09-21-2015, 09:11 AM
Not seeing any negative feedback around the output transformer. Typically It's used to enhance the low frequency response of the audio amp. What you will see on the diagram is a connection from the secondary of the output transformer back to the cathode of the input audio stage though a few resistor and a cap. This does have a connection to the secondary but it goes to the terminal strip on the back of the set.
Terry
Terry