually forget you have it running, congrats! It works!

First up, move the I/O jack pair modules to the ends of the 1U row and co-locate their functional modules there. This gets these cables out of the way of the patchpanel. Then dump the buffered mult, since you've really not got anything here that requires it; use some inline mults or stackcables instead to save space, and this would open up a bit more 1U space for something like Intellijel's reverb tile.

Reconsider your module ordering here, keeping your SV-1 in mind. Try and lay out the 3U modules in a similar manner to the SV-1, since this will make crosspatching the two systems a bit more intuitive. In other words: Steppy is left, then Plaits, Filter8. Above this (or close to it), relocate the clock/S&H/slew tile, since all of those are needed at left. After this, place modulation: Batumi, Function, Stages. The Mutamix should be at far right.

I'm presuming your MIDI interfacing is via the SV-1, so stacking that close by the Steppy, Plaits, clock, etc will be helpful.

Now for the bad news: you have no VCAs here save for the one (semi-dedicated) on the SV-1. Part of this is due to the mixer you've chosen; the Mutamix can automate mutes...but NOT levels since it has no CVs. You can add a Linix, since the Mutamix is designed to connect to that via a backplane connection. I wouldn't do that, though, since now we're talking about a 34 hp module pair that costs over $600. A much better choice would be a Toppobrillo Stereomix2...which then allows you voltage control over levels on each channel, panning on each, AUX send on each, a CUE send, AUX send/return for effects, etc...AND it costs $479 and fits in 24 hp. This then takes care of your audio VCAs, plus stereolocation, bringing FX in and out...but you also need a couple of VCAs for CVs and modulation signals so that you can control their amplitude as well. So, back to Intellijel and their uVCA2...a pair of summable DC-coupled VCAs with adjustable response. That should do the trick in only 6 hp.

Now...consider adding a waveshaper, perhaps. Tiptop's Fold Processor will add quite a bit of timbral variation, particularly if you route the Plaits through the SV-1's mixer to combine it with its VCOs, and then into the Fold before filtering. The Fold also gives you a suboctave generator...great for creating very destructive bass!

If you were to lose anything from the 3U modules here, it probably should be the Make Noise Function. For one thing, you have a dedicated EG in the SV-1. Secondly, there are smaller two-stage EGs out there, and you can probably jam that same sort of function into a smaller space with something like an ALM Pip Slope (4 hp), Erica PICO EG (3 hp), or a 2hp EG (2 hp...obviously!). Done right, you can cram all of the additional modules above into this 4U cab and it should just fit!

Step 1 - add up all of your modules' current draws, then increase that by 1/4th. That additional draw amount is there to deal with inrush current, which is what you get for the first fractions of a second when the rig is turned on. If the final amperage figure there exceeds the current ratings of the P/S, then you've probably found your problem, and you'll need to replace the Arturia supply with something beefier. If not, then...

Step 2 - After acquring a new supply, remove ALL modules from the rig, then take some canned air and blow out all of the headers on the distro. If there's a bit of wire or something else conductive in there, this should remove it. Shrouded headers are very convenient, they tend to prevent mispolarized connections or connecting a ribbon a step or two off from its proper alignment, but they can hide bits of crap...and if one of those is shorting something, that dead-short will do that. Once this is done, turn on the rig with only one module connected. If the supply blows again, the problem will be a defective busboard. If not, then...

Step 3 - Start adding modules one by one, checking power integrity each time you add a module. And before each time you do this, remove the ribbon from the module and visually check each ribbon beforehand to make sure there are no nicks in the insulation, no shorted-looking bits around the connectors, and especially nothing that looks burnt...as there's enough amperage there to melt insulation if there's a short. Having done this, then blow out the power connection on the module (AWAY FROM THE OPEN MODULAR! You don't want to blow something into the cab to start the whole mess all over again!), then replace the ribbon and connect the module to the busboard. Turn on. If nothing happens each time, then WIN!...you probably had something in a module header. But if the P/S blows up yet again after reinstalling a module, the fault is with that module and now you know who to contact about their defective product.

