I owned a pair of Dyna MKIII's that had been modified a company called electronic industries ( or something close to that ) which I understand was Wm. Johnson's company just before ARC. I still have my SP3 in action today and recently brought it into ARC for a new volume control. They had a NOS rack mount faceplate lying around and I had them put it on.
ARC product history (Audio Research)
I'd like to learn more about the manufacturing dates and specifications (not to mention reviews) of ARC's product line, going back some years. Their website is great, but only covers the current line-up. Are there any ARC enthusiast pages out there? Or other good references?