Maybe your wall plus is not respecting the norm.

So, what you call neutral might the the phase line.

To comply to safety rules, manufacturers must protect the phase line,
not the neutral (VDE, UV, IEC, ANSI...).

a écritÂ*:
I would post this in the basics group but it seems like there are more
responders here. Anyway, I have been looking at DIY single ended tube
amp schematics recently. These are modern schematics using grounded
power cords. And several have in common that the power switch is in
the neutral line and the fuse in the hot. Wouldn't it be safer to have
both the switch and fuse in the hot line?
Thanks,
Eric