Euro Modular Synth ReadMe.1st

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Euro Modular Synth ReadMe.1st

Post by PhineasFreak »

I seem to be answering a lot of questions via PM, msn and email recently about real basic patching of a modular synth - the same stuff i wish someone had told me when i first started, but was afraid to ask and wasnt yet ready to cope with reading whole books on principles of synthesis. (so, for those with zero knowledge here's some slightly oversimplified sweeping generalisations for the sake of easy explanations to those who want to get their newly acquired/setup modular tested and working):

generally there's two sorts of input/output signal:
- Audio - sound in the form of an alternating current (AC) at a frequency (pitch) and amplitude (volume)
- CV - a direct current (DC) signal used to control stuff.
(These are not automatically interchangeable and hence trying to use an audio signal to control a CV input parameter or trying to hear a CV may not work. there are exceptions to this though, especially more so with some module types/manufacturers.)
- all cabling and signals in eurorack are mono - if you want stereo you need multiples of each module or dual modules designed for stereo!

- Oscillators send a signal even with no input. even if there's nothing saying what pitch to play or when to start/stop - that is done by other modules such as sequencers, VCAs etc. This is true for VCOs - they'll make a constant tone and LFOs - they'll make a constant CV (dependent on settings)
- VCAs need a CV to allow sound to pass through. unless there's an offset/initial control set to allow some audio through. In a most basic patch this CV is generally a gate triggered envelope.
- Envelope Generators need to be triggered. This is generally done via a Gate signal, but can be a CV from pretty much anything providing enough voltage.
- Filters can completely silence a sound. since on a basic level filters remove frequencies from an audio signal, at certain settings a low pass filter may, for example, take all the high frequencies out of an audio signal that is just treble so nothing remains.
- Some filters can self-oscillate. Effectively, when certain settigns are cranked up high enough the filter can emit a sound even with no input, generally a relatively loud audio frequency sinewave.
- VCAs and Filters can distort when fed a sufficiently loud audio signal. this can be a very god thing - i love to feed the ASys RS-100 LPF and/or RS-180 VCA a really hot signal by putting a cranked up VCA or Filter with lots of Resonance before them in the signal path because they overdrive in a lovely soft, warm fuzzy way.
- Most Sample & Hold modules require an external input to sample, AND output a DC CV signal. at sufficiently high sample rate settings the CV output can be used as an audio source, but generally the output will be either a stepped sequence of CV signals if the sample is a wave or some random/pseudo-random CV singals if the input is noise or a very complex audio source.
- To split a cv that is to control the Pitch of multiple VCOs you will need a Buffered Multiple. if you use passive multiples or stackcables, too many modules drawing from the same pitch source will affect the voltage causing tuning to be off. you can get away with only a few splits with a passive multiple/stackable, sometimes.
- Buffered Multiples have designated ins/outs - these wont work like a passive multiple. you can't get a signal out of an 'in' or put an in into an 'out' with a Buffered Multiple.
- Some modules can be very sensitive to tiny changes in CV or settings, others can require quite big changes to get any significant difference in output. CVs and Audio signals can sometimes need attenuation or amplification as a result, and sometimes a DC offset can be necessary to allow CV's/Audio signals to be used interchangeably. some modules have controls such as 'Gain', 'CV' amount and 'Offset' built in. otherwise, a dedicated Attenuator, a VCA or an Offset module may prove a valuable, if not essential component of a system.
- Audio can come out much louder or quieter than expected sometimes. there's a myriad of reasons, but to pick just one example, if you have certain wave forms being mixed together, phase cancellation can take place in certain circumstances, resulting in dead sounding quiet zones when sweeping through settings. your module isn't broken. modules like the Doepfer A-136 are absolute sods for this, and they are so sensitive i find that using attenuators in the signal path before the CV inputs can be invaluable since it's so sensitive at some settings...
- Cheaper Ring Modulators tend to be AC-coupled. this means they dont work on CVs. for this you need a DC-coupled Ring Mod.
- something i have just been alerted to: on doepfers homepage where the standards are laid out theres no mention of pitch cvs. generally pitch cvs are between 0 and +10V, but not all vcos can respond to/accurately track the full 10V range. this is why most quantisers dont accept -ve cv values!

to test and get comfortable with new modules or a new system, it helps to use this absolute basic patch:

VCO -> Filter -> VCA -> out

You will require an analogue sequencer/Cv keyboard/computer/midi source plus midi -> CV device to produce 1v/Oct note CVs, Gate signals and so on, unless you want to use LFO's and other modules.

