> For the complete documentation index, see [llms.txt](https://hosted-by.gitbook.io/eurorack-synthesizers-for-dummies/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hosted-by.gitbook.io/eurorack-synthesizers-for-dummies/a-rundown-of-eurorack-synth-components/eurorack-modular-power-supply.md).

# Eurorack Modular Power Supply

## Eurorack Modular Power Supply

A reliable power supply is essential for any Eurorack synthesizer system. All modules require stable and clean power to function correctly and safely. Below is a rundown of the power requirements for Eurorack modules and important considerations for powering your system.

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### Standard Power Requirements

* **Voltage Rails:**
  * **+12V** (main positive rail, required by all modules)
  * **-12V** (main negative rail, required by most modules)
  * **+5V** (optional, used by some digital modules)
* **Connectors:**
  * 10-pin or 16-pin IDC ribbon cables are standard for connecting modules to the power bus board.
* **Current Draw:**
  * Each module specifies its current draw for each rail (e.g., +12V, -12V, +5V).
  * Always add up the current requirements of all modules and ensure your power supply can provide at least 20–30% more than the total needed.

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### Types of Power Supplies

* **Internal Power Supplies:**\
  Installed inside the case, directly connected to mains power. Common in larger or studio cases.
* **External Power Bricks:**\
  Use an external AC adapter or brick, with a power distribution board inside the case. Popular for portable and smaller cases.
* **Bus Boards:**\
  Distribute power from the main supply to each module via ribbon cables. Some include additional filtering for noise reduction.

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### Powering Different Types of Modules

* **Analog Modules:**\
  Usually require only +12V and -12V rails. Current draw is typically lower than digital modules.
* **Digital Modules:**\
  May require significant +5V current in addition to +12V and -12V. Always check the module’s specifications.
* **High-Power Modules:**\
  Some modules (e.g., complex oscillators, granular processors) can draw a lot of current. Plan your power budget accordingly.

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### Maintaining Polarity

> **Important:**\
> Always double-check the orientation of your ribbon cables before powering on your system.
>
> * Most modules and bus boards are keyed to prevent incorrect connections, but not all.
> * Reversing polarity can permanently damage your modules.
> * The red stripe on the ribbon cable usually indicates the -12V rail—ensure it matches the -12V marking on both the module and the bus board.

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### Tips for Safe Power Management

* Never exceed the total current rating of your power supply.
* Leave a safety margin (20–30%) above your calculated total current draw.
* Use high-quality power supplies and distribution boards to minimize noise and voltage drops.
* Regularly check connections and avoid loose or damaged cables.

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A well-designed power system is the foundation of a reliable and safe Eurorack setup. Always consult your module and case documentation for specific requirements.