I was talking by phone to an older audiophile yesterday and he mentioned about reading Audio magazine and High Fidelity magazine as a kid back in the 1960's. A lot of these mags are still available in pdf format at the link below. Many older industry audio, radio, recording, SWL and other mags are available at the link below. Most are searchable so that if you are just interested in say articles (or ads) about Dynaco type gear, you can just search on "Dynaco". Audio and High Fidelity are about halfway down the page ..
Older mags in pdf on the American Radio History web site