[HAM] Wax caps measured and then placed in four pans....

[Dave Bishop]

I know its been pointed out many times, but after the cap and coil were 
matched and installed, the next step in production was to adjust the pickup 
proximity to the tonewheel, a distance that presumably varied with each 
installed cap/coil assembly.  Recapping the coil without adjusting the 
pickup is completing only half the task.  But adjusting 91 pickups without 
knowing the target voltages is potentially courting disaster for a variety 
of reasons.  If all the wax caps in a TWG absorbed water and oil 
approximately equally one would think that a Hammond could age gracefully, 
with the pickups going out of spec in roughly the same degree throughout the 
note range.  Apparantly, however, that doesn't happen.  Replacing all the 
caps with ones of a unifiorm known capacitance has the advantage of reducing 
the wide variation among aged wax caps, with the disadvantage of resulting 
in a capacitance value different than what had been set at the factory for 
(hypothetically) 75% of the notes.

As Drew implies, Hammond would not have gone to the expense of sorting its 
caps and matching them to coils if it wasn't required to do so to make a 
saleable product.  So replacing all the caps with a single capacitance value 
is never going to restore the organ as a whole to its original specs.  For 
some raggity organs it may be an improvement, but for some players it may 
introduce unintended consequences that are their own irritation.  Much of 
the ensuing discussion stems from owners who don't like the way their aged 
Hammond sounded, don't like the results of a wholesale re-cap job, and are 
seeking guidance toward a procedure that gets them a sound that they really 
like.

Its hypothetically possible to parallel tiny caps and fiddle with whichever 
pickups that didn't break when loosened to "regulate by ear" each note until 
the keyboard as a whole sounds the way you personally like it.  But its a 
high risk adventure.

If we all had a "gold standard" Hammond organ available for comparison maybe 
it would be easier to develop some personal judgement about what sounds 
"good" to each of us.  Most of the people who are recapping their organs 
don't have that luxury, so they are trying to find some objective standard, 
like a voltage chart that will be an engineered guide which, if followed 
precisely, will result in what a Hammond "should" sound like. 
Unfortunately,  the critical factory information isn't available, and is 
only inferred by Kon Zeiss's meticulous charts.  More importantly, most 
electronic VOMs can't separate out voltage amplitudes caused by noise from 
the signal amplitude one really wants to measure-- so even if we had the 
official chart, most of us couldn't replicate the specs in our own organ. 
I've been told that the amount of voltage resulting from noise can be 
greater than the entire useful range of adjustment, so without isolating the 
noise the data is pretty imprecise.

We can tell anybody how to oil their Hammond or even how to clean a scanner, 
but nobody has aggregated a list of the equipment, specs, materials and 
procedure to return a wax cap TWG to original factory condition.  Since the 
handful of people who know all that info are getting older, there's a good 
possibility the best solution will be lost to civilization in the next 
couple of decades.

I have a 1949 BV and I love the earthy way it sounds, but I believe it is 
less like a Strativarius violin than a good year of wine:  at some point it 
is still going to turn to vinegar.   I wish I had a choice about whether and 
when.

Regards,

Dave Bishop