The next big “Learning Modular Synthesis” project is Eurorack Expansion. The idea behind it is that you already have a semi-modular synth such as a Moog Mother-32 or perhaps a small modular system, and now you’re wondering what to add next. I’ll be covering a wide range of modules one at a time, demonstrating how they work, what they’re particularly good at, how you would go about interfacing them with your current system, and what new sonic and performance possibilities they would open up for you. The Eurorack Expansion course covers three different modules in each major “category” (such as oscillators, filters, et cetera), and then an ongoing web series of hopefully weekly movies covering additional modules.
But as the saying goes, you need to walk before you can run out and starting adding a second oscillator, more envelopes, an effects unit, et cetera. Therefore, for this series I’ve built up a core set of deceptively boring yet essential modules that will make it easier to interface the Mother (or whatever you’re using as your core) with the fun new modules you’re dying to try out. In this post I’ll spell out what I’m using for that core and why. Note that these are not the only modules you could use – there are plenty of excellent choices available in each category – but I want to get you thinking about what you might need, and what features to look for.
The images describe the initial version of this rack; I have since swapped out a few modules which are mentioned in the text. Click here for a link to the current version of the rack on ModularGrid.
Case & Power
I recently released an introductory course for the Mother-32, which included moving it out of its own enclosure into a Eurorack case. For that course, I used an old Monorocket 104 hp x 6 U skiff. Unfortunately, that skiff-style case is too shallow for some of the modules I want to include in the Eurorack Expansion series. Therefore, I’m going back to the enclosure I used for the original Learning Modular Synthesis course: an open-back 6U 19” desktop studio rack with a pair of 84hp wide Synthrotek rails + rack ears (spray-painted black) with threaded inserts. Going back to a smaller case meant I had less space for support modules; that’s reflected in some of my module choices below.
For the original course, I used a 4ms Row Power 40 to power the case, and was happy with how it worked. It uses an external 15v switching power supply (such as those used by laptop computers), and regulates + filters it down to the +/-12v and +5v required by Eurorack modules. This “hybrid” approach is becoming more common. Rated power output is 1.5 amps on the +12 and +5 volt rails and 1.25 amps on the -12v rail.
When planning your system, remember to always have at least a 20% safety margin between what your particular combination of modules requires, and what your power supply can deliver. Simulating this system on Modular Grid shows the core needs 970ma on the +12v power rail (and much less on -12). Running the math using the Row Power 40, 1500ma (1.5 amps) x 80% = 1200ma, leaving up to 1200 – 970 = 230ma on the +12v power rail for the module I’ll be reviewing in each movie: plenty of room, unless I started getting into power-hungry tube modules.
Clean power is also essential to a properly functioning modular synth. To this end, I’m excited that more companies are starting to offer power distribution bus boards that include additional on-board filtering. Therefore, I originally replaced the flying bus cables I used previously with a pair of MDLR Case Eurorack Busboards. These have lots of power connectors for modules (20 per board!), make it easy to connect to the main power supply of your choice (I ran standard 16-pin Eurorack power cables from the Row Power 40 to a free connector on each board), and even have on-board +5v regulators in the event your power supply only provides +/-12v. They’re also a great deal at 24 euro each, shipping from Holland. I’m considering replacing all of the bus boards in my main system with these. I’ve since exchanged these for a MIDI Hardware POWDIS heavy copper bus board and the Genus Modu Euro Header Adaptor system.
Notes In
Not all semi-modular synths have a MIDI interface built in; the Moog Mother-32 does, including an extra control voltage output that can be assigned to different MIDI controls such as the mod wheel. However, the MIDI controller I’m using – an Akai MAX25 – has a lot of additional control sources, including key velocity, aftertouch, and programmable sliders. I want to take advantage of these too while playing my modular, so I added an Expert Sleepers FH-1 ‘faderHost’ to the Eurorack Expansion system. It has eight outputs, which I’ve assigned to pitch CV, gate, velocity, aftertouch, two of the assignable sliders, and a built-in LFO (which I can control from the other two sliders on the MAX25). I wrote a separate article on programming the FH-1 to do what you want for your own system.
