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.
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.
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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? |
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. |
- 56 posts total