How Can I Use MY IPOD For a Music Source?

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.

Does anyone make a device that connects to the iPod through the dock connection? I'm wondering if this would be a better route than the mini-jack.

What you did should work. As Marty suggests, you might not have had the volume on the iPod set properly. It's also possible that there was an impedance problem with your preamp. Try before you buy (as always), but in general feeding iPods into a system is no big deal.

I haven't used this device but it does provide a line-level output through the dock connection on the iPod.
Sendstation PocketDock Line Out
There are probably other similar accessories out there.

The dock is a much better way to go - it is a fixed output line out signal. Meaning that you need a volume control between the iPod and the amp - a small passive will do the trick.

There are a number of them on the market. Some key differences are:

1) Some are designed to also be simultaneously used as chargers, some are not.

2) Most are designed so that a mini jack then fits into the dock plug, a few are designed so that they can wired up directly to RCAs

Worth looking into the iMod from RedWine Audio. Vinnie does some tricks to pick off the audio out right after the DAC. Its a very sweet sounding rig.