[OKDXA] Magic box supplier?

[Jay Bromley]

HI Peter,

I am not sure about a magic box, but there are hundreds of mods and kits for 
changing mics like the D-104.  Here is one: 
http://www.rbmicro.com/index.php?page=browse&action=list&orderby=2&group=11&cat=6

Several ways to go with this element kit.  The kit doesn't come with the mic 
elements, but you can use elements like a Heil HC5 for DX or since you have 
a 746 Pro  I would recommend using an electret condenser element that is 
already used in all stock Icom mics.  They use to sell these at Radio Shack 
for under $2, but I you can still get these from Mouser, Digi-Key, etc!

If you want to use the stock crystal element, you can add a FET follower to 
the base of at D-104.  That provides a nice super high impedance load for 
the stock D-104 crystal element while providing a nice low impedance to 
drive the rig.  It is a common mis-conception that you can't get the old 
D-104's to sound good with the new rigs.  You just have to add a few parts. 
You can power the FET right from the audio line.  Most of the Icom manuals 
don't show it, but they have 8 volts on the audio line.

Really either way is fairly easy to do, but takes an afternoon to study the 
schematic, which is usually on the D-140 bottom plate, and then get to the 
soldering.  This makes a great project for any mic you like the looks of 
with your modern rig!

BTW, I never use those amplified base modules that were found in the later 
D-104's, they need a 9 volt battery and sounded pretty bad as far as 
quality.  They are super loud if you like that sort of thing.

The electret condenser elements are in everything and cost only a few bucks 
new!  With your 746 Pro's menu you can change the audio from a rag-chew mode 
to a DX war machine if you use the little electret condenser elements.  They 
are very versatile, but you must provide a DC voltage to the element which 
is already on the Icom audio line.  That would need to be block that voltage 
if using the Heil element.

They make two and three wire electret condenser elements.  So you may or may 
not need a blocking capacitor if you use those elements on a Icom rig.

73 de w5jay/jay..

-----Original Message----- 
From: Peter Laws
Sent: Sunday, December 12, 2010 3:04 PM
To: Discussion of OKDXA
Subject: [OKDXA] Magic box supplier?

There is a market for making new mics that work with old rigs and
obviously, there is a market for making new mics that work with new
rigs.  There doesn't appear, to me, to be a market for folks making
old mics that work with new rigs.  :-D

I have a D-104 with the standard G base (not even UG and certainly not
TUG!).  I'd like to use it with my IC746Pro.  I could pull it all
apart (or more likely get someone who knows what they are doing to do
it for me!) and make it work with the modern rig, but I'd like to
leave it in it's existing condition.  After all, I may want to fire up
the HW100 that came with it some day and I'd like to have a mic for
it.

Anyone known of a magic box that lets you plug in an ancient mic,
transform the impedance all handle all the switching needed for a
modern rig?

-- 
Peter Laws | N5UWY | plaws plaws net | Travel by Train!
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