You just need to use a balanced headphone connection to get the higher outputs. A more typical 1/4" headphone connection will get you the lower rates.
It doesn't require XLR connection from the DAC though - if you use the RCA inputs, the amp will convert from single ended to balanced signal internally, and then proceed as if it was getting a native balanced signal via XLR. You lose a little bit of purity in the process but you don't lose power.
Thank you very much.