Most small signal tubes that are used in audio components, such as the 12AX7's and 6SN7's, use indirectly heated cathodes (meaning that filament and cathode are different elements). The filaments in some designs are powered with low voltage ac supplied directly from a winding on the power transformer, in which case tube vs. solid state rectification has no bearing on the in-rush current to the filaments that occurs at turn-on. Better designs often incorporate dc filament supplies, in which case the design may provide better in-rush control.
Sir,
Pardon my ignorance and I hope you do not mind me asking. I am not looking for a debate, I do not have sufficient knowledge on this topic to hold one, and although my questions are pretty direct, I am just trying to understand what you wrote. So, if you do not want to answer my questions, I do understand.
What if there's a thermistor on the primary winding of the tube amp, for example, what happens to the inrush current analogy? At t=0, caps (in the PSU) are shorted, does the inrush current reach the signal tubes?
I have never encountered a tube failing on preamps because of cathode stripping. Some tubes last for ages, like Telefunken for instance, are they not affected by cathode stripping? How many cycles does it take on the average before cathode stripping is really an issue? Is the decrease in gm be considered as a good measure? Is it safe to assume that cathode stripping only matters on high power tubes where bias voltages are over 1kV and not those tubes whose bias voltage is less?
Again, I apologize for being direct and I hope that you will not take my questions as a challenge to what you have posted.
regards,
Abe