Yes, this sounds like a kludgy way of troubleshooting a power issue. But the fact is that a typical Eurorack contains so much that's going on on the inside that, without a test module (such as Synthrotek's TST or vpme.de's p0wr) that lets you check module functionality, this is about the only systematic way to do this. Annoying, yes...but it comes with the territory. One other suggestion would be to invest in a cheap multimeter. With that, you could check the busboard to see if there's any continuity between the "hot" rails and ground (WITH THE POWER SUPPLY REMOVED AND RIG OFF!!!). If you see continuity between those, then something's wrong as those rails should only connect through the components connected to them. And while the Arturia Rackbrute distro does have filtering, none of that should be a problem as long as you check for continuity in BOTH polarity directions; if you see what seems to be a short, then reverse the polarity of the multimeter probes...and if this persists, then it IS a short. If not...then no, you're just getting continuity through a polarized component, and reversing the direction of current causes the polarized component to block the multimeter's DC. That's what you want to see.

Which brings up another point that needs to be mentioned: modular synthesizers are NOT entry-grade technology. Not even close. While this all seems like plug-n-play stuff, really, it's not...and there's a certain level of technical capability that anyone considering getting into modular synths needs to have before spending that first dime on a new rig. Having a multimeter and knowing how to use it is important. Basic skills with electronics tools such as soldering irons and wire strippers...those come in handy more than you'd think, if just to repair patchcables. Understanding how to logically troubleshoot by elimination (what's going on above in this post) is an essential. And a good appreciation of what an amp or two of "low-voltage" DC is capable of is another essential...which, frankly, you don't want to obtain first-hand.

I'm just not getting it, period. It occurs to me that this just isn't the right application for modular; it would make far more sense to control externals with a proper hardware sequencer (Squarp Pyramid, Kilpatrick Carbon, etc) than to try and cobble one together from Eurorack modules. Don't get me wrong...modular _is useful..._but this is one of those instances where employing modular synth hardware to do something that can be done more smoothly with a dedicated device just isn't the right move.

For generative? One thought: it's too small. Another thought: why are there two buffered mults in a rig that really has only three "oscillators" (one of which has input buffering)? A third: where are the filters?

This isn't going to work for the purpose you're aiming for. Proper generative systems involve A LOT of modulation sources, various ways of altering timing structures, plenty of ways of combining and interacting between modulators, and a rather extensive but generally uniform set of audio paths. For example: there's two VCAs here, but the 2180 VCA isn't one that can work with CVs or modulation signals. It's not a DC-coupled linear VCA, and instead, it's one primarily for audio work. Cool beanz for audio...but if you want variation with your modulation levels, that won't be happening here.

While the addition of a tile row (and, IMHO, the correct sort of tile row...sorry, Intellijel!) is a really great idea for moving basic utilities out of the 3U turf, this rig isn't where it needs to be overall. For one thing, you're trying to use a very small cab for a "big cab" purpose, and this never works well. Secondly, there's lots missing. My advice would be to start over...and if you're intent on doing proper generative work, you should start with a case that's several times this size. In fact, that advice goes for ALL builds; NEVER start in a small case, but instead, start very large and pare down from there to the point where the functionality you want is just supportable. THEN resize the case.

The other thing I would suggest would be to get a copy of VCV Rack. Work out your generative ideas in there, then start figuring out how to transfer the ideas from that virtual Eurorack environment to a real one. This should not only give you a much better idea of the scale you should be working on here, but a very clear idea of what sort of modules this needs, what sort of actual outlay is involved, etc.

EDITED Oct 10th 2019, 22:22

I'm not getting this at all. So, this is a pair of Rackbrutes. But the bottom 6U may just as well be a Minibrute 2S. And since that's a cheaper alternative, then why not just use a Minibrute 2S? A smarter move would be to not put the Boog in the cab in the first place, since it already has its own cab and that cab already has power. Use your Eurorack space for things that NEED the housing and power instead.

