Microphonic from Vacuum Tubes?

HI,  I have a question regarding microphonic from vacuum tube.  I have a Cary SLP-05, and I've changed the output gain tubes to some NOS RCA, and also recently purchased a pair of Linlai for the balanced buffer stage.

I now occasionally hear a loud pop in the music.   It doesn't happen very often, but when it does, it is quite loud.   This happens when I am streaming digital music, so it can't be those occasional pops you hear from vinyl.  

Can someone tell me if this loud pop possibly caused by microphonic in my tubes?  if so, how do I track down which tubes?   My guess there is no easy way but change one tube at a a time, which can be extremely time consuming.   Also I don't own a tube tester.  I wonder that would help tracking it down.

Also I read something about vacuum tube damper rings,  would that help calming down possible microphonic?

I still  consider myself a newbie in tubes,  so any hep will be appreciated.  Thanks very much.


I believe that @dekay is on to something, a bad seated tube, meaning tube sockets may have a bad joint or same case elsewhere on circuit board, as @atmasphere said pops are not suggesting a microphonic tube but most likely a bad tube or source.

Something else that came to my mind is whether these pops are happening with same music or song.

I think you have a good plan.  first suspect the last change you made and if it happens again put the old tubes back in.  

I'll add that tubes are the most likely culprit.  don't see this much with ss amps.


Hi @immatthewj,  I don't own a CD player anymore.  It is so 20th century.  😀 

I'm inclined to think that the culprit could be something with the preamp or the new tubes.  Also @petg60, I'm pretty sure the pops are not happening with the same song.  Otherwise, it would be easy to reproduce the problem.

My experience is that I had a high pitched ringing or a vibration like hum. This was alleviated initially by cooling and reinstalling the tubes. As the tube aged they got worse and we’re replaced. The 2 times I experienced a single pop, it was t preceding a tube failure , but with power tubes. Once the glass envelope failed with a poof and I shut it down. The second was a violent pop that resulted in a blown capacitor and resistor that required Mr Had to repair my amp. That one involved a brand new Gold Lion that he said failed and caused the damage. Good luck with your issue.  

@buellrider97 , as a fellow Cary amp owner, which Cary amp was that?


I'm inclined to think that the culprit could be something with the preamp or the new tubes.

I understand gut feelings.  As we have the same preamp, I follow your threads with interest.  You have been up & running with it for quite a while now since that earlier fiasco you experienced, haven't you?  I sort of remember you posting about the tubes you bought from Brent Jesse and it seems like that was a good bit ago (which obviously wouldn't eliminate them), but it sounds as if the Linlais are a fairly new addition.  Maybe you are on to something with your theory, so I'll wish you luck tracking this down, but just out of curiosity, with all else aside, have you been able to form an impression of the Linlais yet?