This patch will give a standard monophonic note follows note at given pitch, with given length, synth patch. To test other modules most effectively, try patching their cv outs to the Filter cutoff or the EG Decay time for example.

p.s. You're using a modular - rules are meant to be broken; with the exception of manufacturer warnings about specific module settings, inputs and outputs that dont like being used in certain ways, experiment! the whole point of a modular is to mess about and find unusual ways to trigger an envelope or shape a filter cut-off etc.

this link may be of interest/use to many:
Last edited by PhineasFreak on Tue Aug 25, 2015 5:31 am, edited 4 times in total.
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Post by nrdvrgr »

Envelope Generators need to be triggered.
True, but not all of them - Maths, Envelator, A-143-1 etc etc can be cycling, which makes them LFO´s / oscillators.

Some filters can self-oscillate.
...which makes most of them excellent oscillators as well.

Hell, almost anything can be something else than they were intended to be. The beauty of modulars I guess...

BTW, great thread and idea!
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Post by shred »

:yay: :guinness:
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Post by Pfurmel »

Great idea, maybe a good addition to the Start your own Modular sticky in the general discussion forum?
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Re: Euro Modular Synth ReadMe.1st

Post by »

PhineasFreak wrote:to test and get comfortable with new modules or a new system, it helps to use this absolute basic patch:

VCO -> Filter -> VCA -> out

You will require an analogue sequencer/Cv keyboard/computer/midi source plus midi -> CV device to produce 1v/Oct note CVs, Gate signals and so on, unless you want to use LFO's and other modules.

This patch will give a standard monophonic note follows note at given pitch, with given length, synth patch. To test other modules most effectively, try patching their cv outs to the Filter cutoff or the EG Decay time for example.
Since this is for noobs, we should be more specific: this also requires an Envelope being triggered via something to open said VCA.

Below is a visual of a typical East Coast, single VCO mono patch.

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Post by Drumdrumdrumdrum »

Is the difference between an attenuator (passive) and a VCA (active) is that one boost a signal and the other cuts a signal?
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Post by tehyar »

Drumdrumdrumdrum wrote:Is the difference between an attenuator (passive) and a VCA (active) is that one boost a signal and the other cuts a signal?
The difference is that one passively cuts a signal, and the other boosts it by an amount relative to the voltage you provide. (VCA = Voltage Controlled Amplifier)
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Post by glitched01 »

Also, the "passive" part of "passive attenuator" means that it requires no power.
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Post by Meat Parade »

Awesome thread, good to go back and read some basics...
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Post by suboptimal »

When a friend first got the modular itch I sent him the following as an intro. Somewhat tailored for his preferences, of course.


Google “basic sound synthesis” and read some articles to get a sense of basic building blocks of synthesizers. You’ve already played around some so you’ve got an idea, but getting a more specific picture and learning more about the terminology is a good idea before you start researching specific modules. is the toy store of choice.

Download “Rack Planner” and the package of Euro module images from here:

and here: ... browse.php

(You may need to click on the “Euro” button at the top to get to the Euro section. Click on the down arrow by “Euro” at the top of the screen and download the whole zip).

This will let you play modular tetris as you think about which modules you want to buy and how they’ll fit together.


Cases are measured by height (3U per row) and width (the standard width is 84 HP, 1 HP being the width between two mounting screw taps). Most modules come in even HP widths: 4, 8 and 10 are common. A few modules come in odd widths, which is a pain.

