Kim talks Vintage Guitar Parts

The pickup were wound with #42 plain enamel wire. On original PAFs the bobbin wire appears purple, versus later PAF and patent# pickups that appear reddish. Gibson eventually switched to polyurethane coated wire around 1963. When wire coatings change, the sound of the pickup does change, contributing to the PAF following. The amount of wire (and coating) wound on each bobbin determines the pickup’s resistance. When the bobbins are wound with more than a nominal amount of wire (either on purpose or by accident), they are more powerful with fatter midrange but less treble. Due to the human factor and the wide tolerance of the manually-run pickup winding machines used by Gibson from 1956-1961, PAF pickups usually measure between 7.5 and 9.0 thousand ohms (K ohms). By 1962 (the end of the PAF era), Gibson was making pickups very consistently with 7.5k ohms of wire (give or take .25k ohms). The separate bobbins of a PAF can measure very differently due to Gibson’s manufacturing techniques. For example one bobbin could measure 3.5k, and the other 4.5k ohms (for a total of 8k ohms). This mis-matched ohms is actually a good thing, as certain frequencies will stand out if both bobbins have different resistance. This contributes to why two PAF pickups can sound quite different. The coil winder was a Leesona 102, and did have auto stop counters to keep pickups windings consistent. But these winders ran using a fiber gear and were prone breakage. The work around to fixing the counters is to time the winding process. That is one reason for the randomness of PAF pickup resistance. Around 1965 to 1968 (exact date unknown), Gibson changed from a manually-run pickup winding system to a fully automated system. Because of this their humbucking pickups all became a consistent 7.5k ohms from 1965 and later. The manual-run system had a machine operator that decided when a pickup bobbin reach about 5000 turns of wire. So there was plenty of room for under and over-winding. When the fully automated system came into place, the pickups were very consistent in their windings (and hence total ohms). A fantastic clip by the Allman Brothers Band featuring Duane Allman and Dickey Betts: