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Old November 2nd 06, 09:06 PM posted to rec.radio.amateur.boatanchors
Roger D Johnson Roger D Johnson is offline
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First recorded activity by RadioBanter: Jun 2006
Posts: 12
Default National NC-120 audio transformer

Don wrote:
I need an audio output transformer for an NC-120, which I understand is
the same as the military RAO. I have also been told the NC-100 is the
civiliam model. The ROA-2 manual lists the transformer as 36000 ohms to
600 ohms but the NC-100 manual lists it as 5000 ohms to 500 ohms. Is
the 36000 a misprint? The transformer couples the 6V6 to the
loudspeaker. The National number on the transformer can I took out of
my NC-120 is CNA-30884
Thanks

Hi Don...

It appears to be the same transformer that is used in my RAO-3. The
specs in my manual are identical. The only thing I can figure is that
many shipboard radios were not designed for use with a loudspeaker.
The audio normally went to a distribution panel and was routed to
an amplifier located somewhere else on the ship. This ratio may be
necessary to limit the audio output from the receiver to prevent
over driving the headphones or external amplifier.

73, Roger

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