I'm trying to find information about a piano accordion I bought long ago at a Wisconsin garage sale. It's a 120-bass Mason Symphonic. If I had to guess I might say it was circa 1970s, but that's not based on much. I've done many a web search and come up utterly empty-handed looking for accordions made by a Mason brand. My only thought is that perhaps the Mason piano company also made accordions, but I'm grasping at straws there. Can anyone help? Many thanks, Margaret