I'm thinking about getting an ODAC for use in the car with my Samsung Galaxy S III as the source.  I don't want the phone to power the DAC, so I was thinking about using a 5V car charger to power the DAC.  I will splice the 5V car charger into pins 1 (+) and 5 (-) of the USB cable.  Will this work?  Will it also charge the phone?  Does it matter if I use an OTG (on the go) cable or not?  OTG cables have pins 4 and 5 shorted at (I believe) the phone end of the cable.