Quote:
Originally Posted by vitreouswindows  The Acrolites shells were fashioned from aluminum and the Supraphonics were (as previously noted) fashioned from brass; in the early sixties they switched to a copper alloy to save money. The Supraphonics were chrome-plated and the Acrolites were not. |
This is true that some Supras were made of brass, but later they were changed to aluminum. I can't give an exact date, but I believe it was late sixties. This is why they're plagued with pitting -- aluminum doesn't take chrome very well.