Thank you! I searched for more background and found another guess why the Soviets used valves instead of transistors: "Unable to afford the thermal-resistance

Thank you! I searched for more background and found another guess why the Soviets used valves instead of transistors: "Unable to afford the thermal-resistance provided by a titanium frame, the MiG-25’s designers used vacuum tubes over transistor-based modern electronics — which made the planes resistant to high-temperatures and cheaper to maintain."[0] [0] http://warisboring.com/one-soviet-defector-shoved-japan-into-the-superpower-struggle/ http://warisboring.com/one-soviet-defector-shoved-japan-into...