isolation transformer needed...

[tincan]

I have purchased a Superior TV-11 tube tester and need to add an isolation transformer to the circuit as it has an autotransformer from the factory. I can't seem to find what I need and not really sure what to look for. I'm only aware that using the tester with it's original autotransformer can be a potential shock hazard.

Can someone help out with this project?

Thanks...