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From: crmo~heel.dcn.davis.ca.us (Adam Filippino)
Date: Wed, 20 Sep 1995 09:09:09 -0700
Subject: Astatic cartridge mod.

Recently I decided to modify an Astatic JT30VC to a magnetic cartridge mic
using a Shure element. In all honesty, as i began the conversion I was
unsure how to connect the new element as it had 3 terminals vs. the crystal
element's 2. I took my best guess; plugged in and did a quick check to
insure I wouldn't be cooked on first contact and boy what an improvement.
However, and this is where I'm soliciting the help of Harp-Lers with
knowledge in this area, the mic makes a low crackly/hum when I touch it and
the sound amplifies when I touch someone else. It is silent when placed on
the floor. And yes my other JT 30 is silent. What follows is a description
of the connections I made. If it seems obvious what I've done wrong *
please* set me straight.

The Shure element has three terminals. Two on "top" one closer to the
"face" of the element and one closer to the rear. The third is at the
bottom closer to the cable jack. I will label these one, two & three
respectively. To # 1 I connected the white wire that seems to be mounted to
a grounding tab of some kind but then continues to the left (as one looks
into the housing) terminal of the pot. To # 2 I connected the other white
wire which eminates directly from the cable jack. And to #3 I connected the
red wire which leads to the right hand side of the pot.

The mic did work. Is this in fact wrong? Could the problem be in the
interface between mic and amp (Champ)?

Any help would be appreciated.

Blue Skies (BD)
Adam