Cat5 cable can be cheap, it’s pretty light and thin but surprisingly well shielded with 4 twisted pairs in there which will all resist interference. It also has 100 ohms impedance, which isn’t far off the AES/EBU standard of 110 ohms, so should be able to carry digital audio a fair distance.
So I’ve done a bit of a make and an experiment to make a lightweight 4 way multicore:
I got a couple of Neutrik NE8-FDY-C6-B connectors- these are fairly easy to assemble, there’s instructions on the site, and don’t even need a soldering iron- just some snips, really. You could probably prep one with your teeth if in a desperate situation.
On the other end I attached 4 XLRs
As they’re not meant to be cable mounted (and there isn’t an appropriate connector) I had to improvise with sugru and heatshrink
Anyhow, they work and with shielded CAT5 cable (you have to look quite carefully at the specs, most isn’t) they’ll work with phantom power too.
There are also a few commercially available solutions for audio over cat5, the “balun” boxes don’t usually do any more than this.
I’ll hopefully have another make done next week (you wait ages for one…)