[Elecraft] D-104 Mic Element Replacement

[Bob McGraw]

Most D-104 mikes are not suited for use with today's radios.  The 
original D-104 was designed to work into a load impedance of 4 meg-ohms 
or higher.  Today's radios microphone input is about 50k ohms or so.   
The result is then excessive load on the D-104 element.  This is the 
major cause of frequency response issues.

The D-104 with the TG stand {amplified mike stand} uses the FET device 
as a buffer, thus it is providing a very high impedance for the mike 
element and adequate gain to drive a 50k ohm or lower microphone input.

As to replacing the D-104 element, if yours has output, likely it is OK 
and is suffering from the issue of improper load on the element.  
Remember, this mike was designed to operate with tube type microphone 
amplifiers, having an input impedance of several meg-ohms.

The D-104 on my TUG8 stand has the original Rochelle salt element and 
the FET amplifier in the base.  It sounds great on any of my radios.  My 
comment is that one should use the mike such that moisture or spittal 
from the mouth does not accumulate on the mike face and element.  Also 
don't leave it in a position where the equipment will heat the D-104 
above room temperature and surely left in the direct sun.

I frequently hear hams talking about using a D-104 with a Heil 
element.   Fact is, it no longer is a D-104, it is a Heil HC-4 or HC-5 
or whatever.

73

Bob, K4TAX


On 2/23/2022 1:57 PM, elecraft-request at mailman.qth.net wrote:
> Message: 2
> Date: Tue, 22 Feb 2022 17:35:58 -0500
> From: Dean Adinolfi<kd3anx at gmail.com>
> To:elecraft at mailman.qth.net
> Subject: Re: [Elecraft] D-104 Mic Element Replacement
> Message-ID:
> 	<CAD3T48KMu4JSn8rctBx2L_WQdOq6m+MpPu9tq=o3AUJrGaENbg at mail.gmail.com>
> Content-Type: text/plain; charset="UTF-8"
>
> W2ENY element works great.
>
> https://www.w2eny.com/
>
> Dean, KD3ANX