From The Galaxy of Strats Book
By Yasuhiko Iwanade (Publisher Rittor Music)
The Galaxy of Strats book was written in Japanese in Japan in 1998. The below translation has been made by Yasuhiko Iwanade.
P 158
The Stratocaster’s pickups are supported at two points on both ends of the bobbin, and this support method is a distinctive feature. What’s interesting is the size, which is exactly between the size of the Telecaster’s front pickup and the Precision Bass.
The bobbin, made up of two pieces of fiber material pierced by magnets, is another example of Leo Fender’s unique approach, which is shared across different models. The main difference is that while the pickups on the other two models are directly attached to the body with wood screws, the Stratocaster’s pickups are suspended from the pickguard. This is because the pickguard also serves as an assembly plate into which the pickups are mounted, resulting in a different effect on the vibrating system compared to direct mounting, which significantly influences the sound quality.
The magnet wire coating also differs from the Telecaster and Precision Bass, which use enamel, as the Stratocaster uses “formvar” coating. This also affects the sound due to differences in inter-wire capacitance. The number of coil turns is also unique. Additionally, the Stratocaster was a pioneer in adjusting the magnet height for each string and adopting a plastic cover. In the early models from 1954, the magnet for the 3rd string was slightly lower, but by 1955, it was the same height as the 4th string. In the early days, just like the Telecaster’s lead pickup, black wax was applied to prevent howling (feedback).
CAPTIONS
TOP VIEW
This is a typical Stratocaster pickup from the late 1950s to early 1960s. The magnets are of the staggered type, meaning the height is adjusted according to the strings. Two eyelets serve as terminals, to which the coil wire and lead wire are soldered.
BOTTOM VIEW
On the bottom of the bobbin, the magnets are flat. The lead wires use a material known as “cloth wire,” which has a fabric-like insulation that offers excellent heat resistance.
① 1954
In the 1954 version, the magnet for the 3rd string is lower than that of the 4th string, which alters the volume balance between the strings compared to other years.
② 1955 to ’70s
From 1955 onward, the magnet for the 3rd string became the same height as the 4th string. This specification remained in place until the mid-1970s.
③ From 1965 onward, the bottom of the bobbin became gray, known as the “gray bobbin” type.
PICKUP WINDING
One of Fender’s production philosophies was to manufacture as many parts as possible in-house. Pickups were no exception, and they were produced almost entirely from raw materials.
Abigail Ybarra joined Fender in 1956 and was responsible for pickup winding under the supervision of Leo Fender. She remains an expert in this field today. According to her, Leo’s instructions were detailed and focused on achieving both durability and sound quality.
The winder used at Fender at the time was designed by Leo and built in-house. A sewing machine motor with pedal control was used to power it. The bobbin was mounted horizontally on the shaft and was driven by a belt, not a direct-drive mechanism. This design was intended to avoid concentrating wire tension at both ends of the bobbin, and Abigail recalls that, in search of the softest possible belt, they ended up using ordinary rubber bands.
In the early Fender winding machines, there was no mechanism to control wire feed or tension. Instead, workers would adjust the wire feed and tension simultaneously by holding the wire between the thumb and forefinger of their right hand.
Abigail says that Leo gave detailed instructions, especially regarding how the wire layers should be spaced. He preferred avoiding tightly packed winding so that adjacent layers would be as far apart as possible, which was Leo’s way of ensuring that high-frequency tones, which shape the sound’s definition, would not be lost due to increased inter-wire capacitance.
After the winding was completed and the lead wires attached, the entire bobbin was dipped in wax for feedback prevention and treated for impregnation. Leo believed this process could also remove trace amounts of moisture contained in the fiber material, which could cause pickup deterioration.