Doepfer A-183-9 Quad USB Supply

Module A-183-9 is a simple power supply for up to four devices which can be powered or charged via USB (e.g. keyboards, smartphones).

The module has no USB function but provides only the +5V supply for USB devices.
A control LED shows if the +5V voltage is present.

Technical note:

Each of the four USB sockets is connected to the +5V supply of the A-100 Bus via a 0.3 Ohm resistor. These resistors work as protection against short circuits. On the other hand this measure causes a voltage drop that depends upon the current which is taken by the USB device. For example 1A current causes a 0.3 Ohm * 1A = 0.3V voltage drop so that only 4.7V remain. Some USB devices may then not recoginze the USB supply and will not be charged. The only solution is to shorten the protection resistor in question on the A-183-9 board e.g. by means of a solder joint. The resistors are named R1...R4. Pay attention that in this case the short circuit protection gets lost.