I’m a big fan of using a buffered multiple for pitch control voltages inside my modular (this article demonstrates and explains why). Therefore, I added a Malekko Performance Buffered Mult to this system, to drive both the Moog and any other VCOs I might add. I also followed the calibration procedures for both the FH-1 and the Mother-32 to make sure they gave me an accurate foundation to build on. (To match the voltage ranges required by different VCOs, I’m also including an Expert Sleepers Disting to use as a precision adder – I’ll talk more about the Disting below.)
To split the less-critical gate signal, I’ll be using a Black Magic Modular MonoMult. I also happen to like their cables, especially since I color-code the cables in my patches to make them easier to follow. I’ve also started using Hosa Hopscotch cables to perform simple 1:2 splits of audio and modulation signals.
Sound Out
On the output side, many users just plug the very high level signals from their modular straight into their mixer, and the use a combination of input pads & trims plus channel faders to reduce the signal down to the level they need – and that works fine, as long as your mixer has enough headroom. I personally prefer bringing the signal into my mixer at a “normal” level so I don’t have to keep remembering to treat those channels differently, as well as to preserve headroom (as sometimes I like to slam things really loud).
Therefore, I like to include a dedicated output module in my racks. The one I use most often is a WMD Pro Output. It has a headphone amp (great for monitoring without a mixer) as well as unbalanced -10 (“line level”) and balanced +4 outputs. I use the latter, as it helps suppress noise induced by external power transformers.
Mixing and Matching Signals
I strongly believe every system – regardless of its size – benefits from having one or more utility mixers in it. By utility, I mean a module that can not only attenuate and combine signals, but one that can also invert them if necessary, as well as add a steady positive or negative offset voltage to the result. Among other things, this allows you to adjust the voltage range of any one output to match what you need as an input to another module.
To fill that roll, I initially used a Happy Nerding 3xMIA that features six channels grouped together as three pairs. Each channel can be attenuated, inverted, or replaced with an offset voltage; pairs are sub-mixed together, and can be cascaded down the chain to the pair below it. And, it’s only 6hp wide! In later movies added onto the course, I swapped out the 3xMIA for an Erogenous Tones LEVIT8, because I found its ability to amplify – not just attenuate – signals to be very important. And even more recently, I’ve started using the Frap Tools 321 as it’s both compact and versatile.
Envelope Issues
It’s a trend in small synths these days – including semi-modular systems – to provide a single envelope generator, often switchable between AD and AR modes. Personally, I prefer different envelopes for my filter and amplifier: I like to use an AD or an ADSR shape with a low sustain level to “pluck” the filter, and then keep the amplifier open on sustained notes using an AR or another ADSR with a relatively high sustain level. On top of that, I might want to modulate another parameter or two with a different envelope or LFO.
To fill this roll, I’ve been using the Roland 540: It contains two ADSRs that can be looped as well as a voltage-controlled LFO with initial delay and multiple waveshapes inside one package (16 hp wide). I also happen to like the sound of its envelope shape: it has the classic logarithmic attack and exponential decay + release that I feel sounds more natural in many applications.
More VCAs
When a user shares their modular system in a forum and asks “what am I missing?”, many race to chime in “more VCAs!” In general, these allow you to shape the amplitude of other signals – such as LFO or FM depth – as you route them around your system. In the specific case of the Mother-32 I’m using as my “starter synth,” there is also no external audio input for the Mother’s own VCA – meaning if you want to try out a different filter with this system, you need to route it through the Mother-32s existing filter (Moog’s tip: set it to High Pass, and turn both the cutoff and resonance all the way down). The Mother’s own VCA is also hard-wired to its envelope: You can add to this envelope’s effect on the VCA, but you can’t replace it using the Mother’s patch panel.
Therefore, you’re eventually going to want to add more VCAs to your system. I prefer ones that can be switched or continuously dialed between linear and exponential response, and which also have an offset control so you can “open up” the VCA to hear what’s going through it without having to send it a voltage – akin to the Mother’s VCA Mode switch. For this system I chose an Intellijel uVCA II, which ticks all of those boxes and also is only 6hp wide.
What About a Make Noise Maths?
