A stereo mini (i-pod headphone) to rca (preamp in) cable should be fine. I use this set-up on all my systems with no problem. As long as your i-pod's volume is up fairly high, you shouldn't be have meaningful volume limitations. That is, the output level on the i-pod should be similar to (or maybe slightly lower than) the output level from a typical line level source.
Marty
PS - Belkin makes a product called the tune stage. It's a bluetooth (wireless) adc/transmitter that connects to your i-pod and a receiver/dac that connects to your pre-amp. This allows you to use your i-pod as a remote wirelss source up to +/- 35 ft. from your pre-amp.
Marty
PS - Belkin makes a product called the tune stage. It's a bluetooth (wireless) adc/transmitter that connects to your i-pod and a receiver/dac that connects to your pre-amp. This allows you to use your i-pod as a remote wirelss source up to +/- 35 ft. from your pre-amp.