Tube Tinkling... wha?

I just put back my EL34s back into my Prima Luna integrated… just for fun. Way cheaper than buying a new amp. I love it. But… not as transparent as the KT150s I had in there for over a year. But… tinkling!!

The EL34s tinkle. They make noise when powered up and when cooling down. The KT150s don’t do this. So…

  1. What is going on inside them?
  2. Is this audible? I usually let the amps quiesce before use… but got me wondering… how long does it take to fully stop tinkling?

So… take the too-much-beer and prostate jokes out it… what’s up here?

Bruce in Philly

Bruce in Philly

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I adore the ticking sounds of EL34s, especially when cooling. And they possess a magical mid-range in use.

I do not know why they make these sounds. I hope someone here does.

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My guess is thermal expansion and contraction. My kt66’s tink when cooling down.


Yes, but what is actually moving and creating the sound? And why do some tubes do this while others are silent? (I did not know KT66s do this as well.)

The sixteen (16)!!! 6550s in my VTL monoblocks did this too. Scary actually.

Bruce in Philly

Not sure why different tubes are more or less prone. There is a lot of different materials that are touching each other, each cooling (or heating) at different rates. How tight or loose the components are together might be why some tubes do it more than others.


What always interested me about the noise, is that there is a physical change going on… To a degree that I would think is incompatible with accuracy and consistency in manufacturing. Odd for a high-end component regardless if for audio, or military, or in a tool. So me thinks.

Bruce in Philly

I’ve fond memories of a similar tinking sound of small engines cooling down. ATV’s, lawnmowers, Gokarts and etc.

Have you been on thick ice on a lake? Every once and awhile it will make a really deep noise that also has a higher frequency ting-whoosh-waaaah. It can be unsettling the first few times you hear it. I’ve been told, never verified. That that is the ice thickening as it gets colder and expands it needs to go some where. When the ice moves because of that it makes the noise.

An electric cook top also makes noise as it’s cooling down.

Concerning tubes as long as it has consistent tolerances at temperature that is what’ important.

I don’t see the noise as an indication of quality.

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My old 911 does this after I shut it off. I should look again but I’m pretty sure there aren’t any tubes under there.
But for your tubes, as long as the electrons are boiling such that they still sound good and they’re not leaking air into the tube, I wouldn’t be concerned.

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I’m about to head so shutting down my amp, I took a quick video of the noise.

Tube Tinking ← Video of tinking tubes.

EDIT: added click on link for video.

Oh man! Amp is dusty! need to get some cleaning done this weekend!

Sometimes old tubes will do that. I put in a set of old GE el 34s in one PL HP amp and ran into that phenomena when they were warming up after setting for years. Nothing to worry about. I’m curious as to whether it continues after a week or two of use. I ended up removing those old tubes after a couple tripped the red diodes. A lot of protection is built into those PLs!

New EL34s do it as well. I expect there is something in this tube’s construction.

I like it.

Jeebus - oh, wait - that’s like only 8 per side. Whew😝

Anyone with recording capability (including phone) please post tinklings.

from memory all of my el34s did it, as did ecl86s triode/pentode dual valve. all were prob mullard and a few brimar.
nice sound :slight_smile:

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See my above post… :slight_smile: I don’t know how to embed the video, you need to click the link.