[Milsurplus] Command set, CCT46104

[Al Klase]

Gentlemen,

I was thinking along the same lines.  The RCA data sheet suggests a 7500 
ohm load for a 12A6 at 250 volts.  The impedance ratio is, in deed, the 
square of the turns ratio.  So 7500/64=117ohms.  This is not 
unreasonable, as the receiver may be called upon to drive a whole bunch 
of headsets.  In this case, six 600 ohm headsets would be a near-perfect 
match, and considerably more phones would not be a major problem.

Another factor thats often overlooked is that there is a series-pot gain 
control in each crew member's jackbox, so the audio coming out of the 
receiver is quite "hot" if one just connects a headset.

Regards,
Al

D C *Mac* Macdonald wrote:

> If I remember correctly, impedance ratio varies
> as the SQUARE of the turns ratio.  Therefore,
> an 8:1 turns ratio will provide a 64:1 impedance
> ratio.  I have no idea as to what the audio out
> tube operating impedance is, but it might be
> found in an old RCA Receiving Tube Manual.
> I wasn't able to find it in mine.....
>
>

-- 
Al Klase - N3FRQ
Flemington, NJ
http://www.skywaves.ar88.net/