Garfield's right about the envelopes, also...there's not really any proper ones there. Ripping out the Boog will give you back 70 hp (a RIDICULOUS amount of space for any module to take up, fyi) and that should allow for proper EGs, attenuverters (you want to be able to invert envelopes...a big "win" with VCFs, especially) and all of the other bits that need to be there. Oh, and about that Antiphon...you do realize that it's a DIY module and also has a 150 mm reverb tank that will require space inside that Rackbrute for mounting, right? If that hadn't occurred to you, it might also be a candidate for removal, as it's yet another ginormous module in a little cab, which is always a bad idea.

What's missing here isn't some magic module -- it's SPACE. You're trying to cram two different machines in a space that's really suited for only one. As a result, there are A LOT of things missing...VCAs, attenuators, FILTERS (good lord!), and so on. This is a poster child build for "Sexy Module Syndrome", to be sure.

First of all, get rid of this idea that you can cram a proper synth voice AND a full-on drum machine into a 6U Rackbrute. Ain't happening...at least, not with these huge spacehog modules. And this statement: "I considered the Arturia Minibrute 2S but I don't really need the synth engine there although I could be swayed if anyone has an opinion on it"...uh, no. Right now, if you intend on sticking with this build (which I do not advocate), all of the things you need to make this work are in the MiniBrute.

There's absolutely no way you can do proper "creative sound design" with the bottom row as it stands. There's far too much missing...there's not even a "voice" there, tbh. Delete this, start over...and the next time around, decide if you want drums or (NOT "and") a synth voice in the Rackbrute first and then build that out. And before building, study some other builds that have been done right to see what they require to do what they do. Otherwise, sticking with this sort of plan will result in building a black hole that sucks in money...but which puts out nothing useful in return.

I'm in agreement with Ronin here, actually. It might be a far better idea for you to get a copy of VCV Rack and start to explore these musical ideas in that environment, both to get some chops up as well as to get a clearer idea of what you'll actually need to accomplish this should you opt to work this out in hardware.

Fact is, there's a big "WARNING" sign in your initial post. Generative rigs that work really well tend to be larger setups, not the sort of thing you'd have in a Rackbrute 6U. While that initial module choice has nothing glaringly wrong with it, it's small enough that there's plenty of room for things to go that way as the design progresses. Since you have a clear musical direction in mind here, don't work it out in hardware, as you're apt to discover that you took a wrong turn a few purchases back and a $250 error in judgement will have turned into a $1250 one. Figure out how to get to where you want to go with ZERO expense first in order to avoid this.

Stupid exists, yep. But one other thing that's perhaps not so stupid are duty limits. I know that from Germany to the USA, anything electronic music-wise entering US Customs with a value of less than $800 is duty-free. You might check and see if a similar duty-free limit exists from the USA to your own locale.

And if that works, then I'd suggest also looking at G-Storm's VCFs. Not only are they spot-on (I have a Jupe-6 at present, and the 2600 is something I know all too well across about 40 years), they also have the smart addition of a 2-in mixer for audio. And they do a kickin' ARP 4012 clone-job...

The question that's most relevant here would be "how much experience do you have with synthesizer programming?" If the answer is "not much" or something along those lines, I'd strongly suggest getting experience with either VCV Rack (a virtual Eurorack environment, free to DL at vcvrack.com ) or a more basic patchable (there's quite a few of these, ranging from the inexpensive Behringer Neutron up thru pricier options such as the Pittsburgh Modular Voltage Lab) and figuring out how to get the sounds you want in those before hurling a large sum of money into the void. Fact is, if you don't have fairly strong programming chops before moving to a full modular, you might as well be buying a pricey wall decoration, because it's extremely easy to get poor results under those circumstances.

Equipment doesn't fix things that you need to work on your chops on. Keep that in mind.

