Behringer has a huge range of Eurorack modules at very reasonable prices. Most of them are based on vintage modular systems such as the Roland System 100, Moog Modular and ARP 2500. While they are great, they are also quite particular to those systems and are more geared towards people wanting to recreate those classic synths. However, Behringer has started to produce some more mainstream modules, and that kicked off with BRAINS.

BRAINS is based on the Open Source firmware from the Mutable Instruments Braids & Plaits modules, which are probably the most popular modules in all of Eurorack. It’s a voltage-controlled oscillator (VCO) that contains 20 different synthesis algorithms making it an incredibly versatile sound source.

You’ve got your regular virtual analog waveforms like triangle, saw and square, but you’ve also got waveshaping, wavetables, supersaw, FM synthesis, drum synthesis, noise, strings, chords and speech. BRAINS can be every sort of oscillator you could wish for. Each algorithm has three parameters to play with or control via CV. You’ve even got two audio outputs with the second one offering an alternative version of the first.

To top it all off it’s got a rather nice-looking oscilloscope display showing you the waveforms that are being produced. BRAINS is undoubtedly a great place to start.

Street Price: $159
Behringer.com

It has a strange name and an unusual front panel compared to Eurorack’s preferred aesthetic of silver and black, but Capt’n Big-O packs quite a punch as a warm and characterful analog oscillator.

If analog is your thing then you will find a lot of like there. For starters, you have four individual waveform outputs for the sine, triangle, sawtooth and square shapes that it generates. You have both coarse and fine-tuning over the pitch, a hard sync input and support for both linear and exponential FM modulation. These are all the things you’d expect on an analog VCO.

However, Capt’n Big-O has some special features. Built alongside the oscillators is a wave-folding circuit and a unique overdrive designed by Pittsburgh Modular. The wavefolder turns the waveform in on itself to create more complex timbres. It’s connected to the Sine wave by default but you can patch in anything you want. The overdrive adds bulk and character to the sound is completely independent and waiting to be patched. That’s the really cool thing about these two circuits is that you can patch any waveform or another oscillator into them making it useful for more things than just itself, and that’s what we like.

Street Price: $149
Cre8audio.com

The Eurorack modular format was created by Dieter Doepfer as a cost-effective alternative to the big Moog and Buchla modular systems. His Doepfer brand has a huge range of very affordable modules and you’d do well to check them all out. But there’s one that I like in particular and that’s the Wasp Filter.

The Wasp was a quirky little synthesizer built by EDP in the UK in the 1970s. The filter was particularly celebrated for its grit and energy. Doepfer has recreated the circuitry for the filter and put it into a rather good-looking, aggressive and expressive-sounding package.

It’s a 12dB multimode filter where you can mix the balance of high and low pass filter modes, or take the bandpass version on its own. It excels at bite and distortion and if you want things clean then don’t push it anywhere past 6 on the level dial. It has two CV inputs, one with attenuation, for control over the cutoff frequency and a very screamy manual resonance control.

The special edition version features the black and yellow stylings of the original synth which looks tasty in any rack.

Street Price: $105
Doepfer.de

The Eudemonia is part of Dreadbox’s Chromatic range of colourful and good-value Eurorack modules. The great thing about it is that it incorporates a mixer, VCA and a filter making it brilliantly versatile and perfect for a small system.

So, first of all, you’ve got three audio inputs at the top which can be mixed by the three knobs and overdriven with additional gain. A perfect companion to something like the Capt’n Big-O where you could mix three of the waveforms together to create a more harmonically rich combination. From there the mix goes through the 24dB/oct low pass and 18dB/oct high pass filter before arriving at the VCA where you can control the shape of the output with an envelope or LFO.

The resonance can put in a lot of energy to the point where it starts to self-oscillate. Using the 1v/oct input you can actually use those oscillations as a VCO.

With an oscillator and Eudemonia, you are ready to go.

Street Price: $99
Dreadbox-FX.com

Something “Simple” is always appreciated and this envelope from Blue Lantern is good, cheap and has some special skills that are very useful.

