The Eurorack Standard: All you need to know!


The Eurorack standard is a modular synthesizer format that has become increasingly popular in the world of electronic music production. It was first developed by Dieter Doepfer in Germany in the late 1990s and has since grown to become one of the most widely used formats for modular synthesizers. In this article, we will take a closer look at the mechanical and electrical standards, control voltages and signals, and other important aspects of the Eurorack standard.

Mechanical and Electrical Standards

The Eurorack standard is based on a 128mm (height) with each module being standardized. This allows for easy mixing and matching of different modules within a single rack. The width of Eurorack modules is typically measured in HP (horizontal pitch), with 1 HP being equal to 5mm. This allows for modules to be easily mounted side by side in a Eurorack case.

Electrically, the Eurorack standard uses a +12V and -12V power supply, with a maximum current draw depending on your power supply. This allows for modules to be powered from a single power supply, making it easy to set up and use a Eurorack system. The standard also specifies a certain number of power connectors for each module, making it easy to connect and disconnect modules from the power supply.

Control Voltages and Audio Signals

One of the key features of the Eurorack standard is the use of control voltages (CV) and signals to control various parameters of modules. CV is a type of analog voltage that is used to control the pitch, amplitude, or other characteristics of a sound. CV signals come in a lot of different flavours. They can differ from manufacturer to manufacturer or even between modules from a single manufacturer. You can find them ranging from -2.5V to +2.5V or from 0 to 5V, sometimes there are modules that have a CV input range up to +8V or +10V. That said, its very handy to have some utility modules at hand for shifting, attenuating or amplifying your CV signals to get the desired input range of your CV controlled module.

Another Type of CV signal is the Gate signal for controlling digital parameters such as on/off states or specific values. Most of the time they have a voltage range or 0V to +5V.

Audio signals, on the other hand, are used to transmit audio from one module to another and have an amplitude of around +/- 5V.

All numbers at a Glance

Mechanical Standard3U (128mm) height, width measured in HP (5mm per HP)
Electrical Standard+12V/-12V power supply
Control Voltage (CV)Analog voltage used to control pitch, amplitude, and other characteristics of a sound. Different flavours (-2.5V-+2,5V / 0V-5V / 0V-8V / 0V-10V ).
Just RTFM 🙂
Gate SignalUsed to control the on/off states of a module. Range of 0V to +5V
Audio SignalUsed to transmit audio from one module to another. Amplitude of +/- 5V
Power ConnectorsSpecified number of connectors for each module to connect to power supply

Please note that the table above is a general overview of some of the standards and signals used in Eurorack modular synthesizers and that some modules or manufacturers may have different specifications. It’s always recommended to check the specific documentation or specifications of the module or system you are using.

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