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.


Does the loud pop occur in just one channel or both channels, and if in both, does this happen simultaneously in both channels?  Does it happen when the music is playing at high volume levels or under other consistent conditions, or is it seemingly random? I am not a technical expert, but, this sort of additional information might help others diagnose your problem.  I have not heard of large occasional pops being an issue related to a tube being microphonic. Can you reproduce that noise by lightly tapping on any of the tubes?  If a tap gets you the same kind of pop, that tube might be microphonic.  Otherwise, I would suspect that something in the power supply, maybe a capacitor, might be at fault or perhaps you have a tube socket going bad.   I have tubes that occasionally, quite suddenly, develop loud crackling noises that last for a few moments and up to a few minutes and then the noise goes away (I was told that this is caused by something flaking off in the tube and falling on the heater, with the noise lasting until the flake is burned away).  The loudest pop I've heard involved an output transformerless amp where a tube socket was going bad--that pop was loud enough to almost trigger a heart attack.   

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


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. 


@xcool OK- keep in mind to make no assumptions. That can lead you on a wild goose chase.

The first thing to do is swap the interconnect cables left for right at the amplifier inputs and see if the problem moves.

If yes => the cable, preamp or source is on the hook

If no => the amplifier is the problem.

So do that and get back to us.

Or, if the problem moved, the next thing to do is swap the connections from the source at the input of the preamp.

If the problem moves its the source or its interconnect cable.

If the problem stays put then the preamp is on the hook.

If you get to that point then you swap tubes from one channel to the other, a pair of tubes at a time. Between each swap you play the system until you can determine which channel has the bug. If it moved you know which tube is bad, if it didn't then you proceed to the next pair of tubes and repeat the process - do this until the problem moves and then you've located the bad tube.

Good Luck!

Thanks @atmasphere for your instructions.  The problem is that I think I've heard the pop from either left and right channel before, but not at the same time.   So the problem doesn't seem to be specific to a single channel.

I sure hope that this is not an issue with my Cary preamp.  I've had enough problems with it since I bought it about 7 months ago.  😀

@xcool Like I said, don't make any assumptions. Right now it sounds like you need to sort out for real which channel its in or if its in both.

If its randomly in both, FWIW I'd be more suspicious of your source... but keep an open mind. That's the first rule of troubleshooting. The second is not to make assumptions.

I would start by pulling and reseating all the tubes (rectifier included) when the amp/tubes are cold.

If the popping persists replace the new tubes with the old ones.

If there is no popping after this systematically swap in the new tubes one @ a time.

Aside from a bad tube poor pin/socket contact can cause the noise you describe.

This will take time, but it's easy.



Thanks @atmasphere ​​​​@dekay.   My hunch right now is the preamp or the tubes are the culprit.   That's because I've never had any issues with my system before the introduction of the Cary.   

This is probably going to take a while to track down because it doesn't happen that often, and I can't really reproduce it.   I think I will start with putting the old tubes back if I hear the pop again, and go from there.  

Thank you all!

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.


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.

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?



I’m pretty sure you are not having Microphonic issues.  Do you use a power conditioner? Are you streaming when this happens? what service are you using?  I’m using Amazon and there is often a pop when the tracks change.  It’s kind weird, like they are using tracks from different recordings. 

Just a thought.

@buellrider97, thanks for sharing your experience. I might try reinstalling my new tubes and see what happens. When I first got the Linlai tubes, I was inserting them into a pair of tube socket savers. I did that because I was thinking about doing some A/B testing with the stock EH tubes. After deciding that the Linlai do sound better, I removed the socket savers and inserted the Linlai directly into the sockets of my preamp. I cannot remember when the very first time I heard the pop, whether the socket savers were already removed. The latest pop I heard was this morning, and I know for sure the socket savers were no longer there.

@immatthewj, yes I did buy the NOS RCA tubes from Brent and I do like them better than the stock EH tubes. The EH tubes sounded a little too bright for me at the gain stage. The RCA took the edge off and sounded warmer. As with the Linlai, I do like them quite a bit. I was going to post an update to the long going Linlai thread, but haven’t gotten around to it. The Linlai has tighter bass and better sound stage than the stock EH tubes.

As with the Cary, I actually had another issue a couple of months ago. I was so pissed off that I was going to start another thread venting my anger, but I decided not to. I did mention it in an old thread because someone posted a question. Lucky it was a fairly minor issue and I was able to resolve it without having to ship the unit back to Cary.

@curiousjim, I do have a power conditioner. I was most likely streaming from Tidal when I heard the loud pop. Thanks for sharing your experience with Amazon. It does seem kind of weird.

Slightly off topic , but in the same area. You might want to add some sort of unit isolation underneath and tube dampers too. Not related to your popping , but at your level of involvement it never hurts. Cheers , Mike. 

Thanks @buellrider97,  I've been thinking about tube dampers.   I have read some good comments about them.

It’s likely haunted...few people mention this but it can’t be cured by tube dampers as it requires an exorcism (performed by any holy person, or simply a "holier than thou" person). This can also help with cable break-in, "otherwordly" soundstage anomalies, and mold retention.

+1 @wolf_garcia , Wolfie nailed it ! I appreciate your prospective . Personally I’ve run into brightness issues when doing any exorcisms as the silver adds too much brightness and causes the demon screams to hurt my ears. However Silver gel works great on mold and bacterial issues. Joking aside Ralph has more knowledge and experience than the rest of us put together, I’d advise following his direction. A logical SPOC like search working backwards from present will reveal the culprit. And always employ “ Rule 62 “ on Agon, “ I can’t take myself so damn seriously “. 😆

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


When you make a change and things go south its a good bet that the problem is associated with something you did.

