Modular Form Factors

There are two dominant modular synthesizer form factors:

Moog Unit - also called MU or 5U, is a large, full-figured module format. This is the format built by Synthesizers.com. MU is 8.75" tall (5U) and comes in widths of 2.125" which is 8 spaces in a 19" rack. Modern MU uses the same panel size as Moog modulars but uses the Synthesizers.com power connector which has become a standard. Power is +/-15v and +5v. MU uses large knobs and 1/4" jacks. Panels are typically black with exposed metal flanges on each side. Enclosures can be hardwood, portable or 19" rack.

EuroRack - is the popular small format at 128.5mm tall which is about 5" and close to 3U. Eurorack uses the smaller 3.5mm jacks and usually smaller knobs. Power systems for Eurorack use a flat cable to provide +/-12v,5V. Panels are a variety of colors, often silver. Typical enclosures are boxes, foldable or 19" rack.

Other form factors are less common but still available:

FrackRack - is 3U tall (5.25"), uses a power connector like MOTM with +/-15v and 3.5mm jacks. Frackracks are close to Eurorack and they can be used together with certain considerations. Panels are a variety of colors, often black. Enclosures are typically 19" rack.

MOTM - 5U = 5x1.75"=8.75 tall like MU, but comes in different width increments and has a thick flat panel. MOTM uses a 4-pin power connector to provide +/-15v, later offering 5v. MOTM modules use 1/4" jacks. Enclosures are typically 19" rack.

4U - 4x1.75"= 7" tall panels, typically flat and silver. These include Buchla, Serge and others. Connectors are often a combination of banana jacks for control signals and 3.5mm for audio. Power is typically +/-15v but vary in connector style. Enclosures are typically 19" rack but sometimes foldable boats. 4U systems often are used without a traditional keyboard controller.

This list shows some of the common modular patchable synthesizer makers and form factors - modern and vintage.

Manufacturer Model Format Connector Height Smallest
Width
Power
Moog 900 MU 1/4" 8.75" (5U) 2.125" +12,-6
Synthesizers.com Q MU 1/4" 8.75" (5U) 2.125" +15,-15,+5
Doepfer A100 EuroRack 3.5mm 128.5mm (~3U) 10mm (.4") +12,-12,+5
EuroRack Modular EuroRack 3.5mm 128.5mm (~3U) 10mm (.4") +12,-12,+5
MOTM Modular MOTM 1/4" 8.75" (5U) 1.75" (1U) +15,-15
Modcan B Series MOTM 1/4" 8.75" (5U) 1.75" (1U) +15,-15,+5
Blacet Modular FrackRack 3.5mm 5.25" (3U) 3" +15,-15
Paia 9700 FrackRack 3.5mm 5.25" (3U) 1.5" +15,-15
Paia 2700/4700 3.5mm 4" 2" +9,-9
Buchla 100/200/200e 4U Banana & TiniJax 7" (4U) 4.25" +15,-15,+5, +12,+24
Serge Modular Rack Banana 7" (4U) 17" +12,-12
Polyfusion 2000 1/4" 7" (4U) 3" +15,-15
PPG 300 1/4" 220mm 110mm +12,-12
Steiner-Parker Synthasystem 3.5mm 150mm 45mm +12,-12
EMU 2000 1/4" 6" 3" +15,-15,+5
ARP 2500 3.5mm 8" 3" +15,-15,+12
Roland 100M 3.5mm 230mm 104mm +15,-15,+22
Digisound 80 3.5mm 9" 3" +15,-15,+5
Aries 300 TiniJax/3.5mm 9" 3" +15,-15,+5
Modcan A Series Banana 9" 2.25" +15,-15,+5
Cynthia A Series Banana 9" 2.25" +15,-15,+5
KB Elec. Wavemakers 1/4" 10" 2" +12,-12
CMS Modular 3.5mm 10.3" 3" +15,-15
Wiard 300 3.5mm 10.5" (6U) 2.83" +15,-15
Roland 700 1/4" 11" 2.56" +15,-15,+14.4
Technosaurus Selector 1/4" 15.75" (9U) 1.6" +18,-18

 

Special thanks to: Sam, Mike, Mark, Steve, Bernie, Nicola, Andre, Steve, Ruud, and John for helping me collect this information. -Roger.