T-Top Magnets?

[Daver]

Do any of you guys know what type of magnet would be in an early '80's Gibson T-Top pickup? I assume Alnico 5, but what do I know? Thanks!
Dave

[Stan H]

Pretty sure they were A5.

[Possum]

...

Yeah alnico 5 and shorter, and thinner too

[Daver]

OK, that confirms it. Thanks, guys.
Dave

[JGundry]

They can have very thick A5 short magnets as well. I have a early T-Top with a magnet that is .138"-.140".

[Possum]

...

I didn't read the post well enough, early 80's I don't know what they used, the thin short magnets were more like early 70's

[David Schwab]

Possum has a point... I didn't read it well enough either.

I started to answer the original post telling about the sand cast Alnico V magnets in the Shaw pickups.... then I saw he said T-tops.

I'm pretty sure the early 80's would be the Tim Shaw pickups, and not the T-tops. My '81 LP Standard had Shaws. You can't get much earlier than that.

[Daver]

Thanks for all the input. The pickups I have are T-Tops. I've pulled the covers off. They have black bobbins and measure about 7.4K to 7.5K or so. They came out of a Flying V I bought new around 1980 or 1981. The pickups have the patent number metal stamped into the base plate and no ink stamped dates. Maybe they are some of the last T-Tops? What's the deal with the Shaw humbuckers? I've heard about them, but never really paid attention. Good, bad, indifferent? Thanks.
Dave

[David Schwab]

The pickups have the patent number metal stamped into the base plate and no ink stamped dates.

Those sound like Shaw baseplates. Do the bobbins have a "T" on them? They shouldn't, unless they had some parts left over.
Those might be some of the last T tops.

Tim Shaw was given the task of reproducing the PAF within a limited budget. He said he had to make some compromises because they wouldn't pay for some stuff to be made. I think the bobbins were modified T tops or something like that. There's was an interview on the 'Gibson site once:

Whether it was rivalry between plants or increased market awareness, the Nashville plant jumped into the reissue action in 1980. By this time, one of the most glaring deficiencies of new Les Pauls (compared to the originals) was the humbucking pickup. In preparation for its first attempt at a reissue, Gibson assigned engineer Tim Shaw the job of designing a reissue of the original Patent-Applied-For humbucking pickup-within certain restrictions. "This was 1980 and Norlin was already feeling the pinch," Shaw said, referring to Gibson's long decline through the 1970s and early '80s. "We weren't allowed to do much retooling. We redid the bobbin because it was worn out. We got some old bobbins and put the square hole back in. We did it without the T-hole, which stood for Treble."

To replicate the magnets, Shaw gathered up magnets from original PAFs and sent them to a lab to be analyzed. "Most were Alnico 2's," he said, "but some were 5's. In the process of making an Alnico 5, they stick a magnet in a huge coil for orientation, but an unoriented 5 sounds a lot like a 2. They started with Alnico 2 and then switched to Alnico 5."

Shaw discovered that the original magnets were a little thicker than 1980 production magnets. "Magnetic strength is largely a function of the area of the polarized face; increasing the face size gives you more power," he explained. So he specified the thicker magnet for the new PAF.

Wiring on the originals was #42 gauge, which Gibson still used. However, the original wire had an enamel coating and the current wire had a polyurethane coat, which also was of a different thickness or "buildup" than that of the original, which affected capacitance. Norlin refused to go the extra mile-or extra buck, as it were. Enamel-coated wire cost a dollar more per pound than poly-coated. Shaw could change the spec on the buildup without additional expense, so the thickness of the coating was the same as on the original wire, but he was forced to use the poly coat. The difference is easy to see: purple wire on the originals, orange on the reissues.

Shaw later found a spec for the number of turns on a spec sheet for a 1957 ES-175. "It specified 5,000 turns because a P-90 had 10,000 turns and they cut it in half," Shaw said. In reality, however, originals had anywhere from 5,000 to 6,000 turns, depending on how tight the coil was wound. Shaw later met Seth Lover, who designed and patented Gibson's humbucker, at a NAMM show. Lover laughed when asked about a spec for windings, and he told Shaw, "We wound them until they were full."

The spec for resistance was even less exact, Shaw said. The old ohmeter was graduated in increments of .5 (500 ohms). Anywhere between 3.5 and 4 on the meter (3,500 to 4,000 ohms) met the spec. Consequently, Shaw pointed out, there is no such thing as an exact reissue or replica of the 1959 PAF pickup. There can only be a replica of one original PAF, or an average PAF. As Gibson would find out in the early 1990s, the same could be said about the entire guitar.

Shaw's PAF reissue debuted on Gibson's new Nashville-made Les Paul Heritage 80 in 1980. Compared to anything Gibson had previously made (which is to say, compared to nothing), it was an excellent reissue of a sunburst Les Paul Standard. It had a nice top, thin binding in the cutaway, nickel-plated parts, more accurate sunburst finish and smaller headstock, but the body shape, body size and three-piece neck, among other details, were just regular production. It appears that Gibson still didn't understand the demand for an accurate reissue, because Gibson accompanied the Heritage 80 with fancier versions: the Heritage 80 Elite, with an ebony fingerboard that had no relevance to the reissue market (although it did have a one-piece neck) and the Heritage 80 Award, with gold plated hardware that also had no relevance to the reissue market.

Here's an '81 Shaw I rewound recently. You can see the date stamp along with the patent number (which is not the patent for the humbucker! ...still. You'd think they would have changed that by then)

[Daver]

David,
Yes, the bobbins on both pickups have the "T" on them. My base plate is a little different than the one you have pictured. The legs are a little longer and the side for the slug bobbin only has two holes for the mounting screws compared to the six extra on your's. I don't know what the magnets look like. I've only removed the covers. So, I guess they are late T-Tops or leftovers as you suggested. Thanks!
Dave