This afternoon, I made a fascinating discovery in my old Rickenbacker 4001 I had sequestered in my parent's basement when I returned home and looked at the parts. The pickup was an aftermarket replacement from the previous owner, which I vaguely remembered. Having access to both the dismantled instrument AND the internet for the first time, I have come to discover that this is not a Bass pickup at all, but rather a humbucker for 6-string guitars. The humbucker is black and is stamped with a spartan Hi-A on the face, with no other markings anywhere else on the pickup. After searching the internet I discovered that Bartolini made pickups under the Hi-A name from 1973 to 1977, where they subsequently discontinued the name. The Rickenbacker is a 1975 model, so I suspect the replacement happened between 1975 and 1977 although it is possible it could have happened anytime after that until I picked the guitar up. That said, I am curious to know about this pickup. Since it has no stampings whatsoever, I can only assume its nature. It is identically shaped to a guitar humbucker, the obvious choice being the 1-C... their first humbucker that debuted in 1975. Does anybody know for certain what this actually is? Also I am curious to know what they sound like from those with experience. Finally, does anybody have a clue about the value of these? I imagine there has to be some value associated with it seeing how there was a 2 year time window of manufacture and Bartolini is still making pickups. Any input you have on the pickup would be appreciated. Here is a picture: I have since removed the decayed foam strip which revealed an unmarked brass strip beneath it.