D-104 mic element

[Jim Bromley, K7JEB]

Phil, W7BW, wrote:
>  I need an element for one of my D-104s. Where to buy
>  or is there anyone out there with an extra one?? Or a substitute??

I've found that the Kobitone 25LM024 crystal element works
well.  Mouser stocks it.  It is on page 1722 of their catalog:

 http://www.mouser.com/catalog/633/1722.pdf

and the data sheet is here:

 http://www.mouser.com/catalog/specsheets/KT-400025.pdf

The only downsides found are that the Kobitone element isn't
quite as sensitive as the original Astatic one (it's smaller, so
that's natural) and the frequency response is skewed towards
the high end with a peak response at 3 kHz vs 2 kHz for the
original.  The sensitivity is a non-issue in an amplified D-104
and the frequency response can be tailored by placing a sheet
of polyethylene cut from freezer baggy in front of the element
inside the housing.  You will also have to put some kind of
sponge rubber behind the element to hold it in the D-104
'head'.  The Kobitone unit is much more robust than the original,
and a good deal cheaper at $5.26 each.

Jim, K7JEB

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