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

[Brad Baker]

On 11/22/06, Don Erickson <derick at zeni.net> wrote:

> Then, if what you're saying is true, the whole "matched caps" argument is
> fallacious.  It's sort of like throwing darts, except you're throwing the
> dartboard at the darts, which are on different planes.

Based on Kon's earlier...

Say the original caps were 20% tolerance, so they sort the 20% spread
into four bins of 5% tolerance each.  The goal is to peak the output
of each coil using an appropriately valued cap.  If this were
attempted using a full assortment of 20% values it could take a while.
 So by presorting the bins into 5% ranges a quick selection of the bin
to use could be made and then if necessary a finer match could be made
using the 5% spread in that bin.  The unknown is the value of the
coils, whether they vary 20% or whatever.

Does this mean that a particular TG could have all filters hand
matched to peak, but that the cap values required to do this could
vary up to 20%?

However, if the filters were tuned by selecting caps to peak the
filter at the tonewheel's frequency, then how could a mismatched cap,
one that mistuned the filter, result in an amplitude that could ever
be *louder* than stock (leading to the shrill sounding organ)?  It
couldn't.  So something else is going on here:
- the original cap's de-Q'd the circuit, lowering the resultant
  peak voltage.
- the filters weren't necessarily tuned to peak, maybe just
  to some range to allow a good TG calibration to occur.
- they were out of the correct cap that day.

It is safe to say we will probably never know the answer to this one
but fortunately we don't really need to (calibrate).

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