A1 Modular synth formats, sizes, cables and power


The most common and popular modular synth format today is eurorack modular. Common eurorack case sizes are  3u 60hp (4ms pod), 4u 62hp (intelligel), 4u 84hp, 6u 84hp (doepfer), 1u 104hp (moog), 6u 104hp (tiptop audio) and 7u 104hp.  U is the hight of the module, eurorack modules come in 3u and 1u format. 1u in eurorack is 1.75 inches. If a case is 4u it has one row for 3u modules and one row for 1u modules. If a case is 7u it has two rows for 3u modules and one row for 1u modules.  Hp or horizontal pitch is the width of a module. 1hp in eurorack format is 1/5th of an inch. Modules come in various hp sizes. Hp size differs from format to format. Eurorack modules are patched with 3.5mm mono/unbalanced cables. (Important to note these cables carry signal and ground). Eurorack cases and modules run off of a +-12v power supply. Eurorack modules send voltage in the ranges of +10 and -10 volts.


Serge full panel modules are 4u and 17” wide, serge modules also come in various widths. 1hp in serge is approximately 1.06 inches. Common serge module sizes are 4x4 (random source, 4u by 4hp) and 2hp (CGS, Loudest Warning, NLC).  Standard serge cases are often called boats and are 17inches to wide with varying depths. Note that some boats only have mounting holes for 17in modules or 4x4 modules.  Serge modules are patched with banana cables, which only carry signal. (Be careful when patching between different modular synth formats, as they carry different voltage ranges, and be sure to ground, if your patching to a system whose cables don’t carry ground). You can patch between euro rack and serge with a format jumblr. You can make a format jumblr by soldering the signal of your eurorack jacks to your banana jacks and the ground from your eurorack jacks to a dedicated ground banana jack. You can then use this ground jack to connect the ground of your jumblr to the ground of your serge system.

Serge systems (sometimes called boats) run off of a +-12v power supply as well as eurorack and modules output similar voltage ranges. Serge and eurorack share 1v/oct meaning pitch can be tracked accurately between the two formats.

Note on 1v/oct:
        One volt represents one octave, so the pitch produced by a voltage of 3 V is one octave lower than that produced by a voltage of 4 V. Each 1 V octave is divided linearly into 12 semi-tones.


Buchla modules are 4u and often 4.25 or 8.5 inches wide.

Buchla modules are patched with two types of cables. CV or control voltage, such as LFOs, envelopes or sequencer voltages are patched with banana cables. Audio rate signals such as the final output of oscillators, filters or effects units are patched with 1/8th inch mono/unbalanced and 1/8th inch stereo/balanced cables.

Buchla cases run off of a +-15v power supply. Buchla modules often output voltages in the full range of +-15v. (Be very careful when patching Buchla modules to serge or eurorack, because the voltage range is higher it may fry certain serge or eurorack modules if it exceeds 12v). Buchla oscillators track 1.2v/oct. There is a handy algorithm on the Disting mk4 and Disting EX eurorack modules for converting 1v/oct to 1.2v/oct and the other way around.

Moog, Modcan B and MOTM

(moog 900 series)

(Daft Punk’s Modcan B System used to create the Tron Legacy soundtrack)

  Moog, Modcan B and MOTM modules are 5u. 1hp in this format is 2.25 inches wide. Modcan A modules are almost 5u but not quite.

Moog 900 series and above, Modcan B, and MOTM modular synthesizers use 1/4 unbalanced cables. Moog 900 series systems run off of +-12v power supply.

    Frac, Bugbrand and Metalbox



These modular synthesizers are 3u. Frac modules are 2.98 inches wide. Bugbrand modules are typically 1.5inches wide

Frac modules are patched with 3.5mm unbalanced cables and run off a +-15v power supply. Voltage ranges from modules are similar.

Bugbrand modules are patched with banana cables and run off a +-12v power supply. Voltage ranges from modules are similar to serge and eurorack.

Metalbox modules are based off of CGS schematics, but for +-15v ranges. Metalbox modules fit into Frac cases and are patched with both 1/8th in unbalanced cables and banana cables, depending on the module.


Wiard modules are 6u and approximately 3.1inches wide.

Wiard systems are patched with 3.5mm cables and run off of a +-15v power supply. Wiard audio rate signals are +-5 volts and +-10 for cv, like eurorack.