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Modular synth power basics

Please read to avoid breaking the important modular
Here you will find basic information and precautions regarding the power connection. Please note that malfunctions caused by power problems are not covered by the warranty. The most important thing is to connect the module and the power supply in the correct direction, but there are other power supply related notes at the end of the page, so please read to the end. If you do not know the connection direction for each module, please attach a photo of the power connection part on the module board and contact us.


■ Connect 12V together

When you connect the module to the Eurorack power supply and build a modular synth, you have to connect the power supply in the right direction. for that purpose,"Match and connect -12V sides together"Is important. If they are not connected in the correct direction, the module or power supply may fail. It can also damage other modules in the same power supply but connected in the correct orientation, rather than the wrong orientation.

Most of the time, there are markings on the power supply side, the module side, and on the ribbon cable that connects them, which side the -12V is on, so connect them together. The mark may be a white line or written as "red stripe" or "-12V". Let's see how -12V is shown on bus boards and module boards.

-12V on the bus board

There are various types of bus boards, such as a board-like board and a flying bus board that branches the voltage with a cable.

 
In this case, the -12V side on the bus board is shown as a white line. Since it is a 10-pin ribbon cable, as mentioned above, modules that do not use 5V are connected.


On the flying bus board, the -12V side is colored.

-12V on module board


"red stripe" indicates -12V.

 
The thick white line shows -12V.

-12V with ribbon cable

There are two types of ribbon cables, 10-pin and 16-pin, but the rule for matching -2V is the same. In the ribbon cable, the -12V path is usuallyRed stripeIt is indicated by. So it's almost okay if you attach the ribbon cable so that the red stripes will come to the -12V side on the bus board and the -12V side on the module board.

A little annoying is that the -12V designation on the ribbon cable is also not completely unified. Mostly red, but sometimes blue. Both lines are gray except for -12V. Also, some manufacturers use rainbow-colored cables. The most annoying thing is that it is very rare, but sometimes it shows the opposite side in color instead of -12V. In such a case, of course, we will also explain and call attention to this, but please connect according to the principle of "connecting -12 V with chitin on the bus board and module side".

■ How to check if the connection is correct?

There is no easy way to check if the connection is correct and without turning on the power. Be sure to double-check or triple-check all modules to prevent mistakes. In addition to reverse connection, also check that the pins are not connected in a row.

Once you are confident that you are connecting properly, try powering on. At this time, checking the LED may be useful. If you are using a module with LEDs or a display and the part that should have been lit is not lit, you may have made a mistake in the reverse connection. Also, if there are LEDs on the power supply that indicate if each voltage is being supplied, check that they are all lit.If the LED lighting is abnormal, immediately turn off the power,Please check the connection again.


Example of LED on power supply. If any one of them disappears, there is an abnormality.

Also, even if the power is turned on, it may shut down immediately or the behavior of the LEDs of the digital module may be strange. In this case, the power supply from the power supply is often insufficient. Try reducing the number of modules and then turning on the power again.

■ Other notes

In addition to the connection direction, pay attention to the following points to avoid power problems.
  • Allowable amount of protection: The power supply is a form of the amount of current that can be used, and the capacity is often determined for each 12V / -12V / 5V rail. If you use it in a state close to the allowable amount, the power supply may become hot, noise may increase, etc., and eventually the power supply may shut down or restart repeatedly. It is possible that the capacity may temporarily exceed the capacity due to the large current flowing through the spikes at startup, so be sure to maintain a sufficient margin for the power supply. It depends on the power supply, but as a guide, be careful when the allowable amount is 6 to 7%.
  • Connect to power supply, place in correct position and then power on: Do not connect the module while the power is on.
  • Be careful of pins other than power supply: In addition to the power pins, there may be pins on the module board for connecting to other modules or for programming the internal firmware. If these pins come into contact with the power pins on the bus board, it may cause a malfunction. Be careful of contact with pins other than the power supply.
  • Be careful of cable damage: If the coating of the ribbon cable or flying bus board is peeled off, it may cause a short circuit. If the coating peels off even a little, replace it.
  • Do not touch the board with your hands: Human hands also conduct electricity. Also, be careful not to touch the board with your hands, as static electricity may damage the circuit.

■ More details-Voltage used in Eurorack power supply

Eurorack power supplies supply voltage via power modules and bus boards and ultimately through 16 pins. The 16 pins are paired and arranged in 2X8 rows.



The picture above shows 16 pins on the bus board, but as you can see in the picture, the voltage of 12V, -12V, 5V is supplied, and each module works well by using those three voltages. Is designed. There are also "CV" and "GATE" pins, but they exist to carry CV and gate signals through the power cable instead of the patch cable, and some modules may use these CV / Gate buses. There is. It has nothing to do with the power supply.

Between 12V and -12V is "GND" (ground), which corresponds to 0V. 0V sounds unimportant, but ground is very important. To properly transfer voltage between different modules or devices, the 0V reference must be connected and common in all systems. Therefore, 6 pins are used to ensure the thickest possible conduction.

Some ribbon cables use only 16 pins in addition to the cables that use all 10 pins. In that case, since the 12-pin cable is inserted toward the -10V side, "6V", "CV", and "GATE" that correspond to 5 pins that are not connected to the module are not used.

* 5V is used only by some modules, so some power supplies do not supply 5V. When using a module that requires 5V on such a power supply,Such an adapterConnect to the same power supply as the module you want to use 5V.

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