Notes on Ampex plug-in Transformers
The Ampex AG series machines were shipped with dummy plugs (4030034-30) that set the input for a direct recording with unbalanced signals. The dummy plugs jumpered pins 3 and 4, pins 6 and 7 and pins 2 and 8 (for ground & plug shield).
In order to use a balanced signal for recording, input transformers were installed in place of the supplied dummy plugs.
Transformer 4580200-01 is a balanced-bridging transformer with unity gain and an input impedance of 20KΩ.
There is an alternate Matching transformer that can be used--pn 4580200-02-- and it provides about 14dB gain with an input impedance of 600Ω.
On these transformers, pins 4 and 8 are the primary signal input, pins 3 and 2 are the output and pin 1 is the case shield.
