CPU whine through one monitor speaker

[Matt Picone]

On 5/28/20 9:24 AM, Joost Schuttelaar wrote:
> On 27 May 2020, at 13:18, Joost Schuttelaar <joost at joostschuttelaar.nl> wrote:
>
> Yep, noise this morning. Went away after about 45 minutes.
> Bad filtering of mains power perhaps? A degraded cap in the speaker’s PSU?
>
I used to infrequently hear a noise in my monitors. It was a 
high-pitched, almost-mechanical whine. I checked everything. I turned 
off all of the circuit breakers except the one I was using. Nothing. 
Madness.

When summer came and I worked with the door open, I heard a strange 
sound outside my house at the precise moment the noise began!

  It took just a short while to track it down to some kind of industrial 
power supply unit that my neighbor would sometimes turn on in his wood 
shop around the corner! Even with expensive power filtering in place 
here it made no difference. Thankfully, he almost never uses that shop 
anymore as he finished his home renovation project.

Joost, my guess is that it you have a faulty component in that monitor, 
and that this is making it susceptible to some external variable. This 
could even be causing an intermittent imbalance in the ground. I wonder 
if you can try a cheater on its power and/or lifting the cable.