Hi Buzz_R and Catwavez,

Catwavez: Thanks a lot for that module link. The module looks just what we need here! :-) Pity I don't know this brand and I can't find a closeby (European) dealer that sells this brand.

You might be better off ordering directly from G-Storm; they're located in Oklahoma (if I remember right) and are a relatively small operation. Their recreations of classic ARP and Roland filters, though...those are quite accurate and nicely-implemented. No reason to think their MS-20 converter wouldn't be of the same calibre.

Lots missing here...you're going to need VCAs (both for audio as well as CVs/modulation), for starters, otherwise this will turn into a pointless exercise pretty quickly. Maths is also a useful thing, and you might also look into a Batumi for straight LFOs. Also, if you're insisting on using the Chord as a VCO (I wouldn't do that, frankly), you need to consider a second on so that you can detune them against each other, do sync, etc for a "bigger" sound. That'll be spendy, though, at about $600 for a pair of poly VCOs...which is why I said I wouldn't do that.

Lugia: Interesting and indeed a pity that's so difficult to get to that kind of industrial Eurorack stuff, could be interesting to have such indeed.

"Interesting" doesn't even begin to describe it. See here: https://www.technical-furniture.com/images/joomlart/knuerr/pdf/en/knurr-technical-furniture-workstation-for-electronic-engineers-product-catalogue.pdf ...and when you get to Page 52, things will start to look really familiar.

Sort of infuriating, really...I was really hyped over the possibilities this sort of thing would open up, but dealing with whoever's dealing with Knurr in the USA (that's yet another issue with this) now was immediately frustrating. Definitely a "no habla individual users"-type of situation. Maybe some users in Europe might have better success, since the actual firm is based in (I think) Switzerland.

Dieter did one other smart thing: when he set up the Eurorack modular standard, he based it on an existing industrial standard for EE modules. That way, Eurorack could take advantage of a sizable installed base that already existed when speccing parts and specs for Eurorack. You actually can get Eurorack enclosures that are made by industrial equipment firms (Knurr's Elicon system comes to mind here) that have some different designs that make for very nice fixed-installation Eurorack cabs.

The sole downside of this supply avenue, however, is that these firms do not "speak music". They're used to dealing with large industrial/technical concerns and in institutional-sized orders, so trying to source some of these...or even get a price for components...is a royal PITA. I attempted some time back to contact the US distributor for Knurr, for example, and they couldn't wrap their heads around the application I intended. Similarly, workstation furniture manufacturers such as Winstead also have this same "issue" of user scale, where if you want just one or two things, you're not worth their time...or at least, you're made to feel that way. Thankfully, the subcomponents such as rails, etc are easily gotten from distributors such as Mouser or Allied in quantities that work for this user base...but it would be SO snazzy to be able to get a full-tilt Elicon rig if that were a suitable possibility.

Those voltages all seem quite safe in the Eurorack environment. Be very careful, however, not to patch these into outputs by mistake!

Actually, Korg and Yamaha did use a gate/trigger system that was compatible with Moog, since they also used a negative-going trigger.

The following are non-standard synth manufacturers and models, plus why:

Moog (thru Micromoog), Yamaha (CS-series monosynths), Korg (everything up thru the MS-series), Crumar (some): negative triggering
Yamaha, Korg (both same as above): Hz/V scaling
EML: 1.2 V/8va scaling
Buchla: no actual scaling standard (100 series)

...and of course, faithful copies retain these traits. The Korg and Behringer reissues of the MS-20 behave the same as the original, and the EMW 200/300 both use EML's old 1/10th volt scaling.

I see impending problems here...for one thing, this build is way too small to support having something huge like the Verbos Complex Oscillator in it. You're occupying far too much space for a relatively simple function with that module and even though you already have it, you might consider other complex VCO options that make more sense, space-wise. I could probably say the same thing about the Toolbox, too; you'd probably be better off with an outboard sequencer for something this small, or with some Expert Sleepers hardware that can be addressed by a computer. Next...and I sound like a frickin' parrot about this, but hey...VCAs. You have some VCA control via the X-Pan, but this is primarily an audio device. As for VCAs for modulation and CVs, there's zero available. This is also probably why you're not seeing the point of having attenuverters in the system...aside of also not having much in the way of conventional envelopes, which are something that often gets fed thru attenuverters for manual level control and inversion (very important thing to have for interesting envelope tricks).