Many modular users – including those building their systems around a semi-modular core like the Moog Mother-32 – add a Make Noise Maths as one of their first expansion modules. A Maths can act as a utility mixer…or a pair of simple AD or AR envelope generators…or a pair of LFOs…or a slew limiter to smooth out signals…and much more. If you are a bit technical and are comfortable translating the Maths’ raw capabilities into the functions you require, then you will probably love this module or something in a similar vein such as the classic Serge Dual Universal Slope Generator; many do. On the other hand, if you are relatively new to the concepts in modular synthesis, you may find it easier to have dedicated modules for the functions you need – at least starting out.
(Tweaky side note: As hinted above, I have a personal preference for logarithmic attacks and exponential decays for my envelopes; the Maths is continuously variable from log for both, through linear, to expo for both – not quite the combination that is my first choice. But if you’re using very fast attacks, this distinction doesn’t matter, and envelopes is just a small part of what a Maths can do. )
Distings: The “I Wish I Had Another…” Module
When you get into modular synthesis, you will find that you always wish you had one more module to finish a patch – one more envelope, one more LFO, one more VCO, or an esoteric utility module that might be tied up elsewhere in the patch. To save money and space, I turn to the Expert Sleepers Disting (4hp and well under $200 each) to solve this problem.
The Disting is a chameleon module that can change personalities. The Mark 1 and 2 models supported 16 different functions, shown in the chart below:
The Mark 3 and 4 models contain over 50 functions (and growing!), including envelopes, filters, effects, audio and MIDI file players, and more.
Quite often, I’ll be using one of the Distings in this rack to transpose oscillators that use a different voltage reference for Middle C than the Mother-32 does (this is an issue in any modular system). The other will be used to fill in gaps as needed, such as a second VCO (mode 4C has really nice FM, and both 4C and 4D have huge-sounding sawtooth waves), a sample and hold, an extra LFO or filter or envelope, and more. Proving that I practice what I preach, I have five(!) Distings in my personal system to cover these “I wish I had another” situations.
Visual Aids: The Mordax DATA
If you’ve already seen a few of the modular movies I’ve created, you know I believe in connecting what you’re hearing to an understanding of what’s going on with the actual voltages and audio signals inside a modular system. Therefore, I’ve included a Mordax DATA in this rack, so I could constantly show you what the signals inside a patch are doing. For me, this is how you really grasp what’s going on with a waveshaper, resonance in a filter, and so forth.
The DATA is also much more than just a modular oscilloscope – it can also measure voltages and frequency (great for tuning or tweaking modules), generate its own oscillator and clock outputs, and it has its own spectral analyzer and spectrograph displays – so it’s well worth checking out.
(I’ll also be supplementing the DATA with the Spectre software to display harmonic spectrums.)
And Now: You’re Ready to Get Started!
Once you have a collection of seemingly mundane but essential modules similar to those above to cover your interfacing needs, I feel like you’re finally ready to start adding more exotic modules to your system. (I know; you wanted to get to the fun stuff first – I’m that well-meaning parent that insists you finish your vegetables before you get dessert.) That’s what the hole in the system above is for: to plug in a different module each movie. In the Learning Modular Synthesis: Eurorack Expansion course that will appear on Lynda.com and LinkedIn Learning this summer, I’m going to dive into a variety of modules in each basic category for you to consider:
The idea behind the selection of modules above is to give you a taste for the variety of choices available in each basic category. For example:
- For an additional oscillator, we’re going to try an analog VCO with multiple waveshapes and good tracking (the Intellijel Dixie II+), a versatile digital VCO (the Mutable Instruments Braids Macro Oscillator), and a “West Coast” style dual oscillator (the Verbos Complex Oscillator) to get a taste for AM, FM, and waveshaping.
- For an additional filter to supplement the Mother-32’s classic Moog transistor ladder four-pole design, we’re going to try a classic state variable multimode two-pole design (a Doepfer A-106-5 clone of the Oberheim SEM), a filter prized for its extremeness and instability (the Erica Dtech enhanced clone of the Polivoks filter), and a “formant” style multiple-peak filter (the Doepfer A-127 VCRF Triple Voltage Controlled Resonance Filter).
