I build a power supply based on a 7Ah Lead battery and used an Arduino microcontroller and two relays to switch between regular power supply and battery. The Arduino is programmed to detect music flowing through the Dac and than switches to battery power immediately. Between songs the Arduino...

How much current (milliAmpere) does the V-DAC use?   I used an Arduino micro controller to measure Voltage and Ampere on my V-DAC.  As power supply I used a 12,5V battery as seen below with the Arduino fixed in front of it:   In use the power consumtion is 12,6*0,244 = 3 Watt Idle...