Installing 3 prong on Italian 220V amp

[LarBal]

Looking for some guidance here. This 220V beast of an amp has a step up transformer bolted to the bottom of the cab, but only a 2 prong for 120V to get to the primaries.
Where do I ground the new green wire, is it as simple as running a loooong wire up to the chassis of the amp, as usual?

[LarBal]

here's the plug for the secondaries of the step up to the 220v xformer in the chassis

[Jon Snell]

Looking dangerous!

If you are going to do it, do it properly and use 3 pin connectors with an earthing point.

[LarBal]

Yea, I was thinking the same, this is how it came to me.

[Helmholtz]

Safety grounding must comprise amp chassis as well as the step-up transformer core /brackets.

Make sure no one can touch the transformer terminals. Electrical tape is not safe enough.
Install a strain relief for the power cable.

A self-contained step-up transformer would be a better/safer solution.
An exposed "PT" without endbells is not safe.