HIgh-pitched noise when on USB-C power

MNT Pocket Reform
1

Recently I noticed a high-pitched and somewhat irregularly fluctuating noise from my Pocket when it’s connected to USB-C power, both when charging and just sitting at 100% battery.

I know this isn’t too unusual for electronic devices but also it can be a sign of vibrations that shouldn’t be there and might lead to failure of some components over time. I use my Pocket a lot so it might experience this type of wear relatively quickly maybe.

I’m just wondering, if others have that issue too and if I should worry about it. Also it is a bit annoying when I’m trying to work in a quiet space.

3

Really unnecessary comment. And no, I’m not. I just have good hearing.

And the noise isn’t coming from the USB power supply but from the laptop itself.

4

I think it’s coil whine from the RK3588 module, which is unfortunately “normal”. I didn’t hear it yet on Pocket Reform though, only on classic sometimes. It is something I’d like to fix, but don’t know how to do yet. Maybe it’s about the coil or capacitors on the 5V->4V buck on RCORE, but could also be on the iCore itself, I wasn’t able to differntiate that yet.

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Would it help to pinpoint the source more precisely with a microphone?

I think I could record a video for that (slowly moving a mic across the module and amplifying the audio)

6

Yes, if you can pinpoint it, that would help.

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Any update on this? This would be a bit of a deal breaker for using this machine in a audio / music setup I think.

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YMMV on the loudness of this.

9

It is very faint.

Using the trackball or keyboard (including the trackball buttons, and with the quiet red switches) is already much louder than this little noise.

In general the Pocket is not a silent device due to the mechanical input devices. That’s unavoidable.

The closest point of comparison is probably a mechanical “gaming” keyboard with linear switches. Those are also relatively quiet (compared to those with clicky or tactile switches) but definitely audible.

10

Thanks for the reply, this is helpful.

I am ok with the device making noise when I press a key, but having it on the table next to me while I am mixing something on my studio monitors could potentially be annoying.

Doesn’t sound like a deal breaker though.

Would be cool if you made that video :slight_smile: .

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I also have a RK3588 Pocket Reform and am not able to make out any noise even when holding my ear very close to it. Are maybe my ears just bad?

@selfawaresoup do you know of an easy way for somebody who apparently cannot hear the high pitched noise to make sure whether it exists or not?

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Not really, no. I still want to make that video but I’ve been busy and personal life was a mess lately.

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You could make an audio recording and either check it yourself on a spectrum analyser or you can upload it here and I can check it for you.

If you do it in video format we even have the visuals to go with it, but you would need to put the microphone very close to the device.

Coil whine is very often in very high frequency so it is very common that one person can hear it and another person cannot.

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Like so?

15

Here you go. I am playing the video back in half speed so everything is pitched down by 50%. You see there are some things going on around 5khz in the video (10khz in real time). The things around 600hz in the video is bird song :slight_smile:

I have to admit it is very hard to say how loud this is in real life with the lid on + how it sounds acoustically vs on a microphone, but at least you can see things going on.

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