Basic cases come in two flavors: 6U (2 rows) and 9U (3 rows). If you plan to stick to a small system, 6U is fine. I started with 9U because I knew that I'd get obsessed with this stuff. 9U is the cheapest option per HP, which is the unit used to measure the width of modules. The standard 3U row is 84 HP in width. The cases I have are all from Doepfer. Other case manufacturers are Modular World (a Chinese outfit with some quality control issues, but least expensive) and Monorocket (very nice cases, but availability is an issue). You can also buy rails and power supplies separately and build your own case. TipTop Audio offers a complete 3U solution called the “happy ending kit” as well as separate rails and PSUs. Flight of Harmony also offers a power supply.

The Doepfer A-100-LC6, the “Low Cost 6U” wooden case, is probably your best starting point. It has a robust power supply and is well made.


Manufacturers in General

There are a lot of synth builders. I recommend focusing on a handful of them for your initial system.

Doepfer is the German company that really got Euro started, although technically they didn’t “invent” the format. They offer a ton of different modules, many of which are basic, fundamental building-block type modules and others that are quite exotic and great sounding. Doepfer stuff is less expensive than a lot of others but still good quality.

Malekko is located in Portland, Oregon. They’ve got a partnership with an old school modular guru named Grant Richter who is behind the Wiard Synthesizer company. Malekko/Wiard modules are among the best in Euro, and as a bonus, they’re not too expensive for what you get. A nice bonus is you can order directly from Malekko to save tax and shipping costs.

MFB is another German “budget” module builder. They offer a nice dual oscillator and a nice dual LFO that are good basic modules for small systems. Worth considering because they are inexpensive and sound pretty good, although I ended up selling on the dual VCO for something with a bit more I/O. MFB stuff is cheap feeling and cuts corners, but for basic utility it’s not bad.

Make Noise is behind the MATHS and a bunch of other awesome stuff. Easily the hottest manufacturer out there.

Intelligel offers ultra-dense small modules that pack a huge amount of power into a tiny space. They’ve got a wide slate of incredible utility modules that are a bit expensive but powerful, “buy once” kind of modules.

Bubblesound makes outstanding, dense stuff, including the uLFO, the module with the 30 minute cycle time.

TipTop Audio is a high quality builder with some good stuff available at decent prices. His oscillator and filter are both high quality and not too expensive.

Synthesis Technology aka MOTM is operated by another of the old school modular designers who has recently expanded from the 5U format to making Euro modules. The E350 oscillator is from them.


Oscillators produce the basic waveform that gets sound going in your system. Although other modules can produce a waveform (such as resonant filters) a dedicated oscillator or two is an important basic component of a fun system.

Oscillators are also referred to as VCOs (“Voltage Controlled Oscillators”), although some oscillators are actually DCO (“Digitally Controlled Oscillators”). In the old days, DCOs were ridiculed as have terrible sound quality compared to analog VCOs, but these days there are a number of DCOs that are really amazing.

Oscillators that go into sub-audio range for use as modulation sources are LFOs (“Low Frequency Oscillators”). You can save space by getting VCOs that can be used as both audio and LFO sources.

Things to look for in an oscillator are:
· Number of simultaneous outputs and waveform types – the more the merrier.
· Number of CV inputs, specifically
o Lin and Log FM inputs (hopefully simultaneous, but many VCOs only offer one or the other, or a switch between the two, which is ok)
o V/Oct input (nice to have more than one, but this is rare)
o Other magical inputs
o Frequency range – usability in audio and sub-audio (LFO) ranges.

My two cents about oscillators I’ve used, or read a lot about:

Dopefer A-111: Doepfer’s oscillator options are often overlooked but their “High End VCO A-111” has a great reputation for quality. I’ve never used it but it’s worth having on your radar.

Malekko Oscillator and Anti-Oscillator: Two very different modules but both have excellent sound quality. The Anti-Oscillator incorporates a wavefolder into its design, which for practical purposes has an effect not dissimilar to a filter. Capable of very complex tones. The Oscillator (also referred to as the “Unkle”) is a very powerful VCO with a lot of awesome features. Two worth noting are its ability to be used as an LFO (the “fine tune” knob pulls out and switches it into low frequency mode) and its phase control (essentially allowing it to produce very complex waveforms). Starting out with one of each of these isn’t such a bad way to go.

