Audio out mini-jack of Mac Mini to SPDIF DAC

I don't know of any cable that will do the job but I have used a M-Audio CO2 bi-directional converter box which costs around $50. I am sure that there are a number of other boxes out there that can do the job.

Not sure about the sound quality aspects as this was just a temporary solution for me. Lots of debate around the sound quality of various options but for right now I am happy with my glass optical cable from my mini mac to Bryston BDA-1.

The mac mini has an optical spdif out built into the headphone jack requiring a special toslink cable that is readily available. I recommend real glass fiber ones.

YOu can get a toslink to coax converter like Dms1 mentioned, but I don't see how it could make a difference. In fact, the extra conversion could make things worse.

Get a good glass mini toslink to toslink cable and call it a day. Or, a usb to spdif converter will also work if you are set on coax. ]

With a good dac, the glass toslink can sound excellent. I have determined that I prefer the glass toslink out of a mac mini to a certain asynchronous usb/coax converter that I own. The toslink sounds more relaxed and musical in my system. However, the difference between the two is not night and day.