Heavy formvar typically has a brighter, more open tone, while plain enamel has a warmer, grittier, and more aggressive tone with a tighter low end
. These differences arise mainly because heavy formvar has a thicker insulation coating, which creates more space between wire turns and alters the coil's dimensions. This allows heavy formvar pickups to be wound with slightly more turns, leading to a higher inductance and brighter sound compared to plain enamel.
Feature
| Heavy Formvar | Plain Enamel | |
|---|---|---|
| Tone | Brighter, clearer, more open | Warmer, grittier, more aggressive |
| Midrange | Slightly less prominent | More prominent grit |
| Highs | More prominent highs | Can be perceived as having a slight treble reduction |
| Low end | Fuller | Tighter |
| Coil Properties | Thicker insulation creates more space, allowing for more turns | Thinner insulation allows for a more compact coil |
| Common Use | Vintage Fender pickups (e.g., Strats, Jazz Basses) | Vintage Gibson humbuckers and P-90s; early Fender pickups |