A few years ago I purchased a Creek OBH-11 Headphone Amplifier.  Ever since I got it, it seemed that the balance was always slightly off.  Not off enough to be completely obvious, but just enough for things to feel not quite right.  I had feared the worse for the little amplifier suspecting that there might be a bad capacitor or something else gone wrong slightly out of whack inside.  I brought it home from the office this weekend determined to find out what was the matter with it.  Although I had taken it apart before, this time I noticed an allen socket on the back of the volume control, which is labeled A20k in the picture above.  I figured it was just a way to couple a motor to the potentiometer for remote volume control, but, figuring I had nothing to lose, I stuck a 5/32″ allen wrench in there anyway.  It turned out to be a balance control and with some careful tweaking I was able to get the OBH-11 sounding balanced.  My googling on this issue turned up nothing so I thought I would note my solution here.