No idea which broadcast or military equipment this came from, in the past I have dismantled masses of equipment and my records of components removed are not complete.
I suspect this audio transformer is interstage and most likely from vintage broadcast comm's equipment or military.
I have image searched the company logo stamped onto the casing but even TinEye has been unable to identify who made this transformer.
Audio transformer
Rectangular format - press/welded sealed metal
Measures:
Body: 70mm length x 60mm wide x 21mm height
Mounting tabs extend the length by a further 13mm each side
Flying leads 100mm length
Markings are exactly as below:
1127-8107
2031
962132-1
REV-B
Stamped onto the top is the manufacturers logo - see the photograph closeup of this
COSMETIC CONDITION:
Excellent
TESTING (limited)
DC Resistance tests
Yellow/Green leads - 26 Ohm
Blue/Purple leads - 26 Ohm
Orange/Brown leads - 52 Ohm
Red/Orange or Red/Brown - 26 Ohm
In other words, the Red lead is a centre tap of the windings colour coded Orange/Brown
As I have a few different audio transformers that I no longer need, I decided to dig out some basic test equipment to provide more detail on the transformer characteristics
Test equipment used: AWA Low Distortion Audio Oscillator G232, Leader AC Voltmeter
Audio source was input to Yellow/Green and the measured output at Orange/Brown
Input to the transformer under test was made at 100mV @ 50Hz, 100Hz, 1Khz, 5Khz, 10Khz, 20Khz & 50Khz
Using test signal @ 1Khz, I have determined the following:
Turns ratio: 1: 0.50
Impedance ratio: 1: 0.25
Frequency response (a very rough test and not graphed) was surprising, this particular transformer stands out due to the flat response from 50Hz to 50Khz, barely a 1dB change across the whole frequency range.
It would seem that this audio transformer is fine for general or high end audio use
Note that these tests were not exhaustive but at least shine a little more light on the characteristics of this audio transformer
