I did the copper thing too. I read some where it could be a yeast making the smell and to try sodium metabisulfite it kills yeast dead in its tracks. kms or potassium metabisulfite won't kill the yeast. Since I added 5 Camden tablets otherwise know as sodium metabisulfite the smell has significantly decreased. It think it is fine now.
Quick update. Still can't find a penny.Bumping the thread as I've got the same issue with a Baco Noir (from grapes). I commented early that it had an off-odor that I judiciously applied KMS & stirring. I left it alone for 3 months adding KMS again in January (but not checking on it further as I was tied up).
My 3gal batch still has the sock-scent (4mos) when I racked it yesterday. While Canada no longer has pennies (easy source of copper): I had a length of copper pipe leftover from some plumbing repairs that I sanitized and stirred a little bit with.
I left the copper pipe in the carboy about 10 mins before tidying up and taking a sample and it still had the sock-scent.
The good thing, however, is that the taste is fine.
I'll scrounge around to see if I can find a copper penny (I might have one of those ones with the Lincoln memorial on them...) to try it out in a single glass.