Firebird mag dimensions

[Zhangliqun]

Getting more inquiries about Firebird mini's and could use some help with dimensions on the two mags -- and also what, if anything, goes between the bobbins and the baseplate, since there's no bar mag below, only the two in the bobbin slots. Anyone have an exploded view of a Firebird mini?

[J S Moore]

It was a ferrous shim that went between the two magnets, sort of where the magnet would have been. You can experiment with different types of steel there. I don't know what the magnet dimensions would have been but they might have just been the magnets they used in the regular mini's.

[Zhangliqun]

Going by my bobbins, they have to be no more than 2-1/8" long, but the standard 1/8" thick spec is apparently fine.

[J S Moore]

They're probably the same dimensions as the ones they used in the regular humbuckers at the time. I think they used them in the Melody Maker pickup as well. I've got a couple and they're 2 1/8" long. I really can't see Gibson ordering 2 or 3 different magnet sizes.

Now that I think of it I'll bet one of the reasons the magnets got smaller was so they could be used in the mini's. Saves on ordering.

[Peter Naglitsch]

The Deluxe Mini HB have a different sized magnet so Gibbo definitely had at least two sizes of magnets.

[trioderob]

Getting more inquiries about Firebird mini's and could use some help with dimensions on the two mags -- and also what, if anything, goes between the bobbins and the baseplate, since there's no bar mag below, only the two in the bobbin slots. Anyone have an exploded view of a Firebird mini?

zhang-

take a look at the early firebird photos in this book
there is something very hard about getting the this pickup just right,
and I have been trying to figure it out !

I think even the compounds in the spacers are important.

jason does a very good job with this pickup and I have his pup in my historic
firebird 1.

I love it but not sure if he nailed the tone 100 % as all the little details are
important in the construction.

[J S Moore]

I have a 1963 Firebird pickup in my hand right now. Here are the specs:


Magnet: 2.044"L x 0.317"W x 0.125"H

There is a maple piece underneath with a strip of ferrous metal on top. Very thin and slightly less in size than the maple piece which fits roughly all the space on the baseplate with a little left for the lead.

Maple: 2.147"L x 0.880"W x 0.122"H With the ferrous strip it's 0.138"H

Additionally there was a small strip of metal across the top of the coil near one end. It is magnetic and looks quite deliberately placed straight across the top of the coils.

Strip: 0.942"L x 0.317"W x 0.0085"H

Hope this helps.

[Zhangliqun]

So the width of the magnet is more or less equal to the depth of the bobbins. That figures.

Now the question is what Alnico grade, traditionally?

[JGundry]

So the width of the magnet is more or less equal to the depth of the bobbins. That figures.

Now the question is what Alnico grade, traditionally?

I was told by a former Gibson employee that they were always A4.

[J S Moore]

As I promised a forum member, here are some internal photos.

[Zhangliqun]

That's about as helpful as it gets. Thanks, Jon...

[David Schwab]

That thin plate bridging the magnets on top is interesting. Was it under the treble or bass strings?

[salvarsan]

That thin plate bridging the magnets on top is interesting. Was it under the treble or bass strings?

With it, the magnetic and electrical circuits are more alike.

You think it was to add a controlled amount of eddy currents
so as to tame the high frequencies?

-drh

[David Schwab]

With it, the magnetic and electrical circuits are more alike.

You think it was to add a controlled amount of eddy currents
so as to tame the high frequencies?

I don't know, but if you short the two poles like that on a pickup, you have less magnetic pull (if any). Generally you don't get much output from the pickup.

The bottoms of the magnets were already connected with that plate. So I'm puzzled as to the reason they included it.

[JGundry]

That's about as helpful as it gets. Thanks, Jon...

I guess I should qualify it by saying that I was told all Gibson mini humbucker magnets were A4. I took that to mean that included Firebird mini humbuckers.