Summary: The Cambridge iD100, unfortunately, is not compatible with all digital "pre-amps." I purchased the McIntosh D100 Digital Pre-amp, powered by McIntosh's MC302 300W Stereo Amp. I connected the Cambridge iD100 unit first using the "optical" connection. I inserted the proper iPod interconnect & then my updated iPod. Any music I played through "Music" on the iPad repeatedly skipped. So, I then removed the "optical" connection and switched to the "coaxial" connection.