If you currently own an AC/DC welder then a high frequency box added to your set up would be a viable addition.
You have to be careful of some of the old AC/DC Machines the cirquit boards some time can not handle the High Freek options. They can burn up. I have a Lincoln Vantage 400 about 4 years old and was told NEVER add the High freek by a Lincoln rep. it would damage the electronics in the machine. I am a Lincoln man but Miller probably make the very best TIG machine for the price on the market today. I have a friend that uses a spool gun in the field and a Miller TIG in his shop. When TIG welding you do not need the high freek if you are welding mild or stainless steels. Aluminun and some exotic steels require the high freek. Good luck in your search!
