are using AX8 out to your audio card in?
do you get any sound with your DAW not running?
With AX8 output 1 connected into Saffire input 1 (XLR), using direct monitoring on my interface I do get sound without my DAW running. I can also monitor/record on the DAW.
With AX8 s/pdif out connected into Saffire s/pdif input I don't have sound either thru direct monitoring or on my DAW. The channel is complete silent with absolutely no movement on the vu meters.