Hearing a low buzzing noise when charging a laptop through KVM (USB-C PD)?

Hey all,

We recently saw a case with the HDC202-X24 where a user noticed a low-frequency electrical noise (buzzing / coil noise) from the KVM when their laptop was charging via USB-C.

Understandably, the first reaction was:
“Is this going to damage the KVM or my laptop?”

Short answer:

No — this is not a safety issue.

What’s actually happening (in simple terms)

When the KVM provides power to a laptop over USB-C (PD), different laptops request different voltage/current profiles and adjust load dynamically.

Under certain load conditions (especially higher voltage or fluctuating power draw), components inside the power circuit — typically inductors — can produce slight mechanical vibration.

That vibration can become audible as a buzzing / coil whine.

You’ll see similar behavior in:

• USB-C chargers
• Docking stations
• Power adapters

Some laptop original chargers are quieter simply because they have more power headroom and stricter noise tuning.

Real talk

While this is technically normal behavior across power electronics, we also understand:

It can be annoying.

Especially in quiet environments, even a small electrical noise becomes noticeable.

What we did in this case

In the reported case, we went ahead and provided a replacement unit for the customer.

Even though this doesn’t indicate a functional or safety issue, we’d rather make sure the user experience is as clean as possible.

Curious to hear from you

• Have you ever noticed similar noise on KVMs, docks, or chargers?
• Does it vary depending on the laptop model you’re using?
• Any setups where it’s completely silent?

Would be great to compare notes and see how common this is across different setups.