The signal (volts following the music) are coming from the DAC, the tiny current also follows the signal and is caused by the input impedance of your amp. That impedance is there no matter if the amp is switched on. Just make sure that the input selector matches the XLR input you connect the cables to. Sometimes the input selectors disconnect the "other" inputs and the input impedance goes to "open circuit" and no current will flow. Give the break-in enough hours.
Good luck and happy listening!