However, that bet can also blind you to what is really going on; pursuit of the problem in that manner can yield no results if its not really the issue.

Equipment turning on or off can create pops that come into the equipment on the AC line. IME, most so-called high end audio 'conditioners' are not really all that good at their job and may be unable to filter such events, or they could even cause them. Some preamps are more susceptible to this sort of thing so it is possible that the Cary is working fine but simply can't reject events like this. I see this hypothesis as unlikely since we'd have heard of it before on this forum...

And of course the popping could be a failing power tube that is arcing.

So it is worthwhile to do your due diligence.

When doubt contact customer service! Thats why they have a contact number: I don't know why people consult a forum when every reputable manufacture has a support number & its free & you won't waste money on random ideas that may make your issue worse. If its known issue, you will have your answer quick: If not, they can guide you to the cause or where to seek help.

@jb1  , OP isn't sure which component in his system is causing the anomaly, and since they are all from different manufacturers. . . .

Also, I own Cary products and I like them very much, but do you know what now happens when you call Cary up for tech support?  Unlike in the good old days of Cary Audio Design they now tell you to send them an email.  My experience has been they are not always super prompt with a response.

I think the trickiest thing about this issue is that it happens so infrequently, and I can’t reproduce the problem. So diagnosing will take a long while. That’s why my obvious focus is the latest change that I make to my system.

I have never come across anything similar to this issue ever for as long as I’ve been listening to music on any of my equipments that I ever owned. I was hoping someone in this forum had experienced similar issue and offer a quick way to diagnose and track down the culprit, but I guess there is no easy way to tackle this.

Thanks for everyone’s comment so far. I will definitely update you guys if I find and fix the issue!

I have had unlistenable crackling and pops from streaming a bad file. It would be nice if you used a different source to see if it occurs without streaming.

@acman3   +1

I have had unlistenable crackling and pops from streaming a bad file. It would be nice if you used a different source to see if it occurs without streaming.

Thanks @acman3,  I wonder if it can indeed caused by a hiccup from streaming.  So far I've only experienced this issue while streaming from Tidal or my own MinimServer running on my NAS.   If I  know how to edit a digital file, maybe I can reproduce this issue.

My only other source is my vinyl setup, which I only use 10% of the time, and I haven't heard this popping noise while I was listening my vinyls.

I get that popping noise on qobuz when a track switches from CD to high resolution and back again.

@invalid, thanks for sharing that.  Does this happen consistently?   That must be so annoying.  I think that would bug me to no end.   😀

It does it consistently, I believe it's my bluesound node 2 when using the digital output. 

How many hours are on the Linlai tubes? If they are brand new they might need more time to settle in. My Psvane 845 and 300b tubes came with a card in the box saying they could need up to 150hrs until they are fully broken in. I did get some infrequent “odd” noises from the speakers for the first 50hrs or so after installing them but it’s been smooth sailing since then. The noises I was getting were the occasional crackle or ringing sound but never a loud pop that made me think my amp might be in danger. 

I might have missed your source, but if you are playing vinyl I believe the problem is static electricity. I have similar issue with my Manley chinook. 

@durte30,  I think I've got about 120 hrs on the Linlai at this point.

@cub,  this only happens from my digital source, i.e. my streamer.

Tube dampeners come on all of my Audio Research components small tubes, as the did on my Sonic Frontiers components. 

Pops, maybe tubes or capacitors. Tubes most likely.

Thanks @ghdprentice, assuming the issue is from one of the tubes, do you think tube dampeners may help minimize the chance of these popping noise?

I doubt that tube dampers will do anything for the cause of the popping noise.  This is a problem with a tube, a problem with a tube socket (this is the most common source of such problems) or a problem somewhere else where a charge builds up and then suddenly discharges (probably somewhere in the power supply circuit). 

Tube dampers work to minimize microphonic ringing, but that is not an issue here.  Do they improve the sound?  In some cases they do, in others they make the sound "drier" which may actually make the sound less pleasant.  Consider tube dampers and other damping products (platforms for gear, weights to put on the chassis, etc.) as tuning devices--they alter the sound which means they can also alter the sound in the wrong way.

So far I've only experienced this issue while streaming from Tidal or my own MinimServer running on my NAS.  

@xcool Really! That is telling you something.

In that case play the LPs only for a week. If you don't hear any pops, I'd look into issues with your digital setup- as @acman3 points out, digital is quite capable of making loud pops!



I do not think tube dampeners would help popping.

If a tube is the culprit, I would find it and eliminate it. It means there is a big bursts of electrons jumping between the plates… that should not happen. I personally do not want any badly behaved tubes in my system just in case it foreshadows a failure. Although cataclysmic failure are uncommon, they are not unknown.

If a capacitor, would get that fixed as well.


I am not an electrical engineer, but have enjoyed and successful employed tubes for decades. I have never had a bad event. But I very occationally get a badly behaving tube and get rid of it.

Thanks everyone again for your advices and sharing your experiences.  I will post an update if I’m able to make any progress on tracking this down.   Who knows, it might not happen again 😄

I sometimes get a pop noise when a major appliance turns on….like the heat or air conditioner. I have 2 dedicated lines and it still happens sometimes.

Tube(s) getting too hot….all you have to do is wait for pop then generously spray all the tubes with water. The bad tube(s) will obviously be obscured by a cloud of vapor.

Tube(s) getting too hot….all you have to do is wait for pop then generously spray all the tubes with water. The bad tube(s) will obviously be obscured by a cloud of vapor.


@sevestan , you are joking, right?

When capacitors go bad.  Could be anywhere as the noise also travels back to the PS if common to both channels.  Hard to troubleshoot sorry.