If you want better sound than plugging the Ipod into your preamp with RCA (and therefore use the Ipod's dac), try the Wadia iTransport. It takes digital out from the Ipod, and converts it to SPDIF RCA which you can then plug in your cambridge audio.
http://www.musicdirect.com/product/82178
Arguably you can get better sound out of your PC directly... but the cost and especially the complexity to do it right are much higher.
http://www.musicdirect.com/product/82178
Arguably you can get better sound out of your PC directly... but the cost and especially the complexity to do it right are much higher.