Then there's the Mobenthy module...basically, if you don't know what something does, you should find out before letting it eat up 8 hp. Seriously...this is a VERY SMALL cab, and wasting space on a whim is extremely ill-advised.

Ultimately, you've tasked a very small rig with doing some rather complex functions, but then loaded it with several modules that eat up so much space that the "boring" modules you need are being squeezed out. My advice would be to chuck this 3 x 56 cab, for starters...for one thing, you have the same panel space as a more typical 2 x 84 here, but because it's broken up so strangely, you have none of the advantages of the 84 hp rows and dropping just ONE large module in is enough to wreck the architecture of the synth in general. Go with something more conventional and larger if you're trying to get this to sequence, and do bass lines, and do percussion, and and and...otherwise, you're building a money pit here.

Then, having done this, look at the functions here and figure out how to make the modules that do them smaller. As you shrink those, space then opens for the other, necessary modules that make these snazzy ones capable of doing all the amazing things they can. Otherwise, the other gameplan here would be to stay in this case and replicate all of the functions with 4 hp and smaller modules in order to get the operational profile you want to happen...but then that leads to an unwieldy control surface that's a tangle of patchcables and thickets of knobs.

To start with, this: https://www.modulargrid.net/e/the-harvestman-english-tear or something similar. Otherwise you're going to be driven insane by all of the mistracking, reverse triggering, etc. Neither the Korg MS series (original or the MS-20 Mini reissue...and, rather tellingly, Behringer's MS-clone) or Yamaha's vintage CS monosynths are set up for 1V/8va tracking or positive trigger/gates.

I follow a general rule of thumb: "up-left and down-right". Basically, control signals migrate upward on the left side, through the modulation/timing, then up to the VCOs at the top. VCO signals then go toward the right and downward; in smaller builds, the VCF is likely to be on that same "voice" row but if the space is larger, I tend to put VCFs between the VCOs and the mixing/output area at the lower right. This also should leave the VCFs and some of the VCAs in proximity to the modulation (envelopes, especially) for convenience and to keep the cable pattern somewhat sensible. The idea basically is an adaptation of the flowpath of the ARP 2600, save that modular architecture allows for considerably more flexibility in function placement than the 2600's fixed panel design.

OK...going off of the earlier PM, I went ahead and moved this over to the public forum instead. This is what you started with:

...and this is my final result:

This is a markedly different build, although it still has a lot of the existing modules. However, the original design was just unworkable and obtuse. It was missing a LOT of necessary functions (fixed), numerous utilities (also fixed), had a lot of "why?" modules (fixed), and a bad case of "sexy module syndrome". I'm not surprised that the original was that sonically unimpressive, actually. Lots of useful things...but only IF the other parts were there, which they weren't. Here's what we have:

Row 1: No. Totally reworked this so that your entire "voice" is on this row. Disting on left for various control functions. DPO replaced by the VOID complex VCO, Gravitational Waves. Telharmonium and STO replaced with Codex Modulex clones of the Braids and Plaits; in this case, you could also do two Braids or two Plaits if that seems better. Submix via Veils clone, then a Rings clone for filtering/resonance modeling. Your ring mod, btw, is now part of the VOID Gravitational Waves. The LxD follows as a stereo pair of LPGs. After this is the Morphagene, allowing it to function as a "voice source" instead of consigning it to the bottom rows where your effects processing needs to be. The QPAS is next, which lets the Morphagene feed this directly OR the Morphagene can feed into two channels of the A-138s alongside the two LPG outs, and this stereo mix can then feed into the QPAS. Similarly, you can reverse the patching of the LxD and the Rinks, which then allows you to feed the LPG "plooks" into the Rinks and have that function as a "resonant cavity" for their output.

