A DAC can make a huge difference, but for your gadget, I recommend you just use your Sony ES receiver and save up for a DAC that will give you a noticeable improvement. All you need to do this is a "mini toslink to standard toslink cable". Stay away from "mini toslink" adaptors.
That Sony ES receiver has a fairly good DAC section that will sound good in "direct stereo" mode. There is a "mini optical" output on the iMac. If you have any questions or need help, feel free to contact me.
That Sony ES receiver has a fairly good DAC section that will sound good in "direct stereo" mode. There is a "mini optical" output on the iMac. If you have any questions or need help, feel free to contact me.