MFB OSC-02: A pair of oscillators in a single panel. Limited I/O, but a lot of people love the sound. Personally I found the lack of controllability limiting, but the cost is ridiculously low and it does sound nice. I think this is more of a “musician’s VCO” than an experimental VCO like the Malekko stuff.

TipTop Audio Z3000: A hugely popular VCO. I’ve not used it but it sounds great and is quite economical.

Livewire AFG: The Livewire AFG is huge by HP measure, but also an incredible module. Very, very popular for its depth of tonal shaping power. I found it was too big but I mention it because it might appeal to you. Beautiful module that’s exquisitely built. These come up used pretty often and are a bargain for what you get. Also can serve as a LFO.

SynthTech E350 Morphing Terrarium. This is the wavetable oscillator that I would not be without. Hard to get used, hard to get new. Just plain hard to get. Also can serve as a LFO.

Bubblesound uLFO: Excellent LFO that also goes well into audio range and sounds great. An excellent alternative to the Malekko modules. Tons of I/O. One of my favorite modules.

Harvestman Hertz Donut: I mention this because it’s badass. Harvestman is a digital wizard and his modules are expensive as hell, but this module is capable of some very unique stuff. A dual oscillator so you’d only need this to be set in the oscillator department, though it’s I/O is not as deep as some others and it can’t go into LFO range.

MFB Dual LFO: If you go with VCOs that don’t go into low range, the MFB Dual LFO is a cheap and quality way to get a pair of LFOs into your system.


I recommend that you get at least one filter, or VCF (Voltage Controlled Filter). Huge range of options here, including things that aren't technically filters, like wave shapers/folders, though those tend to be more expensive. Things to look for in filters:
· Number of signal and modulation inputs. The more the merrier.
· Response curve (typically 12db or 24db). This affects the tone of the filter.
· Mode types: Typical filter modes are Low Pass, Band Pass, High Pass and Notch. Low Pass is the one I use heavily, but having a multi-mode filter is pretty useful. Some filters offer outputs for different modes at once.
· Tonal features: Highly subjective. Some filters can be overdriven in beautiful ways. Others respond more or less well to audio rate modulation at the V/Oct input. Search Muffs.

Filters I’ve used or read about:

Cwejman DMF-2: This is the green module that I talked about being too expensive for your initial foray. Gorgeous sounding with tons of I/O, but Cwejman is the ultra-premium brand in Euro and his prices are getting higher all the time. These occasionally come up used but get snatched up within hours of being offered.

Malekko Borg and Boggie: Both of these filters have deep modulation options and sound great. Also not too expensive. They use vactrols (light-based parts) which have a unique, “round” tone.

TipTop Audio Z2040: I’ve not used this but it gets rave reviews. Nice small form factor.

Topobrillo Triple Wavefolder: Hugely popular alternative to conventional filters that looks like a lot of fun. I’ve not used one of these but lust after one.

Suit and Tie Guy Wavefolder: Love this module and consider it one of the more musical modules in my system.

Harvestman Polivoks VCF: I didn’t like this one especially but a lot of people do.

Doepfer, generally: Doepfer filters are generally considered to be underrated. I’d love to try all of them some day.


Envelopes are useful modulation sources. I’d cut to the chase here and say that the MATHS or the Malekko Envelator are the things to consider. Personally I think the MATHS is too good to pass up. It can act as an audio source, LFO, trigger source, slew (smoothing) generator on signals, waveshaper (pseudo-filter), envelope follower, trigger delay, etc.etc.etc.


A lot of modules don’t have built-in attenuators to control the level of signals going into them, and I can’t think of one that lets you attenuate output. Attenuators can be passive (unpowered) and these are very cheap to build (just a knob , two jacks and some wire). But powered attenuators are much better.

VCAs (“Voltage Controlled Amplifier”) are a core building block of any synth. VCAs come in a lot of stripes. I often use a filter as a VCA, but in a small system I think it's better to look at a normal VCA. What a VCA lets you do is not only control the level of a signal (i.e. acting as a volume knob) but also lets you control that volume level from an external source.

