Hi Lemming,
the attachment is a very crude sketch, that shows how, in my opinion, to connect the Zero Dac to the differential input of your ampli.
I take for granted that the two capacitors are already present in the ampli board.
If the Zero and the ampli are more than few centimeters far I suggest you to use a twisted pair cable for the audio signal, as shown in the sketch.
Let me know if this can help you.
Marco
