How to connect headphone amp when system has separate transport and DAC?

Why don’t you just use the RCA output on your DAC? Why do you want to use the XLR output? 

What transport do you have Stuart? 

@pauly:

My Aqua La Voce S2 DAC has one pair of RCA outs and one pair of XLR outs.

As the RCA's are already in use, my only option is the XLR's.

photo:

https://www.usaudiomart.com/details/649395475-aqua-la-voce-s2-dac/images/1710537/

After the Neutrik adaptor debacle, I decided get my A. Zen Silver Reference IC's reterminated with XLR's on one end.

While this is more expensive than most (but not all) adaptors, I see it as an approach that's less likely to compromise the sonic perfromance of the IC's, compared to an adaptor.  

My transport is the Moon 280.  

My bad, I wasn't aware that you had a second amp consuming the RCA outs. I thought you were doing headphones only. 

After the Neutrik adaptor debacle, I decided get my A. Zen Silver Reference IC's reterminated with XLR's on one end.

While this is more expensive than most (but not all) adaptors, I see it as an approach that's less likely to compromise the sonic perfromance of the IC's, compared to an adaptor

Agreed, it should be much better sonically than both adapter and Y splitter.

Anther option is connect the dac rca output to Schiit Magi headphone amp input and connect the amplifier input to Magi rca output.

https://www.schiit.com/public/upload/images/magni3plus-rear-1920.jpg