- For waveshapers and other sound modifiers, we’ll be playing with the Random*Source authorized clone of the much-loved Serge Wave Multipliers, the AJH Synth Ring SM (that contains a ring modulator, subharmonic generator, and mixer), and a Happy Nerding Super Sawtor that makes one oscillator sound like a buzzing mass of oscillators.
- For additional modulation sources, we’ll take a look at the Industrial Music Electronics Kermit “Dual Modulation Aid” digital LFO, what is perhaps the ultimate single envelope generator in the WMD Multimode Envelope with its expander, and the Buchla-inspired Sputnik West Coast Random Source for continuously fluctuating, quantized, and “stored” random voltages.
- In the area of additional amplifiers and mixers, we’ll explore an STG Soundlabs .mix that recreates the unusual clipping characteristics of the modular Moog’s CP-3 mixer, the Verbos Scan & Pan with voltage control over level, panning, and blending between four channels of signals, and the new Lifeforms Dynamic Impulse Filter: an evolution of the classic West Coast LPG (Low Pass Gate).
- And finally for effects, we’ll look at an analog phase shifter and chorus/delay unit (the Roland 572), a digital stereo delay (the WMD/SSF DPLR), and an update on the classic digital reverb effect (the brand-new Synthrotek VERB – so new, Modular Grid doesn’t have an image of it yet; an image of their DLY is standing in for now).
Since there’s far more modules in the Eurorack world than just the 18 mentioned above, I’m going to keep creating movies of additional modules and releasing them through the Learning Modular web site, including adding them to the version of the Eurorack Expansion course streamed through this web site. So stay tuned; it’s going to be a fun couple of years while we explore different ways of expanding the sonic territory you can explore with your modular synth.
Best of luck with the new series Chris, looking forward to absorb your insight and wisdom 😉
Thanks, Guido. I just finished most of the recording for it this week, and was happy I was able to fit in a lot of synthesis techniques in addition to reviewing each module. However, the “cost” of that approach is now I have a LOT more material recorded than I originally expected (hours and hours), so I’m going to be editing this course for the rest of the month!
Thank you for your articles Chris! I’m starting my first rack now (Linnstrument – FH-1, SEM, and modules) so your work is exactly what I need!
Thank you, Vlad! I’m just finishing up the Eurorack Expansion course, and I’m happy to say this rack has worked out very well. When I started I questioned myself about whether two Distings or a triple mixer were overkill, but as I kept trying out different modules, there were times when I used both Distings or all 3 mixer channels – I can’t emphasize enough how useful utility and “glue” modules are!
Hi Chris, thanks a lot for sharing your know-how! I have just finished your Moog Mother 32 training videos on Lynda. You are a great teacher and I’m looking forward to start watching your other two courses.
I will attend Superbooth 2017 later this month in Berlin and hope to lean more about Eurorack modular as well as to get to know all the different brands. Any hints on how to approach such an event to get the most out of it? I can imagine that the amount of information and impressions is overwhelming in short time. What strategy, if any, might be useful?
Cheers!
The best advice I can give is: assume you won’t have time to see everything, so prioritize to make sure you see what you really want.
For example, there may be specific modules you want to check out; make sure you visit those companies first. In general, I put a higher priority on seeing modules I buy for their sound, such as oscillators, filters, effects, and percussion. Modules such as LFOs or envelopes or sequencers that I would buy based on their features rather than their sound, I can always learn about later on the internet etc. So, I personally look at the list of exhibitors before the show, and divide them into three levels of priorities (really want to see/hear = #1; #2 = interested but I can learn more later; #3 is I don’t think I’m that interested, but if I have time I’ll visit in case they surprise me).
But another priority is once-in-a-lifetime experiences versus ones you can have later. That means listening to talks and concerts that may give you inspiration and which are only going to happen once and possibly never again, compared to module demos where someone may post a video later. For the talks, I find the most useful ones are individual musicians or engineers sharing their opinions or memories as they often have specific advice; less useful (for me) are panels where they talk about “the future of the industry” etc. which are less specific.
