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-   -   Superhub : Superhub plug noise (https://www.cableforum.uk/board/showthread.php?t=33700667)

heero_yuy 25-04-2015 13:42
Re: Superhub plug noise
 
The switchers we design for industrial panel equipment can sometimes make a noise at high line input and low load. It's a normal consequence of the supply trying to square the input / output circle and the pressure to cut costs. The operating frequency can fall low enough to be audible.

Just on the odd occasion we've had clients mention it and only once raised it as an issue. For that client we had the transformer specially impregnated with additional varnish to cut down the volume to an acceptable level.

Sephiroth 25-04-2015 15:02
Re: Superhub plug noise
 
... and the switchers you design for poxy Superhub PDUs...? LOL!

heero_yuy 25-04-2015 15:26
Re: Superhub plug noise
 
Quote:
Originally Posted by Sephiroth (Post 35773801)
... and the switchers you design for poxy Superhub PDUs...? LOL!
Not me m8 :D

Just saying that because there's some noise it ain't about to blow.

Sephiroth 25-04-2015 16:47
Re: Superhub plug noise
 
Who knows? This sort of noise is vibration, right? Things tend come loose when they vibrate, in this case electrical things. I understand why glue is applied to the potentially noisy components, but if the electrolyte (if any) has started to leak from the capacitor.....

I wouldn't be happy.

heero_yuy 25-04-2015 16:53
Re: Superhub plug noise
 
Quote:
Originally Posted by Sephiroth (Post 35773826)
Who knows? This sort of noise is vibration, right? Things tend come loose when they vibrate, in this case electrical things. I understand why glue is applied to the potentially noisy components, but if the electrolyte (if any) has started to leak from the capacitor.....

I wouldn't be happy.
It's called magnetostriction. It comes from magnetising the core of the transformer. It slightly changes the dimensions and thus makes a noise.

Normally we try to run the PSU's at above 20kHz so users simply can't hear it.

Sephiroth 25-04-2015 17:52
Re: Superhub plug noise
 
Quote:
Originally Posted by heero_yuy (Post 35773827)
It's called magnetostriction. It comes from magnetising the core of the transformer. It slightly changes the dimensions and thus makes a noise.

Normally we try to run the PSU's at above 20kHz so users simply can't hear it.
Does that frequency apply to the poxy Superhub PSUs?

And to interpret your explanation, change of dimension means vibration, the frequency of which defines the noise pitch. The vibration can transmit to other components that in a confined space such as a poxy Superhub PSU, need to be glued into a more stable alignment.

Am I wrong?

qasdfdsaq 25-04-2015 18:44
Re: Superhub plug noise
 
Quote:
Originally Posted by heero_yuy (Post 35773827)
It's called magnetostriction. It comes from magnetising the core of the transformer. It slightly changes the dimensions and thus makes a noise.

Normally we try to run the PSU's at above 20kHz so users simply can't hear it.
Chances are the buzzing on the SH's adapter is 50Hz hum from the primary side, not the switching on the secondary.

---------- Post added at 19:44 ---------- Previous post was at 19:38 ----------

Quote:
Originally Posted by Sephiroth (Post 35773848)
Does that frequency apply to the poxy Superhub PSUs?

And to interpret your explanation, change of dimension means vibration, the frequency of which defines the noise pitch. The vibration can transmit to other components that in a confined space such as a poxy Superhub PSU, need to be glued into a more stable alignment.

Am I wrong?
Not entirely sure what you're getting at. The very basis of electromagnetic transformers involves electromagnetic fields and thus forces being applied to the components. When things are subject to forces, they move.

All electromagnetic transformers vibrate and whine. How much exactly is a matter of design and manufacturing tolerances, but it's no different to the buzzing you hear around overhead mains transformers and substations. Doesn't mean it's broken or about to blow up.

Sephiroth 25-04-2015 19:21
Re: Superhub plug noise
 
Quote:
Originally Posted by qasdfdsaq (Post 35773864)
Chances are the buzzing on the SH's adapter is 50Hz hum from the primary side, not the switching on the secondary.

---------- Post added at 19:44 ---------- Previous post was at 19:38 ----------



Not entirely sure what you're getting at. The very basis of electromagnetic transformers involves electromagnetic fields and thus forces being applied to the components. When things are subject to forces, they move.

All electromagnetic transformers vibrate and whine. How much exactly is a matter of design and manufacturing tolerances, but it's no different to the buzzing you hear around overhead mains transformers and substations. Doesn't mean it's broken or about to blow up.
What I'm getting at is that in a cheap product like the poxy Superhub PSU, noise due to vibration should be regarded as a fault because vibration in such a device is not certain to be harmless - contrary to Heero's view.

qasdfdsaq 26-04-2015 00:02
Re: Superhub plug noise
 
I disagree. I'm not aware of any case where anyone has ever been harmed by a buzzing Superhub PSU.

Cheapo products are more likely than expensive ones to exhibit vibrational noise, that's intentional and by design.

Sephiroth 26-04-2015 06:02
Re: Superhub plug noise
 
Quote:
Originally Posted by qasdfdsaq (Post 35773919)
I disagree. I'm not aware of any case where anyone has ever been harmed by a buzzing Superhub PSU.

Cheapo products are more likely than expensive ones to exhibit vibrational noise, that's intentional and by design.
Then mine (all of them past & present) must be a manufacturing fail as none have ever exhibited vibrational noise to my ear.

Ken W 26-04-2015 07:48
Re: Superhub plug noise
 
Quote:
Originally Posted by Sephiroth (Post 35773930)
Then mine (all of them past & present) must be a manufacturing fail as none have ever exhibited vibrational noise to my ear.
None of mine have exhibited a noise, maybe we should phone VM and ask for a power module that makes a noise.:)

qasdfdsaq 26-04-2015 14:44
Re: Superhub plug noise
 
Quote:
Originally Posted by Sephiroth (Post 35773930)
Then mine (all of them past & present) must be a manufacturing fail as none have ever exhibited vibrational noise to my ear.
Ermm, no, try reading back up a bit :)

heero_yuy 26-04-2015 15:01
Re: Superhub plug noise
 
Quote:
Originally Posted by Sephiroth (Post 35773848)
Does that frequency apply to the poxy Superhub PSUs?

And to interpret your explanation, change of dimension means vibration, the frequency of which defines the noise pitch. The vibration can transmit to other components that in a confined space such as a poxy Superhub PSU, need to be glued into a more stable alignment.

Am I wrong?
Just comes from a dimensional change in the transformer core when it is magnetised. If this happens to be below ~18KHz then you'll hear it. If I get close to my SH1 plug-top PSU I can hear it singing but as it runs cool then there's no issue. Most of them are singing their heads off, it's just ultrasonic so you can't hear it. Mind you your dog or cat might. Encapsulating the transformer will cut the noise but it costs.

But I've only designed these sort of switching supplies for 30+ years so what do I know?;)


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