Connecting Cable Box to Preamp

The quality of the signal over a cable box is usually pretty low, like 96 or 192 kbps. Assuming the cable box has RCA outs, I doubt that getting a separate DAC will provide much better sound than the DAC in the cable box. If the box has RCA outs, I would start with a set of RCA to balanced cables, like the ones available like the Monoprice for $5 a piece.

If the box does not have RCA outs, I would go with a very cheap DAC, given the low quality of the source. It does not have to have balanced out, since you can go RCA to balanced with cables or adapters.

I do not know what quality your cable provider delivers, but I doubt that this is ever going to be a high quality source.

Do the satellite companies have better signals? What about a sate;lite radion receiver?

No expert, but I think the satellite signals are worse. The cable music is fine for background music. Do you have RCA outputs? If so, spend $15 and get the Monoprice RCA to XLR cables and give it a listen. A little more detail on your box and provider would help.