Agilent/Keysight power supplies humming !

[felixsys]

Hello !

I think one of the most typical and common "feature" of keysight / agilent power supplies is the humming noise. (E36 series)
I don't have this issue with keithley/siglent or rigol power supplies, Is something typical with Agilent/Keysight/HP.
What can be the reason ? Bad quality transformer ? bad lamination ?
Is possible to reduce this annoying humming?
I think I'm not the only one who's going crazy with this sick noise.

[gamalot]

I think it may be caused by the high mains voltage. My mains voltage is usually between 250 and 260V. My 4 Agilent power supplies (E3640A, E3642A, 6612C, 66319B) have humming noises.

[felixsys]

I measured the mains voltage and is max 240V, same here all my Agilent power supplies makes me crazy with this noise.
especially when there are two or three that are running at the same time .. it's humming bird party !   
Agilent/Keysight should deliver noise canceling headphones as a default accessory with the power supplies: D

[HighVoltage]

I have / had many Agilent Keysight power supplies over the years and may be one or two were humming. All the others did not have this problem. So, I would conclude that it is a transformer problem but only on a few transformers from a "Monday" transformer production.

[rsjsouza]

I think it may be this indeed - either Friday afternoon parts/assembly or perhaps individual to some series. I have a HP6113A and a much newer Keysight E36312A - both very silent in the humming department (the Keysight has a fan, so under load it gets a bit noisier)