High-pitched noise when connecting left half of UHK 80 to USB-C for charging

General
1

I just received my UHK 80 today. It’s the version with batteries.

When I connect the left half to my Mac via USB-C while the battery is around 50% charged, there is a high-pitched noise - I guess it happens when charging the battery.

It’s not that loud, but loud enough that I cannot work while it is connected.

I couldn’t find that particular issue mentioned in the forums.

Reducing the LED brightness doesn’t help.

If I use the bridge cable and load the battery through the right half instead, I also hear a high pitched noise from the left half, but it’s not as loud.

If this cannot be fixed in firmware, I’ll have to return the keyboard and get back to my UHK 60…

Is anyone else seeing this issue?

2

Update: it does seem to be related to LED brightness. The sound is pretty much gone while the USB-C cable is connected when I set the brightness of the LED in UHK Agent to 30 or lower or when the LEDs turn off.

Setting LED brightness to something like 127 while the USB-C cable is connected to the left half is enough to cause the high-pitched noise. Remove the cable and the noise is gone.

I used a spetrum analyzer app on my iPhone. It tells me the sound has a peak at 8140 Hz:

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3

It’s discussed all over the forum.

Makes noise. Uhk60 did too. 80 can be quite loud alright.

4

I just connected my UHK 60. The LED brightness is at 255. The spectrum analyzer does also pick up some noise, but it’s much, much less loud!

This is a really a different problem and only happens this pronounced when connecting a USB-C cable to the left half.

5

I’ve two UHK60s, the red LED ones, they can be quite loud but I agree not as loud.

6

Did you try to connect a USB-C cable to the left half while the LED brightness is at least 50%?

I hear it loudest when putting my left ear next to the “G” key.

7

Here’s another thing I found out:

Connecting the left half to the right half using the bridge cable also makes the loud high-pitched noise immediately appear despite no change in LED brightness.

Steps to reproduce:

  • Use left half standalone: disconnect from USB-C and also don’t connect to the right half
  • Connect right half to USB-C
  • Set LED brightness to 255 for both USB-powered and battery-powered
    → I don’t really hear noise from the left half unless I get really close
  • Now connect the left half to the right half using the bridge cable
  • As soon as you connect the two halves, there is immediately a relatively loud high-pitched sound
  • Disconnect the halves and the noise is immediately gone, despite having the same LED brightness

So this must be more than just the LED brightness.

I hope this can be fixed in software. It’s unbearably loud and headache-inducing.

8

Thanks for elaborating! I’m working on a solution and will keep you updated.

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