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…
What is going on inside them?
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?
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.)
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.
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.
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.
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!
