Eurorack Modular synthesizer system
Standard sizes, control and power voltages allow setting up eurorack synthesizer using great modules from different manufacturers.
Eurorack modules
Based on DIN 41494 industrial standard Eurorack modules have height of 3U which is around 133.4 mm (5.25 inch). Their width is measured in HP units, 1 HP makes 5.08 mm (0.2 inch). Small 1U modules are also common, at the moment we are focused on developing 3U modules.
These modules have standard power supply sockets. Euorack case is equipped with a transformer that provides standard voltages to power rails installed for each row of Eurorack case. This makes it very convenient to organize modules as they can be placed anywhere inside the synthesizer.
Modular case
Eurorack modular cases come in variety of formats, from tiny to collosal ones. Most common s dual 84HP, enough space for installing various modules.
Case comes equipped with power transformer providing several amps of standard +12V, -12V and +5V. Depending on the transformer synthesizer can handle a certain amount of modules. Each module has specs with how much power it consumes from each power lane.
Eurorack standard allows customising synthesizer with modules that artists finds useful with a wide variety to choose from.
Analog control voltages (CV)
Eurorack modules are connected to each other using patch cables that carry both control and audio signals.
These voltages are standard (usually from 0 to 5V or-5V to 5V) making sure that all modules from different manufacturers would be compatible.
Basically in Eurorack synthesizer system standard you can connect both audio or CV voltages using the same cables and patch them to any control input. Audio voltages provide fast modulation which is basis of AM and FM synthesis.
1 Volt per Octave pitch standard
Pitch information to oscillators and filters is usually carried in 1 Volt per Octave linear standard meaning that that if 0 Volts corresponds to C1, 1 Volt would be C2, 2 Volts – C3 and so on. Other notes between octaves would correspond to linear divisions (1/12th of Volt per semitone).
Actual relation between notes and sound frequencies are exponential, with each octave increase the frequency doubles. Pitch based Eurorack modules receive linear pitch CV and convert it to precise exponential music note frequencies using integrated analog exponential converter circuits.
Unified power connectors
Eurorack modules receive power through standard 10 or 16 pin IDC connectors (two row, 2.54mm between pins). 10 pin connectors provide bipolar power of +12V, ground and -12V . 16 pin connector provides additional power lane of +5V.
Eurorack case receives its power from internal or external transformer and distributes it via power rails with multiple IDC power sockets. When installing a new module you can simply plug its flat ribbon power cable to one of available power sockets. Additionally, Power connectors are designed in the way that you could only connect power ribbon cable on the correct side. This provides reverse voltage protection.