Have fun! I hope to get to Superbooth someday – maybe next year…
Chris, many thanks for your invaluable advice. I really didn’t know what to expect from Superbooth as I am quite new to modular synths. But this event was simply amazing! Well organized, huge selection of modules, cases and other stuff, fun DIY workshops, inspiring live performances and talks. Best of it all: talking to so many passionate people. Especially some (i.e. many) exhibitors – often the owners/founders themselves – were incredibly nice and helpful. Also LM was recommended several times…
I am looking forward to your next series Eurorack Expansion!
Thank you for the follow-up – I really appreciate it!
So I’m very interested in this series and can’t wait for rest of the videos. I have a Mother 32 and couple of modules and just starting out. Is there a place I can post a setup I put together and you can check out and give recommendations?
Longer-term, I’m looking at maybe setting up a private Facebook group (some have suggested for Patreon subscribers) that would allow for that a bunch of other things. But in the immediate term, feel free to post it here and I’ll lend what help I can. Ideally, if you use ModularGrid.net, make the rack public and share the link here; it’s easier to explore the rack and the links for each module on ModularGrid than it it to just look at a photo. Otherwise, share what you have.
Thank You. Here’s what I have so far from what I looked over so far and some you recommended in this article.
https://www.modulargrid.net/e/racks/view/454321
Preliminary comments; I may add more once I get a better idea about a few things.
The first question always is: What do you want to do with this rack? What type of music and sounds do you hope to create?
How much of this have you bought already, versus are considering buying? I ask in particular concerning the envelope generators – both the Blue Lantern and the Maths have an attack shape that I don’t think is optimal, and I would recommend replacing at least one of them with something else – the WMD MultiMode Envelope being my favorite in terms of flexibility; the Roland 540 is also a workhorse although maybe not as sexy as the WMD or Maths.
And how big of a hurry are you in? (I’d recommend replacing the Pittsburgh Distro with a Frap Tools 333, as I trust the impedance of the Frap to make it a better-behaved module, but it’s just started shipping from Italy – it might take a few weeks to get one in the US; I don’t even have mine yet coming direct from Italy.)
How many voices (independent sounds) are you hoping to play at once? You have a lot of oscillators and a lot of buffered multiples; that’s why I ask. (I have a lot of VCOs too and like variety, but knowing how many voices you want to play at once will help me hone in on what to recommend on in the buffered mult department in particular.) My initial reaction – beyond replacing the Distro with a 333 – is to replace the Intellijel Buffered Mult (which is very good, mind you) with an AJH V-Scale. (See https://learningmodular.com/improving-intonation-using-the-ajh-synth-v-scale/ for more on why I feel so strongly about the V-Scale.) If you’re going for only one strong voice, you might also be able to leave out one oscillator (either the Dixie or the Z3000), and use that space and money on something else.
Are you planning on using the Moog as your MIDI to control voltage interface?
The uZeus is not my favorite power supply; it’s been known to cause noise issues with some modules (such as the Intellijel Polaris). You’ll need the “big” switching power supply to connect to it in order to power this many modules, and make sure you leave the -12v load jumper (see its manual) connected. If you haven’t already bought it, I think you’d be better off with a 4ms Row Power 40, or one of the new Synthrotek supplies.
There’s nothing wrong with the MIX4, but for the same money, a Happy Nerding 3x MIA is more flexible (more channels; the ability to invert the inputs as well). I actually like the Erogenous Tones LEVIT8 even more as it can boost a signal by up to 2x, but it might be more rack space and $ than you want to spend.
Those are my very first impressions; once I learn more about what you want to do, and what you already have, I’ll take another pass.
I want to be able to make my own sounds for leads, basses, pads, atmosphere, drums and have some that make sounds similar to what Moog, Dave Smith, Oberheim and Waldorf do. I have the Moog though I considered if I should get one more or two more. I also watched a video of a guy take a Maths, Z3000, Cwejman VCA-4MX and LFO and made all types of bass drum sounds and other tom like sounds. Which is something I found interesting. I’m starting out with 9-12U of space, and I’ll expand
once I reach that point.
I write hybrid cinematic and electronic music.
