It doesn't, that's what I'm confused about. If I go from my 610 to the front inputs (xlrs) it sounds fuller, louder, etc than when I go into the back 1/4's. I was wondering whether it was because they were 1/4 inputs, whether it's because the back inputs are 96hz and the fronts are 192. ?? It's obviously (to me anyway) not the preamp, it's the input because no matter what pre I use going into the 1/4's it sounds thin, and likewise, no matter what I use into the XLR's it sounds much better.