What kind of neon sign transformers are used for tesla experiments?

Question

I have read that the older neon sign transformers are better as the new ones are solid state and will not work for some reason or get overloaded easy????

Answer 1

Firstly the older neon sign transformers are good as they are coated with asphalt for protection to avoid damage of the transformers and insulation

but

due to advancements in technology

now the researchers are using swith mode power suppliers to generate the same voltage and current ranges as iron cored transformers, but in a much smaller, lighter, and more efficient design at high frequency (not the common 50-60 Hz). They are gradually replacing old neon sign transformers