[Elecraft] Astatic D-104 Microphone

[Joe Subich, W4TV]

The easiest way to use an unamplified D-104 with the K3, or replace a
bad/noisy transistor preamp is this single FET circuit from W9AC:
http://72.52.250.47/images/D104.pdf

The single FET is uniquely suited for the high impedance crystal
element and "bias on the mic" power.  When handled properly the
Astatic crystal element is far superior to the commodity dynamic
elements sold at tremendous mark-up by the "name" amateur vendor.

73,

    ... Joe, W4TV


On 1/28/2014 8:40 AM, John Fritze wrote:
> I am currently in the middle of converting a D-104 Eagle into a usable mic
> and have had a bit of experience in the past with them.  I am trying to
> recapture a bit of the nostalgia from my early ham days.  I paid too much
> for it, but not only is the chrome flawless, but it came with the original
> box which surprisingly is in really good condition.
>
> Anyway what Don says is true, there were several models and until you
> dismantle it you will not know what one you have.  BUT on the plus side,
> when I removed the bottom plate, "looky-looky" there was a schematic
> diagram pasted to the inside with the wire colors for my model listed.  My
> mic had a large element (probably carbon) and an amplifier circuit with 9V
> battery (still in there---yuck) in the base.  So remove the bottom, and if
> there is no schematic, but your mic sounds like it is the same model I
> described, let me know and I will try to send you a picture of the
> schematic.
>
> I ordered a Heil 5.1 rebuild kit from: * http://www.dxstore.com/heil_parts.html
> <http://www.dxstore.com/heil_parts.html> * for $50.  I needed some small
> parts for several of my older head sets like foam pads and so forth, so
> perfect timing.
>
>
>