For short distances (say, 3 or 6 feet) at sampling rates such as 44.1 and 48 kHz, you can use any decent RCA-RCA audio cable. Characteristic impedance doesn't become meaningful until you reach some appreciable fraction (say 1/4) of an electrical wavelength.
For 44.1 kHz, the electrical wavelength in air would be about 20 feet. This is why the honest vendors don't sell 3' "S/P-DIF" cables, nor do they claim a rated impedance on the packaging (which would ideally be 72 Ohms--but as I said, this is utterly irrelevant for such short cables; getting it "absolutely right" would be no better than having it be horribly wrong).
Do watch out for Radio Shack cables that have slightly "bulbous" pins in the plugs, though--they're supposedly designed to improve the contact quality, but if you use them, they can spread apart the contacts in the socket and cause a poor connection the next time you use a standard-size pin plug.
Personally I'm a fan of Sony's RCA cables--they're durable and flexible, and they don't suffer from Radio Shack's spasmodic attempts to "improve on" the industry standard dimensions of various plug types. (I've also had equipment damaged by Radio Shack mini plugs, which got stuck in various sockets until I learned better.)
--best regards
Topic: Digi Coaxial Cable for MT (Read 1531 times)