Hi,

As far as I'm aware, Apple discontinued the optical output from the 2017 iMac.

I'm not sure about which particular USB DACs have a digital output, but you could try and pick up an (original) Explorer and use the optical output from that to feed your 218.
While an Explorer might be a bit difficult to find in Sydney, they aren't too big to ship one from the UK, so you could put a wanted ad in the restaurant.

I was interested to hear your reaction to Roon, so I'm also keen to hear how you get on.

Brian

Last edited by bxd; 2019-11-27 13:51. Reason: addition
Main: G65, MD600 Sooloos, MC200 Roon Core, MS600, 210, 218, UHD722, DSP5200SE, DSP5200HCSE, M6 & DSW.2
System 2: AC200 MS200, WiiM Pro+, M6.
Other: DSP5000 (96/24v1), DSP3300.