[Milsurplus] TCS: T-17 and RS-38 Microphone Mystery

[WA5CAB at cs.com]

Hue,

Yes, 677N213 is the Collins part number for the TCS mic transformer.

Robert Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480

Unless the secondary was bifilar wound, you would expect the resistance of 
the outer half of the winding to be greater than that of the inner because 
the mean turn length increases as you go out.  And it is worse percentage 
wise with small transformers than with large.

In a message dated 12/21/2015 14:29:16 PM Central Standard Time, 
kargo_cult at msn.com writes: 
> I have a mic transformer here that might be from TCS. It's marked part 
> number 677N213
>  sez ratio pri to sec 41:1, that means each half of the CT sec is 20:1
>  Oddly, i found a 400 imbalance from 1/2 the sec to the other 1/2. I don't 
> know if this is an
>  internal fault or what. The secondaries are around 2500 and 2800R, and 
> the pri around 10R.
>   
>  I tended to save carbon mic transformers because i thought their high 
> ratios were interesting.
>  Reverse-used, they could work in a passive crystal radio to step down to 
> medium low-Z 
> headphones.
>  -Hue Miller 
> 
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