Doepfer A-183-9

If you need to:

Plug a USB light
A Microfreak
A Korg SQ-1
etc with a USB power

you need this

Very simple module, does exactly what you expect. Make sure you have a 5V rail avaliable in your case, or it won't work! ((There are products like Kavis no-drain to get 5V from the -12V if you need it.))

Be wary that some USB keyboards etc are NOISY, ie, introduce a hum or buzz into your rack. There might be ways to alleviate this, with better cables etc, but i just used different keyboards.

I use this for powering a pair of Korg SQ-1's. No problems so far.