[HAM] Generator output levels

[David Anderson]

-----Original Message-----
>From: Alan Lenhoff <alenhoff at yahoo.com>
>Sent: Apr 16, 2007 2:19 PM
>To: Hammond at zeni.net
>Subject: [HAM] Generator output levels
>  
>  1.Could differences in storage conditions or how much they were played affect the aging rate of the >   caps?

Environmental conditions play a big part. High temperatures, large temperature swings, and high ambient humidity all contribute to wax cap deterioration and drift, especially if combined with movement/vibration.

>  2.      This is clearly a “your tastes may vary” situation. Some of the organs that were 
>  described (presumably by their owners) as bright-sounding showed curves that would 
>  suggest they’re pretty dull-sounding.  And some of the organs that looked like they might 
>  be very bright based on their curves were described as mellow.  (I suppose that might 
>  just be what the owner is used to, the acoustics of the room it’s generally in, or the 
>  condition of the Leslie/Tone Cab they’re playing it through.)

The state of the organ's preamplifier has a LOT to do with how it sounds, as does the speaker.
 
>  3.      While the mylar capped organs tended to have similar shaped curves, there still was 
>  quite a bit of variation among them – including notes here and there whose outputs were 
>  significantly above or below neighboring notes. The conventional wisdom is that the 
>  mylars don’t drift in value. Is it possible that they only drift far less than the wax caps?
>    Or is this variation likely due to inconsistent processes (or components) used during 
>  initial assembly?

Conventional wisdom has a tendency to ignore the scientific fact that mylar (polyester) can absorb moisture; its tendency to do so is half that of paper, but it is still a factor. Also, the way that those capacitors were encapsulated in plastic required high temperatures, which could have unpredictable effects on the mylar dielectric down the line. That's why they don't make them that way anymore.

Polypropylene, polystyrene, and teflon, the big three of audiophile capacitors, are very impermeable to water, according to a friend of mine who works in textile engineering.
 
>  There is something wonderful about realizing that, whatever the reason, every 
>  Hammond speaks in a slightly different voice. 

Quite true.

David