Another reason why Georg Neumann must had underheated the VF14 electron tune on the U47 microphone

The grid is near the cathode.


If the cathode is at high temperature, the grid would be at a sufficient high temperature so that it too becomes an emitter of electrons. Would this cause grid current?



Reference;


Principles of Electron Tubes H. J. Reich - 1st edition - 259 - 1941