A high school classmate put one together from a purchased kit circa 1957 or so. It involved a shoulder bag like case and used batteries rather serious in both voltage and price as I remember it; a capacitor or two the size of beer cans (well maybe not quite!)

I'm thinking I bought a little Honeywell unit around the mid-sixties. Having semiconductors that could handle enough juice to drive an inverter allowed getting away from the bazillion cell high voltage batteries.