awesome_Tube 以真空管为主的资源收集 Project HeadWize Memorial Tube simulation audiodesignguide Sijosae's Gallery Simulation Bordodynov's LTspice lib Tube simulation toolchains Tube simulation loadline-calculator Triode / Pentode Loadline Simulator Lib&Book nj7p Tube Lib Klausmobile Russian Tube Directory Nixie Tube Data Archive Tube-Tester.com some books which have expired copyrights and are now in the public domain.