hogy
Member
- Joined
- Nov 4, 2005
- Messages
- 715
Hi there. There seems to be somewhat of a lack of knowledge of how a vintage Gibson Firebird is constructed. Today I got a chance to take apart a vintage '63 Firebird III pickup to repair a problem with a dead coil due to a faulty coil lead. The good news is that I was able to fix the pickup without having to rewind it. The better news is I have pictures to dispel all myths regarding the makeup of these things. They are not at all like a '70s mini humbucker. What they basically are, design wise, is two shrunken Melody Maker pickups wired as a humbucker.
First, the whole thing is held together by the cover and base plate, and a bit of glue.
Under the base plate are a couple of thin maple shims:
The dual coils are simply sitting inside the tight fitting cover. Under the wooden shims is a thin, ferrous metal plate:
Under that are two coils made up of thin, flimsy, translucent plastic bobbin formers. Inside each bobbin is a bar magnet. Picture a regular humbucker magnet cut in half horizontally. One coil has the North facing up, South on the other. The ferrous plate mentioned before is simply held in place by those magnets and is magnetically coupling them:
The coils themselves are wound with the typical, purplish/maroon Formvar wire as found on period or earlier humbuckers and P-90s. Each coil measures around 3.2k and they are connected in series like a PAF.
On the other side of the bobbins, the one facing the cover, there is another small strip of ferrous metal glued across the magnet bars. Again, apparently, to magnetically couple the two coils. On top of that there's simple transparent adhesive tape to insulate the magnets from electrical contact with the cover:
In a regular PAF style humbucker the magnet is in direct touch with the base plate, cover, and pole pieces. Obviously, the FB pickup's designer took efforts to avoid this. The wood spacers on the bottom and insulating tape on top of the bobbins ensure that the magnets have no contact to electrical ground. I'm no pickup designer and I'm not sure why this matters, but here it is.
b
First, the whole thing is held together by the cover and base plate, and a bit of glue.
Under the base plate are a couple of thin maple shims:
The dual coils are simply sitting inside the tight fitting cover. Under the wooden shims is a thin, ferrous metal plate:
Under that are two coils made up of thin, flimsy, translucent plastic bobbin formers. Inside each bobbin is a bar magnet. Picture a regular humbucker magnet cut in half horizontally. One coil has the North facing up, South on the other. The ferrous plate mentioned before is simply held in place by those magnets and is magnetically coupling them:
The coils themselves are wound with the typical, purplish/maroon Formvar wire as found on period or earlier humbuckers and P-90s. Each coil measures around 3.2k and they are connected in series like a PAF.
On the other side of the bobbins, the one facing the cover, there is another small strip of ferrous metal glued across the magnet bars. Again, apparently, to magnetically couple the two coils. On top of that there's simple transparent adhesive tape to insulate the magnets from electrical contact with the cover:
In a regular PAF style humbucker the magnet is in direct touch with the base plate, cover, and pole pieces. Obviously, the FB pickup's designer took efforts to avoid this. The wood spacers on the bottom and insulating tape on top of the bobbins ensure that the magnets have no contact to electrical ground. I'm no pickup designer and I'm not sure why this matters, but here it is.
b
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