Using vacuum tubes did have some advantages - notably being more EMP resistant than normal electronics. Given one of the MiG-25's roles was to intercept incomin

Using vacuum tubes did have some advantages - notably being more EMP resistant than normal electronics. Given one of the MiG-25's roles was to intercept incoming nuclear bombers this was presumably an important requirement. https://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-25#Western_intelligence_and_the_MiG-25 https://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-25#Wester...