I have a Pi 3B and want to buy a Audiophonics TDA 1387 X8 to make a DAC.
I have a ZK1PA wireless contact to turn off/on the solution.
I need a DC 5V 3A supply for the Pi and the Audiophonics card and DC 12V for the ZK1PA.
I have found this little psu at minipc.de/catalog/il/761. You only have to get a switch between pin13 an pin14 of the atx connector to switch this psu on and off. I use this psu with my pi3 and hifiberry amp+. You need an extern 12V power supply too.