Usb sockets buzzing

[CharlieB1981]

I recently switched some sockets over in a room.
Changed several to sockets with USB ports, and on a couple of others put in standard sockets (sockets were already there I’ve just replaced them whilst decorating)

those with the usb buzz constantly- very quiet and you need to be a few inches away to hear it.

those with standard sockets don’t. All same make/style - only difference is the USB ports

Is this normal? First time using sockets with usb so I’m unsure.

thanks

 

[BS3036]

It wouldn't surprise me. Cheapest possible transformers in power supply circuit are very likely to buzz.

 

[winston1]

It wouldn't surprise me. Cheapest possible transformers in power supply circuit are very likely to buzz.

Any transformers they have will be tiny and operating at very high frequency of a SMPS not 50Hz.

But, I've not known USB ports to buzz. I would return them as faulty and get another brand.

 

[CharlieB1981]

Any transformers they have will be tiny and operating at very high frequency of a SMPS not 50Hz.

But, I've not known USB ports to buzz. I would return them as faulty and get another brand.

Is it likely to be something dangerous? In all honesty the buzzing doesn’t bother me as you can’t hear it.

 

[bernardgreen]

The Switch Mode Power Supply ( SMPS ) in the socket ( it creates the 5 volt USB supply ) should not buzz. Buzzing suggests something is vibrating and 9 times out of ten this vibration is from the isolation transformer. The vibration could lead to a breakdown of insulation between 230 Volts and the 5 Volt USB supply, not good for anything that is using the USB supply,

Also if an SMPS fails it might trip the MCB or RCD and then the socket would have to be replaced before the MCB or RCD could be reset,

 

[plugwash]

In my experience buzzing is not uncommon with switched mode power supplies under light/no load.

Nothing is 100% rigid and transformers will often buzz at their operating frequency. Generally switched mode power supplies use an ultrasonic operating frequency so you can't hear their buzz in normal operation, but under light load the operating frequency often drops and can become audible.

 

[bernardgreen]

Nothing is 100% rigid and transformers will often buzz at their operating frequency.

Vacuum impregnation with resin ( or even hard wax ) will silence a transformer and prevent the windings being damaged.

Problem is vacuum impregnation takes time and money.

 

[CharlieB1981]

well i picked up some other LAP and BG sockets to try them today- same issue, then on investigation found they are actually manufactured at the same place and same spec as the 'home brand' i already had installed- just packaged up differently....

so far what i've found is the LAP, BG and 'good homes' sockets all have a low buzz, the MK sockets ive tried don't