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previous: Fred Hammon I've actually heard of somebody who... -- 9/16/2004 6:20 AM view thread

Re: Damaged magnet wire?

9/16/2004 1:14 PM
Joe Gwinn
Re: Damaged magnet wire?
Water? A major reason Leo Fender invented wax potting was to prevent moisture from accumulating in the windings, dulling the sound.  
 
It's only alluded to in his patent (#4,885,970), but the problem appears to be that if a cold pickup was brought into a warm moist environment (like bringing a cold guitar from the car into a packed nightclub for a gig), water would condense on the pickup and soak into the windings. Once in, it was slow to evaporate, being protected by the windings. This caused the tonal quality of the pickup to vary greatly, apparently at random, and probably also by the season.  
 
As for the spool of wire in the bucket, the heat of the subsequent potting of the coil may drive the moisture away, if done for long enough, but will leave mineral deposits behind, the amount depending on how hard the local tapwater is. At least condensation has no minerals.  
 
If one is potting an old pickup, it may be best to allow it to dry out first, perhaps by keeping it warm for a few hours.  
 
There is no mention of microphonics in the patent.