I do not have the Pro Model. I am using an XLR splitter cable to the 4 channel amp, then using the RCA outputs to a sub.
Really loving the EQ ! I have a small bump at 120 and 500 for a little punch increase. I hear no negative effects from this. While not exactly cheap I believe the combo of functionality and sound quality make it tough to beat. When I finally go back in the office I may take it in for headphone listening.