Oddball Triad mic/line input transformer question

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Quayhog

Well-known member
Joined
Oct 11, 2014
Messages
135
Location
Bay Area California
Does anyone know the DCR measurements of a Triad HS-3 or know another way to identify its primary and secondary loading?  I have a transformer that is obviously wound by Triad.  It's marked P-90120 input.
It meets the dimensional specs in the UTC catalog.

It's pinout meets the HS series of input transformers.  I suspect it was removed from a hi fidelity piece of gear.  Surly nicer than the typical PA gear from the 50/60's, possibly a tape recorder.
 
primary dcr will be about 10 ohms per section if it has taps,

secondary ohms for a 1:14 will be up there, probably 500 to 1000 ohms,

use signal generator and volt meter to figure out turns ratio,

no sig gen? use a variac set to 5 volts for the primary, 
 
If you have a meter that reads AC impedance clip a 47K or 51K resistor on the secondary and then read the impedance on the primary taps.  You should be able to easily identify the typical values for an input from that era - 600, 250, 150 ohms etc.

But, if you use it in a circuit do not load it with 47K (unless you want an input impedance that low).  It was probably meant to work into an open grid so you don't need to load it with any resistor unless it's ringing really bad but that could also be due to something elsewhere.
 
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