I used some supercaps (3F) as DC blocking caps to mod my ipod but after the mod I measured some dc offsets from the line out dock. Initially it was measured around 150 mV on both channels, but recently I measured it again the dc offsets seemed having grown to 250 mV on both channels. I am fairly sure the dc offsets are related to the caps as I have a pair of mods with the same caps, and both mods were measured with almost identical dc offsets.
I am more puzzled by the growth in dc offsets than the dc offset itself.
So my questions are ...
1) Are supercaps prone to produce dc offsets? (FYI, my other mods with film caps produced no DC offsets.)
2) Why do the dc offsets go up with time?
I have been using these mods with the supercaps for a while and have not noticed anything unusual (e.g., no distortions). The amps and iem's seem doing just fine.