Can a 75 ohm digital rca cable be used in place of a regular rca interconnect?

I'm thinking more the other way around. I want to use the digital rca that I have in place of an rca.

You can use your digital cable as interconnect.

I did that yesterday.

My regular Audio Note interconnect got some hum due to some internal issue.

I had replaced it with Silnote Audio Morpheus digital cables with good result.

in theory a digital cable may have a higher nominal impedance than a conventional rca audio cable; the extent to which you can hear the difference is another matter. i've used 75ohm digital cables as a 2ch audio interconnect (and likewise used a rca cable as a digital interconnect) with no ill effect; i do understand that the differences are more perceptible in video applications.

Interesting... so if anything bc of the impedance it might lower the volume/signal?

Nominal impedance is so because of the specific operating frequency that the measurements are taken. Obviously, a cable designed to convey a 500MHz Manchester encoded digital signal will be capable of conveying audio spectrum just as well, but noise rejection is not a strong suit of unbalanced cables to begin with. Better quality cables are made with two inner conductors (a pair) of the same wire, and an outer foil shield surrounded by 100% braided shield with a drain wire. The two inner conductors go to the signal hot and signal ground respectively on each side, and the drain wire is either connected to signal ground on the source side, or (better) to chassis ground to protect from noise infiltration on both of the signal carrying conductors. The only way to improve on this is taking the leap to XLR connectors and fully balanced differential circuits, but that’s not always practical to do.