NOTE: The images and info on these webpages are taken from a customer's job that is in progress in my shop, ....and have not been edited yet specific to my questioning whether a Diamagnetic Anomalous Hall Effect might have been designed into this guitar's pickup at it's factory.
Since this entire electronics assembly was broken and a previous repair attempt was obviously initiated (but thankfully abandoned); I've had to study this pickup design and theoretical function and function nuances before starting to rebuild the pickup guts.
While studying pot metal to try to identify this electronics plate's alloy composition, ....I ran into some quite interesting info that might explain the pickups quite unusual design and magnetic polarity readings of it's separate disassembled parts.
In short; The pot metal's appearance is similar to a Bismuth alloy, .....which led to finding info about Bismuth having the strongest natural diamagnetic properties, .....which converged with info about the Hall Effect, .....which led to info about the Anomalous Hall Effect in the presence of an electromagnetic field / current, which the pickup coil might provide IF a Hall Effect is involved.
A number of unusual design factors and meter readings of residual magnetism & polarities in the disassembled parts of the pickup assembly, .....makes me wonder if an Anomolous Hall Effect was built into this pickup.
I will edit and add info here as I am able to during this investigation, ....after initiating some discussions about the possibilities of an Anomalous Hall Effect being built into this pickup, and reporting same here as I am able.
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NOTE: Bismuth is said herein to mean a bismuth alloy; A pot metal in this pickup's case. I chose bismuth as a starting point because it has exceptionally good properties for diamagnetics, Hall Effect, Anomalous Hall Effect and use in pot metal alloys. Because pure bismuth is a poor electric conductor, and this pickup's cover / casing is case ground for the circuit, a use of bismuth would have to be a conductive alloy, reducing bismuth's diamagnetic properties ...but bismuth has such high diamagnetic properties that a reduction might still contribute substantially to diamagnetic properties, IF such properties are designed into this pickup. A different diamagnetic alloy might be indicated, although it seems to me that bismuth would have been chosen in such a design. Click here for references at the bottom of this page.
After WWII there was an abundance of recycled war materials, particularly metals, at low prices during that period of surplus abundance and a robust economy as American industry transitioned from a strained war economy back to rebuilding a civil industries economy. Bismuth is mentioned as being a common substitute for lead in pot metals used for diamagnetic applications.
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Outstanding Questions:
() Are the unusual polarity orientations of the magnets correct to the original factory design and assembly? () Is there a Hall Effect in the pickup's unusual magnetic orientation design? () Are the unusual polarity orientations of the magnets someone's reinstallation mistake while working on this pickup in the past? () Should the magnets be changed to sychronize their polarities with each other, thereby creating only 1 pole at the top and 1 pole at the bottom of the rail plates like all other pickups I've seen?
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The pickup is a twin-rail type. A single coil surrounds one of the two rail plates. The 2 rail plates clamp 2 magnets between them oriented in opposite magnetic polarities. The pickup is not a dual coil with one coil missing as a first glance hints at; A second coil would not mount into the pickup assembly.
The pickup actually worked on the Regal Steel guitar, even with it's cover / housing shattered; Although I did not do a comprehensive analyis of output voltage (sound) nor a lateral string gauge compensation balance check. The pickup did not sound weak so ops testing it more comprehensively would normally be done better once the houseing cover was repaired, the pickup guts cleaned up and checked, and everything reinstalled for ops checks / tests.
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