Eurorack

(Portions of the following text were excerpted from Randall's excellent post at the Electro-Music modular forum.)

Euro is a modular synthesizer format, (sometimes called "Eurorack").

The height of Euro format synthesizer modules is 5.25" or 1.33.35mm, which is equal to three vertical units in a standard 19" equipment rack. (This standard height is called "3U".) Note also that the panels of the Euro format are often shorter than the 3U would suggest. This is not due to allowances for paint and fitting, (which is seen in many of the other formats), but rather due to the shape of the top and bottom extrusions used by PROMA. These have a lip which "uses up" some of the height. So Euro rack modules are often approximately 5mm shorter than the technically exact 3U height of 133.35mm (5.25").

The width of Euro modules is typically measured in "HP" (or "TE"); 1 TE/HP is equivalent to 5.08mm, or 1/5 inch. So a 24 TE/HP width is 24/5, or 4.8". In millimeters, it becomes 24 x 5.08, or 122mm.

Note that even though the height of both Frac and Euro modules are 3U, differences exist in the mounting hardware. So, each format requires its own mounting system (screws, rails, etc).

Power requirements for Euro modules are usually +/-12VDC and 5VDC. Current draw depends on the module.

Euro modules typically use 1/8" or 3.5mm connectors and plugs for patching.

Refer to the List of Modular Synth Equipment Manufacturers page for a list of Euro module manufacturers.

Module Depth
Following is a list of Euro module depths. This information is important when purchasing or planning construction of a case or rack for your modules. (courtesy of felix, from this thread)

Livewire  Frequensteiner - 1.50" (38.1mm) Dual Cyclotron - 2.25" (57.15mm)

Plan B  Model 28 - 2.50" (63.5mm) Model 15 - 1.75" (44.45mm) (MKII, MKI is much deeper) Model 14 - 3.75" (95.25mm)

The Harvestman  Tyme Sefari - 2.00" (50.8mm) Malgorithm - 1.50" (38.1mm)

Doepfer