The Magnetic Amplifier – A Lost Technology of the 1950s
One of the most interesting articles I've ever read.<p>I did a fair amount of reading about vaccum tubes back in the day, and my family owned a tube-powered commercial Seeberg 45 RPM jukebox, but I never made the mental leap to all-magnetic "circuits."<p>This jukebox was in our living room (size of a refrigerator):<p><a href="https://www.prosoundweb.com/put-another-nickel-in/" rel="nofollow">https://www.prosoundweb.com/put-another-nickel-in/</a><p>One disadvantage of magnetic amplifiers that I can think of is that any heavy-current application would require specialized training to service. For example, I work with 1-phase electricity as needed, but I won't even open a 3-phase panel. Can you imagine poking a screwdriver around in a magnetic circuit? :)<p>Fun fact: after the first vacuum tube amplifier was patented, patent trolls would solder random collections of vacuum tube logic (VTL) and patent those. But when cross-examined in court while defending their patents, they could not explain how they worked. Kind of like the first spaghetti code, but in hardware.<p>It would be very cool if somebody made a graphical simulator for magnetic circuits and amplifiers, like Kerbal Space Program (KSP.)