The cable box may have 2 channel analog outs that can feed the Tascam. Its DAC is not that good, but for the quality of the music, it is probably OK.
Is your cable box connected to a receiver? If so, you might be able to set the receiver to output 2 channel analog that could go to your Tascam. Given the low rez of the Cable signal, the receiver DAC would probably sound as good as you external DAC. It is also possible that the receiver will downmix the 5.1 Dolby to 2.0 PCM and output that over a digital out port.
The cable music signal is probably 128 kbps or lower. As Kal says, I would not stress over getting the signal to a good DAC.
Gefen makes a optical/S/PDIF DD to analog converter.
http://www.gefen.com/gefentv/gtvproduct.jsp?prod_id=5980
If you get it working, one trick, at least for non-classical music, is to use Sound Hound on your phone to develop a list of songs being played. It is a manual process but I use it when I get files that are not tagged.
Is your cable box connected to a receiver? If so, you might be able to set the receiver to output 2 channel analog that could go to your Tascam. Given the low rez of the Cable signal, the receiver DAC would probably sound as good as you external DAC. It is also possible that the receiver will downmix the 5.1 Dolby to 2.0 PCM and output that over a digital out port.
The cable music signal is probably 128 kbps or lower. As Kal says, I would not stress over getting the signal to a good DAC.
Gefen makes a optical/S/PDIF DD to analog converter.
http://www.gefen.com/gefentv/gtvproduct.jsp?prod_id=5980
If you get it working, one trick, at least for non-classical music, is to use Sound Hound on your phone to develop a list of songs being played. It is a manual process but I use it when I get files that are not tagged.