In the early days of Music Man up until roughly half way through 1977 Music Man pickups had pole pieces or magnets that extended down into the body. These long pole pickups absolutely produced a different sound than the pickups with magnets that were flush against the bottom of the pickup casing. The name that many collectors call these pickups are the “John Holmes” Long Pole pickups due to them having long poles.
The largest magnets were found in the early 1976 basses and it is interesting that there is a general agreement amongst collectors that the 1976 Stingray Basses sound the best. The Radio Knob Stingray is most well known for its outstanding deep thump and full tone and these features the pickups with the longest magnets out of all of the Stingray basses. The first picture shows the Long Pole magnets that are in the pickups of a 1976 and the 2nd picture which features a natural bass shows a 1977 pickup. The 3rd picture shows the underside of a 1979 Stingray Bass pickup and as you can see the magnets are nearly flush with the pickup casing.
Leo Fender is well known for being a genius in guitar design and the early Music Man pickups were absolutely representative of his genius. There is an obvious and noticeable difference in sound in Stingray Basses from various years and a part of this difference in sound can be found in the “John Holmes” Long Pole Pickups.