What I have so far are Moog Mother 32, Intellijel Multiple, Blue Lantern Simple ADSR, TipTop Z3000 MKII, and Pittsburgh Outs MKII. The ones I have or mocked up in the rack are ones I’ve heard of or known of. Blue Lantern was only one I didn’t but it was inexpensive.
Roland 540 probably would be my pick but that WMD MultiMode Envelope looks great though.
I’m not in a hurry, I’m bascially putting together a shopping list to expand on what I have so far. Then start purchasing later this year. Never heard of Frap Tools 333 but looks like a better choice.
At least two voices starting out and expand it later.
I plan on using the Moog for midi then buy one or two Expert Sleepers modules later on to send midi from my DAW.
TipTop uZeus was included in the Happy Ending Kit I purchased. So which would be better to get, 4ms Row Power 40, or Synthrotek Deluxe Power Module?
I would be happy with either Happy Nerding 3x MIA or the Erogenous Tones LEVIT8.
I didn’t add them but the Make Noise 0 Coast and Pittsburgh Lifeforms VCO’s looked good to me too.
Thanks for your response and feedback. I just wanted to plan ahead before I started buying anything else. I’ll be looking forward to more videos here and on Lynda.
Hi, Daniel –
Thanks for the explanations!That helps. For example, saying you create cinematic music, and note the Waldorf as one of your reference points, reinforces you should definitely get the Braids (or at least some wavetable-capable VCO, although the Braids also does a lot of other things as well including drum sounds).
Speaking of drum sounds: For percussion sound patch ideas, watch the tutorials by David Bessell of Node: https://www.youtube.com/user/ManorRecords
The Frap Tools 333 is available now, BTW – I saw Perfect Circuit has then in stock. (Plus they have a 10% discount on everything over most holiday weekends…)
I’m torn on the Roland 540 vs. WMD MME (MultiMode Envelope). The 540 is a workhorse, with two nice ADSRs plus a VC LFO. OTOH, if you are the type of person who likes to focus on how a single note evolves, the adjustable shapes per segment of the MME really allow you to dial in that evolution. If pushed, I’d say keep the Maths (if you have the inclination to spend some time learning it – it’s very powerful, but not as “obvious” as some modules; it’ll reward time spent with it), sell the Blue Lantern ADSRv2 to free up some space and funds, get the Roland 540 for now, and then look at adding the WMD MME down the road.
Continuing the theme of saving money and space for other modules in the near term, since you already have the Z3000, I think you can pass on the Dixie for now. The Dixie is great, but the Z3000 is fine too, and they cover similar territory. (The Distings can be used as second oscillators if needed to fatten up a voice, plus they have really good sine and triangle waves; their sawtooth and square sound great for bass, but know that they start to alias when you play them at higher pitches.)
I’m very curious to try out the new Pittsburgh Double Helix oscillator. But in the meantime, if you want an FM pair, you can patch it with the modules you already plan on getting – for example, the Braids in FOLD mode through a VCA and into the Disting in Linear FM mode makes a really nice, solid-tracking pair. And in general, I’d think about getting a wavefolder of some description (I like the Random*Source Serge Wave Multipliers; I know others love the UltraFold an uFold) to give yourself more West Coast-ish timbral choices.
Speaking of West Coast techniques, the 0-Coast is a fun little unit, and a great introduction to West Coast approaches (despite its “no coast” name).
If the choice was between a 4ms Row Power and a Synthrotek Deluxe, I would go with the Row Power, as in my experience the Deluxe has some issues of not wanting to start up if there’s a module that needs a lot of power on start-up (in my case, the Verbos Complex Oscillator or WMD Pro Output). They may have that problem fixed in their newer Super Power modules, but I’ve not used them yet.
Hope that helps…
Thank you for the advice. I’ll put that was well in consideration when building my rack.
put in your recommendations and swapped a few, think I got it laid out now. https://www.modulargrid.net/e/racks/view/456771
Looks awesome! As it so happens, I’m just finalizing orders for my own ES-8 and 333 this week.
You’ll eventually want to add some variety in the filter department; in the meantime the Disting has some alternate filter modes you can experiment with.
I put in my order for the 333 too. Should be here Saturday.