Clanging Nixies

[MichaelB]

http://badnixie.com/Web_Files/Clanging%20Nixies.mov

I’ve always thought this an interesting phenomena and have really never seen it mentioned here before, but if you turn up the volume nice and high on this video and listen close you can hear a sort of clanging noise. I believe this noise is the digits expanding and contracting as they heat up and cool down as they are turned on and off. Pretty neat, I think!  My Thomas clocks with IN-18’s all do it and always have, but my other clocks that cross fade from one digit to the next, do not seem to do it.  Maybe because the on and off is more gradual? Anyway, I know, a totally geekie observation, but I thought it would be fun to share with the group.

[jf...@my-deja.com]

On my B7971 clocks, you can hear the tubes “sing” at the mux rate, and the “timbre” would change as the digits changed (the mux’ing also generated at lot of RFI).  I mentioned this many years ago when I said that they had been running 24/7 for over 30 years (now 40) with zero tube failures.  One other list member suggested that I might have been hearing the magnetostriction from the transformers in the SMPS, but I found this unlikely since I could isolate the sound to the tubes and because I had used linear power supplies.

 

BTW, is the “clanging” noticeably louder when multiple digits change simultaneously?  (On my computer, the clanging in the video is not synchronized with the changing seconds digits).

 

You might be able to reduce the noise by increasing the rise time of the current applied to the tubes.

[MichaelB]

You know, I can't isolate which digits are doing it and when. It seems very random which would make sense since I'm sure the the digits cool at varying rates based on their size and shape.

Don't get me wrong, it does not bother me, in fact. I kind of like. It is very subtle.

[Greg P]

All my IN-18 clocks clang.  Must be inherent to that tube.

[gregebert]

>All my IN-18 clocks clang.  Must be inherent to that tube.

Are all of your IN-18 clocks multiplexed ?

My IN-18 clock makes no clanging or any other audible noise. It's direct-drive (non-multiplexed)

[MichaelB]

No, I have both direct and muxed IN-18 clocks. The muxed ones don't do it. Nor do the direct drive clocks do it that have a cross fade feature, i.e. the newer PV clocks.

Curious if your DD clock has the cross fade feature activated? This seems to have a bearing on if the noise is there or not.

[gregebert]

I didn't add cross-fade, PWM dimming, or anything fancy to my clocks. Just plain ol' direct-drive. No noises of any kind.

[MichaelB]

yep, the clocks that do this have none of the fancy stuff either. Jeff Thomas clocks.