audio from comcast and other providers

No, you don't need a DAC for 2-channel. You can simply run the left and right channel audio outputs to the stereo inputs of an amplifier. I don't think you'd even need a preamp because the cable boxes have a volume control.

If you want to go multi-channel then you take the SPDIF digital output from the cable box and run it into the digital audio input of a surround processor or multi-channel receiver.

Thanks!

On the back of this particular set ( 2008 Samsung ln32a650a ) there are audio outs (rca) which I assume are coax? and a single digital audio out (optical). Which do you suggest. jj

Avoid the audio outputs from the TV. If you can go directly from the cable box to the stereo it will sound much better. The TV will just add unwanted noise.
By the way, don't expect the cable music to sound anywhere nearly as good as a cd. This is compressed music.

Yep. Again, more compressed digital content = lower musical fidelity!
Even with Ipods, we have moved to convenience, and away from ultimate sound quality!
I think people don't really care, in- mass, about soundquality. they'd rather have convenience.
amazing!...