Marantz has been using Crystal DACs (Cirrus), which are quite good, and I don't see why they would switch. All the specifications are listed on their website
www.marantz.com. Cirrus is listed for the 7500.
Burr-Brown is now I believe wholy owned by Ti, and I'm curious to see what that means long term.
I'm a big fan of Marantz and I have no problem recommending them. I've owned quite a few of their receivers and all have been solid. What speakers do you plan to run? 5.1 should be no problem for this guy.