[Milsurplus] [ARC5] Carbon mic pops

[antqradio at sbcglobal.net]

WayneAre the two mike filter capacitors originally 50uF?  Since "new" capacitors are so much better then what was used originally, I wonder if you paralleled the caps with high value resistors, would this would reduce the pop?  Perhaps a resistor value that would cause 1/10 the microphone current to leak around the caps?Jim

      From: "hwhall at compuserve.com" <hwhall at compuserve.com>
 To: arc5 at mailman.qth.net; milsurplus at mailman.qth.net 
 Sent: Wednesday, November 30, 2016 12:44 AM
 Subject: Re: [Milsurplus] [ARC5] Carbon mic pops
   
Attached is the schematic of the mic circuit & amp that I'm looking at. The mic internal wiring looks like just a set of PTT contacts in series with the carbon mic button + the small cap across the mic button.

The primary of T-4 has no current thru it until one of the mics is keyed, then suddenly current flows thru primary & carbon mic, inducing a transient in T-4 that appears as a loud initial pop in the headphones. I don't see how they prevented this pop from happening every time a mic was keyed.

By hitting Send I'm about to remind myself whether these forums allow images attached.  :-\

Wayne
WB4OGM


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