“Cathode Stripping” refers to a debatable phenomenon that occurs in vacuum tube amplifiers. In such a context, cathode stripping is understood as a process of damage inflicted upon the cathode surface through ion bombardment. But it’s important to note, it’s not a physical “stripping” off the cathode layer but rather a form of assault on the surface that can result in physical damage.
Let’s delve into the process: In a vacuum tube, the vacuum isn’t perfect and may contain residual gas or even have a slow leak. When an electron, on its course towards the anode of the tube, collides with a gas molecule, an electron can be dislodged from the gas molecule. This results in the gas molecule gaining a positive charge and turning into an ion. As a result of this new positive charge, the ion is now attracted to the negatively charged cathode, and it strikes it with considerable force.
This process is most likely to occur when voltage is applied to the tube before the cathode has had a chance to warm up. The application of voltage causes the electrons to start moving even while the cathode is still cool. The movement of the electrons increases the likelihood of them hitting gas molecules and creating positively charged ions that then strike the cathode.
Despite this understanding, cathode stripping is a topic of debate among tube experts. Some question its existence, doubting whether it ever occurs. Others propose that it’s restricted to directly heated tubes, while some argue that cathode stripping only occurs under high voltages, typically above 10 kilovolts.
Hence, understanding cathode stripping demands a deep understanding of vacuum tube amplifiers and an open mind to entertain differing opinions in the field. Regardless of the debate, what is unanimously agreed upon is the importance of the cathode’s health for the overall functionality of the vacuum tube amplifier.