GFC-43 GENERATOR FILTER CAPACITOR KIT

Hammond tonewheel generators use tuned LC filters to remove unwanted harmonics and artifacts from the generated tones. For all organs manufactured prior to 1964, the capacitors used in these filters were of paper / wax construction. These capacitors can be identified by their distinctive tan or brown wax-covered outer surface. Over the years these capacitors tend to absorb moisture and this causes their capacitance to deviate dramatically from the original value. When this occurs the filters are no longer be able to effectively pass their assigned notes. Since these filters are only used on the generator's mid and upper frequencies (#49 through #91), the result is an instrument where the lower notes still sound at the proper volume, but the mids and highs of the organ become muffled. Since this deterioration occurs gradually over an extended period, it is often not noticed by the organist until they have an opportunity to play a later vintage instrument which did not utilize paper / wax capacitors, or one that has been restored.

​NOTE: Starting in 1964, Hammond changed the capacitor type used on generator filters from paper / wax to Mylar. (Mylar is DuPont's trade name for polyester / PET). These capacitors have proven to be largely immune to the moisture absorption and resulting value change of the older capacitors. Mylar capacitors can be identified by their hard plastic outer surface which has a dark red appearance.
In our opinion, organs with Mylar capacitor generator filters usually DO NOT require replacement of the capacitors.

*For an interesting look at an early DuPont Mylar ad featuring the Hammond organ click here.