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

There was a time when I use to use a Nordost RCA Valhalla cable as a digital cable and it seem to work fine at the time. At least until I was able to save up for a real digital cable. 

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. 

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

No not at all.  75 ohm is the characteristic impedance of a coax cable.  Google it for a proper technical explanation.  

@loomisjohnson 

You are going to be concerned about frequency spectrum and bandwidth with 15kHz analog video (which is obsolete) much, much, much more than with analog audio. Noise rejection is another thing that lowly unbalanced analog audio cables fare poorly at. 

@rotarius 

No not at all. 75 ohm is the characteristic impedance of a coax cable. Google it for a proper technical explanation.  

Nope. Not even remotely correct. Coaxial cables come in more than one characteristic impedance, and that is “Z” for impedance, not resistance, which is a static value, regardless of the operating frequency range. There are many more different coaxial cable impedance specs as there are hat sizes.  Two of the more common values are 50 ohm and 75 ohm. Impedance is what describes the dynamic, frequency-affected component due to capacitive and inductive reactance. 

...so it's ok to use a 75ohm digital RCA cable instead of a regular rca cable from receiver to amplifier without messing up the audio signal or components?

75 ohm digital cable is no worse than garden variety coaxial audio cable for conveying analog audio signals. The downfall of coaxial cable is that only the center conductor benefits from the shielding. You may want to step up to single pair analog audio or single pair digital audio shielded cable. In this application, the signal runs on one wire of the pair, the signal ground runs on the other wire of the pair, and both are shielded by a foil and braid with a drain wire connected to (ideally) chassis earth ground or (less desirably) signal ground, in each case only at one end (usually the pre-amp) of the cable.

OP
it is going to work just fine but only your ears in your system are going to tell you if it is better or not.
You are not going to damage anything so try it as you have it.