[AMRadio] Ranger Audio

Grant Youngman nq5t at tx.rr.com
Wed Nov 15 09:57:18 EST 2006

> cause.  Honestly, all
> D-104 mics I have and have used have a tinny sound, that 
> seems to be normal.

I suspect it's "normal" only because most of the time they are run into a
preamp stage with a grid resistor that's too small.  That small resistor,
along with the impedance characteristics of the element make a nice
high-pass filter, and there goes the low end.

On a non-amped mic, put a 10M grid resistor in the radio's input stage.

On an amplified mic (and the biggest thing wrong with the amplified mic is
that people run the gain too high), increase the size of the input resistor
in the mic preamp -- or better yet, put a 5M or so pot in there, and you
will be able to adjust the low frequency response to your liking.  The
amplified mic, as I recall, only has about 500K of input impedance in the
preamp stage, which is insufficient.  

A D-104 crystal element can sound surprisingly good, if it is terminated
properly, and if it hasn't been left to sit out in the sun on a pickum-up
truck at a summer hamfest and cook for a few hours :-)


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