Yes,that at was wrong. You can't use the C5D as a DAC and Amp in the case of the AK100 as the C5D has no optical input. But you can use the normal Headphone output and connect it to the C5D line in to use the C5D amp. Remember to switch the headphone output to line out in the settings of the ak100. But also remember to switch that back and control your volume before using the ak100 alone again.
You guys have helped me a lot... many thanks for your effort...