Row 2: Also no. The original row was a hodgepodge of functions, very easy to get lost in. In this build, your "percussives" are on the left, in the form of a Delptronics LDB-2 and its expander. This drum module uses the time-tested TR-808/606-type drum sound set. Next to that, I added a Tiptop ONE for one-shot samples, then the X-PAN is used for a stereo submix for these. The rest of the row is 100% modulation: another Veils clone for VCA processing of modulation signals, the Wogglebug, then an Erica Black Modulator for an extra LFO, sample and hold, and noise. Maths follows, then a pair of expanded Xaoc Zadars, as the original really had nothing in the way of proper envelope generation. And since the Zadars can loop, this also lets them serve as user-definable LFOs in addition to envelope generation. At the end of this row is a DC-coupled triple attenuverter/mixer, allowing you to manipulate and/or mix your modulation outputs.

Row 3: I cut the original WAY back to a single Rene, plus its Tempi. This should lower the confusion factor considerably. The Euclidean Circles got added to this row, as well as a Starling GateSeq, which is an interesting logic-driven combo of normal and probabilistic sequencers. All of this is intended to feed the percussives above it, but there's ample output so that some of the timing can be routed elsewhere. Tempi/Rene next, then effects, which is where the Erbeverb and Mimeophon wound up. More about that in a bit.

Row 4: I put the Shared System utility row here. The reason will be obvious momentarily.

Row 5: The Brains/Pressure Points combo was retained. I added a much more flexible and intutive clocking system to its left, in the form of 4ms's Quad Clock Distributor and its expander. THIS is what a master clock should be for a large system such as the one you've acquired, and it's capable of outputting numerous clocks with various divisions and multiplications under CV control. Note also that since most things that can take external clocks will know what to do with a +5V pulse, this module pair can actually serve as your studio's clocking "nexus", besides handling all of the internal clocking duties imaginable. On the other side of the Pressure Points, I put in a Tiptop MISO; the intention here is to give you a CV/modulation control point located conveniently between your manual controller and your mixer so that you can route critical modulation paths through this and adjust them there, improving the control paradigm considerably. Next, I put in a stereo compressor/limiter, which should prove extremely useful on your stereo drum path. Then, a Toppobrillo Stereomix. This is a proper performance mixer, allowing CV over level, panning, and AUX send. You can manually mute on this, plus you also have a cue send which allows you to audition channels offline for changing patches or settings during a performance. This is also where the Erbeverb comes in; since it uses the same mono-in/stereo-out that the Stereomix wants to see for its AUX send/return, you can now use the Erbeverb as a global reverb...probably its best use. As for the Mimeophon, this can either be used as a thruput for another stereo bus (either from the "voice" row altogether, the Morphagene, or the percussion bus) or it can be used as a final processor for the entire stereo mix. With these co-located by the Stereomix, this also reduces the ergonomic issues required in controlling all aspects of the final mix. And the output on the Shared System tile is in between the Stereomix and the Mimeophon, making it convenient to either module.

OK, so...it's not all black now. Mmmm...well, eh. Trying to go with all of your modules as one color at the expense of functionality is a very bad idea. It would be like specifiying that you want all of the hammers in your piano redone in purple felt because...PURPLE. Ergo: expensive and pointless. Since you didn't exactly have a functional instrument with the "paint it black" approach, that was actually the very first thing I discarded from the original, primarily because it's a pointless limitation. You should be more concerned with what's behind the panel, to start with, then whether or not you can make sense of the panel as a whole so that programming and playing the instrument isn't a brain-shattering chore. Anything beyond that makes no sense.

I also worked to synergize functions here, which was another thing missing from the original build, and also something that was almost certainly contributing to the build's annoying non-usefulness. Everything is now grouped while still maintaining the up-left/down-right general flow, although it should be very easy to patch outside of that flow pattern when necessary. So...timing is down and left, audio generation is across the top, drums are immediately above the timing/sequencing, modulation sources are central and to the right, sequencing is lower and central, and output + processing is lower-right.

