• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Tube amplifier line voltage requirement solutions

Palustris, you are correct. No power transformer has either primary or secondary connected to ground. At the electrical panel neutrals are all connected to ground but all the wiring in the building and all connected appliances keep neutral and ground separate. That's the whole point of 3-wire systems as opposed to the old 2-wire. Safety.