Well, honestly... I think my design is better and makes a much better cable, but it's definitely very hard to make. ...if this is your first diy cable, I would just buy the the stefan cable instead, if it's really $50... that's pretty reasonable. I mean, if you buy the stuff for my diy cable, materials might cost up to $15... but you're gonna screw up a lot (I still do)... and it will take many hours to do perfectly.
...but anyway... if you have the courage... I haven't seen the HD-590, so I dunno what the connectors look like. You said it's a "single cable design"... do you mean that instead of splitting into one connector per earcup, there's just one connector going into one cup, and internally the signal is split?
well... it doesn't really matter too much.... you're still gonna end up splicing their connector. i still recommend two Canare L-4E6S cables, twisted together. it makes for a relatively heavy cable... but it remains very flexible.
here's a cable I made from the same design, but with connectors for an AKG K1000:
yours will look about the same, but instead of the XLR, you will splice on the original HD-590 connectors.
let me know if you have questions.
dean