|[AMRadio] Re: D-104 hardware|
k4kyv at charter.net
Thu Aug 16 18:36:28 EDT 2007
> I'm trying to put my old D-104 back together.
> I've go everything except the screws that hold the front
> and back covers in place.
> Does anyone have a junker D-104 laying around
> that still has the screws.
One thing to consider is how "old" your D-104 is. If it was made before
1937, the head was a full 1" thick. Sometime that year they went to the
familiar thinner head, that is 13/16" thick. So the screws that held the
older ones together will not fit the newer ones and vice versa.
Also make sure you have both ends of each screw assembly. One end is a
threaded hollow tube (female), and the other is a screw that fits inside
(male). Both male and female parts have a screw head that is seen
externally on the assembled mic. I have seen some of these that appear to be
identical, but some have fine threads and others coarse threads. Make sure
both pieces match, since you cannot mix thread sizes in the same screw
Another difference between the older microphone and the later version is
that the knurling around the rim of the older version is more distinct than
that of the newer version. Also, the older version has screws in the back
plate to hold a bracket that clamps down the shielded cable coming out of
the mic, since the older version does not use the plug-in head assembly.
The wire just comes out of the head of the older one through a brass sleeve.
The very oldest ones also have a large screw at the centre of the back
plate on the head. Evidently the earliest elements were held into place
with a screw instead of the foam rubber and glue that hold together the more
recent versions. Those early versions were spring mounted inside a ring,
just like the old double-button carbon microphones, so maybe they didn't
think they needed to shock mount the element inside the head with foam
rubber. I'm not sure they even had foam rubber in 1933, when the mic first
came out. All the older versions I have even taken apart had a replaced
element using foam rubber, and a nut was used to hold the large screw in
place to stop up the hole.
For a photo of the early ring-mounted version, check out the PA0ASD web
site. Scroll down to the middle of the page to view the photos. It looks
like he was using a black lacing cord or elastic band material instead of
metal spring to hold his.
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