[AMRadio] Microphone assistance

Jay Adrick jadrick at cinci.rr.com
Thu Aug 31 19:46:26 EDT 2006


Message: 1
Date: Thu, 31 Aug 2006 16:29:10 -0400
From: "david knepper" <collinsradio at adelphia.net>
Subject: [AMRadio] Microphone assistance
To: <amradio at mailman.qth.net>, <boatanchors at mailman.qth.net>
Message-ID: <013d01c6cd3c$1e4b21d0$6501a8c0 at david2e3ehqtvj>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";

Can anyone assist me in converting a low impedence microphone to high 
impendence.  I bought several 600 ohm studio microphones (plastic housing) 
that come with a 9 foot cable and microphone plug.  I am interested in using

the microphone with a high impedence input transmitter on AM.   Any 

Perhaps, I should use a mixer unit that has low impedence input with a high 
impedence output.

Thank you

Dave, W3ST
Publisher of the Collins Journal
Secretary to the Collins Radio Association
www.collinsra.com - the CRA Website
Now with PayPal
CRA Nets: 3805 Khz every Monday at 8 PM EST
and 14255 every Saturday at 12 Noon EST 


You need to properly match the low impedance broadcast microphone to you Hi
Z rig input using a matching transformer. The solution that I have used here
is a Heil Sound transformer that I picked up at the local ham store for $15.
It has a 600 Ohm winding and a 30K Ohm winding, is small in size and is
rated a microphone rather than line levels. My low Z sources work great into
the S-Line using the transformer built up in a small diecast box with
connectors.  I have one version for microphone level input and another with
a 60db pad in front of the transformer so that I can feed the rig with the
broadcast audio chain

Check Bob's web site and you will find the transformer listed under his
microphone accessories.

I run a Harris broadcast audio console and professional processing here and
have also used the transformers to match HI Z microphones into the
microphone inputs on the console.

All the best

Jay   K8CJY

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