Anatomy of 1941 ES-300 Electric Pickup
The following page is dedicated to the break-down of an early '41/42 ES-300 pickup. For the full specifics on the evolution of the electric pickup, please see 'History of the Electric Pickup'. This unit is the 2nd version of an early P-90. The first version can be seen on the 'long slant' 1940 ES-300. This 2nd version can be seen on the 'short slant' 1941-1943 ES-300 and the 1940-'42 EH-150 (also the EH185 '40-'42, EH250 '40 and EH275 '40-'41) models.
The slant pickup that you will see on this page has been something I have waited a long time to break apart. Up until now, I have read numerous articles on how these early pickups were made, but have never seen photos of the inner workings.
The evolution of the electric pickup is fascinating. The following photos will take you from top-to-bottom of one of the most important milestones of the time. From the evolution of the bulky 'Charlie Christian' bar magnets, to the introduction of smaller, more powerful ALNICO magnets, these photos will hopefully give you a glimpse into a very important time in the evolution of the electric pickup.
Brass base-plate fastened to the electric pickup unit. The outer screws are used to mount the unit to the inside of the guitar.
2 wooden blocks can be found right below the brass base-plate. These blocks are directly underneath the ALNICO magnets.
Metal core between the wooden blocks. The core is where the pole-pieces will eventually screw into. Note the green is the corroded wire wrappings found above the magnets.
Top left shows 2 wires coming out of the hidden wire coil (green). These wires will lead from the finished pickup unit to the tone/volume pots and eventually to the input jack.
Outer brown blocks are wood. Inner black/grey block are the ALNICO (aluminum, nickel and cobalt mixture) magnets.
Note the bumps on the top are pole-pieces. 6 of these are screwed through the wire coil, 2 celluloid plates and into an inner metal core. The ALNICO magnets and wood blocks are on either side of the metal core in which the pole pieces are screwed into.
Bottom left shows the removed wood block Exposing the inner metal core and ALNICO magnets. The screws on the bottom attach the brass base-plate to the metal core.
Fascinating that the 6 screws above are actually the pole pieces. The wire coil will wrap around the screws and they will eventually be sandwiched by 2 flat celluloid plates.
6 adjustable pole pieces, 1 metal core with 8 threaded holes, 2 ALNICO magnets, 2 wood blocks, 2 screws with washers and 1 brass base plate form the inside workings of these early P-90 pickups.
6 adjustable pole-pieces, or long screws, ready to be threaded through the inner metal core.
View of the center pole-piece 'screwed' completely through the metal core into a very low position.
Wood block and ALNICO magnet ready to be placed on either side of the metal core.
Wood block and ALNICO magnet placed on opposite side.
Wood block and ALNICO magnet placed on both sides of the metal core.
Top view with the heads of the adjustable pole-pieces (long threaded screws) positioned between the 2 ALNICO magnets.
Pole-pieces are fixed and ready for the wire wrappings which will ultimately form the coil of this pickup.
Several thousand turns of wire are wrapped around a celluloid core. They are then sandwiched between a bottom and top piece of flat celluloid and the pole-pieces are then screwed through the core, thus mounting the wire to the pickup.
Top view of the pole-pieces screwed through the celluloid wire wrapping and into the metal core on the inside of the pickup. Note the broken piece of the flat celluloid which ultimately covers the finished pickup.
From top: pole-pieces inserted through 1 flat celluloid plate, inner celluloid and wire wrappings, bottom celluloid plate and screwed into an inner metal core positioned with 2 ALNICO magnets, 2 blocks of wood and finally screwed into a brass base plate.
Introduction of the side celluloid cover which wraps around the pickup in order to make it one complete unit. Note the wires protruding out of the wire coil of the pickup. These will connect to the wires pictured a bit further down.
Note the wood blocks are in plain view.....once the pickup is mounted, only the pole-pieces and top celluloid plate will be seen.
Note the space inside of the pickup. Also, the bottom piece of flat celluloid can be viewed from the inside as well as the middle celluloid core.
View of the upper and lower celluloid plates which 'sandwich' the wire coil.
Another view of the top and bottom celluloid plates. Note the plates form a compartment for the wire coil. The ALNICO magnets and wood blocks are below this compartment. The pole-pieces inserted through the coil are magnetized.
Completed unit is ready to mount.
Ground wire will be screwed to the brass base-plate. The other end is wrapped around the shielding pictured above.
2 wires above will connect to the inner wrapped wire coil of the pickup.
Top left shows the input jack. Top middle view is of original potentiometers (volume/tone pots), original capacitor and wire shielding...all of the inner workings to 'wire up' a prewar ES300 electric guitar!
Side view of complete ES-300 pickup unit, installed.
Complete ES-300/early P-90 pickup unit.
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