> return of the transformer outside.
> A home also has a ground rod.
> How can this knowledge be applied to whats going on inside this guitar amp
The "Neutral" carries (unbalanced) power current back to PSE&G.
The green wire caries "hot chassis" current back to PSE&G to blow a fuse and save your butt.
The Dirt-Rod is not (much) to do with normal PSE&G power. The obvious function is to be a return for power from Lightning (a different power source). A secondary function is to be a (poor) path for unintended faults in PSE&G's transformers (23KV leaking to 240V winding).
My main point was "Draw the WHOLE circuit". Winding, to diode, to load, and back to winding.
On your side-drift, a point would be to draw the whole circuit_S_ for multiple power sources (or loads). The dirt rod has no effect on your lights or PSE&G bill. The Neutral to the pole may have very little effect on a lightning strike. (Probably more than minor: a mile of dirt-grounded poles is a better dirt-rod than anything I can hammer on my land, though the 500'-5000' of line isn't a great transient path.)
Note that a "whole circuit" for the lightning-hit would include my line, the line down the street, the dirt-resistance on each pole, (the missing bonds where thieves have stolen the copper!), the earth resistance for miles around. On top of the dirt-rods under the porch, at my pole, and at my lower barn, and the wires connecting these.
In practical fact, house-wiring is standardized and Codified. Do it by the book (including Inspection), you will be fairly safe and fairly blameless. The most likely fault in home "grounding" is ineffective dirt-rod.
