The digital solution works really well. When I adjust the volume on the computer, it automatically adjusts the balance to cooperate. Even better, adjusting the volume on the receiver won't change the balance on the headphones, even though the computer is not accounting for this. It would seem that the flaw, then, is inherent in the receiver's balance adjustment circuit, not analogue balance adjustment in general.
So I'm a bit worried. Why? At some point in the far future, I can see myself buying another pair of headphones. Perhaps from Grado, perhaps from AKG, it could be another brand; the point is that I'll be using two pairs of headphones from one setup. When this happens, I won't want to go into my sound preferences every time I switch headphones, and I won't want to use the balance control on my receiver.
A solution that my mind has though of is some sort of short extension cable for my HD 555 with an inline balance control, sort of like a volume control. I'd leave this on my Sennheiser headphones, and I'd never have to worry about adjusting balance again. However, I've never heard of such a thing, and there's not much reason for it to exist.
Do any fellow Head-Fi'ers have any ideas that might be helpful? I need a method to keep the balance of one pair of headphones adjusted, but that will only affect that one pair of headphones. That way, all I need to do to switch to a different pair is to switch to that different pair. I don't mind if the solution is not exceptionally Hi-Fi; it just needs to be effortless, and pretty, if possible.
I appreciate any help!