High Pitch Sound Isolation

[Bobfromoh]

Not sure where to post this but I'll start here? This is actually a question concerning hobby items: neon lights on a toy HO scale train display with a power supply that causes high pitched annoying noise. I have four picture displays connected to one power supply. It doesn't matter though, one or four displays cause the same problem. I am older so I don't hear the high pitched sound. But anyone younger complains that it is annoying.

I tried hiding the power supply under the platform and it helps, but not enough. I called the manufacturer and they said there is nothing I can do about it. The power supply is about 3" x 4" x 3/4" thick. So the question is, is there someway to enclose the power supply to greatly reduce or eliminate the noise. Also, it get fairly warm so heat dissipation is a problem also.

 

[drawoh]

Bobfromoh,

I am not sure of the numbers here. Young people can hear something up to 20kHz. We older folk are able to hear up to something like 8-10kHz. Your frequency is 8-20kHz. This is easily isolated, unless the problem is the noise, which it is.

Can you poke inside this thing? If you contact whatever is vibrating, you will drastically affect the noise. This may give you an opportunity to reduce this.

--
JHG

 

[Bobfromoh]

Thanks for the reply.
I know that I can hear only up to 8K. It's ok for conversation
but music doesn't sound very good to me anymore...I hate that.
The power supply is on a circuit board so everything is exposed.
I will have to get my son (who complains about the noise) to help
out on this.

 

[BrianE22]

Do a google search on "neon lights noise". Looks like there's quite a bit out there on the subject.

 

[btrueblood]

Do you have a smart phone? Download an FFT app (I have FFTWave 3.0 on my android), and let it find the peak frequency (-ies) for you.

Unfortunately, truly fixing the problem may be impossible, as the circuit likely oscillates at 10-20 kHz to generate high voltage to fire the neon lamps, and the noise likely emanates from a circuit element that you can't dampen without breaking. It might be possible to tweak the circuit to raise the frequency of the oscillator, but you'd have to know how the circuit worked, or give us a schematic of it...and then get the sparkies involved, and that's just asking for trouble... I'd look for another circuit, i.e. one driving LED's.