Hello Mike:
What would be your explanation for the theory of allowing to use of the same nodes to measure loop response as Vout/Va as the nodes where the signal is injected with floating nodes from the transformer?
Therein will be found the reason for using the opamp differential outputs as well with decoupling caps. The theory is the application of the "law of superposition"...right?
see attached.
-pl share your thoughts.
r