microphonic ceramic caps...

[JimAnsell]

if a ceramic cap makes any noise at all with the chopstick test, should it be replaced? or is a little bit of "bonk" when tapped ok as long as it doesn't cause feedback or excessive noise?

 

[glpg80]

Sounds like an internal micro crack. They don’t normally go microphonic and are normally very reliable even in old radio equipment.

I have had 500V silver micas made in Mexico go straight short circuit before when not even overvoltaged.

Definitely suspicious. I’d consider replacing it.

 

[SpiderWars]

I didn't do the chopstick test but I put an old Lemco in my Super lead build and the amp was so close to being unstable. I replaced it with a new blue Murata and that settled it down a little.