Simple is a four-stage envelope generator with knob controls over the Attack, Decay, Sustain and Release. There’s also a Time knob which plays with the length of the envelope which also effects the speed of the loop. Because this isn’t just a one-shot envelope, it can also loop into an interestingly shaped LFO.

There are three modes: Normal for regular envelope generation in response to a trigger or gate, Looping mode, or Gated mode where it loops as long as the gate is high. It has two envelope outputs which is really useful for running a VCA and a filter from the same gate signal. And unusually it has a “Thru” meaning that the incoming Gate signal is routed back out again to trigger something else. That’s a really great workflow.

Street Price: $89
BlueLanternStore.com

The 3PT is a good-looking module with that single middle knob surrounded by three competing halos. It’s very hands-on but very multi-functional with lots of different modes hidden behind the handsome front panel.

3PT is a three-channel voltage generator and it can do all sorts of useful things to add spice and movement to your modular. There are seven different modes in total. These include a performance tool, chord generator, randomiser, quantiser, sequencer and LFO.

The most obvious and default mode is LFO. The main knob sets the main speed and then the controls for each channel let you adjust a frequency multiplier and change the shape of oscillation. That’s three LFOs all running relative to a central clock. For chords and quantization, you take the incoming CV and can set it against a scale with different outcomes on each output. Randomisation is brilliantly easy and can also be quantized to scale. The sequencer will give you up to 8 steps that you set on the outside 8 of the grid of 9 knobs. And finally, for patterns, it has a simple Euclidean rhythm generator.

3PT is usually available as a kit which brings in an added sense of achievement and tends to lower the cost. Many Eurorack modules are available as kits so you can build them yourself. This will require a bit of soldering and a lot of your time but it’s a great way to get to grips with how modules work and save some dollars.

This module is not intended to be a deep dive into any of those modes, but rather offers a simple and instant way to create lots of different things in the one module. Simply as an LFO, it’s a beautiful thing to have in your rack.

Street Price: $119
Robaux.io

Eurorack really comes alive once you start running it through some effects. The Pico DSP is an excellent way of incorporating some great-sounding effects into your rack in a very small space.

It couldn’t be simpler to use. You’ve got a button to step through the effects, an LED to indicate which one you’re on, a Dry/Wet knob, two parameter knobs, an input and a stereo output. Inside are 8 custom effects, including mono delay, pitch shift delay, stereo delay, granular delay, reverb (one of the best), saturated reverb, Leslie speaker and overdrive/bit crushing. I have this module permanently wired into my Eurorack as a reverb, although all the effects are top-notch.

Erica Synths has a whole range of useful Pico modules at great prices provided you don’t mind the knobs being a bit fiddly. They also have a range of educationally minded DIY kits, which is a great place to start if you want to learn about soldering and circuit design. You can build an entire modular system for around $500.

Street Price: $149
EricaSynths.lv

This is probably one of the most useful modules in Eurorack. The Turing Machine is a random looping sequencer that consistently produces fabulous sequences of notes or modulation that vary and wander off over time. It was inspired by the shift register pseudorandom synth circuits from modules such as the Buchla 266 Source of Uncertainty.

While you can’t program a sequence, you can steer it in one direction or another. The big knob controls how the sequences loop, from complete randomisation to fixed lengths and slipped lengths where notes occasionally change. You can set a loop length to push it into rotating around 2 to 16 notes. You can also Scale the output to focus in, around a handful of notes or expand across many octaves.

An added bit of genius is the Pulse output, which generates a gate in line with the sequence but runs on its own rules. This gives a fascinating rhythm to the Turing Machine.

Pump it through a quantizer for instantly satisfying melodies, leads and basslines. Or patch it into a CV input to randomise all sorts of parameters while being clocked to your system. It really is a beautiful module.

This is only available as a kit and it’s a really straightforward build, the first module I ever soldered together. If you like the idea of the module but are horrified by the idea of having to make one then 2HP also do a very very narrow version.

Street Price: $129
MusicThink.co.uk