Back when I was a young kid in the late 1950's and early 1960's the only source of information on Hi-Fi was magazines. The magazines at the time were maybe 35 cents to 75 cents each. Now and then I would be able to come up up with the cash to buy one. These mags were filled with many facts about early audio and give a good look into the evolution of early audio gear. The mags range from 1952 to 1962 and some months are missing. They span the pre-stereo era (1952 - 1957) and the early stereo era (1958 - 1962). Lots of great reading for those interested in the early history of Hi-Fi. Link below ...
1952 - 1962 editions of Audio, Hi Fidelity and Hi-Fi Stereo Review
Bob
1952 - 1962 editions of Audio, Hi Fidelity and Hi-Fi Stereo Review
Bob