There is no good reason to use a transformer with a pro dynamic mic with
a ham rig. In an XLR, pin 1 is the shield, pin 2 is mic +, pin 3 is mic
return. To connect it to a ham rig, connect pin 2 (mic+) to the mic+ pin
on the radio, tie pin 3 (mic return) and pin 1 (shield) together and
connect them to the chassis.
An alternate wiring that also works fine -- mic+ to mic+, mic return to
mic return, and shield to the chassis.
73, Jim K9YC
On Sat,8/16/2014 10:47 AM, K8JHR wrote:
A few random ideas ...
I would try to find a data sheet on the microphone that should
indicate what the transformer does and how it is wired. I would also
scour the internet and look for an inexpensive dynamic microphone
cartridge to wire into it. I recently "restored" an old Shure "550"
Unidyne (the larger, original Elvis type microphone built in 1947) and
used an inexpensive dynamic mic cartridge I purchased on eBay for
$10. (I can send you photos and a sound sample if you like.) It
turned out swell, but I would be tempted to look for a little better
one next time.
DATA SHEET --
http://www.coutant.org/ev638/ev638.pdf
More info on it:
http://www.coutant.org/ev638/index.html
THIS MODEL CAME AS HI OR LOW IMPEDANCE - WHICH THE
CUSTOMER SPECIFIED ON ORDERING IT... So I would
think your idea of converting it may be a good one...
but it may depend on the cartridge, and not the transformer,
and other guts, I am not sure - some microphones use the
same cartridge and use transformers and switches to
change impedance, but others seem to use different
mic cartridges as well, so that needs to be checked, but
think the product data sheets suggest the inquiry is
a good one.
I would not try to fit the odd HEIL HC5 cartridge, myself, as I think
you can do better for less. You could buy an inexpensive, maybe
used, Samson RS10s or something similar and cannibalize it for the
cartridge within.
Another option is use the high impedance mic with an inexpensive mic
preamp that would better match the mic to the rig (it would use the
Line-IN input on the rear of the rig if there is one.) I sometimes
use the M-Audio AudioBuddy preamp with my high impedance 1968 vintage
Shure PE-53 Sphere-o-Dyne microphone and the output of the preamp
makes it virtually indistinguishable from a more recent low impedance
mic. (I can send a sound sample if you like...)
Although I have not fully thought this out... it occurs to me that a
direct box (DI box) might be used to match it to the rig... or you
might use an in-line high-to-low-impedance transformer to better match
it to the rig. Need to sleep on that idea...
You might also find you are sitting too far back from the mic to get
its best audio output. Proximity effects... where you sound more full
and bass-y up close, and thin and tinny far away, may be causing you
to reap less than its full capabilities. Some guys use that mic as a
"harp mic" cupping it in their hands, with a harmonica, and so you,
too, may benefit from re-setting the MIC-GAIN after moving closer to
it, maybe speaking 3-4 inches from it, slightly off access to avoid
breathing into it, and maybe you will sound better. Perhaps a number
of the above suggestions will improve its performance... such as close
talking it, and inserting an in-line impedance transformer, or running
it on a suitable preamp, or ... or...
What is the inside diameter (ID) of the mic case that holds the
cartridge?
Random thoughts... maybe something will get the click for you.
Happy days.
--------------- K8JHR --------------------------------
On 8/15/2014 4:30 PM, Bill Ogden wrote:
I have an Orion 1 and an Electrovoice 638 Hi-Z microphone
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