Frac rack

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Frac Rack or Frac, from Fractional Rack, is the modular synthesizer format designed by John Simonton of PAiA. It has a mainly USA following largely through the popularity of Blacet modules.[1][2][3]

Like the Eurorack format, Frac is considered a 3U format. The height of most modern modular synthesizer modules is measured by the number of vertical units it consumes in a standard 19" equipment rack. Modules conforming to the 3U format will take up three vertical units in a 19" equipment rack. Each vertical rack unit is 1¾", so a 3U module is 5¼" tall. The Frac format has a standard width unit of 1½". So 3" and 4½" wide modules are common in this format.[1]

Note that even though the height of both Frac and Euro modules are 3U, differences exist in the mounting system.[2][4][5]

Frac format modules typically use 3.5 mm connectors and plugs for patching, although there are companies that offer modules with banana jacks e.g. BugBrand, Metalbox.[6][7]

Power requirements for Frac modules are typically ±15VDC. Current draw depends on the module. The power connectors are 4 way AMP MTA-156 headers. The control voltage is 1V/octave.[1][2][4]

Frac brands

Template:From Muff Wiggler wiki

See also


  1. ^ a b c Standard measurements in front panels, forum, April 2006
  2. ^ a b c Analog Notes
  3. ^ List of Frac module manufacturers, Muff's Modules & More forum, August 2008
  4. ^ a b Blacet FAQ
  5. ^ Tech Notes, Blacet Research
  6. ^ Banana Frac: The Definitive Guide, Muff Wiggler forum, August 2009
  7. ^ Metalbox Info
  8. ^ which frac filter?, Muff Wiggler forum, Dec 2008
  9. ^ Modular Addict has MFOS PCB's!, Muff Wiggler forum, Sep 2016
  10. ^ a b Source for MOTM Frac DIY, Muff Wiggler forum, Sep 2011

External links