You're talking about C6, that's the cap that's omitted in the Cleft version. C2, C6 & C9 all do the same thing: they roll-off treble in the 1st, 2nd & 3rd stages, respectively. Making those caps bigger darkens the sound; making them smaller brightens the sound. How much of a difference it makes by leaving C6 out is anyone's guess. I stopped trying to understand why EQD does the things they do. If it sounds good the way it is, maybe it's time to put down the soldering iron, screw on the bottom cover and play guitar.