using 75 ohm cables digital intr for analog?

They won't damage anything but might be bad for analog for few reasons:

- shield grounded on both ends might introduce ground loops
- noise induced in shield used as a return appears as a
signal
- dielectric material is not the best
- low grade copper often silver plated,since HF signal
travels on the surface only (skin effect)

If it sounds good to you then use it (and save money).

I often use analogue cables for digital. Some sound better than most of my dedicated digital ones.