I bought this, I think...its been awhile.

https://www.amazon.com/gp/product/B00T8HWVEY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Wow I honestly didn’t know optical was an option on some PCs, thought it was a HT cable mostly. Something I just remembered is my MacBook Pro supports optical out through mini-toslink built into the 3.5mm jack. That might be the best cable to use if I can find a mini-toslink to RCA style cable...

EDIT: I’m dumb, that cable wouldn’t exist because optical is digital and RCA is analog. If I use this in conjunction with a DAC similar to the one I linked to then connect to the Rolls, that should work and eliminate as much noise as possible I imagine.