The External Inputs can be effected by the bias part of the Distortion iirc, but not the Distortion, it does feed the Compressor, but you’ll need a decent level coming in. So the signal can be distorted, but not by the bulk of the distortion circuit
Okay it’s called Symmetry in the manual
SYM (Distortion Symmetry) offsets the whole signal (in the y
direction, if visualized as a wave cycle on a 2D graph) either up
(positive values) or down (negative values) before applying distortion. This makes asymmetric distortion of the signal possible,
fringing only the crests or the troughs of the wave. Range (-64-
+63).