3 simple steps:
1: install Remote in the ap store with your ipad (the blue icon with side black rectangle thing-its free!!). Sync the Ipad to itunes on your macbook through remote. Now you can control your Imac Itunes with your Ipad.
2nd get a USB dac and plug a usb cable from your macbook to usb dac.
3rd go rca out of the dac to your preamp.
voila
1: install Remote in the ap store with your ipad (the blue icon with side black rectangle thing-its free!!). Sync the Ipad to itunes on your macbook through remote. Now you can control your Imac Itunes with your Ipad.
2nd get a USB dac and plug a usb cable from your macbook to usb dac.
3rd go rca out of the dac to your preamp.
voila