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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.

128x128xcool
fuzztone's avatar
fuzztone
5,510 posts
 

Microphonic is amplification of a microphone like source.  Tubes AND other electronics can exhibit this behavior. Good luck finding a pop source. Static electricity can do it, the dry season is coming.

 

immatthewj
1,412 posts
 

If its randomly in both, FWIW I'd be more suspicious of your source...

I was wondering about that myself, but I don't know anything at all about streaming.  Do you have a CD player you could run for an extended period of time to see if it pops with that as your source?  If it didn't, I would think that would point to the DAC or something else in your streaming chain.

petg60
1,486 posts
 

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.

carlsbad's avatar
carlsbad
1,551 posts
 

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.

Jerry

xcool's avatar
xcool OP
273 posts
 

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.

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