The Doepfer A-132-3 Dual VCA is an outstanding module in terms of price and performance. I’d just plan on getting one of these.


There are lots of options for mixing signals. Doepfer’s mixers are cheap and good enough. Other options are the Suit and Tie Guy .MIX (a bit more expensive but better sounding, IMO).

A mixer is a good “output stage” option since it lets you control levels before you hit your audio interface with a hot signal. The Malekko Output module provides some quasi-stereo capability.


I buy almost all my cables from Ad Infinitum. Good quality, great service. TipTop Audio makes “stack cables” which are expensive ($8 each) but handy to have a few, especially in a small system. They act as multiples, letting you patch one signal to multiple destinations.
Last edited by suboptimal on Thu Oct 06, 2011 11:08 pm, edited 1 time in total.
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Post by haven »

tehyar wrote:
Drumdrumdrumdrum wrote:Is the difference between an attenuator (passive) and a VCA (active) is that one boost a signal and the other cuts a signal?
The difference is that one passively cuts a signal, and the other boosts it by an amount relative to the voltage you provide. (VCA = Voltage Controlled Amplifier)
Actually VCAs usually do not add positive gain. They are more like Voltage Controlled Attenuators since they actually turn things down. Max CV into a VCA control input will set the amplifier to unity gain or 0dBv (no gain). 0v CV into the VCA will cause it to fully attenuate ie -80dBv.

A VCA is Voltage Controlled.
An Attenuator has no voltage control.
That is the operational difference.

note- some VCAs do provide some gain but this is rare as the traditional use of a VCA is to turn down a signal until control voltage is applied.
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Post by euroarg »

great great great! :yay: this is an amazin tutorial. Big Thanks.
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Post by euroarg »

suboptimal great info! very usefull to choose the right modules!
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Euro Modular Synth ReadMe.1st

Post by construct09 »

Great thread...thanks for sharing :hail:
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Post by dalasv »

suboptimal wrote:Malekko is located in Washington state.
Here in Portland, Oregon, actually ;)
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Post by mattysal »

this is an awesome thread,

just started my euro 3 months ago and cleared some stuff up for me i wasn't so about!
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Post by suboptimal »

dalasv wrote:Here in Portland, Oregon, actually ;)
Fixed! :tu:
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Post by z3r01 »

Awesome thread! Thank you all for the information. :tu: :tu:
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Post by Leoespejo »

Fantastic Thread, I think it shloud be in the Sticky Topics zone of the forum..........I wih i had read something like this when starting...
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Post by lag »

great thread!thank you very much for all the information :tu:
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Post by mystico »

thanks guys you rock :sb:
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Post by thanatronique »

This is exactly the kind of thread I was looking for. Thanks guys!
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Post by dude »

this is great stuff for the beginner for the most part! i do wish it were in modular general as the vast majority of this stuff is not euro specific but c'est la vie.
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Post by mornel »

Thanks to everyone who has contributed to this thread! Even though I've had my modular for a few months, and have been using synths for almost 15 years, I learned a lot of good stuff here.
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Post by baboo »

more tips:
Subtractive is also cool - even for a frequency modulation patch it is sometimes a good idea to start with a typical monosynth patch and add the good stuff as you progress
remember about gain and attenuators there are many VCAs and filters out there that overdrive when you input non-attenuated signals to them. a single wave from a vco is sometimes enough to distort. this can be a good thing but if you're going for a clean, transparent sound, try attenuating your signal
if a module doesn't have CV control over something it doesn't necessarily mean it is uncool. just send a signal thru a VCA before this module to control it with cv- your amount of gain can be the CV control.
when setting up an FM patch don't reduce it to two oscillators sine on sine. use more modulators in chain, experiment with different waveforms, filtered ones, wavefolders. And use a VCA between your modulator and carrier! A noise source with it's own filter and envelope can also add much variety
Remember that you can modulate anything with anything you can modulate your oscillators but also a bunch of other stuff- VCAs, filters, wavefolders, VC-mixers, the list goes on.

have fun!
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