Astatic D-104 Silver Eagle Mic Mods

Astatic D104 Silver Eagle Mic

lollipop 

The D-104 range of mics were first and foremost communications grade microphones. Remember that fact and say it twice.

The were not design to be recording units,but for amateur\non-critical\radio use. In that role, and coupled correctly, the D-104 is a great communications microphone. Clean, CRISP, highly intelligible audio that makes each syllable perfectly understandable.

Larry King audio... nope.....ESSB audio...nope, but if you want that, spend a ton of money or use AM or FM. SSB was designed ( and works well ) to be an efficient, narrow bandwidth mode. The audio part of it was deemed acceptable ...and still is.


They always had crisp, CLEAN, and understandable audio.


Used D-104's usually need to be re lubricated, and it does not hurt to re-solder all contacts.  Adding a electret element to replace a working UNDAMAGED original element is pure folly, and there are those that have done it. Kind of like putting a Ferrari engine in a Corolla and then hoping somehow that it will be a Ferrari.

There is NOTHING wrong with the audio of a D-104 if one remembers what it was designed to do ,AND if it is not over driven AND is electrically and mechanically working.

Most new hams, however, have no idea of the tonal design plan that was incorporated into this mic and think it should sound like a studio mike. Then again, even experienced hams still believe that somehow, someway, SSB can become and deliver AM or FM quality audio easily. Sorry folks but there is one word preventing that.......BANDWIDTH!!

Modifications:

(from left to right on the circuit diagram, not on the picture of the bottom side

1. Add a 33 kOhm resistor in the green line which is coming from the capsule to the preamp input.
2. Change the 10 nF capacitor to 220 nF (ceramic type, no electrolyt type !!!)
3. Change the loo nF capacitor to 4,7 — 6,8 pF/25V, electrolyt type
4. Change the 5 uF capacitor to 1,5 pF/25V, electrolyt type
5. For ACC supply from the TRX add a loo uH coil and two 100 nF capacitors to the PCB line where the +9V (red) line of the 9V clip goes to. You can see the necessary circuit in the “Connection to my Yaesu FT-450D/897” below. * Remove the 9V clip or isolate it !! * On the left side of the coil you see the yellow cable which I removed from the PTT switch. I use it now for the ACC support. * This mod couldn’t work with transceivers when their RX audio line is also connected via the PTT (on RX position). You’ll get audio regenerations cause the mic is also supplied and the mic preamp is working on RX position ! And you can’t do mod no. 6.
6. You also see the white audio wire which is coming directly from the winding cable (to the TRX). So I bypassed the audio PTT and I never had any problems with old and scratching PTT switches on the audio side.

A must upgrade ::
W2ENY D-104 HiFi MIC ELEMENT UPGRADE KIT
$22 complete with instructions
https://www.qrz.com/lookup/W2ENY
Robert Langston -  Cornwall-on-Hudson, N.Y. 12520

https://www.w2eny.com/D104UpgradeKit/

http://www.mods-ham.com/02_Mods/Other-Mods/Astatic%20D-104/DG2IAQ%20Modification%20Sheet%20ASTATIC%20D-104%20Silver%20Eagle.pdf

http://www.mods.dk/mod/other/DG2IAQ_Modification_Sheet_Astatic_D-104_Silver_Eagle.pdf

https://www.qsl.net/hcara/Improving_the_D-104_N9WB_rev2.pdf

https://n6pet.com/mod-astatic-d-104/

Andre VA3AGV
https://www.va3agv.com/2014/11/andre-vanier-toronto-andre-vanier.html#more

Chat. ::   https://www.worldwidedx.com/threads/d104-modification.206638/