Click Here to view & shuttle an electronics schematic on a separate page. |
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End of pics and info ...for the time being. |
References: Diamagnetic; material opposes a magnetic field opposite of field. Paramagnetism; material aligns domains to match a magnetic field's. Remanence (metals ability to hold a magnetic charge). Bar magnet flux field. ------- o ------- Hall Effect; And Anomalous Hall Effect resulting from electric field induced into Hall Effect: Basics and references; Georgia State U. Physics Dept: Hall Effect; Basics expanded; Wikipedia confirmed: Anomalous Hall Effect; Basics expanded; Wikipedia confirmed: Hall Effect; More info and charts: Hall Effect; Comprehensive Physics Paper: ------- o ------- Pot Metal: Bismuth. Strong diamagnetic; Highest Hall coefficient. Bismuth alloys: CLICK ON THIS IMAGE FOR THIS HALL EFFECT CHART WITH TECHNICAL TEXT: |
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. ------------ oOo ------------ 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. ------------ oOo ------------ 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? ------------ oOo ------------ 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. ------------ oOo ------------ |
Analyzing a unique pickup in a 1947 Regal Lap Steel. Investigating: Unusual magnetic polarities in this pickup assembly, and; Whether Diamagnetics, and/or 'Hall Effect' and/or 'Anomalous Hall Effect' is designed into this pickup: Page 1; Data and Images: |
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. ------------ oOo ------------ 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. ------------ oOo ------------ 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? ------------ oOo ------------ 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. ------------ oOo ------------ |
Here is the shatterd pot metal pickup / electronics mounting plate that is the repair job which led to disassembly of the pickup, finding it's unusual magnetic polarity orientations and questioning whether a Hall Effect was designed into the pickup. |
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N |
S |
S |
Pickup (removed from cover) shown prior to disassembly. Shown upside down here. Polarities of the magnets and rail plates are shown. Notice the unusual polarities of the magnets and the residual polarities on the rails / plates that the magnets are in direct contact with. It is possible that someone in the distant past installed one of the magnets in the wrong polarity direction and thus magnetizing the rail plates in the very unusual magnetic polarities as the pickup was when I disassembled it, shown here in each step of disassembly. |
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Shown below is the Electronics / Pickup plate after it was repaired; Bottom view; Shown here for reference of how the pickup mounts onto the cover plate via a central mounting finger on the cover plate. The coil's rail plate slot noted in yellow; Non-coil rail plate slot noted in gold. The slots in the pickup cover surround the pickup rails / plates very closely, with nothing in the design to prevent the cover from touching the rail plates. The cover and rail plates are also electrically common to ground. |
This page is under construction, and will be revised as this investigation progresses. |
Here are some graphics to better show what we're looking at in the pictures. |
The magnets are chunks of some flat-ends surplus magnets that were broken into useable (smaller) pieces by striking the donor magnets with a punch ! The smaller chunk goes on the bass bout side and the larger piece on the treble bout side; Compensating for string mass. The pickup assembly can also be tilted for string gauge compensation by loosening the bolt that holds the pickup together, then tightening it back in a new tilt position. |
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N |
N |
S |
S |
References: Diamagnetic; material opposes a magnetic field opposite of field. Paramagnetism; material aligns domains to match a magnetic field's. Remanence (metals ability to hold a magnetic charge). Bar magnet flux field. ------- o ------- Hall Effect; And Anomalous Hall Effect resulting from electric field induced into Hall Effect: Basics and references; Georgia State U. Physics Dept: Hall Effect; Basics expanded; Wikipedia confirmed: Anomalous Hall Effect; Basics expanded; Wikipedia confirmed: Hall Effect; More info and charts: Hall Effect; Comprehensive Physics Paper: ------- o ------- Pot Metal: Bismuth. Strong diamagnetic; Highest Hall coefficient. Bismuth alloys: CLICK ON THIS IMAGE FOR THIS HALL EFFECT CHART WITH TECHNICAL TEXT: |
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N |
S |
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N |
S |
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Flux lines and polarity of the Regal pickup at issue, looking at the front or rear face of the non-coil rail plate: |
The Regal's pickup flux lines and rail plate polarity looking at the front of the coil's rail plate, showing the magnets general placement and polarities facing the viewer: |
Flux lines of a conventional rail plate / bar pickup, viewed from the side; Magnetic Polarity not important here since it could be N or S in either direction. |
Misc. Views: |
Pickup assembly and mounting into pickup / electronics plate / cover; Shown upside down here: |
Magnets |
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Magnets |
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Top View |
Front View of coil rail blade |
Side View |
Front View of non-coil rail blade |
Pickup blades |
Pickup cover |
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Coil |
Rubber washer |
Coil |
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Rail Blades / Plates |
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End of pics and info ...for the time being. |
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Top of the pickup cover plate (primed after initial repair to reveal any details that need further finishing). |
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Non-coil rail plate |
Coil's rail plate |
Coil |
Magnet |
Magnet |
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A Look at Flux Fields: |
A conventional pickup with pole pieces for each string, or a rail plate / bar would look generally similar, shown here hypothetically for illustration purposes as though the flux field were an infalted tube: |
S |
N |
Here's some things on my work bench for relative size comparisons: |
Copper sleeve tightly grounds coil begin wire to the rail blade. |
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Here is the hypothetical inflated tube idea for the Regal's rail, with lines to simulate the extended magnetic field, and showing the guitar strings oriented to one pickup rail and field. : |
Bare rail plate shown just for illustration purpose. |
Up / Down / Vertical |
Lateral / Horizontal |
Click Here to view & shuttle an electronics schematic on a separate page. |