But a lot of the previous modules got chucked out. And rightfully so, I think; in some cases, they didn't provide "bang for the buck" and took up space that could be used in better ways. And in other cases, they were obvious culprits in the confusionality you were describing. But by doing all of that culling, THAT opened up a large amount of space that allowed me to rebuild this...with actually quite a few of the existing modules, really...with the proper additions that will actually allow the modules that remain from the original build to outperform what they were capable of in the original. So, in the long run, this makes a helluva lot more sense to me as an instrument than it did before, and it should be far more capable than its prior incarnation might've led you to believe!

No, the Erica LINK is just fine for this purpose. Go ahead and use that. But keep in mind that it's just a passive attenuator bank, so you still need to control your levels carefully on the modular side of it, as it can still output something relatively hot if you hit it really hard on the modular side.

One other thing to remember, also...this is likely to be a simple resistive circuit and this means that it can pass DC. That's Garfield's concern here, since your interface can also pass DC. The best solution, eventually, will be to exchange the LINK module with something that has transformer balancing/isolation, which prevents the DC from going beyond the transformer itself. There's another method of preventing DC from passing, though...but I can't look at the PCB side of the LINK module or find any data on Erica's site that says whether or not the attenuated outputs have capacitors that work as DC stops. Not quite as preferable as transformer isolation, but still quite workable.

Solution to this should be simple enough: if you're running your audio path in the patch example you give through a VCA in linear mode, this behavior is what you should expect. To eliminate the VCO leakage, try changing the VCA's response to exponential. You will need to adjust the envelope's "ballistics", but that should fix the VCO leak issue. If it persists after that, turn the VCA's CV level down and change the envelope so that it's outputting a hotter envelope signal into the CV input.

My personal take on "copying " is a bit different. Personally, I don't think anyone here is re-inventing the wheel in sonics/sound/noise spectrum. It's physics/electronics, under clear laws based on human ears.

Don't be so sure about that. There are modules that turn up on a somewhat-routine basis on MG that are gamechangers. Yes, music is a big physics experiment, but there's always going to be new methods with which to ply those physical laws.

This is actually a problem I ran into in my final academic stint at Illinois. The Experimental Music Studios, by the time I'd gotten there, had devolved into a highly-compartmentalized situation in which, if you were working with analog synthesis, you were expected to stay within analog synthesis. If you worked with any of the digital hardware, you were supposed to keep your business confined to those studios. There weren't any tie-lines between these studios, either; if you wanted to, say, run some of the Kyma (in Studio D) output through the Buchla (in Studio A)...well, not only was that made deliberately difficult, just suggesting it would elicit howls of protest from the powers that be at that time. I also ran into this at Tennessee, but it was far easier to circumvent the problem there, plus the professor who ran the studios there wasn't very savvy about what he was hearing in other peoples' work...so if you felt like dragging the Synthi AKS from Studio 1 to Studio 2 to process the Synclavier, you could get away with it.

But in my own studio, I've allowed all of the different methods to interplay. Back in Nashville, we never believed that you had to do things that way, because it stifles development. So as a result, my own studio starts with the early 1920s (albeit a bit updated: Moog Theremini) and goes to right-frickin'-NOW, and allows in every working paradigm in that span with zero operational barriers between them. And by putting all of these disparate methods side by side, a lot of new ideas do emerge. True, the same physics applies...but the endless combinations of possible results frequently suggests new ideas for that tired ol' wheel we're all so accustomed to.

Even just within the modular environment, you see this sort of thing going on. For example, there's no reason why you can't have some elaborate wavetable-scanning oscillator with the very latest tech feeding into replicas of Don's gates from the early 1960s. Hell, you can even buy them at the same store!

