Chantaipan, welcome to the madhouse! It would be an addiction if it wasn't so rewarding!
The DIP is a small box made by Monarchy audio. They can be found for sale regularly on this site, since they are very popular. You can also buy it new from Audio Advisor, and try it for 30 days.
It takes digital coax/toslink signal and re-clocks it removing quite a bit of jitter (a huge topic, with tons of info; some people on the net will tell you jitter is inaudible, but I don't think anyone on this forum will say that.)
It then allows you to output coax or balanced digital to your DAC.
If you get a used one, get at least the MkII DIP.
The new ones are 24/96 (note that the MkII only 16/44, but this is fine for CD's) so they can also be used on DID players for HT (DD, DTS). I have one of each, they both seem to work about the same for CD's. Changing the power on it improve the sound a bit as well.
I also recommend (for mega changer users) the Slink-e device. This let's you control your changer from your computer. It'll scan the player for you, get all the album/track info from the net, and let you create playlists, search for songs, and what not. But it only works with Sony S-link connections.
KP