D104/Electret Mike

[StuLyon]

Jerry,
If you're back from R/S, I hope you picked up a 270-90 electret, some foam
and two 5.1K resistors. The links document how I mounted the RadioShack mike
into a D104 head.

Fig 1 http://home.earthlink.net/~s.d.lyon/images/D104/D104_1.JPG
Fig 2 http://home.earthlink.net/~s.d.lyon/images/D104/d104_2.JPG
I used three 1/4" conductive foam circles cut to the inside dia of the D104
head. The front foam has about a 1-1/4" hole in its center. The center foam
has a tight-fit hole for the electret. The back foam has no hole. This
sandwich is squashed into the 104 head. Use the existing breath filter.
RG174 co-ax connects the mike to the header plug. Tape over the mike
terminals. I used conductive foam because I had it -- none-conductive foam
will probably work.

Fig 3 http://home.earthlink.net/~s.d.lyon/images/D104/d104_3.JPG
On the amplifier end, I connected a 5.1K resistor between the mike lead and
gnd and a second 5.1K between the mike lead and +9volts. This provides a
2.6K pull-up for the mike to a 4.5volt power supply. I used the existing
pre-amp although I could have jumped as well -- the electret has low enough
Zout to drive anything.

I used this mike for awhile but ended up with a couple working D104s as
payment for a repair job and went back to using them.

73, Stu W6CUX
Winnetka, CA
s.d.lyon at earthlink.net



Fig 2
----- Original Message -----
From: "Edwin J Forwood" <e.j.forwood at JUNO.COM>
To: <BOATANCHORS at LISTSERV.TEMPE.GOV>
Sent: Thursday, January 29, 2004 10:00 AM
Subject: Re: D-104 elements


> Thanks Glen,
> I'm Headed for R/S now!
> 73 de Jerry, KØEJF
>
> On Thu, 29 Jan 2004 09:57:59 -0800 (PST) Glen Zook <gzook at yahoo.com>
> writes:
> > Actually, I have never used any Heil products, so I
> > can't make any recommendation as to which ones to use
> > and which ones not to use!  I have used some Radio
> > Shack elements and those worked fine.  In fact, there
> > was a posting on one of the reflectors a couple of
> > weeks ago about someone who had done a lot of
> > experimentation with various elements including the
> > Heil, Radio Shack, etc.  It seems that when the
> > microphones were "buttoned up" and used on the air
> > that no one could tell the difference!
> >
> > Glen, K9STH
> >
> >
> > --- Edwin J Forwood <e.j.forwood at JUNO.COM> wrote:
> >
> > Do you have any recommendation on which Heil element
> > to use on old boat anchors?
> >
> > =====
> > Glen, K9STH
> >
> > Web sites
> >
> > http://home.comcast.net/~k9sth
> > http://home.comcast.net/~zcomco
> >
> > __________________________________
> > Do you Yahoo!?
> > Yahoo! SiteBuilder - Free web site building tool. Try it!
> > http://webhosting.yahoo.com/ps/sb/
> >
> >
>
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