Unfortunately the Wadia masi61 mentioned isn't made anymore, I use one between my IPOD Classic and my Aqua LaVoce S3 Dac. You might want to check out one of the DACs from High Resolution Technologies , link below, to see if it will meet your needs. I have one of their IStreamer Dacs that I use in my headphone system if I want to use the IPOD Classic in that system. It will definitely sound better than trying to go from your IPAD directly
http://www.highresolutiontechnologies.com/
http://www.highresolutiontechnologies.com/