I couldn't gather this from the web. Polling forum wisdom. The Thunderbird pickup design changed a couple of times. Does anybody have details about when what changes happened: The first construction IIRC was flat-lying coils with a bar magnet inside the coils (which means no polepieces), using Alnico. Just like the Firebird pickups Then there are additional plates of magnetic material (steel?) that reshape the magnetic field That seem to have change to various other humbucker constructions. This photo of a 1992 points to passively magnetic polepieces in the coils and magnet(s) on the bottom http://forums.vintageguitarandbass.com/showthread.php?432-Thunderbird-Bass-Pickups Today's pickups are ceramics. When did that start? With the 1987 reissues? This is a great post, which I might want to bump later. http://www.talkbass.com/forum/f8/gibson-thunderbird-old-vs-new-760804/#post10747632 Unfortunately it isn't clear on which variants of Thunderbird humbuckers had upright coils and which one had face-to-face coils. Anyone knows? As a mildly crazy question, how close would the Carvin soapbars (the ceramic humbucker version) come to current production Thunderbird sounds? I would be interested but since Carvin has decided not to make their soapbars compatible with regular Thunderbird style soapbars you'd be stuck with theirs.