Eurorack Controller

euro-controller-full-caseA controller for use mostly by hands, but also with brain waves.

I don’t use piano-like keyboards, but I wanted to have more ways to interact in real time to make improvised performances.  I had been thinking about the SoundMachines brain interface, since I saw one in a Eurorack modular case a while back.  This can be put into a self-contained case, but I also wanted some manual controllers.   So I started looking around on Modular Grid and came up with this setup.

Case and Power


Selecting a case and power proved to be a bit of a challenge for me, a Euro newbie.  I ended up choosing a 4ms Row Power 40.  I’d originally planned on a 104 HP skiff, so the Row Power 40 is overkill for this 84 HP one.  I found a Sound Machines FMJ3 case on eBay.  It’s perfect for a controller case, with it’s slanted front.  I removed the included power supply, which works fine, and saved it to use for a bench supply.  Though there isn’t a picture here, I added a banana jack to the back of the case for power supply ground.  I discovered that the 4ms supply ties the AC ground to the chassis ground, as well as to the power supply grounds.

Sound Machines BI1 Brainterface

The BI1 Brainterface translates the levels of numerous brain wave in near real time into control voltages.  It uses a Neurosky MindWave Mobile headset to detect and transmit brain activity by Bluetooth.   New sample levels are transmitted once per second.  This can result in a cadence of sorts, which I wish were more controllable.  However, when I patch a brain CV into one of the Octal Switch CV inputs, I can generate an independent gate.  There is a Gate output, based on the level of the Raw EEG, and you can adjust the threshold.  I wish the software had implemented the blink detection of the Mindwave Mobile for Gate generation.  Nevertheless, having ten simultaneous CV output that reflect my brain states is great.

Sound Machines Light Plane and Light Strips

euro-controller-lp1-ls1The Light Plane and Light Strip are touch controllers with recording capability.  These put out a control voltage proportional to the location on the strip where you’re finger touches.  The Light Plane has simultaneous X and Y vectors, plus a Z output that’s proportional to the pressure on the pad.

Three different modes afford flexibility.  I won’t detail all of these here.  One limitation of these is that after recording a sequence of touches, it plays back at a constant rate.  Another limitation, in my opinion, is that in Hold mode, where the CV out holds after removing your finger, the gate output just stays on.  It would be nice to have an option to have the gate output blip when you touch again.  But I can work with these limitations.

Softwire Octal VC Switch

euro-controller-octal-switchThe Octal Switch is very cool!  It’s eight bi-directional signal switches, each with both a CV input and a manual touch pad for control.  The CV and the touch pad operate as a logical OR, meaning that you can trigger the switch with both a CV input and manually at the same time.  The top four switches latch, i.e. toggle back and forth with each trigger, whereas the bottom four are momentary.

Any input can be used on the CV, and the switch triggers at a threshold of 2 volts.

Something interesting I found, when testing grounding on this rack, is that the sleeves of all of the jacks on the Octal Switch just float; they are not connected to anything.  All of the other modules ground the sleeves of their jacks.

Unknown Pleasures

I’ve described this little gem in a previous post: Unknown PleasuresUnknown Pleasures is quite useful in this rack to add a bit of weird audio texture to an improvised piece.

Pressure Pads and Knob Recorders

euro-controller-fsr-phoSynthwerks FSR-1N is a pressure sensing module that’s very straightforward.  There are CV and Gate outputs and you have variable range (up to +10 volts) on the CV output, and a variable threshold (independent of the CV output) for the Gate.

Super Synthesis PH01 is a knob recorder.  It has just one CV output jack.  But this is way cool.  It is a loop sampler that take input from a knob position.  You have manual control over the sampling rate.  When you want to record, you press the record button and hold it for the duration of what you want to record.  It’s easy to make steps and swoops.  And you can then change the loop time.  It can loop so fast that it becomes an audio oscillator!

There’s an updated version of the PH01, the PH01-II, which added a sync in and out, plus CV over the sample rate.  That would be nice, but the basic function is simple and easy to use.

The PH01 came with cream colored knobs, but I replaced them with some gray knobs that I had, just because it seemed to fit the color scheme of the whole box better.

Patched In

euro-controller-patchedUpdate:  Latest Photo

eurorack-manual-skiffAfter the Brain Interface migrated to the Pittsburgh Modular case, there was more room in this controller case.  I added the second Unknown Pleasures, plus a Flame C-3 Knob Recorder (on the left).  Later I scavenged the 4ms Row Power 40 for my newest Eurorack box, and re-installed the original power supply that came with the Sound Machines case.  I had added a 5-volt power regulator, so it was all set.  The last 4 HP slot was filled with a third Sound Machines LP1.

See here for the latest updates.



One Response to Eurorack Controller

  1. Davide says:

    Great article!
    We shared this on our FB page!


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