Older DAC connection to my Macbook??

there are convertors - Berkley has a nice one for $2,000

why not use the Toslink output from your macbook?

you may be thinking it has only a mini-jack but check it out

I would go with a USB/SPDIF converter. I have used many with older DACs. Use an Audiophileo 2 with Pure Power power supply. They come up used here on AG. Wiith the added power supply probably run ~$500-$600. In the interim you might get a Music Fidelity V-Link or M2tech Hiface converter. Either should run~$100 used and easier to find I use the Hiface in a 2nd system. 

Or just use the digital optical output on the macbook. Like @randy-11 said, the headphone output is also the toslink output. You’ll just need one of those little adapters to put on the end of the optical cable so it can attach to the ’headphone’ jack. That will be way less expensive than multi hundred dollar converters.

Thank you for the replies. The last one seems the most likely. I guess that's why those Dac prices seem to drop so much. Features and current connections are very important.

Indeed. As well as constantly advancing DAC chip technology. But there's nothing wrong with older units if the rest of your system isn't top of the line, state of the art stuff.