Ore-some Volts

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A Eurorack synthesiser module that generates truly random control voltages, gates and triggers.

Radioactive events from a jar filled with uranium ore can be used to control compositional parameters.


A borosilicate glass jar filled with uranium ore is mounted in front of a Geiger counter, which detects ionising radiation emitted by the rocks.

The timings of the radioactive events are mapped to a control voltage output and a number of gate/trigger outputs.

These can be useful to create truly random unpredictable variations in your synth patches.

Features and controls

There is a trigger output that creates a pulse whenever an event is detected, and also a group of six outputs that can be set as either triggers or gates. The group of six outputs are activated again depending on the activity from the ore. A relatively long pause followed by two clicks in quick succession will activate output number 1, for example.

There are three knobs for adjusting the CV output:

RANGE: Sets the range of the voltage from 0 to 10Vpp. Adjust this to create subtle variations or dramatic jumps.

OFFSET: Sets the area in which the control voltage operates. For example, if range is set to max then the offset can be used to set the voltages to operate from -5V to +5V or from 0V to 10V.

GLIDE: Sets the amount of glide between the changes in voltage levels. Set to max and remove the jar to create slowly drifting voltages triggered by background radiation.

The jar is removable, but pushes into place with a fairly tight fit, to prevent it falling out of portable modular systems. The activity of the module changes when the jar is removed. Take care when removing or replacing the jar.

The lid of the jar has been glued shut. Please do not attemp to open the jar - handling/inhaling/swallowing dust or fragments of the ore must be avoided.

A switch has been provided to turn off the internal Geiger counter click.

How it works

The system initially waits for three clicks, and then uses the position of the middle click to set the proportional level of the CV output. For example, if the central click occurs relatively close to the first, the voltage will be lower.

The system then waits for the next click to replace click 3, and re-assigns the previous 2 and 3 to the new 1 and 2.

Technical details

Width: 20HP

Depth: 41mm behind 2mm thick panel

Current @ +12V: 75mA

Current @ -12V: 20mA

CV range: -5V to +10V

Gate & trigger level: 8V

Trigger length: 20 milliseconds

Download large images here (45MB)


Cost of one module is GBP £500 plus a flat rate of £20 shipping worldwide. No extra shipping if you buy multiple modules in the same transaction.

Shipping is fully tracked and will require a signature. Shipping will be to your registered PayPal address unless you contact me before placing the order.

For all non-UK orders the jar of ore will be sent in a second package, just in case for any reason it doesn't make it through customs. There have however been no issues so far with ore sent to the UK, US, Japan, UAE and all over Europe.


The online shop has just been set up - get in touch if you find any issues!

The future

The Nervous Squirrel 5U modular started back in 2008, and contains some unique module designs that are currently being converted to Eurorack. It is hoped that 5U and Buchla 4U formats will also follow.

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