Frac rack
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]
Panel format
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" (133.35 mm) tall. The Frac format has a standard width unit of 1½". So 3" (76.2 mm) and 4½" (114.3) wide modules are common in this format.[1]
Difference between Frac rack and Eurorack
Although both Frac and Euro modules are 3U, use V/octave (CVs are compatible) and have basically the same signal levels the modules aren't interchangeable. Differences exist in the mounting system. The power connectors are different. Frac modules are powered with ±15V and Eurorack with ±12V.[2][4][5][6]
Patching
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.[7][8]
Power
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] PAiA P9700S modules are designed for an ±18V unregulated power with on module regulation where necessary, although ±15V regulated supplies can be used.[9]
Frac brands
- Ad Infinitum
- Analog Metropolis
- Bananalogue – Frac with banana jacks
- Barton
- Blacet Research
- Bridechamber
- BugBrand
- CGS[10]
- Cyndustries
- Encore Electronics
- Flight of Harmony
- j3rk
- KissBox
- Livewire Electronics
- Magic Smoke Electronics
- Metalbox
- MFOS – not format specific and can be powered by +/-15V[11]
- Oakley Sound Systems – some support for Frac and some 5U PCBs can fit behind a Frac panel.[12]
- PAIA – pioneers of the Frac format
- STG Soundlabs
- Stroh Modular
- Synthasonic
- Synthesis Technology MOTM – never supported Frac but some 5U PCBs will fit behind a Frac panel.[12]
- Wiard
- YUSynth
See also
References
- ^ a b c Standard measurements in front panels, Electro-music.com forum, April 2006
- ^ a b c Analog Notes
- ^ List of Frac module manufacturers, Muff's Modules & More forum, August 2008
- ^ a b Blacet FAQ
- ^ Tech Notes, Blacet Research
- ^ Difference between Frac rack and Euro, Vintage Synth Explorer forum, May 2013
- ^ Banana Frac: The Definitive Guide, Muff Wiggler forum, August 2009
- ^ Metalbox Info
- ^ P9700S Series Analog Synthesizer Modules
- ^ which frac filter?, Muff Wiggler forum, Dec 2008
- ^ Modular Addict has MFOS PCB's!, Muff Wiggler forum, Sep 2016
- ^ a b Source for MOTM Frac DIY, Muff Wiggler forum, Sep 2011
External links
- Fractional Rack Modules, Muff's Modules & More forum,
- Standard measurements in front panels, electro-music.com, DIY Hardware and Software forum, May 2007
- About Blacet Research
- Frac on ModularGrid
- EuroSynth – FracRak Comparisons by Laurie Biddulph, 2015
- 1978 PAIA catalog
- PAiA at Marvin Jones' website, also has some issues of Polyphony
- PAiA documents, Synth & Studio Docs Archive