Microphonic from Vacuum Tubes?

Can someone tell me if this loud pop possibly caused by microphonic in my tubes?  

@xcool 

It isn't. Microphonics isn't a popping sound, its the tube being able to vibrate in such a way that it can generate a tone; in some cases I've seen it be so bad you could yell at the tube and be heard in the speakers.

What you are describing is something else. Tubes can make crackling and popping sounds which aren't microphonics and have nothing to do with that. But if we're talking about a tube, @larryi  has some questions that really have to be answered to get anywhere. If in both channels and it were a tube, that tube would have to serve both channels which seems unlikely.

Does this sound occur if the volume is all the way down?

How do you know its in the preamp?

Ralph (atmosphere) thanks, now I know what tube microphonic  sounds.My tubes with microphonic did not last.

As @atmasphere said, it might not be the preamp that is causing the pop.

What are you running for an amplifier?

Generally speaking, when I have had a tube going noisy in my preamp, I could find which one it was by lightly tapping it with my fingernail or the equivalent. Something you could do is to put the tubes back in it, that Cary had in it when you bought it, and see if the pop is replicated. Maybe just put the positive phase buffers in first, and then if you still get the pop, try the input buffers. Or vice versa.

Hi @larryi ​​​​@atmasphere,  let me try to answer your questions.

I don't usually play music at loud level anymore.   I want to preserve my old ears from more hearing loss. 😀   It is usually played at below 70 db level.  

The noise does seem random, and it's coming from one side.  I've only heard it maybe 3 or 4 times, and I think it had happened to either the left or the right channel, but not both.

I just did the tapping test that @larryi suggested, and I hear no pops.

I don't think I've heard it at a very low volume, but then again, It has only happened a few times, so I don't recall what the volume level was at the time, but I think it was probably at my usual listening level of somewhere in the 60 to 70 db range.

I don't know if the problem is the preamp, but it is my newest component.  I've never heard this loud pop before I bought the tube preamp.  So that is my suspicion.   The pair of Linlai 6SN7 tubes are my latest purchase, and I wonder if that can be the culprit. 

Thanks!

HI @immatthewj,  my amp is the solid state Parasound JC5.  Thanks.