Personally I'd run an external pre, but that could just be my preference in sound that I get from my gear selection. I normally run a V2 and think it sounds more detailed and not as "muddy." Well, not quite
muddy, but compared to the V2 (which I supposed is could be considered a bright preamp) the 680 pres are definitely darker.
For Yonder yesterday my V2 battery cable crapped out after the first set, so the first set is AKG CK 1X > V2 > 680, second set is just AKG CK 1X > 680 if you want to take a gander at that and see if it helps at all.
I suppose this won't help that much when comparing sonic signature to Schoeps, but its something I suppose.
http://archive.org/details/YMSB2013-07-28.CK1X.V2.flac16