The volume pot has four independent wipers, two for each channel to control the level of the positive & the negative signals. Every two wipers are rotated by an independent shaft.
These 4 wipers don't track perfectly. that's why we have two shafts to adjust so we can get the balance perfectly in the middle. We adjust the left & right channel in balanced mode
because this is why any one will buy the balanced amp. The balanced between the left & right channels would be perfect.
But because SE mode uses two wipers, the positive signal from each shaft, they have a little variations as they don't track perfectly.
Edited by Ray Samuels - 2/22/13 at 7:11am