Now, every once in a while you DO see something that seriously warps the synth landscape. But the REAL re-inventions are coming from the insane combinatorial math going on when you have a 100% variable topology that consists of several thousand possible elements. And that's where Eurorack is at. Every time something gamechanging appears, the impact of that is so much greater than people suspect, because not only do you have that new thing, its presence has the ability to redefine literally dozens or even hundreds of other modules' functionalities.

So, sure...it's easy to replicate someone else's efforts, and even improve on them in the process. But why would you? Especially when you don't have to. When you open the door of possibilities that exists here, you're getting an opportunity to accomplish something different and potentially better...sort of the diametrical opposite of the academic studios I mentioned above, where everything's set up to trap composers in a given paradigm with little chance of escape. So, in such an open-ended working environment as Eurorack, why set your own traps?

My opinion? This build is pretty much pointless. First up, the tile row (as Ronin also points out) is not possible. Next, there's a trigger sequencer but nothing you'd normally use one with, such as percussives, or other clock-based modules which the step sequencer can modulate. There is a clock...and there's also a MIDI interface with a clock. But you can't send the clock from the Tock out via your MIDI interface, nor can you use both the MIDI clock and the Tock at the same time since there's no logic here to facilitate that.

Then there's the single VCO. OK, fine, you can have a single VCO...but then there's that ring modulator, for which you need a second source. And while that could be the Double Bass, it wouldn't really make much sense to divide the single VCO's output then send it into the ring mod against the VCO itself. Let's say you inputted the dry VCO signal to the carrier at 880 Hz and then the -1 octave, which would be at 440 Hz. Given that ring modulators output the sum and difference frequencies, you would get 440 Hz (again...so, no point to that) and 1320 Hz, which is simply the 2nd harmonic of the octave-down signal, and since the 440 Hz signal would be reinforced by the ring mod's difference output, this would just sound like an A-440 note with a bit more second harmonic. So, pretty much a waste of the ring mod.

There's a single modulation source (the A-140) but a DC-coupled mixer which will have a couple of very not-busy inputs. The VCA isn't exactly right for audio, either. Then there's two distorters. Why?

And then, the things that are NOT THERE: a VCF, an LFO, an exponential VCA for audio, no attenuation, no output module...to be very blunt, you could get a lot more entertainment for your money while achieving the same budgetary hit by simply putting the money necessary for this in your backyard grill and setting it on fire. That's straightforward...as opposed to the frustration that'll be experienced trying to use this build.

So, "cheaper or more efficient" = don't do this, period. You need to get a far better idea of what a synthesizer is made up of and how they work if this build is any indication. Save your money and get a prebuilt patchable instead, learn how it works and why it works, then try coming back to this idea much later. You can't just throw modules into a box with a vague idea of what a synthesizer consists of and expect to get anything useable. The sole result will simply be a waste of money that could be better-applied elsewhere.

An AE system. Honestly, when it comes to energy efficiency, the AE Modular system kicks the crap out of everything else. There already are producers using theirs on solar, battery power, etc. It's also smaller, lighter, and...quite significantly...CHEAPER.

Go with Buchla? Well...it does fit here on MG, although there's no word from Buchla USA as to how much the SFTMC system's going to cost. But it's Buchla, so I'd suggest that people start filling up dumpsters full of money now!

Also worth noting: this contains a bunch of things that currently aren't in the Red Panel lineup.

If you haven't seen this, you probably need to: http://www.synthtopia.com/content/2019/09/13/buchla-100-series-modular-synthesizer-sneak-preview/

No, that's not the Red Panel remake...this is a redo of the original 100 series, aka the "Buchla Box". Vide...

OK...first of all, what keyboard? I suspect that might be the culprit here instead of the modules.

No! That Octasource is insanely useful...its ability to output phaseshifted results alone opens up a bunch of things that...well, just keep it in, you'll see! ;-) It's actually a variant on Suit & Tie Guy's Mankato VCF; see that for some further ideas/inspiration.

Depends. If this is primarily for studio use, the groovebox. But for live work, you might find the arpeggiator configuration better to use on the fly.